//! User code compilation commands.
//! 用户代码编译命令。
//!
//! Provides TypeScript compilation using esbuild for user scripts.
//! 使用 esbuild 为用户脚本提供 TypeScript 编译。

use notify::{Config, RecommendedWatcher, RecursiveMode, Watcher, Event, EventKind};
use serde::{Deserialize, Serialize};
use std::path::Path;
use std::process::Command;
use std::sync::mpsc::channel;
use std::time::Duration;
use tauri::{command, AppHandle, Emitter, State};
use crate::state::ScriptWatcherState;

/// Compilation options.
/// 编译选项。
#[derive(Debug, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct CompileOptions {
    /// Entry file path | 入口文件路径
    pub entry_path: String,
    /// Output file path | 输出文件路径
    pub output_path: String,
    /// Output format (esm or iife) | 输出格式
    pub format: String,
    /// Whether to generate source map | 是否生成 source map
    pub source_map: bool,
    /// Whether to minify | 是否压缩
    pub minify: bool,
    /// External dependencies | 外部依赖
    pub external: Vec<String>,
    /// Project root for resolving imports | 项目根目录用于解析导入
    pub project_root: String,
}

/// Compilation error.
/// 编译错误。
#[derive(Debug, Clone, Serialize)]
#[serde(rename_all = "camelCase")]
pub struct CompileError {
    /// Error message | 错误信息
    pub message: String,
    /// File path | 文件路径
    pub file: Option<String>,
    /// Line number | 行号
    pub line: Option<u32>,
    /// Column number | 列号
    pub column: Option<u32>,
}

/// Compilation result.
/// 编译结果。
#[derive(Debug, Serialize)]
#[serde(rename_all = "camelCase")]
pub struct CompileResult {
    /// Whether compilation succeeded | 是否编译成功
    pub success: bool,
    /// Compilation errors | 编译错误
    pub errors: Vec<CompileError>,
    /// Output file path (if successful) | 输出文件路径（如果成功）
    pub output_path: Option<String>,
}

/// File change event sent to frontend.
/// 发送到前端的文件变更事件。
#[derive(Debug, Clone, Serialize)]
#[serde(rename_all = "camelCase")]
pub struct FileChangeEvent {
    /// Type of change: "create", "modify", "remove" | 变更类型
    pub change_type: String,
    /// File paths that changed | 发生变更的文件路径
    pub paths: Vec<String>,
}

/// Compile TypeScript using esbuild.
/// 使用 esbuild 编译 TypeScript。
///
/// # Arguments | 参数
/// * `options` - Compilation options | 编译选项
///
/// # Returns | 返回
/// Compilation result | 编译结果
#[command]
pub async fn compile_typescript(options: CompileOptions) -> Result<CompileResult, String> {
    // Check if esbuild is available | 检查 esbuild 是否可用
    let esbuild_path = find_esbuild(&options.project_root)?;

    // Build esbuild arguments | 构建 esbuild 参数
    let mut args = vec![
        options.entry_path.clone(),
        "--bundle".to_string(),
        format!("--outfile={}", options.output_path),
        format!("--format={}", options.format),
        "--platform=browser".to_string(),
        "--target=es2020".to_string(),
    ];

    // Add source map option | 添加 source map 选项
    if options.source_map {
        args.push("--sourcemap".to_string());
    }

    // Add minify option | 添加压缩选项
    if options.minify {
        args.push("--minify".to_string());
    }

    // Add external dependencies | 添加外部依赖
    for external in &options.external {
        args.push(format!("--external:{}", external));
    }

    // Run esbuild | 运行 esbuild
    let output = Command::new(&esbuild_path)
        .args(&args)
        .current_dir(&options.project_root)
        .output()
        .map_err(|e| format!("Failed to run esbuild | 运行 esbuild 失败: {}", e))?;

    if output.status.success() {
        Ok(CompileResult {
            success: true,
            errors: vec![],
            output_path: Some(options.output_path),
        })
    } else {
        let stderr = String::from_utf8_lossy(&output.stderr);
        let errors = parse_esbuild_errors(&stderr);

