mod credentials;
mod updates;

use std::collections::HashSet;

use serde::Deserialize;
use tauri::menu::{
    AboutMetadata, Menu, MenuItem, PredefinedMenuItem, Submenu, HELP_SUBMENU_ID, WINDOW_SUBMENU_ID,
};
#[cfg(target_os = "macos")]
use tauri::RunEvent;
use tauri::{Emitter, Manager, Runtime, Theme, WebviewWindow, WebviewWindowBuilder};

const DESKTOP_MENU_COMMAND_EVENT: &str = "ctms:desktop-menu-command";
const VIEW_MENU_ID: &str = "ctms.menu.view";
const NAVIGATION_MENU_ID: &str = "ctms.menu.navigation";
const REFRESH_COMMAND_ID: &str = "ctms.desktop.refresh";
const TOGGLE_SIDEBAR_COMMAND_ID: &str = "ctms.desktop.toggleSidebar";
const BACK_COMMAND_ID: &str = "ctms.desktop.back";
const FORWARD_COMMAND_ID: &str = "ctms.desktop.forward";

#[derive(Deserialize)]
#[serde(rename_all = "camelCase")]
struct DesktopMenuShortcuts {
    back: String,
    forward: String,
    refresh: String,
}

#[derive(Deserialize)]
#[serde(rename_all = "lowercase")]
enum DesktopThemePreference {
    System,
    Light,
    Dark,
}

fn desktop_menu<R: Runtime>(handle: &tauri::AppHandle<R>) -> tauri::Result<Menu<R>> {
    let package = handle.package_info();
    let config = handle.config();
    let about = AboutMetadata {
        name: Some(package.name.clone()),
        version: Some(package.version.to_string()),
        // macOS falls back to CFBundleVersion when this value is omitted, which
        // renders duplicated text such as `Version 0.1.0 (0.1.0)`.
        #[cfg(target_os = "macos")]
        short_version: Some(String::new()),
        copyright: config.bundle.copyright.clone(),
        authors: config
            .bundle
            .publisher
            .clone()
            .map(|publisher| vec![publisher]),
        // Supplying the icon explicitly keeps the native About panel from
        // falling back to the generic macOS application/folder icon.
        icon: handle.default_window_icon().cloned(),
        ..Default::default()
    };

    Menu::with_items(
        handle,
        &[
            #[cfg(target_os = "macos")]
            &Submenu::with_items(
                handle,
                package.name.clone(),
                true,
                &[
                    &PredefinedMenuItem::about(handle, Some("关于 CTMS"), Some(about.clone()))?,
                    &PredefinedMenuItem::separator(handle)?,
                    &MenuItem::with_id(
                        handle,
                        "ctms.desktop.preferences",
                        "设置…",
                        true,
                        Some("CmdOrCtrl+,"),
                    )?,
                    &PredefinedMenuItem::separator(handle)?,
                    &PredefinedMenuItem::services(handle, None)?,
                    &PredefinedMenuItem::separator(handle)?,
                    &PredefinedMenuItem::hide(handle, None)?,
                    &PredefinedMenuItem::hide_others(handle, None)?,
                    &PredefinedMenuItem::show_all(handle, None)?,
                    &PredefinedMenuItem::separator(handle)?,
                    &PredefinedMenuItem::quit(handle, None)?,
                ],
            )?,
            &Submenu::with_items(
                handle,
                "文件",
                true,
                &[
                    &MenuItem::with_id(
                        handle,
                        "ctms.desktop.commandPalette",
                        "打开命令面板",
                        true,
                        Some("CmdOrCtrl+K"),
                    )?,
                    #[cfg(not(target_os = "macos"))]
                    &MenuItem::with_id(
                        handle,
                        "ctms.desktop.preferences",
                        "设置",
                        true,
                        Some("CmdOrCtrl+,"),
                    )?,
                    &PredefinedMenuItem::separator(handle)?,
                    &PredefinedMenuItem::close_window(handle, None)?,
                    #[cfg(not(target_os = "macos"))]
                    &PredefinedMenuItem::quit(handle, None)?,
                ],
            )?,
            &Submenu::with_items(
                handle,
                "编辑",
                true,
                &[
                    &PredefinedMenuItem::undo(handle, None)?,
                    &PredefinedMenuItem::redo(handle, None)?,
                    &PredefinedMenuItem::separator(handle)?,
                    &PredefinedMenuItem::cut(handle, None)?,
                    &PredefinedMenuItem::copy(handle, None)?,
                    &PredefinedMenuItem::paste(handle, None)?,
                    &PredefinedMenuItem::select_all(handle, None)?,
                ],
            )?,
            &Submenu::with_id_and_items(
                handle,
                VIEW_MENU_ID,
                "显示",
                true,
                &[
                    &MenuItem::with_id(
                        handle,
                        REFRESH_COMMAND_ID,
                        "刷新当前视图",
                        true,
                        Some("CmdOrCtrl+R"),
                    )?,
                    &MenuItem::with_id(
                        handle,
                        TOGGLE_SIDEBAR_COMMAND_ID,
                        "显示/隐藏导航栏",
                        true,
                        None::<&str>,
                    )?,
                    &PredefinedMenuItem::separator(handle)?,
                    &PredefinedMenuItem::fullscreen(handle, None)?,
                ],
            )?,
            &Submenu::with_id_and_items(
                handle,
                NAVIGATION_MENU_ID,
                "导航",
                true,
                &[
                    &MenuItem::with_id(handle, BACK_COMMAND_ID, "后退", true, Some("CmdOrCtrl+["))?,
                    &MenuItem::with_id(
                        handle,
                        FORWARD_COMMAND_ID,
                        "前进",
                        true,
                        Some("CmdOrCtrl+]"),
                    )?,
                ],
            )?,
            &Submenu::with_id_and_items(
                handle,
                WINDOW_SUBMENU_ID,
                "窗口",
                true,
                &[
                    &PredefinedMenuItem::minimize(handle, None)?,
                    &PredefinedMenuItem::maximize(handle, None)?,
                    &PredefinedMenuItem::close_window(handle, None)?,
                ],
            )?,
            &Submenu::with_id_and_items(
                handle,
                HELP_SUBMENU_ID,
                "帮助",
                true,
                &[
                    #[cfg(not(target_os = "macos"))]
                    &PredefinedMenuItem::about(handle, Some("关于 CTMS"), Some(about))?,
                    &MenuItem::with_id(
                        handle,
                        "ctms.desktop.help",
                        "CTMS 命令与导航",
                        true,
                        None::<&str>,
                    )?,
                ],
            )?,
        ],
    )
}

