import { settings } from "@lib/api/settings";
import { awaitStorage, createMMKVBackend, createStorage, purgeStorage, wrapSync } from "@lib/api/storage";
import { safeFetch } from "@lib/utils";
import { BUNNY_PROXY_PREFIX, VD_PROXY_PREFIX } from "@lib/utils/constants";
import { DiscordLogger, logger } from "@lib/utils/logger";
import { Author } from "@lib/utils/types";

type EvaledPlugin = {
    onLoad?(): void;
    onUnload(): void;
    settings: React.ComponentType<unknown>;
};

// See https://github.com/vendetta-mod/polymanifest
interface PluginManifest {
    name: string;
    description: string;
    authors: Author[];
    main: string;
    hash: string;
    // Vendor-specific field, contains our own data
    vendetta?: {
        icon?: string;
    };
}

export interface VendettaPlugin {
    id: string;
    manifest: PluginManifest;
    enabled: boolean;
    update: boolean;
    js: string;
}

const plugins = wrapSync(createStorage<Record<string, VendettaPlugin>>(createMMKVBackend("VENDETTA_PLUGINS")));
const pluginInstance: Record<string, EvaledPlugin> = {};

export const VdPluginManager = {
    plugins,
    async pluginFetch(url: string) {
        if (url.startsWith(VD_PROXY_PREFIX)) {
            url = url.replace(VD_PROXY_PREFIX, BUNNY_PROXY_PREFIX);
        }

        return await safeFetch(url, { cache: "no-store" });
    },

    async fetchPlugin(id: string) {
        if (!id.endsWith("/")) id += "/";
        const existingPlugin = plugins[id];

        let pluginManifest: PluginManifest;

        try {
            pluginManifest = await (await this.pluginFetch(id + "manifest.json")).json();
        } catch {
            throw new Error(`Failed to fetch manifest for ${id}`);
        }

        let pluginJs: string | undefined;

        if (existingPlugin?.manifest.hash !== pluginManifest.hash) {
            try {
            // by polymanifest spec, plugins should always specify their main file, but just in case
                pluginJs = await (await this.pluginFetch(id + (pluginManifest.main || "index.js"))).text();
            } catch { } // Empty catch, checked below
        }

        if (!pluginJs && !existingPlugin) throw new Error(`Failed to fetch JS for ${id}`);

        plugins[id] = {
            id: id,
            manifest: pluginManifest,
            enabled: existingPlugin?.enabled ?? false,
            update: existingPlugin?.update ?? true,
            js: pluginJs ?? existingPlugin.js,
        };
    },

    async installPlugin(id: string, enabled = true) {
        if (!id.endsWith("/")) id += "/";
        if (typeof id !== "string" || id in plugins) throw new Error("Plugin already installed");
        await this.fetchPlugin(id);
        if (enabled) await this.startPlugin(id);
    },

    /**
     * @internal
     */
    async evalPlugin(plugin: VendettaPlugin) {
        const vendettaForPlugins = {
            ...window.vendetta,
            plugin: {
                id: plugin.id,
                manifest: plugin.manifest,
                // Wrapping this with wrapSync is NOT an option.
                storage: await createStorage<Record<string, any>>(createMMKVBackend(plugin.id)),
            },
            logger: new DiscordLogger(`Bunny » ${plugin.manifest.name}`),
        };
        const pluginString = `vendetta=>{return ${plugin.js}}\n//# sourceURL=${plugin.id}`;

        const raw = (0, eval)(pluginString)(vendettaForPlugins);
        const ret = typeof raw === "function" ? raw() : raw;
        return ret?.default ?? ret ?? {};
    },

    async startPlugin(id: string) {
        if (!id.endsWith("/")) id += "/";
        const plugin = plugins[id];
        if (!plugin) throw new Error("Attempted to start non-existent plugin");

        try {
            if (!settings.safeMode?.enabled) {
                const pluginRet: EvaledPlugin = await this.evalPlugin(plugin);
                pluginInstance[id] = pluginRet;
                pluginRet.onLoad?.();
            }
            plugin.enabled = true;
        } catch (e) {
            logger.error(`Plugin ${plugin.id} errored whilst loading, and will be unloaded`, e);

            try {
                pluginInstance[plugin.id]?.onUnload?.();
            } catch (e2) {
                logger.error(`Plugin ${plugin.id} errored whilst unloading`, e2);
            }

            delete pluginInstance[id];
            plugin.enabled = false;
        }
    },

    stopPlugin(id: string, disable = true) {
        if (!id.endsWith("/")) id += "/";
        const plugin = plugins[id];
        const pluginRet = pluginInstance[id];
        if (!plugin) throw new Error("Attempted to stop non-existent plugin");

        if (!settings.safeMode?.enabled) {
            try {
                pluginRet?.onUnload?.();
            } catch (e) {
                logger.error(`Plugin ${plugin.id} errored whilst unloading`, e);
            }

            delete pluginInstance[id];
        }

        if (disable) plugin.enabled = false;
    },

    async removePlugin(id: string) {
        if (!id.endsWith("/")) id += "/";
        const plugin = plugins[id];
        if (plugin.enabled) this.stopPlugin(id);
        delete plugins[id];
        await purgeStorage(id);
    },

    /**
     * @internal
     */
    async initPlugins() {
        await awaitStorage(settings, plugins);
        const allIds = Object.keys(plugins);

        if (!settings.safeMode?.enabled) {
        // Loop over any plugin that is enabled, update it if allowed, then start it.
            await Promise.allSettled(allIds.filter(pl => plugins[pl].enabled).map(async pl => (plugins[pl].update && await this.fetchPlugin(pl).catch((e: Error) => logger.error(e.message)), await this.startPlugin(pl))));
            // Wait for the above to finish, then update all disabled plugins that are allowed to.
            allIds.filter(pl => !plugins[pl].enabled && plugins[pl].update).forEach(pl => this.fetchPlugin(pl));
        }

        return () => this.stopAllPlugins();
    },

    stopAllPlugins() {
        return Object.keys(pluginInstance).forEach(p => this.stopPlugin(p, false));
    },

    getSettings: (id: string) => pluginInstance[id]?.settings
};