/* Copyright 2017 Mozilla Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import { assert, CMapCompressionType } from "../../src/shared/util";
import { isNodeJS } from "../../src/shared/is_node";
import { isRef } from "../../src/core/primitives";
import { Page } from "../../src/core/document";

class DOMFileReaderFactory {
  static async fetch(params) {
    const response = await fetch(params.path);
    if (!response.ok) {
      throw new Error(response.statusText);
    }
    return new Uint8Array(await response.arrayBuffer());
  }
}

class NodeFileReaderFactory {
  static async fetch(params) {
    const fs = require("fs");

    return new Promise((resolve, reject) => {
      fs.readFile(params.path, (error, data) => {
        if (error || !data) {
          reject(error || new Error(`Empty file for: ${params.path}`));
          return;
        }
        resolve(new Uint8Array(data));
      });
    });
  }
}

const TEST_PDFS_PATH = {
  dom: "../pdfs/",
  node: "./test/pdfs/",
};

function buildGetDocumentParams(filename, options) {
  let params = Object.create(null);
  if (isNodeJS) {
    params.url = TEST_PDFS_PATH.node + filename;
  } else {
    params.url = new URL(TEST_PDFS_PATH.dom + filename, window.location).href;
  }
  for (let option in options) {
    params[option] = options[option];
  }
  return params;
}

class NodeCanvasFactory {
  create(width, height) {
    assert(width > 0 && height > 0, "Invalid canvas size");

    const Canvas = require("canvas");
    const canvas = Canvas.createCanvas(width, height);
    return {
      canvas,
      context: canvas.getContext("2d"),
    };
  }

  reset(canvasAndContext, width, height) {
    assert(canvasAndContext.canvas, "Canvas is not specified");
    assert(width > 0 && height > 0, "Invalid canvas size");

    canvasAndContext.canvas.width = width;
    canvasAndContext.canvas.height = height;
  }

  destroy(canvasAndContext) {
    assert(canvasAndContext.canvas, "Canvas is not specified");

    // Zeroing the width and height cause Firefox to release graphics
    // resources immediately, which can greatly reduce memory consumption.
    canvasAndContext.canvas.width = 0;
    canvasAndContext.canvas.height = 0;
    canvasAndContext.canvas = null;
    canvasAndContext.context = null;
  }
}

class NodeCMapReaderFactory {
  constructor({ baseUrl = null, isCompressed = false }) {
    this.baseUrl = baseUrl;
    this.isCompressed = isCompressed;
  }

  async fetch({ name }) {
    if (!this.baseUrl) {
      throw new Error(
        'The CMap "baseUrl" parameter must be specified, ensure that ' +
          'the "cMapUrl" and "cMapPacked" API parameters are provided.'
      );
    }
    if (!name) {
      throw new Error("CMap name must be specified.");
    }
    const url = this.baseUrl + name + (this.isCompressed ? ".bcmap" : "");
    const compressionType = this.isCompressed
      ? CMapCompressionType.BINARY
      : CMapCompressionType.NONE;

    return new Promise((resolve, reject) => {
      const fs = require("fs");
      fs.readFile(url, (error, data) => {
        if (error || !data) {
          reject(new Error(error));
          return;
        }
        resolve({ cMapData: new Uint8Array(data), compressionType });
      });
    }).catch(reason => {
      throw new Error(
        `Unable to load ${this.isCompressed ? "binary " : ""}` +
          `CMap at: ${url}`
      );
    });
  }
}

class XRefMock {
  constructor(array) {
    this._map = Object.create(null);

    for (let key in array) {
      let obj = array[key];
      this._map[obj.ref.toString()] = obj.data;
    }
  }

  fetch(ref) {
    return this._map[ref.toString()];
  }

  fetchAsync(ref) {
    return Promise.resolve(this.fetch(ref));
  }

  fetchIfRef(obj) {
    if (!isRef(obj)) {
      return obj;
    }
    return this.fetch(obj);
  }

  fetchIfRefAsync(obj) {
    return Promise.resolve(this.fetchIfRef(obj));
  }
}

function createIdFactory(pageIndex) {
  const page = new Page({
    pdfManager: {
      get docId() {
        return "d0";
      },
    },
    pageIndex,
  });
  return page.idFactory;
}

export {
  DOMFileReaderFactory,
  NodeFileReaderFactory,
  NodeCanvasFactory,
  NodeCMapReaderFactory,
  XRefMock,
  buildGetDocumentParams,
  TEST_PDFS_PATH,
  createIdFactory,
};