use base64::{engine::general_purpose::STANDARD as BASE64, Engine as _};
use notify::{Config, RecommendedWatcher, RecursiveMode, Watcher};
use std::fs;
use std::path::PathBuf;
use std::sync::mpsc::channel;
use std::sync::Arc;
use std::sync::Mutex;
use tauri::AppHandle;
use tauri::Emitter;
use tauri::{WebviewUrl, WebviewWindowBuilder};

struct WatcherState {
    watcher: Option<RecommendedWatcher>,
}

impl WatcherState {
    fn new() -> Self {
        Self { watcher: None }
    }
}

// Handle PNG file processing
fn process_png_file(path: &PathBuf, app: AppHandle) -> Result<(), String> {
    println!("Processing PNG file: {}", path.display());

    // Read the file
    let contents = fs::read(path).map_err(|e| format!("Failed to read file: {}", e))?;

    // Convert to base64
    let base64_string = BASE64.encode(&contents);
    println!("Generated base64 string of length: {}", base64_string.len());

    // Emit the base64 to frontend
    app.emit("png-processed", base64_string)
        .map_err(|e| format!("Failed to emit event: {}", e))?;

    println!("Successfully processed file: {}", path.display());
    Ok(())
}

#[tauri::command]
async fn handle_selected_folder(
    path: String,
    state: tauri::State<'_, Arc<Mutex<WatcherState>>>,
    app: AppHandle,
) -> Result<String, String> {
    let path_buf = PathBuf::from(&path);

    if !path_buf.exists() || !path_buf.is_dir() {
        return Err("Invalid directory path".to_string());
    }

    // Stop existing watcher if any
    let mut state = state
        .lock()
        .map_err(|_| "Failed to lock state".to_string())?;
    state.watcher = None;

    // Create a channel to receive file system events
    let (tx, rx) = channel();

    // Create a new watcher
    let mut watcher = RecommendedWatcher::new(tx, Config::default())
        .map_err(|e| format!("Failed to create watcher: {}", e))?;

    // Start watching the directory
    watcher
        .watch(path_buf.as_ref(), RecursiveMode::Recursive)
        .map_err(|e| format!("Failed to watch directory: {}", e))?;

    // Store the watcher in state
    state.watcher = Some(watcher);

    let path_clone = path.clone();
    let app_clone = app.clone();
    tokio::spawn(async move {
        println!("Starting to watch directory: {}", path_clone);
        for res in rx {
            match res {
                Ok(event) => {
                    println!("Received event: {:?}", event);
                    match event.kind {
                        notify::EventKind::Create(_) | notify::EventKind::Modify(_) => {
                            for path in event.paths {
                                println!("Processing path: {}", path.display());
                                if let Some(extension) = path.extension() {
                                    if extension.to_string_lossy().to_lowercase() == "png" {
                                        if let Err(e) = process_png_file(&path, app_clone.clone()) {
                                            eprintln!("Error processing PNG file: {}", e);
                                        }
                                    }
                                }
                            }
                        }
                        _ => {}
                    }
                }
                Err(e) => eprintln!("Watch error: {:?}", e),
            }
        }
    });

    Ok(format!("Now watching directory: {}", path))
}

#[cfg_attr(mobile, tauri::mobile_entry_point)]
pub fn run() {
    let watcher_state = Arc::new(Mutex::new(WatcherState::new()));

    tauri::Builder::default()
        .plugin(tauri_plugin_dialog::init())
        .plugin(tauri_plugin_opener::init())
        .manage(watcher_state)
        .invoke_handler(tauri::generate_handler![handle_selected_folder])
        .setup(|app| {
            let win_builder = WebviewWindowBuilder::new(app, "main", WebviewUrl::default())
                .inner_size(480.0, 360.0)
                .resizable(true);
            // set transparent title bar only when building for macOS
            #[cfg(target_os = "macos")]
            let win_builder = win_builder.title_bar_style(TitleBarStyle::Transparent);

            let window = win_builder.build().unwrap();

            // set background color only when building for macOS
            #[cfg(target_os = "macos")]
            {
                use cocoa::appkit::{NSColor, NSWindow};
                use cocoa::base::{id, nil};

                let ns_window = window.ns_window().unwrap() as id;
                unsafe {
                    let bg_color = NSColor::colorWithRed_green_blue_alpha_(
                        nil,
                        245.0 / 255.0,
                        245.0 / 255.0,
                        245.0 / 255.0,
                        1.0,
                    );
                    ns_window.setBackgroundColor_(bg_color);
                }
            }

            Ok(())
        })
        .run(tauri::generate_context!())
        .expect("error while running tauri application");
}