fn emit_menu_command<R: Runtime>(app: &tauri::AppHandle<R>, command: &str) {
    if let Some(window) = app.get_webview_window("main") {
        let _ = window.emit(DESKTOP_MENU_COMMAND_EVENT, command);
    }
}

fn restore_main_window<R: Runtime>(app: &tauri::AppHandle<R>) -> Result<(), String> {
    if let Some(window) = app.get_webview_window("main") {
        let _ = window.unminimize();
        let _ = window.show();
        let _ = window.set_focus();
        return Ok(());
    }

    let config = app
        .config()
        .app
        .windows
        .iter()
        .find(|config| config.label == "main")
        .cloned()
        .ok_or_else(|| "未找到主窗口配置".to_string())?;
    let window = WebviewWindowBuilder::from_config(app, &config)
        .map_err(|error| format!("读取主窗口配置失败：{error}"))?
        .build()
        .map_err(|error| format!("重建主窗口失败：{error}"))?;
    let _ = window.show();
    let _ = window.set_focus();
    Ok(())
}

fn is_allowed_shortcut_key(value: &str) -> bool {
    matches!(
        value,
        "[" | "]"
            | ","
            | "."
            | "/"
            | ";"
            | "="
            | "-"
            | "ArrowLeft"
            | "ArrowRight"
            | "ArrowUp"
            | "ArrowDown"
            | "Home"
            | "End"
            | "PageUp"
            | "PageDown"
    ) || (value.len() == 1
        && value
            .as_bytes()
            .first()
            .is_some_and(|value| value.is_ascii_uppercase() || value.is_ascii_digit()))
}

fn normalize_menu_shortcut(value: &str) -> Result<String, String> {
    const RESERVED: &[&str] = &[
        "Mod+K",
        "Mod+,",
        "Mod+W",
        "Mod+Q",
        "Mod+C",
        "Mod+V",
        "Mod+X",
        "Mod+A",
        "Mod+Z",
        "Mod+Shift+Z",
    ];

    if RESERVED.contains(&value) {
        return Err("快捷键与系统或应用保留快捷键冲突".to_string());
    }

    let parts = value.split('+').collect::<Vec<_>>();
    if parts.len() < 2 || parts[0] != "Mod" {
        return Err("快捷键必须以 Mod 开头".to_string());
    }

    let key = parts.last().copied().unwrap_or_default();
    if !is_allowed_shortcut_key(key) {
        return Err("快捷键按键不受支持".to_string());
    }

    let mut modifiers = HashSet::new();
    for modifier in &parts[1..parts.len() - 1] {
        if !matches!(*modifier, "Shift" | "Alt") || !modifiers.insert(*modifier) {
            return Err("快捷键修饰键不受支持或重复".to_string());
        }
    }

