// Copyright © SixtyFPS GmbH <info@slint.dev>
// SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-Slint-Royalty-free-2.0 OR LicenseRef-Slint-Software-3.0

use std::cell::RefCell;
use std::collections::{HashMap, HashSet};
use std::path::{Path, PathBuf};
use std::rc::{Rc, Weak};

use crate::diagnostics::{BuildDiagnostics, Spanned};
use crate::object_tree::{self, Document, ExportedName, Exports};
use crate::parser::{syntax_nodes, NodeOrToken, SyntaxKind, SyntaxToken};
use crate::typeregister::TypeRegister;
use crate::{expression_tree, CompilerConfiguration};
use crate::{fileaccess, langtype, layout, parser};
use core::future::Future;
use itertools::Itertools;

/// Storage for a cache of all loaded documents
#[derive(Default)]
struct LoadedDocuments {
    /// maps from the canonical file name to the object_tree::Document
    docs: HashMap<PathBuf, Document>,
    /// The .slint files that are currently being loaded, potentially asynchronously.
    /// When a task start loading a file, it will add an empty vector to this map, and
    /// the same task will remove the entry from the map when finished, and awake all
    /// wakers.
    currently_loading: HashMap<PathBuf, Vec<std::task::Waker>>,
}

pub enum ImportKind {
    ImportList(syntax_nodes::ImportSpecifier),
    /// re-export types, as per `export ... from "foo"``.
    ModuleReexport(syntax_nodes::ExportsList),
}

pub struct ImportedTypes {
    pub import_uri_token: SyntaxToken,
    pub import_kind: ImportKind,
    pub file: String,
}

#[derive(Debug)]
pub struct ImportedName {
    // name of export to match in the other file
    pub external_name: String,
    // name to be used locally
    pub internal_name: String,
}

impl ImportedName {
    pub fn extract_imported_names(
        import: &syntax_nodes::ImportSpecifier,
    ) -> impl Iterator<Item = ImportedName> + '_ {
        import.ImportIdentifierList().into_iter().flat_map(|import_identifiers| {
            import_identifiers.ImportIdentifier().map(Self::from_node)
        })
    }

    pub fn from_node(importident: syntax_nodes::ImportIdentifier) -> Self {
        let external_name =
            parser::normalize_identifier(importident.ExternalName().text().to_string().trim());

        let internal_name = match importident.InternalName() {
            Some(name_ident) => parser::normalize_identifier(name_ident.text().to_string().trim()),
            None => external_name.clone(),
        };

        ImportedName { internal_name, external_name }
    }
}

/// This function makes a snapshot of the current state of the type loader.
/// This snapshot includes everything: Elements, Components, known types, ...
/// and can be used to roll back to earlier states in the compilation process.
///
/// One way this is used is to create a raw `TypeLoader` for analysis purposes
/// or to load a set of changes, see if those compile and then role back
///
/// The result may be `None` if the `TypeLoader` is actually in the process
/// of loading more documents and is `Some` `TypeLoader` with a copy off all
/// state connected with the original `TypeLoader`.
pub fn snapshot(type_loader: &TypeLoader) -> Option<TypeLoader> {
    let mut snapshotter = Snapshotter {
        component_map: HashMap::new(),
        element_map: HashMap::new(),
        type_register_map: HashMap::new(),
        keep_alive: Vec::new(),
        keep_alive_elements: Vec::new(),
    };
    snapshotter.snapshot_type_loader(type_loader)
}

/// This function makes a snapshot of the current state of the type loader.
/// This snapshot includes everything: Elements, Components, known types, ...
/// and can be used to roll back to earlier states in the compilation process.
///
/// One way this is used is to create a raw `TypeLoader` for analysis purposes
/// or to load a set of changes, see if those compile and then role back
///
/// The result may be `None` if the `TypeLoader` is actually in the process
/// of loading more documents and is `Some` `TypeLoader` with a copy off all
/// state connected with the original `TypeLoader`.
///
/// The Document will be added to the type_loader after it was snapshotted as well.
pub(crate) fn snapshot_with_extra_doc(
    type_loader: &TypeLoader,
    doc: &object_tree::Document,
) -> Option<TypeLoader> {
    let mut snapshotter = Snapshotter {
        component_map: HashMap::new(),
        element_map: HashMap::new(),
        type_register_map: HashMap::new(),
        keep_alive: Vec::new(),
        keep_alive_elements: Vec::new(),
    };
    let mut result = snapshotter.snapshot_type_loader(type_loader);

    snapshotter.create_document(doc);
    let new_doc = snapshotter.snapshot_document(doc);

    snapshotter.finalize();

    if let Some(doc_node) = &new_doc.node {
        let path = doc_node.source_file.path().to_path_buf();
        if let Some(r) = &mut result {
            r.all_documents.docs.insert(path, new_doc);
        }
    }

    result
}

pub(crate) struct Snapshotter {
    component_map:
        HashMap<by_address::ByAddress<Rc<object_tree::Component>>, Weak<object_tree::Component>>,
    element_map:
        HashMap<by_address::ByAddress<object_tree::ElementRc>, Weak<RefCell<object_tree::Element>>>,
    type_register_map:
        HashMap<by_address::ByAddress<Rc<RefCell<TypeRegister>>>, Rc<RefCell<TypeRegister>>>,

    keep_alive: Vec<(Rc<object_tree::Component>, Rc<object_tree::Component>)>,
    keep_alive_elements: Vec<(object_tree::ElementRc, object_tree::ElementRc)>,
}

impl Snapshotter {
    fn snapshot_globals(&mut self, type_loader: &TypeLoader) {
        let registry = type_loader.global_type_registry.clone();
        registry
            .borrow()
            .all_elements()
            .iter()
            .filter_map(|(_, ty)| match ty {
                langtype::ElementType::Component(c) if c.is_global() => Some(c),
                _ => None,
            })
            .for_each(|c| {
                self.create_component(c);
            });
    }

    fn finalize(&mut self) {
        let mut elements = std::mem::take(&mut self.keep_alive_elements);

        while !elements.is_empty() {
            for (s, t) in elements.iter_mut() {
                self.snapshot_element(s, &mut t.borrow_mut());
            }
            elements = std::mem::take(&mut self.keep_alive_elements);
        }
    }

    fn snapshot_type_loader(&mut self, type_loader: &TypeLoader) -> Option<TypeLoader> {
        self.snapshot_globals(type_loader);

        let all_documents = self.snapshot_loaded_documents(&type_loader.all_documents)?;

        self.finalize();

        Some(TypeLoader {
            all_documents,
            global_type_registry: self.snapshot_type_register(&type_loader.global_type_registry),
            compiler_config: type_loader.compiler_config.clone(),
            style: type_loader.style.clone(),
        })
    }

    pub(crate) fn snapshot_type_register(
        &mut self,
        type_register: &Rc<RefCell<TypeRegister>>,
    ) -> Rc<RefCell<TypeRegister>> {
        if let Some(r) = self.type_register_map.get(&by_address::ByAddress(type_register.clone())) {
            return r.clone();
        }

        let tr = Rc::new(RefCell::new(TypeRegister::default()));
        self.type_register_map.insert(by_address::ByAddress(type_register.clone()), tr.clone());

        *tr.borrow_mut() = self.snapshot_type_register_impl(type_register);

        tr
    }

    fn snapshot_type_register_impl(
        &mut self,
        type_register: &Rc<RefCell<TypeRegister>>,
    ) -> TypeRegister {
        type_register.borrow().snapshot(self)
    }

    fn snapshot_loaded_documents(
        &mut self,
        loaded_documents: &LoadedDocuments,
    ) -> Option<LoadedDocuments> {
        if !loaded_documents.currently_loading.is_empty() {
            return None;
        }

        loaded_documents.docs.values().for_each(|d| self.create_document(d));