        Ok(CompileResult {
            success: false,
            errors,
            output_path: None,
        })
    }
}

/// Watch for file changes in scripts directory.
/// 监视脚本目录中的文件变更。
///
/// Emits "user-code:file-changed" events when files change.
/// 当文件发生变更时触发 "user-code:file-changed" 事件。
#[command]
pub async fn watch_scripts(
    app: AppHandle,
    watcher_state: State<'_, ScriptWatcherState>,
    project_path: String,
    scripts_dir: String,
) -> Result<(), String> {
    let watch_path = Path::new(&project_path).join(&scripts_dir);

    if !watch_path.exists() {
        return Err(format!(
            "Scripts directory does not exist | 脚本目录不存在: {}",
            watch_path.display()
        ));
    }

    // Check if already watching this project | 检查是否已在监视此项目
    {
        let watchers = watcher_state.watchers.lock().await;
        if watchers.contains_key(&project_path) {
            println!("[UserCode] Already watching: {}", project_path);
            return Ok(());
        }
    }

    // Create a channel for shutdown signal | 创建关闭信号通道
    let (shutdown_tx, mut shutdown_rx) = tokio::sync::oneshot::channel::<()>();

    // Clone values for the spawned task | 克隆值以供任务使用
    let project_path_clone = project_path.clone();
    let watch_path_clone = watch_path.clone();
    let app_clone = app.clone();

    // Spawn file watcher task | 启动文件监视任务
    tokio::spawn(async move {
        // Create notify watcher | 创建 notify 监视器
        let (tx, rx) = channel();

        let mut watcher = match RecommendedWatcher::new(
            move |res: Result<Event, notify::Error>| {
                if let Ok(event) = res {
                    let _ = tx.send(event);
                }
            },
            Config::default().with_poll_interval(Duration::from_millis(500)),
        ) {
            Ok(w) => w,
            Err(e) => {
                eprintln!("[UserCode] Failed to create watcher: {}", e);
                return;
            }
        };

        // Start watching | 开始监视
        if let Err(e) = watcher.watch(&watch_path_clone, RecursiveMode::Recursive) {
            eprintln!("[UserCode] Failed to watch path: {}", e);
            return;
        }

        println!("[UserCode] Started watching: {}", watch_path_clone.display());

        // Event loop | 事件循环
        loop {
            // Check for shutdown | 检查关闭信号
            if shutdown_rx.try_recv().is_ok() {
                println!("[UserCode] Stopping watcher for: {}", project_path_clone);
                break;
            }

            // Check for file events with timeout | 带超时检查文件事件
            match rx.recv_timeout(Duration::from_millis(100)) {
                Ok(event) => {
                    // Filter for TypeScript/JavaScript files | 过滤 TypeScript/JavaScript 文件
                    let ts_paths: Vec<String> = event
                        .paths
                        .iter()
                        .filter(|p| {
                            let ext = p.extension().and_then(|e| e.to_str()).unwrap_or("");
                            matches!(ext, "ts" | "tsx" | "js" | "jsx")
                        })
                        .map(|p| p.to_string_lossy().to_string())
                        .collect();

                    if !ts_paths.is_empty() {
                        let change_type = match event.kind {
                            EventKind::Create(_) => "create",
                            EventKind::Modify(_) => "modify",
                            EventKind::Remove(_) => "remove",
                            _ => continue,
                        };

                        let file_event = FileChangeEvent {
                            change_type: change_type.to_string(),
                            paths: ts_paths,
                        };

                        println!("[UserCode] File change detected: {:?}", file_event);

                        // Emit event to frontend | 向前端发送事件
                        if let Err(e) = app_clone.emit("user-code:file-changed", file_event) {
                            eprintln!("[UserCode] Failed to emit event: {}", e);
                        }
                    }
                }
                Err(std::sync::mpsc::RecvTimeoutError::Timeout) => {
                    // No events, continue | 无事件，继续
                }
                Err(std::sync::mpsc::RecvTimeoutError::Disconnected) => {
                    println!("[UserCode] Watcher channel disconnected");
                    break;
                }
            }
        }
    });

