/*
 * Vencord, a modification for Discord's desktop app
 * Copyright (c) 2022 Vendicated and contributors
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/

import { registerCommand, unregisterCommand } from "@api/Commands";
import { addContextMenuPatch, removeContextMenuPatch } from "@api/ContextMenu";
import { Settings } from "@api/Settings";
import { Logger } from "@utils/Logger";
import { canonicalizeFind } from "@utils/patches";
import { Patch, Plugin, StartAt } from "@utils/types";
import { FluxDispatcher } from "@webpack/common";
import { FluxEvents } from "@webpack/types";

import Plugins from "~plugins";

import { traceFunction } from "../debug/Tracer";

const logger = new Logger("PluginManager", "#a6d189");

export const PMLogger = logger;
export const plugins = Plugins;
export const patches = [] as Patch[];

/** Whether we have subscribed to flux events of all the enabled plugins when FluxDispatcher was ready */
let enabledPluginsSubscribedFlux = false;
const subscribedFluxEventsPlugins = new Set<string>();

const settings = Settings.plugins;

export function isPluginEnabled(p: string) {
    return (
        Plugins[p]?.required ||
        Plugins[p]?.isDependency ||
        settings[p]?.enabled
    ) ?? false;
}

const pluginsValues = Object.values(Plugins);

// First roundtrip to mark and force enable dependencies (only for enabled plugins)
//
// FIXME: might need to revisit this if there's ever nested (dependencies of dependencies) dependencies since this only
// goes for the top level and their children, but for now this works okay with the current API plugins
for (const p of pluginsValues) if (settings[p.name]?.enabled) {
    p.dependencies?.forEach(d => {
        const dep = Plugins[d];
        if (dep) {
            settings[d].enabled = true;
            dep.isDependency = true;
        }
        else {
            const error = new Error(`Plugin ${p.name} has unresolved dependency ${d}`);
            if (IS_DEV)
                throw error;
            logger.warn(error);
        }
    });
}

for (const p of pluginsValues) {
    if (p.settings) {
        p.settings.pluginName = p.name;
        p.options ??= {};
        for (const [name, def] of Object.entries(p.settings.def)) {
            const checks = p.settings.checks?.[name];
            p.options[name] = { ...def, ...checks };
        }
    }

    if (p.patches && isPluginEnabled(p.name)) {
        for (const patch of p.patches) {
            patch.plugin = p.name;

            canonicalizeFind(patch);
            if (!Array.isArray(patch.replacement)) {
                patch.replacement = [patch.replacement];
            }

            patches.push(patch);
        }
    }
}

export const startAllPlugins = traceFunction("startAllPlugins", function startAllPlugins(target: StartAt) {
    logger.info(`Starting plugins (stage ${target})`);
    for (const name in Plugins)
        if (isPluginEnabled(name)) {
            const p = Plugins[name];

            const startAt = p.startAt ?? StartAt.WebpackReady;
            if (startAt !== target) continue;

            startPlugin(Plugins[name]);
        }
});

export function startDependenciesRecursive(p: Plugin) {
    let restartNeeded = false;
    const failures: string[] = [];
    p.dependencies?.forEach(dep => {
        if (!Settings.plugins[dep].enabled) {
            startDependenciesRecursive(Plugins[dep]);
            // If the plugin has patches, don't start the plugin, just enable it.
            Settings.plugins[dep].enabled = true;
            if (Plugins[dep].patches) {
                logger.warn(`Enabling dependency ${dep} requires restart.`);
                restartNeeded = true;
                return;
            }
            const result = startPlugin(Plugins[dep]);
            if (!result) failures.push(dep);
        }
    });
    return { restartNeeded, failures };
}

export function subscribePluginFluxEvents(p: Plugin, fluxDispatcher: typeof FluxDispatcher) {
    if (p.flux && !subscribedFluxEventsPlugins.has(p.name)) {
        subscribedFluxEventsPlugins.add(p.name);

        logger.debug("Subscribing to flux events of plugin", p.name);
        for (const [event, handler] of Object.entries(p.flux)) {
            fluxDispatcher.subscribe(event as FluxEvents, handler);
        }
    }
}

export function unsubscribePluginFluxEvents(p: Plugin, fluxDispatcher: typeof FluxDispatcher) {
    if (p.flux) {
        subscribedFluxEventsPlugins.delete(p.name);

        logger.debug("Unsubscribing from flux events of plugin", p.name);
        for (const [event, handler] of Object.entries(p.flux)) {
            fluxDispatcher.unsubscribe(event as FluxEvents, handler);
        }
    }
}

export function subscribeAllPluginsFluxEvents(fluxDispatcher: typeof FluxDispatcher) {
    enabledPluginsSubscribedFlux = true;

    for (const name in Plugins) {
        if (!isPluginEnabled(name)) continue;
        subscribePluginFluxEvents(Plugins[name], fluxDispatcher);
    }
}

export const startPlugin = traceFunction("startPlugin", function startPlugin(p: Plugin) {
    const { name, commands, flux, contextMenus } = p;

    if (p.start) {
        logger.info("Starting plugin", name);
        if (p.started) {
            logger.warn(`${name} already started`);
            return false;
        }
        try {
            p.start();
        } catch (e) {
            logger.error(`Failed to start ${name}\n`, e);
            return false;
        }
    }

    p.started = true;

    if (commands?.length) {
        logger.debug("Registering commands of plugin", name);
        for (const cmd of commands) {
            try {
                registerCommand(cmd, name);
            } catch (e) {
                logger.error(`Failed to register command ${cmd.name}\n`, e);
                return false;
            }
        }
    }

    if (enabledPluginsSubscribedFlux) {
        subscribePluginFluxEvents(p, FluxDispatcher);
    }


    if (contextMenus) {
        logger.debug("Adding context menus patches of plugin", name);
        for (const navId in contextMenus) {
            addContextMenuPatch(navId, contextMenus[navId]);
        }
    }

    return true;
}, p => `startPlugin ${p.name}`);

export const stopPlugin = traceFunction("stopPlugin", function stopPlugin(p: Plugin) {
    const { name, commands, flux, contextMenus } = p;

    if (p.stop) {
        logger.info("Stopping plugin", name);
        if (!p.started) {
            logger.warn(`${name} already stopped`);
            return false;
        }
        try {
            p.stop();
        } catch (e) {
            logger.error(`Failed to stop ${name}\n`, e);
            return false;
        }
    }

    p.started = false;

    if (commands?.length) {
        logger.debug("Unregistering commands of plugin", name);
        for (const cmd of commands) {
            try {
                unregisterCommand(cmd.name);
            } catch (e) {
                logger.error(`Failed to unregister command ${cmd.name}\n`, e);
                return false;
            }
        }
    }

    unsubscribePluginFluxEvents(p, FluxDispatcher);

    if (contextMenus) {
        logger.debug("Removing context menus patches of plugin", name);
        for (const navId in contextMenus) {
            removeContextMenuPatch(navId, contextMenus[navId]);
        }
    }

    return true;
}, p => `stopPlugin ${p.name}`);