        Some(LoadedDocuments {
            docs: loaded_documents
                .docs
                .iter()
                .map(|(p, d)| (p.clone(), self.snapshot_document(d)))
                .collect(),
            currently_loading: Default::default(),
        })
    }

    fn create_document(&mut self, document: &object_tree::Document) {
        document.inner_components.iter().for_each(|ic| {
            let _ = self.create_component(ic);
        });
    }

    fn snapshot_document(&mut self, document: &object_tree::Document) -> object_tree::Document {
        let inner_components = document
            .inner_components
            .iter()
            .map(|ic| {
                Weak::upgrade(&self.use_component(ic))
                    .expect("Components can get upgraded at this point")
            })
            .collect();
        let exports = document.exports.snapshot(self);

        object_tree::Document {
            node: document.node.clone(),
            inner_components,
            inner_types: document.inner_types.clone(),
            local_registry: document.local_registry.snapshot(self),
            custom_fonts: document.custom_fonts.clone(),
            exports,
            embedded_file_resources: document.embedded_file_resources.clone(),
            used_types: RefCell::new(self.snapshot_used_sub_types(&document.used_types.borrow())),
        }
    }

    pub(crate) fn create_component(
        &mut self,
        component: &Rc<object_tree::Component>,
    ) -> Rc<object_tree::Component> {
        let input_address = by_address::ByAddress(component.clone());

        let parent_element = if let Some(pe) = component.parent_element.upgrade() {
            Rc::downgrade(&self.use_element(&pe))
        } else {
            Weak::default()
        };

        let result = Rc::new_cyclic(|weak| {
            self.component_map.insert(input_address, weak.clone());

            let root_element = self.create_element(&component.root_element);

            let optimized_elements = RefCell::new(
                component
                    .optimized_elements
                    .borrow()
                    .iter()
                    .map(|e| self.create_element(e))
                    .collect(),
            );

            let child_insertion_point = RefCell::new(
                component
                    .child_insertion_point
                    .borrow()
                    .as_ref()
                    .map(|(e, s, n)| (self.use_element(e), *s, n.clone())),
            );

            let popup_windows = RefCell::new(
                component
                    .popup_windows
                    .borrow()
                    .iter()
                    .map(|p| self.snapshot_popup_window(p))
                    .collect(),
            );
            let timers = RefCell::new(
                component.timers.borrow().iter().map(|p| self.snapshot_timer(p)).collect(),
            );
            let root_constraints = RefCell::new(
                self.snapshot_layout_constraints(&component.root_constraints.borrow()),
            );

            object_tree::Component {
                node: component.node.clone(),
                id: component.id.clone(),
                child_insertion_point,
                exported_global_names: RefCell::new(
                    component.exported_global_names.borrow().clone(),
                ),
                init_code: RefCell::new(component.init_code.borrow().clone()),
                inherits_popup_window: std::cell::Cell::new(component.inherits_popup_window.get()),
                optimized_elements,
                parent_element,
                popup_windows,
                timers,
                private_properties: RefCell::new(component.private_properties.borrow().clone()),
                root_constraints,
                root_element,
            }
        });
        self.keep_alive.push((component.clone(), result.clone()));
        result
    }

    pub(crate) fn use_component(
        &self,
        component: &Rc<object_tree::Component>,
    ) -> Weak<object_tree::Component> {
        self.component_map
            .get(&by_address::ByAddress(component.clone()))
            .expect("Component (Weak!) must exist at this point.")
            .clone()
    }

    pub(crate) fn create_element(
        &mut self,
        element: &object_tree::ElementRc,
    ) -> object_tree::ElementRc {
        let enclosing_component = if let Some(ec) = element.borrow().enclosing_component.upgrade() {
            self.use_component(&ec)
        } else {
            Weak::default()
        };

        let elem = element.borrow();

        let r = Rc::new_cyclic(|weak| {
            self.element_map.insert(by_address::ByAddress(element.clone()), weak.clone());

            let children = elem.children.iter().map(|c| self.create_element(c)).collect();

            RefCell::new(object_tree::Element {
                id: elem.id.clone(),
                enclosing_component,
                children,
                debug: elem.debug.clone(),
                ..Default::default()
            })
        });

        self.keep_alive_elements.push((element.clone(), r.clone()));
        r
    }

    fn create_and_snapshot_element(
        &mut self,
        element: &object_tree::ElementRc,
    ) -> object_tree::ElementRc {
        let target = self.create_element(element);
        self.snapshot_element(element, &mut target.borrow_mut());
        target
    }

    pub(crate) fn use_element(&self, element: &object_tree::ElementRc) -> object_tree::ElementRc {
        Weak::upgrade(
            &self
                .element_map
                .get(&by_address::ByAddress(element.clone()))
                .expect("Elements should have been known at this point")
                .clone(),
        )
        .expect("Must be able to upgrade here")
    }

    fn snapshot_element(
        &mut self,
        element: &object_tree::ElementRc,
        target_element: &mut object_tree::Element,
    ) {
        let elem = element.borrow();

        target_element.base_type = self.snapshot_element_type(&elem.base_type);

        target_element.transitions = elem
            .transitions
            .iter()
            .map(|t| object_tree::Transition {
                is_out: t.is_out,
                state_id: t.state_id.clone(),
                property_animations: t
                    .property_animations
                    .iter()
                    .map(|(nr, sl, el)| {
                        (nr.snapshot(self), sl.clone(), self.create_and_snapshot_element(el))
                    })
                    .collect(),
                node: t.node.clone(),
            })
            .collect();

        target_element.bindings = elem
            .bindings
            .iter()
            .map(|(k, v)| {
                let bm = v.borrow();
                let binding = self.snapshot_binding_expression(&bm);
                (k.clone(), RefCell::new(binding))
            })
            .collect();
        target_element.states = elem
            .states
            .iter()
            .map(|s| object_tree::State {
                id: s.id.clone(),
                condition: s.condition.clone(),
                property_changes: s
                    .property_changes
                    .iter()
                    .map(|(nr, expr, spc)| {
                        let nr = nr.snapshot(self);
                        let expr = self.snapshot_expression(expr);
                        (nr, expr, spc.clone())
                    })
                    .collect(),
            })
            .collect();
        target_element.repeated =
            elem.repeated.as_ref().map(|r| object_tree::RepeatedElementInfo {
                model: self.snapshot_expression(&r.model),
                model_data_id: r.model_data_id.clone(),
                index_id: r.index_id.clone(),
                is_conditional_element: r.is_conditional_element,
                is_listview: r.is_listview.as_ref().map(|lv| object_tree::ListViewInfo {
                    viewport_y: lv.viewport_y.snapshot(self),
                    viewport_height: lv.viewport_height.snapshot(self),
                    viewport_width: lv.viewport_width.snapshot(self),
                    listview_height: lv.listview_height.snapshot(self),
                    listview_width: lv.listview_width.snapshot(self),
                }),
            });

        target_element.accessibility_props = object_tree::AccessibilityProps(
            elem.accessibility_props.0.iter().map(|(k, v)| (k.clone(), v.snapshot(self))).collect(),
        );
        target_element.geometry_props =
            elem.geometry_props.as_ref().map(|gp| object_tree::GeometryProps {
                x: gp.x.snapshot(self),
                y: gp.y.snapshot(self),
                width: gp.width.snapshot(self),
                height: gp.height.snapshot(self),
            });
        target_element.property_declarations = elem
            .property_declarations
            .iter()
            .map(|(k, v)| {
                let decl = object_tree::PropertyDeclaration {
                    property_type: v.property_type.clone(),
                    node: v.node.clone(),
                    expose_in_public_api: v.expose_in_public_api,
                    is_alias: v.is_alias.as_ref().map(|a| a.snapshot(self)),
                    visibility: v.visibility,
                    pure: v.pure,
                };
                (k.clone(), decl)
            })
            .collect();
        target_element.layout_info_prop =
            elem.layout_info_prop.as_ref().map(|(n1, n2)| (n1.snapshot(self), n2.snapshot(self)));
        target_element.property_analysis = RefCell::new(elem.property_analysis.borrow().clone());

        target_element.change_callbacks = elem.change_callbacks.clone();
        target_element.child_of_layout = elem.child_of_layout;
        target_element.default_fill_parent = elem.default_fill_parent;
        target_element.has_popup_child = elem.has_popup_child;
        target_element.inline_depth = elem.inline_depth;
        target_element.is_component_placeholder = elem.is_component_placeholder;
        target_element.is_flickable_viewport = elem.is_flickable_viewport;
        target_element.is_legacy_syntax = elem.is_legacy_syntax;
        target_element.item_index = elem.item_index.clone();
        target_element.item_index_of_first_children = elem.item_index_of_first_children.clone();
        target_element.named_references = elem.named_references.snapshot(self);
    }