    // Store watcher handle | 存储监视器句柄
    {
        let mut watchers = watcher_state.watchers.lock().await;
        watchers.insert(
            project_path.clone(),
            crate::state::WatcherHandle { shutdown_tx },
        );
    }

    println!("[UserCode] Watch scripts started for: {}/{}", project_path, scripts_dir);
    Ok(())
}

/// Stop watching for file changes.
/// 停止监视文件变更。
#[command]
pub async fn stop_watch_scripts(
    watcher_state: State<'_, ScriptWatcherState>,
    project_path: Option<String>,
) -> Result<(), String> {
    let mut watchers = watcher_state.watchers.lock().await;

    match project_path {
        Some(path) => {
            // Stop specific watcher | 停止特定监视器
            if let Some(handle) = watchers.remove(&path) {
                let _ = handle.shutdown_tx.send(());
                println!("[UserCode] Stopped watching: {}", path);
            }
        }
        None => {
            // Stop all watchers | 停止所有监视器
            for (path, handle) in watchers.drain() {
                let _ = handle.shutdown_tx.send(());
                println!("[UserCode] Stopped watching: {}", path);
            }
        }
    }

    Ok(())
}

/// Find esbuild executable path.
/// 查找 esbuild 可执行文件路径。
fn find_esbuild(project_root: &str) -> Result<String, String> {
    let project_path = Path::new(project_root);

    // Try local node_modules first | 首先尝试本地 node_modules
    let local_esbuild = if cfg!(windows) {
        project_path.join("node_modules/.bin/esbuild.cmd")
    } else {
        project_path.join("node_modules/.bin/esbuild")
    };

    if local_esbuild.exists() {
        return Ok(local_esbuild.to_string_lossy().to_string());
    }

    // Try global esbuild | 尝试全局 esbuild
    let global_esbuild = if cfg!(windows) { "esbuild.cmd" } else { "esbuild" };

    // Check if global esbuild exists | 检查全局 esbuild 是否存在
    let check = Command::new(global_esbuild)
        .arg("--version")
        .output();

    match check {
        Ok(output) if output.status.success() => Ok(global_esbuild.to_string()),
        _ => Err("esbuild not found. Please install esbuild: npm install -g esbuild | 未找到 esbuild，请安装: npm install -g esbuild".to_string())
    }
}

/// Parse esbuild error output.
/// 解析 esbuild 错误输出。
fn parse_esbuild_errors(stderr: &str) -> Vec<CompileError> {
    let mut errors = Vec::new();

    // Simple error parsing - esbuild outputs errors in a specific format
    // 简单的错误解析 - esbuild 以特定格式输出错误
    for line in stderr.lines() {
        if line.contains("error:") || line.contains("Error:") {
            // Try to parse file:line:column format | 尝试解析 file:line:column 格式
            let parts: Vec<&str> = line.splitn(2, ": ").collect();

            if parts.len() == 2 {
                let location = parts[0];
                let message = parts[1].to_string();

                // Parse location (file:line:column) | 解析位置
                let loc_parts: Vec<&str> = location.split(':').collect();

                let (file, line_num, column) = if loc_parts.len() >= 3 {
                    (
                        Some(loc_parts[0].to_string()),
                        loc_parts[1].parse().ok(),
                        loc_parts[2].parse().ok(),
                    )
                } else {
                    (None, None, None)
                };

                errors.push(CompileError {
                    message,
                    file,
                    line: line_num,
                    column,
                });
            } else {
                errors.push(CompileError {
                    message: line.to_string(),
                    file: None,
                    line: None,
                    column: None,
                });
            }
        }
    }

    // If no specific errors found, add the whole stderr as one error
    // 如果没有找到特定错误，将整个 stderr 作为一个错误
    if errors.is_empty() && !stderr.trim().is_empty() {
        errors.push(CompileError {
            message: stderr.to_string(),
            file: None,
            line: None,
            column: None,
        });
    }

    errors
}