import { AppPlatform, AppService, ToastType } from '@/types/system';

import { SystemSettings } from '@/types/settings';
import { FileSystem, BaseDir } from '@/types/system';
import { Book, BookConfig, BookContent, BookFormat } from '@/types/book';
import {
  getDir,
  getFilename,
  getBaseFilename,
  getCoverFilename,
  getConfigFilename,
  getLibraryFilename,
  INIT_BOOK_CONFIG,
  formatTitle,
  formatAuthors,
} from '@/utils/book';
import { RemoteFile } from '@/utils/file';
import { partialMD5 } from '@/utils/md5';
import { BookDoc, DocumentLoader } from '@/libs/document';
import {
  DEFAULT_BOOK_LAYOUT,
  DEFAULT_BOOK_STYLE,
  DEFAULT_BOOK_FONT,
  DEFAULT_VIEW_CONFIG,
  DEFAULT_READSETTINGS,
  SYSTEM_SETTINGS_VERSION,
  DEFAULT_BOOK_SEARCH_CONFIG,
  DEFAULT_TTS_CONFIG,
  CLOUD_BOOKS_SUBDIR,
} from './constants';
import { isValidURL } from '@/utils/misc';
import { deserializeConfig, serializeConfig } from '@/utils/serializer';
import { downloadFile, uploadFile, deleteFile } from '@/libs/storage';

export abstract class BaseAppService implements AppService {
  localBooksDir: string = '';
  abstract fs: FileSystem;
  abstract appPlatform: AppPlatform;
  abstract isAppDataSandbox: boolean;
  abstract hasTrafficLight: boolean;
  abstract hasWindowBar: boolean;

  abstract resolvePath(fp: string, base: BaseDir): { baseDir: number; base: BaseDir; fp: string };
  abstract getCoverImageUrl(book: Book): string;
  abstract getCoverImageBlobUrl(book: Book): Promise<string>;
  abstract getInitBooksDir(): Promise<string>;
  abstract selectFiles(name: string, extensions: string[]): Promise<string[]>;
  abstract showMessage(
    msg: string,
    kind?: ToastType,
    title?: string,
    okLabel?: string,
  ): Promise<void>;

  async loadSettings(): Promise<SystemSettings> {
    let settings: SystemSettings;
    const { fp, base } = this.resolvePath('settings.json', 'Settings');

    try {
      await this.fs.exists(fp, base);
      const txt = await this.fs.readFile(fp, base, 'text');
      settings = JSON.parse(txt as string);
      const version = settings.version ?? 0;
      if (this.isAppDataSandbox || version < SYSTEM_SETTINGS_VERSION) {
        settings.localBooksDir = await this.getInitBooksDir();
        settings.version = SYSTEM_SETTINGS_VERSION;
      }
      settings.globalReadSettings = { ...DEFAULT_READSETTINGS, ...settings.globalReadSettings };
      settings.globalViewSettings = {
        ...DEFAULT_BOOK_LAYOUT,
        ...DEFAULT_BOOK_STYLE,
        ...DEFAULT_BOOK_FONT,
        ...DEFAULT_VIEW_CONFIG,
        ...DEFAULT_TTS_CONFIG,
        ...settings.globalViewSettings,
      };
    } catch {
      settings = {
        version: SYSTEM_SETTINGS_VERSION,
        localBooksDir: await this.getInitBooksDir(),
        lastSyncedAtBooks: 0,
        lastSyncedAtConfigs: 0,
        lastSyncedAtNotes: 0,
        keepLogin: false,
        autoUpload: false,
        globalReadSettings: DEFAULT_READSETTINGS,
        globalViewSettings: {
          ...DEFAULT_BOOK_LAYOUT,
          ...DEFAULT_BOOK_STYLE,
          ...DEFAULT_BOOK_FONT,
          ...DEFAULT_VIEW_CONFIG,
          ...DEFAULT_TTS_CONFIG,
        },
      };

      await this.fs.createDir('', 'Books', true);
      await this.fs.createDir('', base, true);
      await this.fs.writeFile(fp, base, JSON.stringify(settings));
    }

    this.localBooksDir = settings.localBooksDir;
    return settings;
  }

  async saveSettings(settings: SystemSettings): Promise<void> {
    const { fp, base } = this.resolvePath('settings.json', 'Settings');
    await this.fs.createDir('', base, true);
    await this.fs.writeFile(fp, base, JSON.stringify(settings));
  }