    fn snapshot_binding_expression(
        &mut self,
        binding_expression: &expression_tree::BindingExpression,
    ) -> expression_tree::BindingExpression {
        expression_tree::BindingExpression {
            expression: self.snapshot_expression(&binding_expression.expression),
            span: binding_expression.span.clone(),
            priority: binding_expression.priority,
            animation: binding_expression.animation.as_ref().map(|pa| match pa {
                object_tree::PropertyAnimation::Static(element) => {
                    object_tree::PropertyAnimation::Static(
                        self.create_and_snapshot_element(element),
                    )
                }
                object_tree::PropertyAnimation::Transition { state_ref, animations } => {
                    object_tree::PropertyAnimation::Transition {
                        state_ref: self.snapshot_expression(state_ref),
                        animations: animations
                            .iter()
                            .map(|tpa| object_tree::TransitionPropertyAnimation {
                                state_id: tpa.state_id,
                                is_out: tpa.is_out,
                                animation: self.create_and_snapshot_element(&tpa.animation),
                            })
                            .collect(),
                    }
                }
            }),
            analysis: binding_expression.analysis.as_ref().map(|a| {
                expression_tree::BindingAnalysis {
                    is_in_binding_loop: a.is_in_binding_loop.clone(),
                    is_const: a.is_const,
                    no_external_dependencies: a.no_external_dependencies,
                }
            }),
            two_way_bindings: binding_expression
                .two_way_bindings
                .iter()
                .map(|twb| twb.snapshot(self))
                .collect(),
        }
    }

    pub(crate) fn snapshot_element_type(
        &mut self,
        element_type: &langtype::ElementType,
    ) -> langtype::ElementType {
        // Components need to get adapted, the rest is fine I think...
        match element_type {
            langtype::ElementType::Component(component) => {
                // Some components that will get compiled out later...
                langtype::ElementType::Component(
                    Weak::upgrade(&self.use_component(component))
                        .expect("I can unwrap at this point"),
                )
            }
            _ => element_type.clone(),
        }
    }

    fn snapshot_used_sub_types(
        &mut self,
        used_types: &object_tree::UsedSubTypes,
    ) -> object_tree::UsedSubTypes {
        let globals = used_types
            .globals
            .iter()
            .map(|component| {
                Weak::upgrade(&self.use_component(component)).expect("Looking at a known component")
            })
            .collect();
        let structs_and_enums = used_types.structs_and_enums.clone();
        let sub_components = used_types
            .sub_components
            .iter()
            .map(|component| {
                Weak::upgrade(&self.use_component(component)).expect("Looking at a known component")
            })
            .collect();
        object_tree::UsedSubTypes { globals, structs_and_enums, sub_components }
    }

    fn snapshot_popup_window(
        &mut self,
        popup_window: &object_tree::PopupWindow,
    ) -> object_tree::PopupWindow {
        object_tree::PopupWindow {
            component: Weak::upgrade(&self.use_component(&popup_window.component))
                .expect("Looking at a known component"),
            x: popup_window.x.snapshot(self),
            y: popup_window.y.snapshot(self),
            close_on_click: popup_window.close_on_click,
            parent_element: self.use_element(&popup_window.parent_element),
        }
    }

    fn snapshot_timer(&mut self, popup_window: &object_tree::Timer) -> object_tree::Timer {
        object_tree::Timer {
            interval: popup_window.interval.snapshot(self),
            running: popup_window.running.snapshot(self),
            triggered: popup_window.triggered.snapshot(self),
        }
    }

    fn snapshot_layout_constraints(
        &mut self,
        layout_constraints: &layout::LayoutConstraints,
    ) -> layout::LayoutConstraints {
        layout::LayoutConstraints {
            min_width: layout_constraints.min_width.as_ref().map(|lc| lc.snapshot(self)),
            max_width: layout_constraints.max_width.as_ref().map(|lc| lc.snapshot(self)),
            min_height: layout_constraints.min_height.as_ref().map(|lc| lc.snapshot(self)),
            max_height: layout_constraints.max_height.as_ref().map(|lc| lc.snapshot(self)),
            preferred_width: layout_constraints
                .preferred_width
                .as_ref()
                .map(|lc| lc.snapshot(self)),
            preferred_height: layout_constraints
                .preferred_height
                .as_ref()
                .map(|lc| lc.snapshot(self)),
            horizontal_stretch: layout_constraints
                .horizontal_stretch
                .as_ref()
                .map(|lc| lc.snapshot(self)),
            vertical_stretch: layout_constraints
                .vertical_stretch
                .as_ref()
                .map(|lc| lc.snapshot(self)),
            fixed_width: layout_constraints.fixed_width,
            fixed_height: layout_constraints.fixed_height,
        }
    }

    fn snapshot_expression(
        &mut self,
        expr: &expression_tree::Expression,
    ) -> expression_tree::Expression {
        use expression_tree::Expression;
        match expr {
            Expression::CallbackReference(nr, node_or_token) => {
                Expression::CallbackReference(nr.snapshot(self), node_or_token.clone())
            }
            Expression::PropertyReference(nr) => Expression::PropertyReference(nr.snapshot(self)),
            Expression::FunctionReference(nr, node_or_token) => {
                Expression::FunctionReference(nr.snapshot(self), node_or_token.clone())
            }
            Expression::MemberFunction { base, base_node, member } => Expression::MemberFunction {
                base: Box::new(self.snapshot_expression(base)),
                base_node: base_node.clone(),
                member: Box::new(self.snapshot_expression(member)),
            },
            Expression::ElementReference(el) => {
                Expression::ElementReference(if let Some(el) = el.upgrade() {
                    Rc::downgrade(&el)
                } else {
                    Weak::default()
                })
            }
            Expression::RepeaterIndexReference { element } => Expression::RepeaterIndexReference {
                element: if let Some(el) = element.upgrade() {
                    Rc::downgrade(&el)
                } else {
                    Weak::default()
                },
            },
            Expression::RepeaterModelReference { element } => Expression::RepeaterModelReference {
                element: if let Some(el) = element.upgrade() {
                    Rc::downgrade(&el)
                } else {
                    Weak::default()
                },
            },
            Expression::StoreLocalVariable { name, value } => Expression::StoreLocalVariable {
                name: name.clone(),
                value: Box::new(self.snapshot_expression(value)),
            },
            Expression::StructFieldAccess { base, name } => Expression::StructFieldAccess {
                base: Box::new(self.snapshot_expression(base)),
                name: name.clone(),
            },
            Expression::ArrayIndex { array, index } => Expression::ArrayIndex {
                array: Box::new(self.snapshot_expression(array)),
                index: Box::new(self.snapshot_expression(index)),
            },
            Expression::Cast { from, to } => {
                Expression::Cast { from: Box::new(self.snapshot_expression(from)), to: to.clone() }
            }
            Expression::CodeBlock(exprs) => {
                Expression::CodeBlock(exprs.iter().map(|e| self.snapshot_expression(e)).collect())
            }
            Expression::FunctionCall { function, arguments, source_location } => {
                Expression::FunctionCall {
                    function: Box::new(self.snapshot_expression(function)),
                    arguments: arguments.iter().map(|e| self.snapshot_expression(e)).collect(),
                    source_location: source_location.clone(),
                }
            }
            Expression::SelfAssignment { lhs, rhs, op, node } => Expression::SelfAssignment {
                lhs: Box::new(self.snapshot_expression(lhs)),
                rhs: Box::new(self.snapshot_expression(rhs)),
                op: *op,
                node: node.clone(),
            },
            Expression::BinaryExpression { lhs, rhs, op } => Expression::BinaryExpression {
                lhs: Box::new(self.snapshot_expression(lhs)),
                rhs: Box::new(self.snapshot_expression(rhs)),
                op: *op,
            },
            Expression::UnaryOp { sub, op } => {
                Expression::UnaryOp { sub: Box::new(self.snapshot_expression(sub)), op: *op }
            }
            Expression::Condition { condition, true_expr, false_expr } => Expression::Condition {
                condition: Box::new(self.snapshot_expression(condition)),
                true_expr: Box::new(self.snapshot_expression(true_expr)),
                false_expr: Box::new(self.snapshot_expression(false_expr)),
            },
            Expression::Array { element_ty, values } => Expression::Array {
                element_ty: element_ty.clone(),
                values: values.iter().map(|e| self.snapshot_expression(e)).collect(),
            },
            Expression::Struct { ty, values } => Expression::Struct {
                ty: ty.clone(),
                values: values
                    .iter()
                    .map(|(k, v)| (k.clone(), self.snapshot_expression(v)))
                    .collect(),
            },
            Expression::PathData(path) => Expression::PathData(match path {
                expression_tree::Path::Elements(path_elements) => expression_tree::Path::Elements(
                    path_elements
                        .iter()
                        .map(|p| {
                            expression_tree::PathElement {
                                element_type: p.element_type.clone(), // builtin should be OK to clone
                                bindings: p
                                    .bindings
                                    .iter()
                                    .map(|(k, v)| {
                                        (
                                            k.clone(),
                                            RefCell::new(
                                                self.snapshot_binding_expression(&v.borrow()),
                                            ),
                                        )
                                    })
                                    .collect(),
                            }
                        })
                        .collect(),
                ),
                expression_tree::Path::Events(ex1, ex2) => expression_tree::Path::Events(
                    ex1.iter().map(|e| self.snapshot_expression(e)).collect(),
                    ex2.iter().map(|e| self.snapshot_expression(e)).collect(),
                ),
                expression_tree::Path::Commands(ex) => {
                    expression_tree::Path::Commands(Box::new(self.snapshot_expression(ex)))
                }
            }),
            Expression::LinearGradient { angle, stops } => Expression::LinearGradient {
                angle: Box::new(self.snapshot_expression(angle)),
                stops: stops
                    .iter()
                    .map(|(e1, e2)| (self.snapshot_expression(e1), self.snapshot_expression(e2)))
                    .collect(),
            },
            Expression::RadialGradient { stops } => Expression::RadialGradient {
                stops: stops
                    .iter()
                    .map(|(e1, e2)| (self.snapshot_expression(e1), self.snapshot_expression(e2)))
                    .collect(),
            },
            Expression::ReturnStatement(expr) => Expression::ReturnStatement(
                expr.as_ref().map(|e| Box::new(self.snapshot_expression(e))),
            ),
            Expression::LayoutCacheAccess { layout_cache_prop, index, repeater_index } => {
                Expression::LayoutCacheAccess {
                    layout_cache_prop: layout_cache_prop.snapshot(self),
                    index: *index,
                    repeater_index: repeater_index
                        .as_ref()
                        .map(|e| Box::new(self.snapshot_expression(e))),
                }
            }
            Expression::MinMax { ty, op, lhs, rhs } => Expression::MinMax {
                ty: ty.clone(),
                lhs: Box::new(self.snapshot_expression(lhs)),
                rhs: Box::new(self.snapshot_expression(rhs)),
                op: *op,
            },
            _ => expr.clone(),
        }
    }
}

