/* LICENSE BEGIN
    This file is part of the SixtyFPS Project -- https://sixtyfps.io
    Copyright (c) 2020 Olivier Goffart <olivier.goffart@sixtyfps.io>
    Copyright (c) 2020 Simon Hausmann <simon.hausmann@sixtyfps.io>

    SPDX-License-Identifier: GPL-3.0-only
    This file is also available under commercial licensing terms.
    Please contact info@sixtyfps.io for more information.
LICENSE END */
#pragma once

#if defined(__GNUC__) || defined(__clang__)
// In C++17, it is conditionally supported, but still valid for all compiler we care
#    pragma GCC diagnostic ignored "-Winvalid-offsetof"
#endif

#include <vector>
#include <memory>
#include <algorithm>
#include <iostream> // FIXME: remove: iostream always bring it lots of code so we should not have it in this header

namespace sixtyfps::cbindgen_private {
// Workaround https://github.com/eqrion/cbindgen/issues/43
struct ComponentVTable;
struct ItemVTable;
}
#include "sixtyfps_internal.h"
#include "sixtyfps_default_backend_internal.h"
#include "sixtyfps_qt_internal.h"

namespace sixtyfps {

namespace private_api {
extern "C" {
extern const cbindgen_private::ItemVTable RectangleVTable;
extern const cbindgen_private::ItemVTable BorderRectangleVTable;
extern const cbindgen_private::ItemVTable TextVTable;
extern const cbindgen_private::ItemVTable TouchAreaVTable;
extern const cbindgen_private::ItemVTable ImageVTable;
extern const cbindgen_private::ItemVTable PathVTable;
extern const cbindgen_private::ItemVTable FlickableVTable;
extern const cbindgen_private::ItemVTable WindowVTable;
extern const cbindgen_private::ItemVTable TextInputVTable;

extern const cbindgen_private::ItemVTable NativeButtonVTable;
extern const cbindgen_private::ItemVTable NativeCheckBoxVTable;
extern const cbindgen_private::ItemVTable NativeSpinBoxVTable;
extern const cbindgen_private::ItemVTable NativeSliderVTable;
extern const cbindgen_private::ItemVTable NativeGroupBoxVTable;
extern const cbindgen_private::ItemVTable NativeLineEditVTable;
extern const cbindgen_private::ItemVTable NativeScrollViewVTable;
extern const cbindgen_private::ItemVTable NativeStandardListViewItemVTable;
}
}

// Bring opaque structure in scope
namespace private_api {
using cbindgen_private::ComponentVTable;
using cbindgen_private::ItemVTable;
using ComponentRef = VRef<private_api::ComponentVTable>;
using ItemVisitorRefMut = VRefMut<cbindgen_private::ItemVisitorVTable>;
}
using cbindgen_private::EasingCurve;
using cbindgen_private::PropertyAnimation;
using cbindgen_private::Slice;
using cbindgen_private::TextHorizontalAlignment;
using cbindgen_private::TextVerticalAlignment;
using cbindgen_private::TraversalOrder;

namespace private_api {
using ItemTreeNode = cbindgen_private::ItemTreeNode<uint8_t>;

struct ComponentWindow
{
    ComponentWindow() { cbindgen_private::sixtyfps_component_window_init(&inner); }
    ~ComponentWindow() { cbindgen_private::sixtyfps_component_window_drop(&inner); }
    ComponentWindow(const ComponentWindow &) = delete;
    ComponentWindow(ComponentWindow &&) = delete;
    ComponentWindow &operator=(const ComponentWindow &) = delete;

    template<typename Component>
    void run(Component *c)
    {
        sixtyfps_component_window_run(
                &inner, VRefMut<ComponentVTable> { &Component::component_type, c }, c->root_item());
    }

    float scale_factor() const { return sixtyfps_component_window_get_scale_factor(&inner); }
    void set_scale_factor(float value)
    {
        sixtyfps_component_window_set_scale_factor(&inner, value);
    }

    template<typename Component>
    void free_graphics_resources(Component *c) const
    {
        cbindgen_private::sixtyfps_component_window_free_graphics_resources(
                &inner, VRef<ComponentVTable> { &Component::component_type, c });
    }

    void set_focus_item(Pin<VRef<ComponentVTable>> c, Pin<VRef<ItemVTable>> item)
    {
        cbindgen_private::sixtyfps_component_window_set_focus_item(&inner, c, item);
    }

    template<typename Component, typename ItemTree>
    void init_items(Component *c, ItemTree items) const
    {
        cbindgen_private::sixtyfps_component_init_items(
                VRef<ComponentVTable> { &Component::component_type, c }, items, &inner);
    }

