import {EventEmitter} from 'node:events';

import {fs, logger, tempDir, util} from '@appium/support';
import type {AppiumServer} from '@appium/types';
import {getResponseForW3CError} from 'appium/driver.js';
import {BasePlugin} from 'appium/plugin.js';
import type {Express, Request, Response} from 'express';
import {LRUCache} from 'lru-cache';
import {WebSocketServer} from 'ws';
import type WebSocket from 'ws';

import {requireValidItemOptions, Storage, StorageArgumentError, validateStorageItemName} from './storage.js';
import type {AddRequestResult, ItemOptions, StorageItem} from './types.js';

const log = logger.getLogger('StoragePlugin');

// @appium/types is still CommonJS, so its `ws` Server type resolves through the "require"
// condition, while this ESM package resolves the same class through "import" — TypeScript
// treats them as structurally distinct even though they are identical at runtime.
// TODO: Remove this workaround once @appium/types is migrated to ESM.
type WSHandlerServer = Parameters<AppiumServer['addWebSocketHandler']>[1];

let SHARED_STORAGE: Storage | null = null;
const STORAGE_PREFIX = '/appium/storage';
/**
 * @deprecated Use `STORAGE_PREFIX` (`/appium/storage`) instead. This alias only exists for
 * backward compatibility and will be removed in a future version of the storage plugin.
 */
const DEPRECATED_STORAGE_PREFIX = '/storage';
const WS_TTL_MS = 5 * 60 * 1000;
const STORAGE_HANDLERS: Record<string, (req: Request, httpServer?: AppiumServer, basePath?: string) => Promise<any>> =
  {};
const deprecatedRoutesLogged: Set<string> = new Set();
const STORAGE_ADDITIONS_CACHE: LRUCache<string, () => any> = new LRUCache({
  max: 20,
  ttl: WS_TTL_MS,
  dispose: (f: () => any) => f(),
});

export class StoragePlugin extends BasePlugin {
  static async updateServer(expressApp: Express, httpServer: AppiumServer): Promise<void> {
    const buildHandler =
      (methodName: string, basePath: string, routePath: string, isDeprecated: boolean) =>
      async (req: Request, res: Response) => {
        if (isDeprecated && !deprecatedRoutesLogged.has(routePath)) {
          deprecatedRoutesLogged.add(routePath);
          log.warn(
            `The '${routePath}' endpoint has been deprecated and will be removed in a future version ` +
              `of the storage plugin. Please use ` +
              `'${routePath.replace(DEPRECATED_STORAGE_PREFIX, STORAGE_PREFIX)}' instead`,
          );
        }

        let status = 200;
        let body: any;
        try {
          const value = await STORAGE_HANDLERS[methodName](req, httpServer, basePath);
          body = {value: value ?? null};
        } catch (e) {
          [status, body] = getResponseForW3CError(e);
        }
        log.debug(
          'Responding to %s with %s',
          methodName,
          logger.markSensitive(util.truncateString(JSON.stringify(body.value), {length: 200})),
        );
        res.set('content-type', 'application/json; charset=utf-8');
        res.status(status).send(body);
      };

    for (const [basePath, isDeprecated] of [
      [STORAGE_PREFIX, false],
      [DEPRECATED_STORAGE_PREFIX, true],
    ] as const) {
      expressApp.post(
        `${basePath}/add`,
        buildHandler(STORAGE_HANDLERS.addStorageItem.name, basePath, `${basePath}/add`, isDeprecated),
      );
      expressApp.get(
        `${basePath}/list`,
        buildHandler(STORAGE_HANDLERS.listStorageItems.name, basePath, `${basePath}/list`, isDeprecated),
      );
      expressApp.post(
        `${basePath}/reset`,
        buildHandler(STORAGE_HANDLERS.resetStorage.name, basePath, `${basePath}/reset`, isDeprecated),
      );
      expressApp.post(
        `${basePath}/delete`,
        buildHandler(STORAGE_HANDLERS.deleteStorageItem.name, basePath, `${basePath}/delete`, isDeprecated),
      );
    }
  }
}

STORAGE_HANDLERS.addStorageItem = async function addStorageItem(
  req: Request,
  httpServer?: AppiumServer,
  basePath: string = STORAGE_PREFIX,
): Promise<AddRequestResult> {
  if (!httpServer) {
    throw new Error('httpServer is required to add a storage item');
  }
  const itemOptions = requireValidItemOptions(parseRequestArgs(req, ['name', 'sha1']) as ItemOptions);
  const [stream, events] = await prepareWebSockets(httpServer, itemOptions, basePath);
  return {
    ws: {
      stream,
      events,
    },
    ttlMs: WS_TTL_MS,
  };
};

STORAGE_HANDLERS.listStorageItems = async function listStorageItems(): Promise<StorageItem[]> {
  return await executeStorageMethod(async (storage: Storage) => await storage.list());
};

STORAGE_HANDLERS.deleteStorageItem = async function deleteStorageItem(req: Request): Promise<boolean> {
  let name: string;
  try {
    name = parseRequestArgs(req, ['name']).name;
    validateStorageItemName(name);
  } catch (e) {
    log.error(`Failed to parse the request body for deleting a storage item: ${(e as Error).message}`);
    return false;
  }
  return await executeStorageMethod(async (storage: Storage) => await storage.delete(name));
};