pub struct TypeLoader {
    pub global_type_registry: Rc<RefCell<TypeRegister>>,
    pub compiler_config: CompilerConfiguration,
    style: String,
    all_documents: LoadedDocuments,
}

struct BorrowedTypeLoader<'a> {
    tl: &'a mut TypeLoader,
    diag: &'a mut BuildDiagnostics,
}

impl TypeLoader {
    pub fn new(
        global_type_registry: Rc<RefCell<TypeRegister>>,
        compiler_config: CompilerConfiguration,
        diag: &mut BuildDiagnostics,
    ) -> Self {
        let mut style = compiler_config
            .style
            .clone()
            .or_else(|| std::env::var("SLINT_STYLE").ok())
            .unwrap_or_else(|| "native".into());

        if style == "native" {
            style = get_native_style(&mut diag.all_loaded_files);
        }

        let myself = Self {
            global_type_registry,
            compiler_config,
            style: style.clone(),
            all_documents: Default::default(),
        };

        let mut known_styles = fileaccess::styles();
        known_styles.push("native");
        if !known_styles.contains(&style.as_ref())
            && myself
                .find_file_in_include_path(None, &format!("{}/std-widgets.slint", style))
                .is_none()
        {
            diag.push_diagnostic_with_span(
                format!(
                    "Style {} in not known. Use one of the builtin styles [{}] or make sure your custom style is found in the include directories",
                    &style,
                    known_styles.join(", ")
                ),
                Default::default(),
                crate::diagnostics::DiagnosticLevel::Error,
            );
        }

        myself
    }

    pub fn drop_document(&mut self, path: &Path) -> Result<(), std::io::Error> {
        self.all_documents.docs.remove(path);
        if self.all_documents.currently_loading.contains_key(path) {
            Err(std::io::Error::new(
                std::io::ErrorKind::InvalidInput,
                format!("{path:?} is still loading"),
            ))
        } else {
            Ok(())
        }
    }

    /// Imports of files that don't have the .slint extension are returned.
    pub async fn load_dependencies_recursively<'a>(
        &'a mut self,
        doc: &'a syntax_nodes::Document,
        diag: &'a mut BuildDiagnostics,
        registry_to_populate: &'a Rc<RefCell<TypeRegister>>,
    ) -> (Vec<ImportedTypes>, Exports) {
        let state = RefCell::new(BorrowedTypeLoader { tl: self, diag });
        Self::load_dependencies_recursively_impl(
            &state,
            doc,
            registry_to_populate,
            &Default::default(),
        )
        .await
    }

    async fn load_dependencies_recursively_impl<'a: 'b, 'b>(
        state: &'a RefCell<BorrowedTypeLoader<'a>>,
        doc: &'b syntax_nodes::Document,
        registry_to_populate: &'b Rc<RefCell<TypeRegister>>,
        import_stack: &'b HashSet<PathBuf>,
    ) -> (Vec<ImportedTypes>, Exports) {
        let mut foreign_imports = vec![];
        let mut dependencies_futures = vec![];
        for mut import in Self::collect_dependencies(state, doc) {
            let resolved_import = if let Some((path, _)) = state
                .borrow()
                .tl
                .resolve_import_path(Some(&import.import_uri_token.clone().into()), &import.file)
            {
                path.to_string_lossy().to_string()
            } else {
                import.file.clone()
            };
            if !(resolved_import.ends_with(".slint")
                || resolved_import.ends_with(".60")
                || import.file.starts_with('@'))
            {
                import.file = resolved_import;
                foreign_imports.push(import);
                continue;
            }
            dependencies_futures.push(Box::pin(async move {
                let file = import.file.as_str();
                let doc_path = Self::ensure_document_loaded(
                    state,
                    file,
                    Some(import.import_uri_token.clone().into()),
                    import_stack.clone(),
                )
                .await;
                (import, doc_path)
            }));
        }

        let mut reexports = None;
        let mut has_star_reexport = false;
        std::future::poll_fn(|cx| {
            dependencies_futures.retain_mut(|fut| {
                let core::task::Poll::Ready((import, doc_path)) = fut.as_mut().poll(cx) else { return true; };
                let Some(doc_path) = doc_path else { return false };
                let mut state = state.borrow_mut();
                let state = &mut *state;
                let doc = state.tl.all_documents.docs.get(&doc_path).unwrap();
                match &import.import_kind {
                    ImportKind::ImportList(imported_types) => {
                        let mut imported_types = ImportedName::extract_imported_names(imported_types).peekable();
                        if imported_types.peek().is_some() {
                            Self::register_imported_types(doc, &import, imported_types, registry_to_populate, state.diag);
                        } else {
                            state.diag.push_error("Import names are missing. Please specify which types you would like to import".into(), &import.import_uri_token.parent());
                        }
                    }
                    ImportKind::ModuleReexport(export_module_syntax_node) => {
                        let exports = reexports.get_or_insert_with(Exports::default);
                        if let Some(star_reexport) = export_module_syntax_node.ExportModule().and_then(|x| x.child_token(SyntaxKind::Star))
                        {
                            if has_star_reexport {
                                state.diag.push_error("re-exporting modules is only allowed once per file".into(), &star_reexport);
                                return false;
                            }
                            has_star_reexport = true;
                            exports.add_reexports(
                                doc.exports.iter().map(|(exported_name, compo_or_type)| {
                                    let exported_name = ExportedName {
                                        name: exported_name.name.clone(),
                                        name_ident: (**export_module_syntax_node).clone(),
                                    };
                                    (exported_name, compo_or_type.clone())
                                }),
                                state.diag,
                            );
                        } else if export_module_syntax_node.ExportSpecifier().next().is_none() {
                            state.diag.push_error("Import names are missing. Please specify which types you would like to re-export".into(), export_module_syntax_node);
                        } else {
                            let e = export_module_syntax_node
                                .ExportSpecifier()
                                .filter_map(|e| {
                                    let (imported_name, exported_name) = ExportedName::from_export_specifier(&e);
                                    let Some(r) = doc.exports.find(&imported_name) else {
                                        state.diag.push_error(format!("No exported type called '{imported_name}' found in {doc_path:?}"), &e);
                                        return None;
                                    };
                                    Some((exported_name, r))
                                })
                                .collect::<Vec<_>>();
                            exports.add_reexports(e, state.diag);
                        }
                    }
                }
                false
            });
            if dependencies_futures.is_empty() {
                core::task::Poll::Ready(())
            } else {
                core::task::Poll::Pending
            }
        }).await;
        (foreign_imports, reexports.unwrap_or_default())
    }