private:
    cbindgen_private::ComponentWindowOpaque inner;
};
}

using cbindgen_private::BorderRectangle;
using cbindgen_private::Flickable;
using cbindgen_private::Image;
using cbindgen_private::Path;
using cbindgen_private::Rectangle;
using cbindgen_private::Text;
using cbindgen_private::TextInput;
using cbindgen_private::TouchArea;
using cbindgen_private::Window;

using cbindgen_private::NativeButton;
using cbindgen_private::NativeCheckBox;
using cbindgen_private::NativeGroupBox;
using cbindgen_private::NativeLineEdit;
using cbindgen_private::NativeScrollView;
using cbindgen_private::NativeSlider;
using cbindgen_private::NativeSpinBox;
using cbindgen_private::NativeStandardListViewItem;

namespace private_api {
constexpr inline ItemTreeNode make_item_node(std::uintptr_t offset,
                                             const cbindgen_private::ItemVTable *vtable,
                                             uint32_t child_count, uint32_t child_index)
{
    return ItemTreeNode { ItemTreeNode::Item_Body {
            ItemTreeNode::Tag::Item, { vtable, offset }, child_count, child_index } };
}

constexpr inline ItemTreeNode make_dyn_node(std::uintptr_t offset)
{
    return ItemTreeNode { ItemTreeNode::DynamicTree_Body { ItemTreeNode::Tag::DynamicTree,
                                                           offset } };
}
}

using cbindgen_private::FocusEvent;
using cbindgen_private::FocusEventResult;
using cbindgen_private::InputEventResult;
using cbindgen_private::KeyEvent;
using cbindgen_private::KeyEventResult;
using cbindgen_private::MouseEvent;
using cbindgen_private::sixtyfps_visit_item_tree;
namespace private_api {
template<typename GetDynamic>
inline InputEventResult process_input_event(ComponentRef component, int64_t &mouse_grabber,
                                            MouseEvent mouse_event, Slice<ItemTreeNode> tree,
                                            GetDynamic get_dynamic, const ComponentWindow *window,
                                            const ComponentRef *app_component)
{
    if (mouse_grabber != -1) {
        auto item_index = mouse_grabber & 0xffffffff;
        auto rep_index = mouse_grabber >> 32;
        auto offset = cbindgen_private::sixtyfps_item_offset(component, tree, item_index);
        mouse_event.pos = { mouse_event.pos.x - offset.x, mouse_event.pos.y - offset.y };
        const auto &item_node = tree.ptr[item_index];
        InputEventResult result = InputEventResult::EventIgnored;
        switch (item_node.tag) {
        case ItemTreeNode::Tag::Item:
            result = item_node.item.item.vtable->input_event(
                    {
                            item_node.item.item.vtable,
                            reinterpret_cast<char *>(component.instance)
                                    + item_node.item.item.offset,
                    },
                    mouse_event, window, *app_component);
            break;
        case ItemTreeNode::Tag::DynamicTree: {
            ComponentRef comp = get_dynamic(item_node.dynamic_tree.index, rep_index);
            result = comp.vtable->input_event(comp, mouse_event, window, app_component);
        } break;
        }
        if (result != InputEventResult::GrabMouse) {
            mouse_grabber = -1;
        }
        return result;
    } else {
        return cbindgen_private::sixtyfps_process_ungrabbed_mouse_event(
                component, mouse_event, window, *app_component, &mouse_grabber);
    }
}
template<typename GetDynamic>
inline KeyEventResult process_key_event(ComponentRef component, int64_t focus_item,
                                        const KeyEvent *event, Slice<ItemTreeNode> tree,
                                        GetDynamic get_dynamic, const ComponentWindow *window)
{
    if (focus_item != -1) {
        auto item_index = focus_item & 0xffffffff;
        auto rep_index = focus_item >> 32;
        const auto &item_node = tree.ptr[item_index];
        switch (item_node.tag) {
        case ItemTreeNode::Tag::Item:
            return item_node.item.item.vtable->key_event(
                    {
                            item_node.item.item.vtable,
                            reinterpret_cast<char *>(component.instance)
                                    + item_node.item.item.offset,
                    },
                    event, window);
        case ItemTreeNode::Tag::DynamicTree: {
            ComponentRef comp = get_dynamic(item_node.dynamic_tree.index, rep_index);
            return comp.vtable->key_event(comp, event, window);
        };
        }
    }
    return KeyEventResult::EventIgnored;
}

