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

use tauri::{webview::{NewWindowResponse, WebviewWindowBuilder}, WebviewUrl};
use tauri_plugin_opener::OpenerExt;

#[tauri::command]
fn set_badge_count(count: u32, window: tauri::Window) -> Result<(), String> {
    #[cfg(target_os = "windows")]
    {
        use windows::{
            core::PCWSTR,
            Win32::{
                Foundation::{BOOL, COLORREF, HWND, RECT},
                Graphics::Gdi::{
                    CreateCompatibleDC, CreateDIBSection, CreatePen, CreateSolidBrush,
                    DeleteDC, DeleteObject, DIB_RGB_COLORS, DrawTextW, Ellipse,
                    ReleaseDC, SelectObject, SetBkMode, SetTextColor, BITMAPINFO,
                    BITMAPINFOHEADER, BI_RGB, DT_CENTER, DT_SINGLELINE, DT_VCENTER,
                    PS_NULL, TRANSPARENT, CreateFontW, DEFAULT_CHARSET, DEFAULT_PITCH,
                    DEFAULT_QUALITY, CLIP_DEFAULT_PRECIS, FW_BOLD, FF_DONTCARE,
                    OUT_DEFAULT_PRECIS,
                },
                UI::{
                    Shell::{ITaskbarList3, TaskbarList},
                    WindowsAndMessaging::{CreateBitmap, CreateIconIndirect, DestroyIcon, ICONINFO},
                },
                System::Com::{CoCreateInstance, CLSCTX_INPROC_SERVER},
            },
        };

        let hwnd = HWND(window.hwnd().map_err(|e| e.to_string())?.0 as _);

        let hicon = if count > 0 {
            let label = if count > 99 {
                "99+".to_string()
            } else {
                count.to_string()
            };
            let label_wide: Vec<u16> = label.encode_utf16().chain(std::iter::once(0)).collect();

            unsafe {
                let size = 16i32;
                let hdc_screen = windows::Win32::Graphics::Gdi::GetDC(HWND(std::ptr::null_mut()));
                let hdc = CreateCompatibleDC(hdc_screen);

                let bmi = BITMAPINFO {
                    bmiHeader: BITMAPINFOHEADER {
                        biSize: std::mem::size_of::<BITMAPINFOHEADER>() as u32,
                        biWidth: size,
                        biHeight: -size,
                        biPlanes: 1,
                        biBitCount: 32,
                        biCompression: BI_RGB.0,
                        ..Default::default()
                    },
                    ..Default::default()
                };
                let mut bits: *mut std::ffi::c_void = std::ptr::null_mut();
                let hbm_color = CreateDIBSection(hdc, &bmi, DIB_RGB_COLORS, &mut bits, None, 0)
                    .map_err(|e| e.to_string())?;
                let old_bm = SelectObject(hdc, hbm_color);

                // Red circle (COLORREF is 0x00BBGGRR)
                let hbrush = CreateSolidBrush(COLORREF(0x003030DD));
                let old_brush = SelectObject(hdc, hbrush);
                let hpen = CreatePen(PS_NULL, 0, COLORREF(0));
                let old_pen = SelectObject(hdc, hpen);
                let _ = Ellipse(hdc, 0, 0, size, size);

                // White bold text centered
                let hfont = CreateFontW(
                    11, 0, 0, 0, FW_BOLD.0 as i32, 0, 0, 0,
                    DEFAULT_CHARSET.0 as u32,
                    OUT_DEFAULT_PRECIS.0 as u32,
                    CLIP_DEFAULT_PRECIS.0 as u32,
                    DEFAULT_QUALITY.0 as u32,
                    (DEFAULT_PITCH.0 | FF_DONTCARE.0) as u32,
                    windows::core::w!("Segoe UI"),
                );
                let old_font = SelectObject(hdc, hfont);
                SetTextColor(hdc, COLORREF(0x00FFFFFF));
                let _ = SetBkMode(hdc, TRANSPARENT);
                let mut rect = RECT { left: 0, top: 0, right: size, bottom: size };
                let _ = DrawTextW(
                    hdc,
                    &label_wide[..label_wide.len() - 1],
                    &mut rect,
                    DT_CENTER | DT_VCENTER | DT_SINGLELINE,
                );