    pub async fn import_component(
        &mut self,
        file_to_import: &str,
        type_name: &str,
        diag: &mut BuildDiagnostics,
    ) -> Option<Rc<object_tree::Component>> {
        let state = RefCell::new(BorrowedTypeLoader { tl: self, diag });
        let doc_path =
            match Self::ensure_document_loaded(&state, file_to_import, None, Default::default())
                .await
            {
                Some(doc_path) => doc_path,
                None => return None,
            };

        let doc = self.all_documents.docs.get(&doc_path).unwrap();

        doc.exports.find(type_name).and_then(|compo_or_type| compo_or_type.left())
    }

    /// Append a possibly relative path to a base path. Returns the data if it resolves to a built-in (compiled-in)
    /// file.
    pub fn resolve_import_path(
        &self,
        import_token: Option<&NodeOrToken>,
        maybe_relative_path_or_url: &str,
    ) -> Option<(PathBuf, Option<&'static [u8]>)> {
        if let Some(maybe_library_import) = maybe_relative_path_or_url.strip_prefix('@') {
            self.find_file_in_library_path(maybe_library_import)
        } else {
            let referencing_file_or_url =
                import_token.and_then(|tok| tok.source_file().map(|s| s.path()));
            self.find_file_in_include_path(referencing_file_or_url, maybe_relative_path_or_url)
                .or_else(|| {
                    referencing_file_or_url
                        .and_then(|base_path_or_url| {
                            crate::pathutils::join(
                                &crate::pathutils::dirname(base_path_or_url),
                                &PathBuf::from(maybe_relative_path_or_url),
                            )
                        })
                        .filter(|p| p.exists())
                        .map(|p| (p, None))
                })
        }
    }

    /// Read a file, taking the `CompilerConfiguration`s `open_import_fallback`
    /// into account when necessary.
    async fn read_file(&self, path: &Path) -> Result<String, std::io::Error> {
        if let Some(fallback) = self.compiler_config.open_import_fallback.clone() {
            let result = fallback(path.to_string_lossy().into()).await;
            result.unwrap_or_else(|| std::fs::read_to_string(path))
        } else {
            std::fs::read_to_string(path)
        }
    }

    async fn ensure_document_loaded<'a: 'b, 'b>(
        state: &'a RefCell<BorrowedTypeLoader<'a>>,
        file_to_import: &'b str,
        import_token: Option<NodeOrToken>,
        mut import_stack: HashSet<PathBuf>,
    ) -> Option<PathBuf> {
        let mut borrowed_state = state.borrow_mut();

        let (path_canon, builtin) = match borrowed_state
            .tl
            .resolve_import_path(import_token.as_ref(), file_to_import)
        {
            Some(x) => x,
            None => {
                let import_path = crate::pathutils::clean_path(Path::new(file_to_import));
                if import_path.exists() {
                    if import_token.as_ref().and_then(|x| x.source_file()).is_some() {
                        borrowed_state.diag.push_warning(
                        format!(
                            "Loading \"{file_to_import}\" relative to the work directory is deprecated. Files should be imported relative to their import location",
                        ),
                        &import_token,
                    );
                    }
                    (import_path, None)
                } else {
                    // We will load using the `open_import_fallback`
                    // Simplify the path to remove the ".."
                    let base_path = import_token
                        .as_ref()
                        .and_then(|tok| tok.source_file().map(|s| s.path()))
                        .map_or(PathBuf::new(), |p| p.into());
                    let path = crate::pathutils::join(
                        &crate::pathutils::dirname(&base_path),
                        Path::new(file_to_import),
                    )?;
                    (path, None)
                }
            }
        };

        if !import_stack.insert(path_canon.clone()) {
            borrowed_state.diag.push_error(
                format!("Recursive import of \"{}\"", path_canon.display()),
                &import_token,
            );
            return None;
        }
        drop(borrowed_state);

        let is_loaded = core::future::poll_fn(|cx| {
            let mut state = state.borrow_mut();
            let all_documents = &mut state.tl.all_documents;
            match all_documents.currently_loading.entry(path_canon.clone()) {
                std::collections::hash_map::Entry::Occupied(mut e) => {
                    let waker = cx.waker();
                    if !e.get().iter().any(|w| w.will_wake(waker)) {
                        e.get_mut().push(cx.waker().clone());
                    }
                    core::task::Poll::Pending
                }
                std::collections::hash_map::Entry::Vacant(v) => {
                    if all_documents.docs.contains_key(path_canon.as_path()) {
                        core::task::Poll::Ready(true)
                    } else {
                        v.insert(Default::default());
                        core::task::Poll::Ready(false)
                    }
                }
            }
        })
        .await;
        if is_loaded {
            return Some(path_canon);
        }

        let source_code_result = if let Some(builtin) = builtin {
            Ok(String::from(
                core::str::from_utf8(builtin)
                    .expect("internal error: embedded file is not UTF-8 source code"),
            ))
        } else {
            state.borrow().tl.read_file(&path_canon).await
        };

        let ok = match source_code_result {
            Ok(source) => {
                Self::load_file_impl(
                    state,
                    &path_canon,
                    &path_canon,
                    source,
                    builtin.is_some(),
                    &import_stack,
                )
                .await;

                true
            }
            Err(err) if err.kind() == std::io::ErrorKind::NotFound => {
                state.borrow_mut().diag.push_error(
                        if file_to_import.starts_with('@') {
                            format!(
                                "Cannot find requested import \"{file_to_import}\" in the library search path",
                            )
                        } else {
                            format!(
                                "Cannot find requested import \"{file_to_import}\" in the include search path",
                            )
                        },
                        &import_token,
                    );
                false
            }
            Err(err) => {
                state.borrow_mut().diag.push_error(
                    format!("Error reading requested import \"{}\": {}", path_canon.display(), err),
                    &import_token,
                );
                false
            }
        };

        let wakers = state
            .borrow_mut()
            .tl
            .all_documents
            .currently_loading
            .remove(path_canon.as_path())
            .unwrap();
        for x in wakers {
            x.wake();
        }

        ok.then_some(path_canon)
    }

    /// Load a file, and its dependency, running only the import passes.
    ///
    /// the path must be the canonical path
    pub async fn load_file(
        &mut self,
        path: &Path,
        source_path: &Path,
        source_code: String,
        is_builtin: bool,
        diag: &mut BuildDiagnostics,
    ) {
        let state = RefCell::new(BorrowedTypeLoader { tl: self, diag });
        Self::load_file_impl(
            &state,
            path,
            source_path,
            source_code,
            is_builtin,
            &Default::default(),
        )
        .await;
    }