STORAGE_HANDLERS.resetStorage = async function resetStorage(): Promise<void> {
  await executeStorageMethod(async (storage: Storage) => await storage.reset());
};

async function executeStorageMethod<T>(method: (storage: Storage) => Promise<T>): Promise<T> {
  const storage = await getStorageSingleton();
  return await method(storage);
}

function parseRequestArgs(req: Request, requiredKeys: string[]): Record<string, any> {
  if (!util.isPlainObject(req.body)) {
    throw new StorageArgumentError(`The request body must be a valid JSON object`);
  }
  for (const key of requiredKeys) {
    if (!Object.hasOwn(req.body, key)) {
      throw new StorageArgumentError(
        `The required argument '${key}' is missing (expected ${JSON.stringify(requiredKeys)})`,
      );
    }
  }
  return req.body;
}

async function prepareWebSockets(
  httpServer: AppiumServer,
  itemOptions: ItemOptions,
  basePath: string,
): Promise<[string, string]> {
  const commonPathname = `${basePath}/add/${itemOptions.sha1}`;
  const streamPathname = `${commonPathname}/stream`;
  const eventsPathname = `${commonPathname}/events`;
  if (!util.isEmpty(httpServer.getWebSocketHandlers(streamPathname))) {
    return [streamPathname, eventsPathname];
  }

  const streamServer = new WebSocketServer({
    noServer: true,
  });
  const eventsServer = new WebSocketServer({
    noServer: true,
  });
  const signaler = new EventEmitter();
  const streamDoneCallback = () => {
    log.debug(`Unmounting stream and events web sockets at ${commonPathname}`);
    void httpServer.removeWebSocketHandler(streamPathname);
    void httpServer.removeWebSocketHandler(eventsPathname);
    setTimeout(() => {
      streamServer.close();
      eventsServer.close();
      signaler.removeAllListeners();
    }, 100);
  };
  STORAGE_ADDITIONS_CACHE.set(itemOptions.sha1, streamDoneCallback);
  eventsServer.on('connection', async (wsUpstream: WebSocket) => {
    signaler.on('status', (value) => wsUpstream.send(JSON.stringify(value)));
  });
  eventsServer.on('error', (e) => {
    log.info(`The ${eventsPathname} web socket server has notified about an error: ${e.message}`);
  });
  streamServer.on('connection', async (wsUpstream: WebSocket) => {
    log.info(`Starting a new server storage upload of '${itemOptions.name}' at ${streamPathname}`);
    const storage = await getStorageSingleton();
    try {
      await storage.add(itemOptions, wsUpstream);
      const successEvent = {
        value: {
          success: true,
          ...itemOptions,
        },
      };
      log.debug(`Notifying about the successful addition of '${itemOptions.name}' to the server storage`);
      signaler.emit('status', successEvent);
      STORAGE_ADDITIONS_CACHE.delete(itemOptions.sha1);
    } catch (e) {
      log.debug(`Notifying about a failure while adding '${itemOptions.name}' to the server storage`);
      // in case of a failure we do not want to close the server yet
      // in anticipation of a retry
      log.error(e);
      const [, errorBody] = getResponseForW3CError(e);
      signaler.emit('status', errorBody);
    }
  });
  streamServer.on('error', (e) => {
    log.info(`The ${streamPathname} web socket server has notified about an error: ${e.message}`);
  });
  await Promise.all([
    httpServer.addWebSocketHandler(streamPathname, streamServer as unknown as WSHandlerServer),
    httpServer.addWebSocketHandler(eventsPathname, eventsServer as unknown as WSHandlerServer),
  ]);

  return [streamPathname, eventsPathname];
}

const getStorageSingleton = util.memoize(async () => {
  let storageRoot: string;
  let shouldPreserveRoot = false;
  let shouldPreserveFiles = false;
  if (process.env.APPIUM_STORAGE_ROOT) {
    storageRoot = process.env.APPIUM_STORAGE_ROOT;
    shouldPreserveRoot = shouldPreserveFiles = await fs.exists(storageRoot);
    log.info(`Set '${storageRoot}' as the server storage root folder`);
  } else {
    storageRoot = await tempDir.openDir();
    log.info(`Created '${storageRoot}' as the temporary server storage root folder`);
  }
  if (process.env.APPIUM_STORAGE_KEEP_ALL) {
    shouldPreserveFiles = ['true', '1', 'yes'].includes((process.env.APPIUM_STORAGE_KEEP_ALL ?? '').toLowerCase());
  }
  if (shouldPreserveFiles) {
    log.info(`All server storage items will be always preserved unless deleted explicitly`);
  } else {
    log.info(
      `All server storage items will be cleaned up automatically from '${storageRoot}' after ` +
        `Appium server termination`,
    );
  }
  SHARED_STORAGE = new Storage(storageRoot, shouldPreserveRoot, shouldPreserveFiles, log);
  await SHARED_STORAGE.reset();
  return SHARED_STORAGE;
});

process.once('exit', () => {
  SHARED_STORAGE?.cleanupSync();
});

export default StoragePlugin;