/*
 * Copyright (C) 2012 Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

import type * as Common from '../../core/common/common.js';
import type * as Platform from '../../core/platform/platform.js';
import * as Workspace from '../workspace/workspace.js';

export interface ChunkedReader {
  fileSize(): number;

  loadedSize(): number;

  fileName(): string;

  cancel(): void;

  error(): DOMError|null;
}
interface DecompressionStream extends GenericTransformStream {
  readonly format: string;
}
declare const DecompressionStream: {
  prototype: DecompressionStream,
  new (format: string): DecompressionStream,
};

export class ChunkedFileReader implements ChunkedReader {
  #file: File|null;
  readonly #fileSizeInternal: number;
  #loadedSizeInternal: number;
  #streamReader: ReadableStreamDefaultReader<Uint8Array<ArrayBuffer>>|null;
  readonly #chunkSize: number;
  readonly #chunkTransferredCallback: ((arg0: ChunkedReader) => void)|undefined;
  readonly #decoder: TextDecoder;
  #isCanceled: boolean;
  #errorInternal: DOMException|null;
  #transferFinished!: (arg0: boolean) => void;
  #output?: Common.StringOutputStream.OutputStream;
  #reader?: FileReader|null;

  constructor(file: File, chunkSize?: number, chunkTransferredCallback?: ((arg0: ChunkedReader) => void)) {
    this.#file = file;
    this.#fileSizeInternal = file.size;
    this.#loadedSizeInternal = 0;
    this.#chunkSize = (chunkSize) ? chunkSize : Number.MAX_VALUE;
    this.#chunkTransferredCallback = chunkTransferredCallback;
    this.#decoder = new TextDecoder();
    this.#isCanceled = false;
    this.#errorInternal = null;
    this.#streamReader = null;
  }

  async read(output: Common.StringOutputStream.OutputStream): Promise<boolean> {
    if (this.#chunkTransferredCallback) {
      this.#chunkTransferredCallback(this);
    }

    if (this.#file?.type.endsWith('gzip')) {
      // TypeScript can't tell if to use @types/node or lib.webworker.d.ts
      // types, so we force it to here.
      // crbug.com/1392092
      const fileStream = this.#file.stream() as unknown as ReadableStream<Uint8Array>;
      const stream = this.decompressStream(fileStream);
      this.#streamReader = stream.getReader();
    } else {
      this.#reader = new FileReader();
      this.#reader.onload = this.onChunkLoaded.bind(this);
      this.#reader.onerror = this.onError.bind(this);
    }

    this.#output = output;
    void this.loadChunk();

    return new Promise(resolve => {
      this.#transferFinished = resolve;
    });
  }

  cancel(): void {
    this.#isCanceled = true;
  }

  loadedSize(): number {
    return this.#loadedSizeInternal;
  }

  fileSize(): number {
    return this.#fileSizeInternal;
  }

  fileName(): string {
    if (!this.#file) {
      return '';
    }
    return this.#file.name;
  }

  error(): DOMException|null {
    return this.#errorInternal;
  }

  // Decompress gzip natively thanks to https://wicg.github.io/compression/
  private decompressStream(stream: ReadableStream): ReadableStream {
    const ds = new DecompressionStream('gzip');
    const decompressionStream = stream.pipeThrough(ds);
    return decompressionStream;
  }

  private onChunkLoaded(event: Event): void {
    if (this.#isCanceled) {
      return;
    }

    const eventTarget = (event.target as FileReader);
    if (eventTarget.readyState !== FileReader.DONE) {
      return;
    }

    if (!this.#reader) {
      return;
    }

    const buffer = (this.#reader.result as ArrayBuffer);
    this.#loadedSizeInternal += buffer.byteLength;
    const endOfFile = this.#loadedSizeInternal === this.#fileSizeInternal;
    void this.decodeChunkBuffer(buffer, endOfFile);
  }

  private async decodeChunkBuffer(buffer: ArrayBuffer, endOfFile: boolean): Promise<void> {
    if (!this.#output) {
      return;
    }
    const decodedString = this.#decoder.decode(buffer, {stream: !endOfFile});
    await this.#output.write(decodedString, endOfFile);
    if (this.#isCanceled) {
      return;
    }
    if (this.#chunkTransferredCallback) {
      this.#chunkTransferredCallback(this);
    }

    if (endOfFile) {
      void this.finishRead();
      return;
    }
    void this.loadChunk();
  }

  private async finishRead(): Promise<void> {
    if (!this.#output) {
      return;
    }
    this.#file = null;
    this.#reader = null;
    await this.#output.close();
    this.#transferFinished(!this.#errorInternal);
  }

  private async loadChunk(): Promise<void> {
    if (!this.#output || !this.#file) {
      return;
    }
    if (this.#streamReader) {
      const {value, done} = await this.#streamReader.read();
      if (done || !value) {
        // Write empty string to inform of file end
        await this.#output.write('', true);
        return this.finishRead();
      }
      void this.decodeChunkBuffer(value.buffer, false);
    }
    if (this.#reader) {
      const chunkStart = this.#loadedSizeInternal;
      const chunkEnd = Math.min(this.#fileSizeInternal, chunkStart + this.#chunkSize);
      const nextPart = this.#file.slice(chunkStart, chunkEnd);
      this.#reader.readAsArrayBuffer(nextPart);
    }
  }

  private onError(event: Event): void {
    const eventTarget = (event.target as FileReader);
    this.#errorInternal = eventTarget.error;
    this.#transferFinished(false);
  }
}

export class FileOutputStream implements Common.StringOutputStream.OutputStream {
  #writeCallbacks: (() => void)[];
  #fileName!: Platform.DevToolsPath.RawPathString|Platform.DevToolsPath.UrlString;
  #closed?: boolean;
  constructor() {
    this.#writeCallbacks = [];
  }

  async open(fileName: Platform.DevToolsPath.RawPathString|Platform.DevToolsPath.UrlString): Promise<boolean> {
    this.#closed = false;
    this.#writeCallbacks = [];
    this.#fileName = fileName;
    const saveResponse =
        await Workspace.FileManager.FileManager.instance().save(this.#fileName, '', true, false /* isBase64 */);
    if (saveResponse) {
      Workspace.FileManager.FileManager.instance().addEventListener(
          Workspace.FileManager.Events.APPENDED_TO_URL, this.onAppendDone, this);
    }
    return Boolean(saveResponse);
  }

  write(data: string): Promise<void> {
    return new Promise(resolve => {
      this.#writeCallbacks.push(resolve);
      Workspace.FileManager.FileManager.instance().append(this.#fileName, data);
    });
  }

  async close(): Promise<void> {
    this.#closed = true;
    if (this.#writeCallbacks.length) {
      return;
    }
    Workspace.FileManager.FileManager.instance().removeEventListener(
        Workspace.FileManager.Events.APPENDED_TO_URL, this.onAppendDone, this);
    Workspace.FileManager.FileManager.instance().close(this.#fileName);
  }

  private onAppendDone(event: Common.EventTarget.EventTargetEvent<string>): void {
    if (event.data !== this.#fileName) {
      return;
    }
    const writeCallback = this.#writeCallbacks.shift();
    if (writeCallback) {
      writeCallback();
    }
    if (this.#writeCallbacks.length) {
      return;
    }
    if (!this.#closed) {
      return;
    }
    Workspace.FileManager.FileManager.instance().removeEventListener(
        Workspace.FileManager.Events.APPENDED_TO_URL, this.onAppendDone, this);
    Workspace.FileManager.FileManager.instance().close(this.#fileName);
  }
}