    /// Load a file, and its dependency, running the full set of passes.
    ///
    /// the path must be the canonical path
    pub async fn load_root_file(
        &mut self,
        path: &Path,
        source_path: &Path,
        source_code: String,
        keep_raw: bool,
        diag: &mut BuildDiagnostics,
    ) -> (PathBuf, Option<TypeLoader>) {
        let path = crate::pathutils::clean_path(path);
        let state = RefCell::new(BorrowedTypeLoader { tl: self, diag });
        let (path, mut doc) = Self::load_file_no_pass(
            &state,
            &path,
            source_path,
            source_code,
            false,
            &Default::default(),
        )
        .await;

        let mut state = state.borrow_mut();
        let state = &mut *state;
        let raw_type_loader = if !state.diag.has_errors() {
            crate::passes::run_passes(&mut doc, state.tl, keep_raw, state.diag).await
        } else {
            None
        };
        state.tl.all_documents.docs.insert(path.clone(), doc);
        (path, raw_type_loader)
    }

    async fn load_file_impl<'a>(
        state: &'a RefCell<BorrowedTypeLoader<'a>>,
        path: &Path,
        source_path: &Path,
        source_code: String,
        is_builtin: bool,
        import_stack: &HashSet<PathBuf>,
    ) {
        let (path, doc) = Self::load_file_no_pass(
            state,
            path,
            source_path,
            source_code,
            is_builtin,
            import_stack,
        )
        .await;

        let mut state = state.borrow_mut();
        let state = &mut *state;
        if !state.diag.has_errors() {
            crate::passes::run_import_passes(&doc, state.tl, state.diag);
        }
        state.tl.all_documents.docs.insert(path, doc);
    }

    async fn load_file_no_pass<'a>(
        state: &'a RefCell<BorrowedTypeLoader<'a>>,
        path: &Path,
        source_path: &Path,
        source_code: String,
        is_builtin: bool,
        import_stack: &HashSet<PathBuf>,
    ) -> (PathBuf, Document) {
        let dependency_doc: syntax_nodes::Document =
            crate::parser::parse(source_code, Some(source_path), state.borrow_mut().diag).into();

        let dependency_registry =
            Rc::new(RefCell::new(TypeRegister::new(&state.borrow().tl.global_type_registry)));
        dependency_registry.borrow_mut().expose_internal_types =
            is_builtin || state.borrow().tl.compiler_config.enable_experimental;
        let (foreign_imports, reexports) = Self::load_dependencies_recursively_impl(
            state,
            &dependency_doc,
            &dependency_registry,
            import_stack,
        )
        .await;

        if state.borrow().diag.has_errors() {
            // If there was error (esp parse error) we don't want to report further error in this document.
            // because they might be nonsense (TODO: we should check that the parse error were really in this document).
            // But we still want to create a document to give better error messages in the root document.
            let mut ignore_diag = BuildDiagnostics::default();
            ignore_diag.push_error_with_span(
                "Dummy error because some of the code asserts there was an error".into(),
                Default::default(),
            );
            let doc = crate::object_tree::Document::from_node(
                dependency_doc,
                foreign_imports,
                reexports,
                &mut ignore_diag,
                &dependency_registry,
            );
            return (path.to_owned(), doc);
        }
        let mut state = state.borrow_mut();
        let state = &mut *state;
        let doc = crate::object_tree::Document::from_node(
            dependency_doc,
            foreign_imports,
            reexports,
            state.diag,
            &dependency_registry,
        );
        (path.to_owned(), doc)
    }

    fn register_imported_types(
        doc: &Document,
        import: &ImportedTypes,
        imported_types: impl Iterator<Item = ImportedName>,
        registry_to_populate: &Rc<RefCell<TypeRegister>>,
        build_diagnostics: &mut BuildDiagnostics,
    ) {
        for import_name in imported_types {
            let imported_type = doc.exports.find(&import_name.external_name);

            let imported_type = match imported_type {
                Some(ty) => ty,
                None => {
                    build_diagnostics.push_error(
                        format!(
                            "No exported type called '{}' found in \"{}\"",
                            import_name.external_name, import.file
                        ),
                        &import.import_uri_token,
                    );
                    continue;
                }
            };

            match imported_type {
                itertools::Either::Left(c) => {
                    registry_to_populate.borrow_mut().add_with_name(import_name.internal_name, c)
                }
                itertools::Either::Right(ty) => registry_to_populate
                    .borrow_mut()
                    .insert_type_with_name(ty, import_name.internal_name),
            }
        }
    }

    /// Lookup a library and filename and try to find the absolute filename based on the library path
    fn find_file_in_library_path(
        &self,
        maybe_library_import: &str,
    ) -> Option<(PathBuf, Option<&'static [u8]>)> {
        let (library, file) = maybe_library_import
            .splitn(2, '/')
            .collect_tuple()
            .map(|(library, path)| (library, Some(path)))
            .unwrap_or((maybe_library_import, None));
        self.compiler_config.library_paths.get(library).and_then(|library_path| {
            let path = match file {
                // "@library/file.slint" -> "/path/to/library/" + "file.slint"
                Some(file) => library_path.join(file),
                // "@library" -> "/path/to/library/lib.slint"
                None => library_path.clone(),
            };
            crate::fileaccess::load_file(path.as_path())
                .map(|virtual_file| (virtual_file.canon_path, virtual_file.builtin_contents))
        })
    }

    /// Lookup a filename and try to find the absolute filename based on the include path or
    /// the current file directory
    pub fn find_file_in_include_path(
        &self,
        referencing_file: Option<&Path>,
        file_to_import: &str,
    ) -> Option<(PathBuf, Option<&'static [u8]>)> {
        // The directory of the current file is the first in the list of include directories.
        referencing_file
            .map(base_directory)
            .into_iter()
            .chain(self.compiler_config.include_paths.iter().map(PathBuf::as_path).map(
                |include_path| {
                    let base = referencing_file.map(Path::to_path_buf).unwrap_or_default();
                    crate::pathutils::join(&crate::pathutils::dirname(&base), include_path)
                        .unwrap_or_else(|| include_path.to_path_buf())
                },
            ))
            .chain(
                (file_to_import == "std-widgets.slint"
                    || referencing_file.map_or(false, |x| x.starts_with("builtin:/")))
                .then(|| format!("builtin:/{}", self.style).into()),
            )
            .find_map(|include_dir| {
                let candidate = crate::pathutils::join(&include_dir, Path::new(file_to_import))?;
                crate::fileaccess::load_file(&candidate)
                    .map(|virtual_file| (virtual_file.canon_path, virtual_file.builtin_contents))
            })
    }

    fn collect_dependencies<'a: 'b, 'b>(
        state: &'a RefCell<BorrowedTypeLoader<'a>>,
        doc: &'b syntax_nodes::Document,
    ) -> impl Iterator<Item = ImportedTypes> + 'a {
        doc.ImportSpecifier()
            .map(|import| {
                let maybe_import_uri = import.child_token(SyntaxKind::StringLiteral);
                (maybe_import_uri, ImportKind::ImportList(import))
            })
            .chain(
                // process `export ... from "foo"`
                doc.ExportsList().filter_map(|exports| {
                    exports.ExportModule().map(|reexport| {
                        let maybe_import_uri = reexport.child_token(SyntaxKind::StringLiteral);
                        (maybe_import_uri, ImportKind::ModuleReexport(exports))
                    })
                }),
            )
            .filter_map(|(maybe_import_uri, type_specifier)| {
                let import_uri = match maybe_import_uri {
                    Some(import_uri) => import_uri,
                    None => {
                        debug_assert!(state.borrow().diag.has_errors());
                        return None;
                    }
                };
                let path_to_import = import_uri.text().to_string();
                let path_to_import = path_to_import.trim_matches('\"').to_string();

                if path_to_import.is_empty() {
                    state
                        .borrow_mut()
                        .diag
                        .push_error("Unexpected empty import url".to_owned(), &import_uri);
                    return None;
                }

                Some(ImportedTypes {
                    import_uri_token: import_uri,
                    import_kind: type_specifier,
                    file: path_to_import,
                })
            })
    }

    /// Return a document if it was already loaded
    pub fn get_document<'b>(&'b self, path: &Path) -> Option<&'b object_tree::Document> {
        let path = crate::pathutils::clean_path(path);
        self.all_documents.docs.get(&path)
    }

    /// Return an iterator over all the loaded file path
    pub fn all_files(&self) -> impl Iterator<Item = &PathBuf> {
        self.all_documents.docs.keys()
    }

    /// Returns an iterator over all the loaded documents
    pub fn all_documents(&self) -> impl Iterator<Item = &object_tree::Document> + '_ {
        self.all_documents.docs.values()
    }

    /// Returns an iterator over all the loaded documents
    pub fn all_file_documents(
        &self,
    ) -> impl Iterator<Item = (&PathBuf, &object_tree::Document)> + '_ {
        self.all_documents.docs.iter()
    }
}

fn get_native_style(all_loaded_files: &mut Vec<PathBuf>) -> String {
    // Try to get the value written by the i-slint-backend-selector's build script