template<typename GetDynamic>
inline FocusEventResult process_focus_event(ComponentRef component, int64_t &focus_item,
                                            const FocusEvent *event, Slice<ItemTreeNode> tree,
                                            GetDynamic get_dynamic, const ComponentWindow *window)
{
    switch (event->tag) {
    case FocusEvent::Tag::FocusIn:
        return cbindgen_private::sixtyfps_locate_and_activate_focus_item(component, event, window,
                                                                         &focus_item);
    case FocusEvent::Tag::FocusOut:
        [[fallthrough]];
    case FocusEvent::Tag::WindowReceivedFocus:
        [[fallthrough]];
    case FocusEvent::Tag::WindowLostFocus:
        if (focus_item != -1) {
            auto item_index = focus_item & 0xffffffff;
            auto rep_index = focus_item >> 32;
            const auto &item_node = tree.ptr[item_index];
            switch (item_node.tag) {
            case ItemTreeNode::Tag::Item:
                item_node.item.item.vtable->focus_event(
                        {
                                item_node.item.item.vtable,
                                reinterpret_cast<char *>(component.instance)
                                        + item_node.item.item.offset,
                        },
                        event, window);
                break;
            case ItemTreeNode::Tag::DynamicTree: {
                ComponentRef comp = get_dynamic(item_node.dynamic_tree.index, rep_index);
                comp.vtable->focus_event(comp, event, window);
            } break;
            }
            if (event->tag == FocusEvent::Tag::FocusOut) {
                focus_item = -1;
            }
            return FocusEventResult::FocusItemFound;
        } else {
            return FocusEventResult::FocusItemNotFound;
        }
    }
    return FocusEventResult::FocusItemNotFound;
}
}

// layouts:
using cbindgen_private::grid_layout_info;
using cbindgen_private::GridLayoutCellData;
using cbindgen_private::GridLayoutData;
using cbindgen_private::LayoutInfo;
using cbindgen_private::Padding;
using cbindgen_private::PathLayoutData;
using cbindgen_private::PathLayoutItemData;
using cbindgen_private::solve_grid_layout;
using cbindgen_private::solve_path_layout;

// models
struct AbstractRepeaterView
{
    ~AbstractRepeaterView() = default;
    virtual void row_added(int index, int count) = 0;
    virtual void row_removed(int index, int count) = 0;
    virtual void row_changed(int index) = 0;
};
using ModelPeer = std::weak_ptr<AbstractRepeaterView>;

template<typename ModelData>
class Model
{
public:
    virtual ~Model() = default;
    Model() = default;
    Model(const Model &) = delete;
    Model &operator=(const Model &) = delete;

    /// The amount of row in the model
    virtual int row_count() const = 0;
    /// Returns the data for a particular row. This function should be called with `row <
    /// row_count()`.
    virtual ModelData row_data(int i) const = 0;
    /// Sets the data for a particular row. This function should be called with `row < row_count()`.
    /// If the model cannot support data changes, then it is ok to do nothing (default
    /// implementation). If the model can update the data, the implmentation should also call
    /// row_changed.
    virtual void set_row_data(int, const ModelData &) {};

    /// Internal function called by the view to register itself
    void attach_peer(ModelPeer p) { peers.push_back(std::move(p)); }

protected:
    /// Notify the views that a specific row was changed
    void row_changed(int row)
    {
        for_each_peers([=](auto peer) { peer->row_changed(row); });
    }
    /// Notify the views that rows were added
    void row_added(int index, int count)
    {
        for_each_peers([=](auto peer) { peer->row_added(index, count); });
    }
    /// Notify the views that rows were removed
    void row_removed(int index, int count)
    {
        for_each_peers([=](auto peer) { peer->row_removed(index, count); });
    }

private:
    template<typename F>
    void for_each_peers(const F &f)
    {
        peers.erase(std::remove_if(peers.begin(), peers.end(),
                                   [&](const auto &p) {
                                       if (auto pp = p.lock()) {
                                           f(pp);
                                           return false;
                                       }
                                       return true;
                                   }),
                    peers.end());
    }
    std::vector<ModelPeer> peers;
};

/// A Model backed by an array of constant size
template<int Count, typename ModelData>
class ArrayModel : public Model<ModelData>
{
    std::array<ModelData, Count> data;

public:
    template<typename... A>
    ArrayModel(A &&... a) : data { std::forward<A>(a)... }
    {
    }
    int row_count() const override { return Count; }
    ModelData row_data(int i) const override { return data[i]; }
    void set_row_data(int i, const ModelData &value) override
    {
        data[i] = value;
        this->row_changed(i);
    }
};

/// Model to be used when we just want to repeat without data.
struct IntModel : Model<int>
{
    IntModel(int d) : data(d) { }
    int data;
    int row_count() const override { return data; }
    int row_data(int value) const override { return value; }
};

/// A Model backed by a SharedArray
template<typename ModelData>
class VectorModel : public Model<ModelData>
{
    std::vector<ModelData> data;

public:
    VectorModel() = default;
    VectorModel(std::vector<ModelData> array) : data(std::move(array)) { }
    int row_count() const override { return data.size(); }
    ModelData row_data(int i) const override { return data[i]; }
    void set_row_data(int i, const ModelData &value) override
    {
        data[i] = value;
        this->row_changed(i);
    }

