#![cfg_attr(not(debug_assertions), windows_subsystem = "windows")]

use notify::{Event, RecursiveMode, Watcher};
use std::path::Path;
use std::time::{Duration, Instant};
use tray_icon::{
    menu::{Menu, MenuItem},
    Icon, TrayIconBuilder,
};
use winit::event::StartCause;
use winit::{
    application::ApplicationHandler,
    event::WindowEvent,
    event_loop::{ActiveEventLoop, ControlFlow, EventLoop},
};

mod filesync;
mod git;

const PROTECT_PREFIX: &str = ".git"; // only at first directory level
const SOURCE_VAULT: &str = "D:\\Cloud\\Syncthing\\obsidian-vault"; // syncthing vault folder
const REPO_VAULT: &str =
    "C:\\Users\\robin\\AppData\\Roaming\\obsidian-git-backup\\obsidian-vault-clone"; // git repo folder
const GIT_COMMIT_DELAY_AFTER_FILE_CHANGE: Duration = Duration::from_secs(30 * 60); // 30 min

#[derive(Debug)]
enum UserEvent {
    MenuEvent(tray_icon::menu::MenuEvent),
    FileEvent(Event),
}

#[derive(Default)]
struct App {
    tray_icon: Option<tray_icon::TrayIcon>,
    menu_changed_status: Option<MenuItem>,
    menu_backup_now: Option<MenuItem>,
    menu_exit: Option<MenuItem>,
    last_change_time: Option<Instant>,
    current_change_count: usize,
}

impl App {
    fn create_tray_icon_menu(&mut self) {
        // Create and show the tray icon
        let menu_item_changed_status = MenuItem::new("Changed: 0", true, None);
        let menu_item_backup_now = MenuItem::new("Backup Now", true, None);
        let menu_item_exit = MenuItem::new("Exit", true, None);

        let tray_menu = Menu::new();
        tray_menu.append(&menu_item_changed_status).unwrap();
        tray_menu.append(&menu_item_backup_now).unwrap();
        tray_menu.append(&menu_item_exit).unwrap();

        let icon_path = Path::new(".\\sync.ico");
        let icon = Icon::from_path(icon_path, None).unwrap();
        let tray_icon = TrayIconBuilder::new()
            .with_menu(Box::new(tray_menu))
            .with_tooltip("Obsidian Git Backup")
            .with_icon(icon)
            .build()
            .unwrap();

        self.tray_icon = Some(tray_icon);
        self.menu_changed_status = Some(menu_item_changed_status);
        self.menu_backup_now = Some(menu_item_backup_now);
        self.menu_exit = Some(menu_item_exit);
    }

    fn start_backup(&mut self) {
        self.last_change_time = None;
        let repo_dir = Path::new(REPO_VAULT);
        git::backup_changes(repo_dir).expect("Changes could not be pushed");
        self.current_change_count = 0;
        self.menu_update_change_count();
    }

    fn process_file_event(&mut self) {
        self.last_change_time = Some(Instant::now());
        let source = Path::new(SOURCE_VAULT);
        let target = Path::new(REPO_VAULT);
        filesync::sync_directory(source, target, Some(PROTECT_PREFIX))
            .expect("Directories could not be synced");
        self.current_change_count =
            git::current_change_count(target).expect("Changes could not get counted using git");
        self.menu_update_change_count();
        println!("Currently changed files: {:?}", self.current_change_count);
    }

    fn menu_update_change_count(&mut self) {
        if let Some(menu_item) = &mut self.menu_changed_status {
            menu_item.set_text(format!("Changed: {:?}", self.current_change_count));
        }
    }
}

impl ApplicationHandler<UserEvent> for App {
    fn resumed(&mut self, _event_loop: &ActiveEventLoop) {
        self.create_tray_icon_menu();
        self.last_change_time = None;
    }

    fn user_event(&mut self, event_loop: &ActiveEventLoop, event: UserEvent) {
        match event {
            UserEvent::MenuEvent(menu_event) => {
                match menu_event.id() {
                    id if id == self.menu_backup_now.as_ref().unwrap().id() => {
                        println!("---> Backup triggered by menu");
                        // Handle push now menu item
                        self.start_backup();
                    }
                    id if id == self.menu_exit.as_ref().unwrap().id() => {
                        println!("---> Exit triggert by menu");
                        // Handle exit menu item
                        event_loop.exit();
                    }
                    _ => {}
                }
            }
            UserEvent::FileEvent(_event) => {
                println!("---> File change detected");
                self.process_file_event();
            }
        }
    }

    fn new_events(&mut self, event_loop: &ActiveEventLoop, _cause: StartCause) {
        let now = Instant::now();

        // Backup changes if last file change time exceeded threshold
        if let Some(last_change_time) = self.last_change_time {
            if now.duration_since(last_change_time) > GIT_COMMIT_DELAY_AFTER_FILE_CHANGE {
                println!("---> Backup triggered by file change");
                self.start_backup();
            }
        }

        // Reset timer
        event_loop.set_control_flow(ControlFlow::WaitUntil(now + Duration::from_secs(5)));
    }

    fn window_event(
        &mut self,
        _event_loop: &ActiveEventLoop,
        _window_id: winit::window::WindowId,
        _event: WindowEvent,
    ) {
    }
}

fn main() {
    // Sync folder and check for changes to back up
    let source_dir = Path::new(SOURCE_VAULT);
    let repo_dir = Path::new(REPO_VAULT);
    filesync::sync_directory(source_dir, repo_dir, Some(PROTECT_PREFIX))
        .expect("Directories could not be synced");
    git::backup_changes(repo_dir).expect("Changes could not be pushed");

    // Create event loop
    let event_loop = EventLoop::<UserEvent>::with_user_event().build().unwrap();
    event_loop.set_control_flow(ControlFlow::Wait);

    // Set up menu event handler
    let proxy = event_loop.create_proxy();
    tray_icon::menu::MenuEvent::set_event_handler(Some(move |event| {
        proxy.send_event(UserEvent::MenuEvent(event)).unwrap();
    }));

    // Set up file change event handler
    let proxy = event_loop.create_proxy();
    let mut watcher = notify::recommended_watcher(move |event| {
        if let Ok(event) = event {
            proxy.send_event(UserEvent::FileEvent(event)).unwrap();
        }
    })
    .unwrap();
    watcher.watch(source_dir, RecursiveMode::Recursive).unwrap();

    // Start event loop
    println!("Starting event loop...");
    let mut app = App::default();
    event_loop.run_app(&mut app).unwrap();
}