    // It is in the target/xxx/build directory
    let target_path = std::env::var_os("OUT_DIR")
        .and_then(|path| {
            // Same logic as in i-slint-backend-selector's build script to get the path
            crate::pathutils::join(Path::new(&path), Path::new("../../SLINT_DEFAULT_STYLE.txt"))
        })
        .or_else(|| {
            // When we are called from a slint!, OUT_DIR is only defined when the crate having the macro has a build.rs script.
            // As a fallback, try to parse the rustc arguments
            // https://stackoverflow.com/questions/60264534/getting-the-target-folder-from-inside-a-rust-proc-macro
            let mut args = std::env::args();
            let mut out_dir = None;
            while let Some(arg) = args.next() {
                if arg == "--out-dir" {
                    out_dir = args.next();
                    break;
                }
            }
            out_dir.and_then(|od| {
                crate::pathutils::join(
                    Path::new(&od),
                    Path::new("../build/SLINT_DEFAULT_STYLE.txt"),
                )
            })
        });
    if let Some(style) = target_path.and_then(|target_path| {
        all_loaded_files.push(target_path.clone());
        std::fs::read_to_string(target_path).map(|style| style.trim().into()).ok()
    }) {
        return style;
    }
    i_slint_common::get_native_style(false, &std::env::var("TARGET").unwrap_or_default()).into()
}

/// return the base directory from which imports are loaded
///
/// For a .slint file, this is the parent directory.
/// For a .rs file, this is relative to the CARGO_MANIFEST_DIR
///
/// Note: this function is only called for .rs path as part of the LSP or viewer.
/// Because from a proc_macro, we don't actually know the path of the current file, and this
/// is why we must be relative to CARGO_MANIFEST_DIR.
pub fn base_directory(referencing_file: &Path) -> PathBuf {
    if referencing_file.extension().map_or(false, |e| e == "rs") {
        // For .rs file, this is a rust macro, and rust macro locates the file relative to the CARGO_MANIFEST_DIR which is the directory that has a Cargo.toml file.
        let mut candidate = referencing_file;
        loop {
            candidate =
                if let Some(c) = candidate.parent() { c } else { break referencing_file.parent() };

            if candidate.join("Cargo.toml").exists() {
                break Some(candidate);
            }
        }
    } else {
        referencing_file.parent()
    }
    .map_or_else(Default::default, |p| p.to_path_buf())
}

#[test]
fn test_dependency_loading() {
    let test_source_path: PathBuf =
        [env!("CARGO_MANIFEST_DIR"), "tests", "typeloader"].iter().collect();

    let mut incdir = test_source_path.clone();
    incdir.push("incpath");

    let mut compiler_config =
        CompilerConfiguration::new(crate::generator::OutputFormat::Interpreter);
    compiler_config.include_paths = vec![incdir];
    compiler_config.library_paths =
        HashMap::from([("library".into(), test_source_path.join("library").join("lib.slint"))]);
    compiler_config.style = Some("fluent".into());

    let mut main_test_path = test_source_path;
    main_test_path.push("dependency_test_main.slint");

    let mut test_diags = crate::diagnostics::BuildDiagnostics::default();
    let doc_node = crate::parser::parse_file(main_test_path, &mut test_diags).unwrap();

    let doc_node: syntax_nodes::Document = doc_node.into();

    let global_registry = TypeRegister::builtin();

    let registry = Rc::new(RefCell::new(TypeRegister::new(&global_registry)));

    let mut build_diagnostics = BuildDiagnostics::default();

    let mut loader = TypeLoader::new(global_registry, compiler_config, &mut build_diagnostics);

    let (foreign_imports, _) = spin_on::spin_on(loader.load_dependencies_recursively(
        &doc_node,
        &mut build_diagnostics,
        &registry,
    ));

    assert!(!test_diags.has_errors());
    assert!(!build_diagnostics.has_errors());
    assert!(foreign_imports.is_empty());
}

#[test]
fn test_dependency_loading_from_rust() {
    let test_source_path: PathBuf =
        [env!("CARGO_MANIFEST_DIR"), "tests", "typeloader"].iter().collect();

    let mut incdir = test_source_path.clone();
    incdir.push("incpath");

    let mut compiler_config =
        CompilerConfiguration::new(crate::generator::OutputFormat::Interpreter);
    compiler_config.include_paths = vec![incdir];
    compiler_config.library_paths =
        HashMap::from([("library".into(), test_source_path.join("library").join("lib.slint"))]);
    compiler_config.style = Some("fluent".into());

    let mut main_test_path = test_source_path;
    main_test_path.push("some_rust_file.rs");

    let mut test_diags = crate::diagnostics::BuildDiagnostics::default();
    let doc_node = crate::parser::parse_file(main_test_path, &mut test_diags).unwrap();

    let doc_node: syntax_nodes::Document = doc_node.into();

    let global_registry = TypeRegister::builtin();

    let registry = Rc::new(RefCell::new(TypeRegister::new(&global_registry)));

    let mut build_diagnostics = BuildDiagnostics::default();

    let mut loader = TypeLoader::new(global_registry, compiler_config, &mut build_diagnostics);

    let (foreign_imports, _) = spin_on::spin_on(loader.load_dependencies_recursively(
        &doc_node,
        &mut build_diagnostics,
        &registry,
    ));

    assert!(!test_diags.has_errors());
    assert!(test_diags.is_empty()); // also no warnings
    assert!(!build_diagnostics.has_errors());
    assert!(build_diagnostics.is_empty()); // also no warnings
    assert!(foreign_imports.is_empty());
}

#[test]
fn test_load_from_callback_ok() {
    let ok = Rc::new(core::cell::Cell::new(false));
    let ok_ = ok.clone();

    let mut compiler_config =
        CompilerConfiguration::new(crate::generator::OutputFormat::Interpreter);
    compiler_config.style = Some("fluent".into());
    compiler_config.open_import_fallback = Some(Rc::new(move |path| {
        let ok_ = ok_.clone();
        Box::pin(async move {
            assert_eq!(path.replace('\\', "/"), "../FooBar.slint");
            assert!(!ok_.get());
            ok_.set(true);
            Some(Ok("export XX := Rectangle {} ".to_owned()))
        })
    }));

    let mut test_diags = crate::diagnostics::BuildDiagnostics::default();
    let doc_node = crate::parser::parse(
        r#"
/* ... */
import { XX } from "../Ab/.././FooBar.slint";
X := XX {}
"#
        .into(),
        Some(std::path::Path::new("HELLO")),
        &mut test_diags,
    );

    let doc_node: syntax_nodes::Document = doc_node.into();
    let global_registry = TypeRegister::builtin();
    let registry = Rc::new(RefCell::new(TypeRegister::new(&global_registry)));
    let mut build_diagnostics = BuildDiagnostics::default();
    let mut loader = TypeLoader::new(global_registry, compiler_config, &mut build_diagnostics);
    spin_on::spin_on(loader.load_dependencies_recursively(
        &doc_node,
        &mut build_diagnostics,
        &registry,
    ));
    assert!(ok.get());
    assert!(!test_diags.has_errors());
    assert!(!build_diagnostics.has_errors());
}

#[test]
fn test_load_error_twice() {
    let mut compiler_config =
        CompilerConfiguration::new(crate::generator::OutputFormat::Interpreter);
    compiler_config.style = Some("fluent".into());
    let mut test_diags = crate::diagnostics::BuildDiagnostics::default();

    let doc_node = crate::parser::parse(
        r#"
/* ... */
import { XX } from "error.slint";
component Foo { XX {} }
"#
        .into(),
        Some(std::path::Path::new("HELLO")),
        &mut test_diags,
    );

    let doc_node: syntax_nodes::Document = doc_node.into();
    let global_registry = TypeRegister::builtin();
    let registry = Rc::new(RefCell::new(TypeRegister::new(&global_registry)));
    let mut build_diagnostics = BuildDiagnostics::default();
    let mut loader = TypeLoader::new(global_registry, compiler_config, &mut build_diagnostics);
    spin_on::spin_on(loader.load_dependencies_recursively(
        &doc_node,
        &mut build_diagnostics,
        &registry,
    ));
    assert!(!test_diags.has_errors());
    assert!(build_diagnostics.has_errors());
    let diags = build_diagnostics.to_string_vec();
    assert_eq!(
        diags,
        &["HELLO:3: Cannot find requested import \"error.slint\" in the include search path"]
    );
    // Try loading another time with the same registry
    let mut build_diagnostics = BuildDiagnostics::default();
    spin_on::spin_on(loader.load_dependencies_recursively(
        &doc_node,
        &mut build_diagnostics,
        &registry,
    ));
    assert!(build_diagnostics.has_errors());
    let diags = build_diagnostics.to_string_vec();
    assert_eq!(
        diags,
        &["HELLO:3: Cannot find requested import \"error.slint\" in the include search path"]
    );
}