  async importBook(
    file: string | File,
    books: Book[],
    saveBook: boolean = true,
    saveCover: boolean = true,
    overwrite: boolean = false,
  ): Promise<Book | null> {
    try {
      let loadedBook: BookDoc;
      let format: BookFormat;
      let filename: string;
      let fileobj: File;

      try {
        if (typeof file === 'string') {
          filename = file;
          fileobj = await new RemoteFile(this.fs.getURL(file), file).open();
        } else {
          filename = file.name;
          fileobj = file;
        }
        ({ book: loadedBook, format } = await new DocumentLoader(fileobj).open());
        if (!loadedBook.metadata.title) {
          loadedBook.metadata.title = getBaseFilename(filename);
        }
      } catch (error) {
        console.error(error);
        throw new Error(`Failed to open the book: ${(error as Error).message || error}`);
      }

      const hash = await partialMD5(fileobj);
      const existingBook = books.filter((b) => b.hash === hash)[0];
      if (existingBook) {
        if (existingBook.deletedAt) {
          existingBook.deletedAt = null;
        }
        existingBook.updatedAt = Date.now();
      }

      const book: Book = {
        hash,
        format,
        title: formatTitle(loadedBook.metadata.title),
        author: formatAuthors(loadedBook.metadata.language, loadedBook.metadata.author),
        createdAt: existingBook ? existingBook.createdAt : Date.now(),
        uploadedAt: existingBook ? existingBook.uploadedAt : null,
        downloadedAt: Date.now(),
        updatedAt: Date.now(),
      };
      if (!(await this.fs.exists(getDir(book), 'Books'))) {
        await this.fs.createDir(getDir(book), 'Books');
      }
      if (saveBook && (!(await this.fs.exists(getFilename(book), 'Books')) || overwrite)) {
        if (typeof file === 'string' && !isValidURL(file)) {
          await this.fs.copyFile(file, getFilename(book), 'Books');
        } else {
          await this.fs.writeFile(getFilename(book), 'Books', await fileobj.arrayBuffer());
        }
      }
      if (saveCover && (!(await this.fs.exists(getCoverFilename(book), 'Books')) || overwrite)) {
        const cover = await loadedBook.getCover();
        if (cover) {
          await this.fs.writeFile(getCoverFilename(book), 'Books', await cover.arrayBuffer());
        }
      }
      // Never overwrite the config file only when it's not existed
      if (!existingBook) {
        await this.saveBookConfig(book, INIT_BOOK_CONFIG);
        books.splice(0, 0, book);
      }

      if (typeof file === 'string' && isValidURL(file)) {
        book.url = file;
      }
      book.coverImageUrl = await this.generateCoverImageUrl(book);

      return book;
    } catch (error) {
      throw error;
    }
  }

  async deleteBook(book: Book, includingUploaded = false): Promise<void> {
    for (const fp of [getFilename(book), getCoverFilename(book)]) {
      if (await this.fs.exists(fp, 'Books')) {
        await this.fs.removeFile(fp, 'Books');
      }
      if (includingUploaded) {
        console.log('Deleting uploaded file:', fp);
        const cfp = `${CLOUD_BOOKS_SUBDIR}/${fp}`;
        await deleteFile(cfp);
      }
    }
  }

  async uploadBook(book: Book): Promise<void> {
    let file: File;
    let uploaded = false;
    for (const fp of [getFilename(book), getCoverFilename(book)]) {
      if (await this.fs.exists(fp, 'Books')) {
        const cfp = `${CLOUD_BOOKS_SUBDIR}/${fp}`;
        if (this.appPlatform === 'web') {
          const content = await this.fs.readFile(fp, 'Books', 'binary');
          file = new File([content], cfp);
        } else {
          file = await new RemoteFile(this.fs.getURL(`${this.localBooksDir}/${fp}`), cfp).open();
        }
        console.log('Uploading file:', fp);
        await uploadFile(file, book.hash);
        uploaded = true;
      }
    }
    if (uploaded) {
      book.updatedAt = Date.now();
      book.uploadedAt = Date.now();
      book.downloadedAt = Date.now();
    } else {
      throw new Error('Book file not uploaded');
    }
  }

