use crate::diagnostic::Diagnostic;
use colored::Colorize;
use parser as test_parser;
use red_knot_python_semantic::types::check_types;
use ruff_db::files::{system_path_to_file, File, Files};
use ruff_db::parsed::parsed_module;
use ruff_db::system::{DbWithTestSystem, SystemPathBuf};
use ruff_source_file::LineIndex;
use ruff_text_size::TextSize;
use std::path::Path;
use std::sync::Arc;

mod assertion;
mod db;
mod diagnostic;
mod matcher;
mod parser;

/// Run `path` as a markdown test suite with given `title`.
///
/// Panic on test failure, and print failure details.
#[allow(clippy::print_stdout)]
pub fn run(path: &Path, title: &str) {
    let source = std::fs::read_to_string(path).unwrap();
    let suite = match test_parser::parse(title, &source) {
        Ok(suite) => suite,
        Err(err) => {
            panic!("Error parsing `{}`: {err}", path.to_str().unwrap())
        }
    };

    let mut db = db::Db::setup(SystemPathBuf::from("/src"));

    let mut any_failures = false;
    for test in suite.tests() {
        // Remove all files so that the db is in a "fresh" state.
        db.memory_file_system().remove_all();
        Files::sync_all(&mut db);

        if let Err(failures) = run_test(&mut db, &test) {
            any_failures = true;
            println!("\n{}\n", test.name().bold().underline());

            let md_index = LineIndex::from_source_text(&source);

            for test_failures in failures {
                let backtick_line = md_index.line_index(test_failures.backtick_offset);

                for (relative_line_number, failures) in test_failures.by_line.iter() {
                    for failure in failures {
                        let absolute_line_number =
                            backtick_line.checked_add(relative_line_number).unwrap();
                        let line_info = format!("{title}:{absolute_line_number}").cyan();
                        println!("    {line_info} {failure}");
                    }
                }
            }
        }
    }

    println!("\n{}\n", "-".repeat(50));

    assert!(!any_failures, "Some tests failed.");
}

fn run_test(db: &mut db::Db, test: &parser::MarkdownTest) -> Result<(), Failures> {
    let workspace_root = db.workspace_root().to_path_buf();

    let test_files: Vec<_> = test
        .files()
        .map(|embedded| {
            assert!(
                matches!(embedded.lang, "py" | "pyi"),
                "Non-Python files not supported yet."
            );
            let full_path = workspace_root.join(embedded.path);
            db.write_file(&full_path, embedded.code).unwrap();
            let file = system_path_to_file(db, full_path).unwrap();

            TestFile {
                file,
                backtick_offset: embedded.md_offset,
            }
        })
        .collect();

    let failures: Failures = test_files
        .into_iter()
        .filter_map(|test_file| {
            let parsed = parsed_module(db, test_file.file);

            let mut diagnostics: Vec<Box<_>> = parsed
                .errors()
                .iter()
                .cloned()
                .map(|error| {
                    let diagnostic: Box<dyn Diagnostic> = Box::new(error);
                    diagnostic
                })
                .collect();

            let type_diagnostics = check_types(db, test_file.file);
            diagnostics.extend(type_diagnostics.into_iter().map(|diagnostic| {
                let diagnostic: Box<dyn Diagnostic> = Box::new(Arc::unwrap_or_clone(diagnostic));
                diagnostic
            }));

            match matcher::match_file(db, test_file.file, diagnostics) {
                Ok(()) => None,
                Err(line_failures) => Some(FileFailures {
                    backtick_offset: test_file.backtick_offset,
                    by_line: line_failures,
                }),
            }
        })
        .collect();

    if failures.is_empty() {
        Ok(())
    } else {
        Err(failures)
    }
}

type Failures = Vec<FileFailures>;

/// The failures for a single file in a test by line number.
struct FileFailures {
    /// The offset of the backticks that starts the code block in the Markdown file
    backtick_offset: TextSize,
    /// The failures by lines in the code block.
    by_line: matcher::FailuresByLine,
}

/// File in a test.
struct TestFile {
    file: File,

    // Offset of the backticks that starts the code block in the Markdown file
    backtick_offset: TextSize,
}