#[test]
fn test_manual_import() {
    let mut compiler_config =
        CompilerConfiguration::new(crate::generator::OutputFormat::Interpreter);
    compiler_config.style = Some("fluent".into());
    let global_registry = TypeRegister::builtin();
    let mut build_diagnostics = BuildDiagnostics::default();
    let mut loader = TypeLoader::new(global_registry, compiler_config, &mut build_diagnostics);

    let maybe_button_type = spin_on::spin_on(loader.import_component(
        "std-widgets.slint",
        "Button",
        &mut build_diagnostics,
    ));

    assert!(!build_diagnostics.has_errors());
    assert!(maybe_button_type.is_some());
}

#[test]
fn test_builtin_style() {
    let test_source_path: PathBuf =
        [env!("CARGO_MANIFEST_DIR"), "tests", "typeloader"].iter().collect();

    let incdir = test_source_path.join("custom_style");

    let mut compiler_config =
        CompilerConfiguration::new(crate::generator::OutputFormat::Interpreter);
    compiler_config.include_paths = vec![incdir];
    compiler_config.style = Some("fluent".into());

    let global_registry = TypeRegister::builtin();
    let mut build_diagnostics = BuildDiagnostics::default();
    let _loader = TypeLoader::new(global_registry, compiler_config, &mut build_diagnostics);

    assert!(!build_diagnostics.has_errors());
}

#[test]
fn test_user_style() {
    let test_source_path: PathBuf =
        [env!("CARGO_MANIFEST_DIR"), "tests", "typeloader"].iter().collect();

    let incdir = test_source_path.join("custom_style");

    let mut compiler_config =
        CompilerConfiguration::new(crate::generator::OutputFormat::Interpreter);
    compiler_config.include_paths = vec![incdir];
    compiler_config.style = Some("TestStyle".into());

    let global_registry = TypeRegister::builtin();
    let mut build_diagnostics = BuildDiagnostics::default();
    let _loader = TypeLoader::new(global_registry, compiler_config, &mut build_diagnostics);

    assert!(!build_diagnostics.has_errors());
}

#[test]
fn test_unknown_style() {
    let test_source_path: PathBuf =
        [env!("CARGO_MANIFEST_DIR"), "tests", "typeloader"].iter().collect();

    let incdir = test_source_path.join("custom_style");

    let mut compiler_config =
        CompilerConfiguration::new(crate::generator::OutputFormat::Interpreter);
    compiler_config.include_paths = vec![incdir];
    compiler_config.style = Some("FooBar".into());

    let global_registry = TypeRegister::builtin();
    let mut build_diagnostics = BuildDiagnostics::default();
    let _loader = TypeLoader::new(global_registry, compiler_config, &mut build_diagnostics);

    assert!(build_diagnostics.has_errors());
    let diags = build_diagnostics.to_string_vec();
    assert_eq!(diags.len(), 1);
    assert!(diags[0].starts_with("Style FooBar in not known. Use one of the builtin styles ["));
}

#[test]
fn test_library_import() {
    let test_source_path: PathBuf =
        [env!("CARGO_MANIFEST_DIR"), "tests", "typeloader", "library"].iter().collect();

    let library_paths = HashMap::from([
        ("libdir".into(), test_source_path.clone()),
        ("libfile.slint".into(), test_source_path.join("lib.slint")),
    ]);

    let mut compiler_config =
        CompilerConfiguration::new(crate::generator::OutputFormat::Interpreter);
    compiler_config.library_paths = library_paths;
    compiler_config.style = Some("fluent".into());
    let mut test_diags = crate::diagnostics::BuildDiagnostics::default();

    let doc_node = crate::parser::parse(
        r#"
/* ... */
import { LibraryType } from "@libfile.slint";
import { LibraryHelperType } from "@libdir/library_helper_type.slint";
"#
        .into(),
        Some(std::path::Path::new("HELLO")),
        &mut test_diags,
    );

    let doc_node: syntax_nodes::Document = doc_node.into();
    let global_registry = TypeRegister::builtin();
    let registry = Rc::new(RefCell::new(TypeRegister::new(&global_registry)));
    let mut build_diagnostics = BuildDiagnostics::default();
    let mut loader = TypeLoader::new(global_registry, compiler_config, &mut build_diagnostics);
    spin_on::spin_on(loader.load_dependencies_recursively(
        &doc_node,
        &mut build_diagnostics,
        &registry,
    ));
    assert!(!test_diags.has_errors());
    assert!(!build_diagnostics.has_errors());
}

#[test]
fn test_library_import_errors() {
    let test_source_path: PathBuf =
        [env!("CARGO_MANIFEST_DIR"), "tests", "typeloader", "library"].iter().collect();

    let library_paths = HashMap::from([
        ("libdir".into(), test_source_path.clone()),
        ("libfile.slint".into(), test_source_path.join("lib.slint")),
    ]);

    let mut compiler_config =
        CompilerConfiguration::new(crate::generator::OutputFormat::Interpreter);
    compiler_config.library_paths = library_paths;
    compiler_config.style = Some("fluent".into());
    let mut test_diags = crate::diagnostics::BuildDiagnostics::default();

    let doc_node = crate::parser::parse(
        r#"
/* ... */
import { A } from "@libdir";
import { B } from "@libdir/unknown.slint";
import { C } from "@libfile.slint/unknown.slint";
import { D } from "@unknown";
import { E } from "@unknown/lib.slint";
"#
        .into(),
        Some(std::path::Path::new("HELLO")),
        &mut test_diags,
    );

    let doc_node: syntax_nodes::Document = doc_node.into();
    let global_registry = TypeRegister::builtin();
    let registry = Rc::new(RefCell::new(TypeRegister::new(&global_registry)));
    let mut build_diagnostics = BuildDiagnostics::default();
    let mut loader = TypeLoader::new(global_registry, compiler_config, &mut build_diagnostics);
    spin_on::spin_on(loader.load_dependencies_recursively(
        &doc_node,
        &mut build_diagnostics,
        &registry,
    ));
    assert!(!test_diags.has_errors());
    assert!(build_diagnostics.has_errors());
    let diags = build_diagnostics.to_string_vec();
    assert_eq!(diags.len(), 5);
    assert!(diags[0].starts_with(&format!(
        "HELLO:3: Error reading requested import \"{}\": ",
        test_source_path.to_string_lossy()
    )));
    assert_eq!(&diags[1], "HELLO:4: Cannot find requested import \"@libdir/unknown.slint\" in the library search path");
    assert_eq!(&diags[2], "HELLO:5: Cannot find requested import \"@libfile.slint/unknown.slint\" in the library search path");
    assert_eq!(
        &diags[3],
        "HELLO:6: Cannot find requested import \"@unknown\" in the library search path"
    );
    assert_eq!(
        &diags[4],
        "HELLO:7: Cannot find requested import \"@unknown/lib.slint\" in the library search path"
    );
}

#[test]
fn test_snapshotting() {
    let mut type_loader = TypeLoader::new(
        crate::typeregister::TypeRegister::builtin(),
        crate::CompilerConfiguration::new(crate::generator::OutputFormat::Interpreter),
        &mut BuildDiagnostics::default(),
    );

    let path = PathBuf::from("/tmp/test.slint");
    let mut diag = BuildDiagnostics::default();
    spin_on::spin_on(type_loader.load_file(
        &path,
        &path,
        "export component Foobar inherits Rectangle { }".to_string(),
        false,
        &mut diag,
    ));

    assert!(!diag.has_errors());

    let doc = type_loader.get_document(&path).unwrap();
    let c = doc.inner_components.first().unwrap();
    assert_eq!(c.id, "Foobar");
    let root_element = c.root_element.clone();
    assert_eq!(root_element.borrow().base_type.to_string(), "Rectangle");

    let copy = snapshot(&type_loader).unwrap();

    let doc = copy.get_document(&path).unwrap();
    let c = doc.inner_components.first().unwrap();
    assert_eq!(c.id, "Foobar");
    let root_element = c.root_element.clone();
    assert_eq!(root_element.borrow().base_type.to_string(), "Rectangle");
}