/* Copyright 2016 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.
 */

if (!pdfjsLib.getDocument || !pdfjsViewer.PDFViewer) {
  // eslint-disable-next-line no-alert
  alert("Please build the pdfjs-dist library using\n `gulp dist-install`");
}

const MAX_CANVAS_PIXELS = 0; // CSS-only zooming.
const TEXT_LAYER_MODE = 0; // DISABLE
const MAX_IMAGE_SIZE = 1024 * 1024;
const CMAP_URL = "../../node_modules/pdfjs-dist/cmaps/";
const CMAP_PACKED = true;

pdfjsLib.GlobalWorkerOptions.workerSrc =
  "../../node_modules/pdfjs-dist/build/pdf.worker.mjs";

const DEFAULT_URL = "../../web/compressed.tracemonkey-pldi-09.pdf";
const DEFAULT_SCALE_DELTA = 1.1;
const MIN_SCALE = 0.25;
const MAX_SCALE = 10.0;
const DEFAULT_SCALE_VALUE = "auto";

const PDFViewerApplication = {
  pdfLoadingTask: null,
  pdfDocument: null,
  pdfViewer: null,
  pdfHistory: null,
  pdfLinkService: null,
  eventBus: null,

  /**
   * Opens PDF document specified by URL.
   * @returns {Promise} - Returns the promise, which is resolved when document
   *                      is opened.
   */
  async open(params) {
    if (this.pdfLoadingTask) {
      // We need to destroy already opened document.
      await this.close();
    }

    const { url } = params;
    this.setTitleUsingUrl(url);

    // Loading document.
    const loadingTask = pdfjsLib.getDocument({
      url,
      maxImageSize: MAX_IMAGE_SIZE,
      cMapUrl: CMAP_URL,
      cMapPacked: CMAP_PACKED,
    });
    this.pdfLoadingTask = loadingTask;

    loadingTask.onProgress = evt => this.progress(evt.percent);

    return loadingTask.promise.then(
      pdfDocument => {
        // Document loaded, specifying document for the viewer.
        this.pdfDocument = pdfDocument;
        this.pdfViewer.setDocument(pdfDocument);
        this.pdfLinkService.setDocument(pdfDocument);
        this.pdfHistory.initialize({
          fingerprint: pdfDocument.fingerprints[0],
        });

        this.loadingBar.hide();
        this.setTitleUsingMetadata(pdfDocument);
      },
      reason => {
        let key = "pdfjs-loading-error";
        if (reason instanceof pdfjsLib.InvalidPDFException) {
          key = "pdfjs-invalid-file-error";
        } else if (reason instanceof pdfjsLib.ResponseException) {
          key = reason.missing
            ? "pdfjs-missing-file-error"
            : "pdfjs-unexpected-response-error";
        }
        this.l10n.get(key).then(msg => {
          this.error(msg, { message: reason.message });
        });
        this.loadingBar.hide();
      }
    );
  },

  /**
   * Closes opened PDF document.
   * @returns {Promise} - Returns the promise, which is resolved when all
   *                      destruction is completed.
   */
  async close() {
    if (!this.pdfLoadingTask) {
      return;
    }

    const promise = this.pdfLoadingTask.destroy();
    this.pdfLoadingTask = null;

    if (this.pdfDocument) {
      this.pdfDocument = null;

      this.pdfViewer.setDocument(null);
      this.pdfLinkService.setDocument(null, null);

      if (this.pdfHistory) {
        this.pdfHistory.reset();
      }
    }

    await promise;
  },

  get loadingBar() {
    const bar = document.getElementById("loadingBar");
    return pdfjsLib.shadow(
      this,
      "loadingBar",
      new pdfjsViewer.ProgressBar(bar)
    );
  },

  setTitleUsingUrl: function pdfViewSetTitleUsingUrl(url) {
    this.url = url;
    let title = pdfjsLib.getFilenameFromUrl(url) || url;
    try {
      title = decodeURIComponent(title);
    } catch {
      // decodeURIComponent may throw URIError,
      // fall back to using the unprocessed url in that case
    }
    this.setTitle(title);
  },

  async setTitleUsingMetadata(pdfDocument) {
    const { info, metadata } = await pdfDocument.getMetadata();
    this.documentInfo = info;
    this.metadata = metadata;

    // Provides some basic debug information
    console.log(
      `PDF ${pdfDocument.fingerprints[0]} [${info.PDFFormatVersion} ` +
        `${(metadata?.get("pdf:producer") || info.Producer || "-").trim()} / ` +
        `${(metadata?.get("xmp:creatortool") || info.Creator || "-").trim()}` +
        `] (PDF.js: ${pdfjsLib.version || "?"} [${pdfjsLib.build || "?"}])`
    );

    let pdfTitle;
    if (metadata && metadata.has("dc:title")) {
      const title = metadata.get("dc:title");
      // Ghostscript sometimes returns 'Untitled', so prevent setting the
      // title to 'Untitled.
      if (title !== "Untitled") {
        pdfTitle = title;
      }
    }

    if (!pdfTitle && info && info.Title) {
      pdfTitle = info.Title;
    }

    if (pdfTitle) {
      this.setTitle(pdfTitle + " - " + document.title);
    }
  },

