import { execAsync, Gio, GLib, GObject, monitorFile, property, register } from "astal";

export { Wallpaper };

@register({ GTypeName: "Wallpaper" })
class Wallpaper extends GObject.Object {
    private static instance: Wallpaper;
    #wallpaper: (string|undefined);
    #splash: boolean = true;
    #monitor: Gio.FileMonitor;
    #hyprpaperFile: Gio.File;
    #wallpapersPath: string;

    @property(Boolean)
    public get splash() { return this.#splash; }
    public set splash(showSplash: boolean) {
        this.#splash = showSplash;
        this.notify("splash");

        this.writeChanges();
    }

    @property(String)
    public get wallpaper(): (string|undefined) { return this.#wallpaper; }
    public set wallpaper(newValue: string) { this.setWallpaper(newValue); }

    public get wallpapersPath() { return this.#wallpapersPath; }

    constructor() {
        super();
        this.#wallpapersPath = GLib.getenv("WALLPAPERS") ?? `${GLib.get_home_dir()}/wallpapers`;
        this.#hyprpaperFile = Gio.File.new_for_path(`${GLib.get_user_config_dir()}/hypr/hyprpaper.conf`);
        this.getWallpaper().then((wall) => this.#wallpaper = wall).catch(r => {
            throw new Error(`Wallpaper: Couldn't get wallpaper. Stderr: ${r}`)
        });

        this.#monitor = monitorFile(this.#hyprpaperFile.get_path()!, async (_, event) => {
            if(event == Gio.FileMonitorEvent.CHANGED) {
                const [loaded, , content ] = this.#hyprpaperFile.load_contents(null);
                if(loaded) 
                    for(const line of content.split('\n')) {
                        const [ key, value ] = line.split('=');
                        if(key.trim().startsWith('#'))
                            continue;

                        switch(key) {
                            case "splash": 
                                this.#splash = /(yes|true|on)/.test(value.trim()) ? true : false;
                                break;

                            case "wallpaper":
                                this.#wallpaper = value;
                                break;
                        }
                    };
            }
        });
    }

    vfunc_dispose(): void {
        this.#monitor.cancel();
    }

    public static getDefault(): Wallpaper {
        if(!this.instance)
            this.instance = new Wallpaper();

        return this.instance;
    }

    private async writeChanges(): Promise<void> {
        if(!this.#wallpaper) return;

        const hyprpaperFile = Gio.File.new_for_path(`${GLib.get_user_config_dir()}/hypr/hyprpaper.conf`);
        hyprpaperFile.create(Gio.FileCreateFlags.REPLACE_DESTINATION, null);
        return hyprpaperFile.replace_contents_async(`# This file is automatically generated when choosing a new wallpaper in colorshell
            preload = ${this.#wallpaper}
            splash = ${this.#splash}
            wallpaper = , ${this.#wallpaper}`.split('\n').map(str => str.trimStart()).join('\n'), null, false, 
            Gio.FileCreateFlags.REPLACE_DESTINATION, null
        ).then(() => {}).catch(r => {
            throw new Error(`Wallpaper: Couldn't write hyprpaper file. Stderr: ${r}`);
        });
    }

    public async getWallpaper(): Promise<string|undefined> {
        return await execAsync("hyprctl hyprpaper listactive | tail -n 1").then(stdout => {
            const loaded: (string|undefined) = stdout.split('=')[1]?.trim();
            if(!loaded) 
                throw new Error(`Wallpaper: Couldn't get wallpaper. There are no loaded wallpaper(s)`);

            return loaded;
        }).catch(stderr => {
            throw new Error(`Wallpaper: Couldn't get wallpaper. Stderr: ${stderr}`);
        });
    }

    public async reloadColors(): Promise<void> {
        return await execAsync(`wal -t --cols16 darken -i "${this.#wallpaper}"`).then(() => {
        }).catch(r => {
            throw new Error(`Wallpaper: Couldn't update shell colors. Stderr: ${r}`);
        });
    }

    public async setWallpaper(path: string|Gio.File): Promise<void> {
        return await execAsync("hyprctl hyprpaper unload all").then(async () => 
            await execAsync(`hyprctl hyprpaper preload ${path}`).then(async () => 
                await execAsync(`hyprctl hyprpaper wallpaper ${path}`).then(async () => {
                    this.#wallpaper = (typeof path === "string") ? path : path.get_path()!;
                    this.reloadColors();
                    this.writeChanges().catch(r => {
                        throw new Error(`Wallpaper: Couldn't write changes to hyprpaper config file. Stderr: ${r}`);
                    });
                }).catch(r => {
                    throw new Error(`Wallpaper: Couldn't set wallpaper. Stderr: ${r}`);
                })
            ).catch(r => {
                throw new Error(`Wallpaper: Couldn't preload image. Stderr: ${r}`);
            })
        ).catch(r => {
            throw new Error(`Wallpaper: Couldn't unload images from memory. Stderr: ${r}`);
        });
    }

    public async pickWallpaper(): Promise<string|undefined> {
        return execAsync(`zenity --file-selection`).then(wall => {
            if(!wall.trim()) return undefined;

            this.setWallpaper(wall).catch(r => {
                throw new Error(`Wallpaper: An error occurred in \`setWallpaper()\`. Stderr: ${r}`);
            });
            return wall;
        }).catch(r => {
            throw new Error(`Wallpaper: Couldn't pick wallpaper, is zenity installed? Stderr: ${r}`);
        });
    }
}