  async downloadBook(book: Book, onlyCover = false): Promise<void> {
    const bookFp = getFilename(book);
    const coverFp = getCoverFilename(book);
    const fps = [coverFp];
    if (!onlyCover) {
      fps.push(bookFp);
    }

    let bookDownloaded = false;
    for (const fp of fps) {
      let downloaded = false;
      const existed = await this.fs.exists(fp, 'Books');
      if (existed) {
        downloaded = true;
      } else {
        console.log('Downloading file:', fp);
        const cfp = `${CLOUD_BOOKS_SUBDIR}/${fp}`;
        const fileobj = (await downloadFile(cfp)) as Blob;
        await this.fs.writeFile(fp, 'Books', await fileobj.arrayBuffer());
        downloaded = true;
      }
      if (fp === bookFp) {
        bookDownloaded = downloaded;
      }
    }
    // some books may not have cover image, so we need to check if the book is downloaded
    if (bookDownloaded) {
      book.downloadedAt = Date.now();
    }
  }

  async loadBookContent(book: Book, settings: SystemSettings): Promise<BookContent> {
    let file: File;
    const fp = getFilename(book);
    if (await this.fs.exists(fp, 'Books')) {
      if (this.appPlatform === 'web') {
        const content = await this.fs.readFile(fp, 'Books', 'binary');
        file = new File([content], fp);
      } else {
        file = await new RemoteFile(this.fs.getURL(`${this.localBooksDir}/${fp}`), fp).open();
      }
    } else if (book.url) {
      file = await new RemoteFile(book.url).open();
    } else {
      throw new Error('Book file not found');
    }
    return { book, file, config: await this.loadBookConfig(book, settings) };
  }

  async loadBookConfig(book: Book, settings: SystemSettings): Promise<BookConfig> {
    const { globalViewSettings } = settings;
    try {
      let str = '{}';
      if (await this.fs.exists(getConfigFilename(book), 'Books')) {
        str = (await this.fs.readFile(getConfigFilename(book), 'Books', 'text')) as string;
      }
      return deserializeConfig(str, globalViewSettings, DEFAULT_BOOK_SEARCH_CONFIG);
    } catch {
      return deserializeConfig('{}', globalViewSettings, DEFAULT_BOOK_SEARCH_CONFIG);
    }
  }

  async fetchBookDetails(book: Book, settings: SystemSettings) {
    const { file } = (await this.loadBookContent(book, settings)) as BookContent;
    const bookDoc = (await new DocumentLoader(file).open()).book as BookDoc;
    return bookDoc.metadata;
  }

  async saveBookConfig(book: Book, config: BookConfig, settings?: SystemSettings) {
    let serializedConfig: string;
    if (settings) {
      const { globalViewSettings } = settings;
      serializedConfig = serializeConfig(config, globalViewSettings, DEFAULT_BOOK_SEARCH_CONFIG);
    } else {
      serializedConfig = JSON.stringify(config);
    }
    await this.fs.writeFile(getConfigFilename(book), 'Books', serializedConfig);
  }

  async generateCoverImageUrl(book: Book): Promise<string> {
    return this.appPlatform === 'web'
      ? await this.getCoverImageBlobUrl(book)
      : this.getCoverImageUrl(book);
  }

  async loadLibraryBooks(): Promise<Book[]> {
    console.log('Loading library books...');
    let books: Book[] = [];
    const libraryFilename = getLibraryFilename();

    try {
      const txt = await this.fs.readFile(libraryFilename, 'Books', 'text');
      books = JSON.parse(txt as string);
    } catch {
      await this.fs.createDir('', 'Books', true);
      await this.fs.writeFile(libraryFilename, 'Books', '[]');
    }

    await Promise.all(
      books.map(async (book) => {
        book.coverImageUrl = await this.generateCoverImageUrl(book);
        book.updatedAt ??= book.lastUpdated || Date.now();
        return book;
      }),
    );

    return books;
  }

  async saveLibraryBooks(books: Book[]): Promise<void> {
    // eslint-disable-next-line @typescript-eslint/no-unused-vars
    const libraryBooks = books.map(({ coverImageUrl, ...rest }) => rest);
    await this.fs.writeFile(getLibraryFilename(), 'Books', JSON.stringify(libraryBooks));
  }
}