    Ok(format!("CmdOrCtrl+{}", parts[1..].join("+")))
}

fn set_menu_accelerator<R: Runtime>(
    app: &tauri::AppHandle<R>,
    submenu_id: &str,
    item_id: &str,
    accelerator: &str,
) -> Result<(), String> {
    let menu = app.menu().ok_or_else(|| "桌面菜单尚未初始化".to_string())?;
    let submenu = menu
        .get(submenu_id)
        .and_then(|item| item.as_submenu().cloned())
        .ok_or_else(|| format!("未找到桌面菜单：{submenu_id}"))?;
    let item = submenu
        .get(item_id)
        .and_then(|item| item.as_menuitem().cloned())
        .ok_or_else(|| format!("未找到桌面菜单项：{item_id}"))?;
    item.set_accelerator(Some(accelerator))
        .map_err(|error| format!("更新桌面菜单快捷键失败：{error}"))
}

#[tauri::command]
fn desktop_menu_set_shortcuts<R: Runtime>(
    app: tauri::AppHandle<R>,
    shortcuts: DesktopMenuShortcuts,
) -> Result<(), String> {
    let back = normalize_menu_shortcut(&shortcuts.back)?;
    let forward = normalize_menu_shortcut(&shortcuts.forward)?;
    let refresh = normalize_menu_shortcut(&shortcuts.refresh)?;
    if HashSet::from([back.as_str(), forward.as_str(), refresh.as_str()]).len() != 3 {
        return Err("桌面快捷键不能重复".to_string());
    }

    set_menu_accelerator(&app, NAVIGATION_MENU_ID, BACK_COMMAND_ID, &back)?;
    set_menu_accelerator(&app, NAVIGATION_MENU_ID, FORWARD_COMMAND_ID, &forward)?;
    set_menu_accelerator(&app, VIEW_MENU_ID, REFRESH_COMMAND_ID, &refresh)?;
    Ok(())
}

#[tauri::command]
fn desktop_window_set_theme<R: Runtime>(
    window: WebviewWindow<R>,
    theme: DesktopThemePreference,
) -> Result<(), String> {
    let theme = match theme {
        DesktopThemePreference::System => None,
        DesktopThemePreference::Light => Some(Theme::Light),
        DesktopThemePreference::Dark => Some(Theme::Dark),
    };
    window
        .set_theme(theme)
        .map_err(|error| format!("更新桌面窗口主题失败：{error}"))
}

pub fn run() {
    let app = tauri::Builder::default()
        .menu(desktop_menu)
        .on_menu_event(|app, event| {
            let command = event.id().as_ref();
            if command.starts_with("ctms.desktop.") {
                emit_menu_command(app, command);
            }
        })
        .plugin(tauri_plugin_single_instance::init(|app, _args, _cwd| {
            let _ = restore_main_window(app);
        }))
        .plugin(tauri_plugin_dialog::init())
        .plugin(tauri_plugin_fs::init())
        .plugin(tauri_plugin_notification::init())
        .plugin(tauri_plugin_opener::init())
        .plugin(tauri_plugin_updater::Builder::new().build())
        .manage(updates::PendingUpdate::default())
        .invoke_handler(tauri::generate_handler![
            credentials::credential_get,
            credentials::credential_set,
            credentials::credential_delete,
            credentials::login_credential_get,
            credentials::login_credential_set,
            credentials::login_credential_delete,
            updates::desktop_update_check,
            updates::desktop_update_install,
            desktop_menu_set_shortcuts,
            desktop_window_set_theme,
        ])
        .build(tauri::generate_context!())
        .expect("error while building CTMS desktop application");

    app.run(|app, event| {
        #[cfg(target_os = "macos")]
        if let RunEvent::Reopen { .. } = event {
            if let Err(error) = restore_main_window(app) {
                eprintln!("{error}");
            }
        }
        #[cfg(not(target_os = "macos"))]
        let _ = (app, event);
    });
}

#[cfg(test)]
mod tests {
    use super::normalize_menu_shortcut;

    #[test]
    fn converts_runtime_shortcuts_to_native_accelerators() {
        assert_eq!(
            normalize_menu_shortcut("Mod+Shift+[").unwrap(),
            "CmdOrCtrl+Shift+["
        );
        assert_eq!(
            normalize_menu_shortcut("Mod+Alt+ArrowLeft").unwrap(),
            "CmdOrCtrl+Alt+ArrowLeft"
        );
    }

    #[test]
    fn rejects_reserved_or_malformed_shortcuts() {
        assert!(normalize_menu_shortcut("Mod+Q").is_err());
        assert!(normalize_menu_shortcut("Ctrl+R").is_err());
        assert!(normalize_menu_shortcut("Mod+Shift+Shift+R").is_err());
        assert!(normalize_menu_shortcut("Mod+F12").is_err());
    }
}