    /// Append a new row with the given value
    void push_back(const ModelData &value)
    {
        data.push_back(value);
        this->row_added(data.size() - 1, 1);
    }

    /// Remove the row at the given index from the model
    void erase(int index)
    {
        data.erase(data.begin() + index);
        this->row_removed(index, 1);
    }
};

template<typename C, typename ModelData>
class Repeater
{
    Property<std::shared_ptr<Model<ModelData>>> model;

    struct RepeaterInner : AbstractRepeaterView
    {
        enum class State { Clean, Dirty };
        struct ComponentWithState
        {
            State state = State::Dirty;
            std::unique_ptr<C> ptr;
        };
        std::vector<ComponentWithState> data;
        bool is_dirty = true;

        void row_added(int index, int count) override
        {
            is_dirty = true;
            data.resize(data.size() + count);
            std::rotate(data.begin() + index, data.end() - count, data.end());
        }
        void row_changed(int index) override
        {
            is_dirty = true;
            data[index].state = State::Dirty;
        }
        void row_removed(int index, int count) override
        {
            is_dirty = true;
            data.erase(data.begin() + index, data.begin() + index + count);
            for (std::size_t i = index; i < data.size(); ++i) {
                // all the indexes are dirty
                data[i].state = State::Dirty;
            }
        }
    };

public:
    // FIXME: should be private, but compute_layout uses it.
    mutable std::shared_ptr<RepeaterInner> inner;

    template<typename F>
    void set_model_binding(F &&binding) const
    {
        model.set_binding(std::forward<F>(binding));
    }

    template<typename Parent>
    void ensure_updated(const Parent *parent) const
    {
        if (model.is_dirty()) {
            inner = std::make_shared<RepeaterInner>();
            if (auto m = model.get()) {
                m->attach_peer(inner);
            }
        }

        if (inner && inner->is_dirty) {
            inner->is_dirty = false;
            if (auto m = model.get()) {
                int count = m->row_count();
                inner->data.resize(count);
                for (int i = 0; i < count; ++i) {
                    auto &c = inner->data[i];
                    if (c.state == RepeaterInner::State::Dirty) {
                        if (!c.ptr) {
                            c.ptr = std::make_unique<C>(parent);
                        }
                        c.ptr->update_data(i, m->row_data(i));
                    }
                }
            } else {
                inner->data.clear();
            }
        }
    }

    template<typename Parent>
    void ensure_updated_listview(const Parent *parent, const Property<float> *viewport_width,
                                 const Property<float> *viewport_height,
                                 [[maybe_unused]] const Property<float> *viewport_y,
                                 float listview_width, [[maybe_unused]] float listview_height) const
    {
        // TODO: the rust code in model.rs try to only allocate as many items as visible items
        ensure_updated(parent);

        float h = compute_layout_listview(viewport_width, listview_width);
        viewport_height->set(h);
    }

    intptr_t visit(TraversalOrder order, private_api::ItemVisitorRefMut visitor) const
    {
        for (std::size_t i = 0; i < inner->data.size(); ++i) {
            int index = order == TraversalOrder::BackToFront ? i : inner->data.size() - 1 - i;
            auto ref = item_at(index);
            if (ref.vtable->visit_children_item(ref, -1, order, visitor) != -1) {
                return index;
            }
        }
        return -1;
    }

    VRef<private_api::ComponentVTable> item_at(int i) const
    {
        const auto &x = inner->data.at(i);
        return { &C::component_type, x.ptr.get() };
    }

    void compute_layout() const
    {
        if (!inner)
            return;
        for (auto &x : inner->data) {
            x.ptr->compute_layout({ &C::component_type, x.ptr.get() });
        }
    }

    float compute_layout_listview(const Property<float> *viewport_width, float listview_width) const
    {
        float offset = 0;
        viewport_width->set(listview_width);
        if (!inner)
            return offset;
        for (auto &x : inner->data) {
            x.ptr->listview_layout(&offset, viewport_width);
        }
        return offset;
    }

    void model_set_row_data(int row, const ModelData &data) const
    {
        if (model.is_dirty()) {
            std::abort();
        }
        if (auto m = model.get()) {
            m->set_row_data(row, data);
            if (inner && inner->is_dirty) {
                auto &c = inner->data[row];
                if (c.state == RepeaterInner::State::Dirty && c.ptr) {
                    c.ptr->update_data(row, m->row_data(row));
                }
            }
        }
    }
};

Flickable::Flickable()
{
    sixtyfps_flickable_data_init(&data);
}
Flickable::~Flickable()
{
    sixtyfps_flickable_data_free(&data);
}

namespace private_api {
template<int Major, int Minor, int Patch>
struct VersionCheckHelper
{
};
}

using cbindgen_private::StandardListViewItem;

} // namespace sixtyfps