                SelectObject(hdc, old_brush);
                SelectObject(hdc, old_pen);
                SelectObject(hdc, old_font);
                SelectObject(hdc, old_bm);
                let _ = DeleteObject(hbrush);
                let _ = DeleteObject(hpen);
                let _ = DeleteObject(hfont);

                let hbm_mask = CreateBitmap(size, size, 1, 1, None)
                    .map_err(|e| { let _ = DeleteObject(hbm_color); e.to_string() })?;

                let icon_info = ICONINFO {
                    fIcon: BOOL(1),
                    xHotspot: 0,
                    yHotspot: 0,
                    hbmMask: hbm_mask,
                    hbmColor: hbm_color,
                };
                let hicon = CreateIconIndirect(&icon_info)
                    .map_err(|e| { let _ = DeleteObject(hbm_color); let _ = DeleteObject(hbm_mask); e.to_string() })?;

                let _ = DeleteObject(hbm_color);
                let _ = DeleteObject(hbm_mask);
                let _ = DeleteDC(hdc);
                let _ = ReleaseDC(HWND(std::ptr::null_mut()), hdc_screen);

                Some(hicon)
            }
        } else {
            None
        };

        unsafe {
            let taskbar: ITaskbarList3 =
                CoCreateInstance(&TaskbarList, None, CLSCTX_INPROC_SERVER)
                    .map_err(|e| e.to_string())?;
            taskbar.HrInit().map_err(|e| e.to_string())?;
            taskbar
                .SetOverlayIcon(hwnd, hicon, PCWSTR::null())
                .map_err(|e| e.to_string())?;
            if let Some(icon) = hicon {
                let _ = DestroyIcon(icon);
            }
        }
    }
    Ok(())
}

pub fn run() {
    let port: u16 = 44548;
    let context = tauri::generate_context!();
    let builder = tauri::Builder::default();

    builder
        .invoke_handler(tauri::generate_handler![set_badge_count])
        .plugin(tauri_plugin_localhost::Builder::new(port).build())
        .plugin(tauri_plugin_window_state::Builder::default().build())
        .plugin(tauri_plugin_opener::init())
        .setup(move |app| {
            #[cfg(debug_assertions)]
            let window_url = WebviewUrl::App(Default::default());

            #[cfg(not(debug_assertions))]
            let window_url = {
                let url = format!("http://localhost:{}", port).parse().unwrap();
                WebviewUrl::External(url)
            };

            let app_handle = app.handle().clone();
            let window = WebviewWindowBuilder::new(app, "main".to_string(), window_url)
                .title("Lotus Chat")
                .disable_drag_drop_handler()
                .on_new_window(move |url, _features| {
                    let _ = app_handle.opener().open_url(url.as_str(), None::<&str>);
                    NewWindowResponse::Deny
                })
                .build()?;

            // Grant camera and microphone to WebView2 automatically.
            // Windows requires an explicit PermissionRequested COM event handler.
            #[cfg(target_os = "windows")]
            window.with_webview(|webview| {
                use webview2_com::{
                    Microsoft::Web::WebView2::Win32::{
                        COREWEBVIEW2_PERMISSION_KIND,
                        COREWEBVIEW2_PERMISSION_KIND_CAMERA,
                        COREWEBVIEW2_PERMISSION_KIND_MICROPHONE,
                        COREWEBVIEW2_PERMISSION_STATE_ALLOW,
                    },
                    PermissionRequestedEventHandler,
                };

                let controller = webview.controller();
                if let Ok(core) = unsafe { controller.CoreWebView2() } {
                    let handler = PermissionRequestedEventHandler::create(Box::new(
                        |_sender, args| {
                            if let Some(args) = args {
                                let mut kind = COREWEBVIEW2_PERMISSION_KIND(0);
                                unsafe { args.PermissionKind(&mut kind) }?;
                                if kind == COREWEBVIEW2_PERMISSION_KIND_MICROPHONE
                                    || kind == COREWEBVIEW2_PERMISSION_KIND_CAMERA
                                {
                                    unsafe {
                                        args.SetState(COREWEBVIEW2_PERMISSION_STATE_ALLOW)
                                    }?;
                                }
                            }
                            Ok(())
                        },
                    ));
                    let mut token = Default::default();
                    let _ = unsafe { core.add_PermissionRequested(&handler, &mut token) };
                }
            })?;

            Ok(())
        })
        .run(context)
        .expect("error while building tauri application");
}