  setTitle: function pdfViewSetTitle(title) {
    document.title = title;
    document.getElementById("title").textContent = title;
  },

  error: function pdfViewError(message, moreInfo) {
    const moreInfoText = [
      `PDF.js v${pdfjsLib.version || "?"} (build: ${pdfjsLib.build || "?"})`,
    ];
    if (moreInfo) {
      moreInfoText.push(`Message: ${moreInfo.message}`);

      if (moreInfo.stack) {
        moreInfoText.push(`Stack: ${moreInfo.stack}`);
      } else {
        if (moreInfo.filename) {
          moreInfoText.push(`File: ${moreInfo.filename}`);
        }
        if (moreInfo.lineNumber) {
          moreInfoText.push(`Line: ${moreInfo.lineNumber}`);
        }
      }
    }

    console.error(`${message}\n\n${moreInfoText.join("\n")}`);
  },

  progress(percent) {
    // Updating the bar if value increases.
    if (percent > this.loadingBar.percent || isNaN(percent)) {
      this.loadingBar.percent = percent;
    }
  },

  get pagesCount() {
    return this.pdfDocument.numPages;
  },

  get page() {
    return this.pdfViewer.currentPageNumber;
  },

  set page(val) {
    this.pdfViewer.currentPageNumber = val;
  },

  zoomIn: function pdfViewZoomIn(ticks) {
    let newScale = this.pdfViewer.currentScale;
    do {
      newScale = (newScale * DEFAULT_SCALE_DELTA).toFixed(2);
      newScale = Math.ceil(newScale * 10) / 10;
      newScale = Math.min(MAX_SCALE, newScale);
    } while (--ticks && newScale < MAX_SCALE);
    this.pdfViewer.currentScaleValue = newScale;
  },

  zoomOut: function pdfViewZoomOut(ticks) {
    let newScale = this.pdfViewer.currentScale;
    do {
      newScale = (newScale / DEFAULT_SCALE_DELTA).toFixed(2);
      newScale = Math.floor(newScale * 10) / 10;
      newScale = Math.max(MIN_SCALE, newScale);
    } while (--ticks && newScale > MIN_SCALE);
    this.pdfViewer.currentScaleValue = newScale;
  },

  initUI: function pdfViewInitUI() {
    const eventBus = new pdfjsViewer.EventBus();
    this.eventBus = eventBus;

    const linkService = new pdfjsViewer.PDFLinkService({
      eventBus,
    });
    this.pdfLinkService = linkService;

    this.l10n = new pdfjsViewer.GenericL10n();

    const container = document.getElementById("viewerContainer");
    const pdfViewer = new pdfjsViewer.PDFViewer({
      container,
      eventBus,
      linkService,
      l10n: this.l10n,
      maxCanvasPixels: MAX_CANVAS_PIXELS,
      textLayerMode: TEXT_LAYER_MODE,
    });
    this.pdfViewer = pdfViewer;
    linkService.setViewer(pdfViewer);

    this.pdfHistory = new pdfjsViewer.PDFHistory({
      eventBus,
      linkService,
    });
    linkService.setHistory(this.pdfHistory);

    document.getElementById("previous").addEventListener("click", function () {
      PDFViewerApplication.page--;
    });

    document.getElementById("next").addEventListener("click", function () {
      PDFViewerApplication.page++;
    });

    document.getElementById("zoomIn").addEventListener("click", function () {
      PDFViewerApplication.zoomIn();
    });

    document.getElementById("zoomOut").addEventListener("click", function () {
      PDFViewerApplication.zoomOut();
    });

    document
      .getElementById("pageNumber")
      .addEventListener("click", function () {
        this.select();
      });

    document
      .getElementById("pageNumber")
      .addEventListener("change", function () {
        PDFViewerApplication.page = this.value | 0;

        // Ensure that the page number input displays the correct value,
        // even if the value entered by the user was invalid
        // (e.g. a floating point number).
        if (this.value !== PDFViewerApplication.page.toString()) {
          this.value = PDFViewerApplication.page;
        }
      });

    eventBus.on("pagesinit", function () {
      // We can use pdfViewer now, e.g. let's change default scale.
      pdfViewer.currentScaleValue = DEFAULT_SCALE_VALUE;
    });

    eventBus.on(
      "pagechanging",
      function (evt) {
        const page = evt.pageNumber;
        const numPages = PDFViewerApplication.pagesCount;

        document.getElementById("pageNumber").value = page;
        document.getElementById("previous").disabled = page <= 1;
        document.getElementById("next").disabled = page >= numPages;
      },
      true
    );
  },
};

window.PDFViewerApplication = PDFViewerApplication;

document.addEventListener(
  "DOMContentLoaded",
  function () {
    PDFViewerApplication.initUI();
  },
  true
);

// The offsetParent is not set until the PDF.js iframe or object is visible;
// waiting for first animation.
const animationStarted = new Promise(function (resolve) {
  window.requestAnimationFrame(resolve);
});

// We need to delay opening until all HTML is loaded.
animationStarted.then(function () {
  PDFViewerApplication.open({
    url: DEFAULT_URL,
  });
});