/* Copyright 2012 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 {
  getPageSizeInches, getPDFFileNameFromURL, isPortraitOrientation, NullL10n
} from './ui_utils';
import { createPromiseCapability } from 'pdfjs-lib';

const DEFAULT_FIELD_CONTENT = '-';

// See https://en.wikibooks.org/wiki/Lentis/Conversion_to_the_Metric_Standard_in_the_United_States
const NON_METRIC_LOCALES = ['en-us', 'en-lr', 'my'];

// Should use the format: `width x height`, in portrait orientation.
// See https://en.wikipedia.org/wiki/Paper_size
const US_PAGE_NAMES = {
  '8.5x11': 'Letter',
  '8.5x14': 'Legal',
};
const METRIC_PAGE_NAMES = {
  '297x420': 'A3',
  '210x297': 'A4',
};

function getPageName(size, isPortrait, pageNames) {
  const width = (isPortrait ? size.width : size.height);
  const height = (isPortrait ? size.height : size.width);

  return pageNames[`${width}x${height}`];
}

/**
 * @typedef {Object} PDFDocumentPropertiesOptions
 * @property {string} overlayName - Name/identifier for the overlay.
 * @property {Object} fields - Names and elements of the overlay's fields.
 * @property {HTMLDivElement} container - Div container for the overlay.
 * @property {HTMLButtonElement} closeButton - Button for closing the overlay.
 */

class PDFDocumentProperties {
  /**
   * @param {PDFDocumentPropertiesOptions} options
   * @param {OverlayManager} overlayManager - Manager for the viewer overlays.
   * @param {EventBus} eventBus - The application event bus.
   * @param {IL10n} l10n - Localization service.
   */
  constructor({ overlayName, fields, container, closeButton, },
              overlayManager, eventBus, l10n = NullL10n) {
    this.overlayName = overlayName;
    this.fields = fields;
    this.container = container;
    this.overlayManager = overlayManager;
    this.l10n = l10n;

    this._reset();

    if (closeButton) { // Bind the event listener for the Close button.
      closeButton.addEventListener('click', this.close.bind(this));
    }
    this.overlayManager.register(this.overlayName, this.container,
                                 this.close.bind(this));

    if (eventBus) {
      eventBus.on('pagechanging', (evt) => {
        this._currentPageNumber = evt.pageNumber;
      });
      eventBus.on('rotationchanging', (evt) => {
        this._pagesRotation = evt.pagesRotation;
      });
    }

    this._isNonMetricLocale = true; // The default viewer locale is 'en-us'.
    l10n.getLanguage().then((locale) => {
      this._isNonMetricLocale = NON_METRIC_LOCALES.includes(locale);
    });
  }

  /**
   * Open the document properties overlay.
   */
  open() {
    let freezeFieldData = (data) => {
      Object.defineProperty(this, 'fieldData', {
        value: Object.freeze(data),
        writable: false,
        enumerable: true,
        configurable: true,
      });
    };

    Promise.all([this.overlayManager.open(this.overlayName),
                 this._dataAvailableCapability.promise]).then(() => {
      const currentPageNumber = this._currentPageNumber;
      const pagesRotation = this._pagesRotation;

      // If the document properties were previously fetched (for this PDF file),
      // just update the dialog immediately to avoid redundant lookups.
      if (this.fieldData &&
          currentPageNumber === this.fieldData['_currentPageNumber'] &&
          pagesRotation === this.fieldData['_pagesRotation']) {
        this._updateUI();
        return;
      }

      // Get the document properties.
      this.pdfDocument.getMetadata().then(
          ({ info, metadata, contentDispositionFilename, }) => {
        return Promise.all([
          info,
          metadata,
          contentDispositionFilename || getPDFFileNameFromURL(this.url),
          this._parseFileSize(this.maybeFileSize),
          this._parseDate(info.CreationDate),
          this._parseDate(info.ModDate),
          this.pdfDocument.getPage(currentPageNumber).then((pdfPage) => {
            return this._parsePageSize(getPageSizeInches(pdfPage),
                                       pagesRotation);
          }),
        ]);
      }).then(([info, metadata, fileName, fileSize, creationDate, modDate,
                pageSize]) => {
        freezeFieldData({
          'fileName': fileName,
          'fileSize': fileSize,
          'title': info.Title,
          'author': info.Author,
          'subject': info.Subject,
          'keywords': info.Keywords,
          'creationDate': creationDate,
          'modificationDate': modDate,
          'creator': info.Creator,
          'producer': info.Producer,
          'version': info.PDFFormatVersion,
          'pageCount': this.pdfDocument.numPages,
          'pageSize': pageSize,
          '_currentPageNumber': currentPageNumber,
          '_pagesRotation': pagesRotation,
        });
        this._updateUI();

        // Get the correct fileSize, since it may not have been set (if
        // `this.setFileSize` wasn't called) or may be incorrectly set.
        return this.pdfDocument.getDownloadInfo();
      }).then(({ length, }) => {
        this.maybeFileSize = length;
        return this._parseFileSize(length);
      }).then((fileSize) => {
        if (fileSize === this.fieldData['fileSize']) {
          return; // The fileSize has already been correctly set.
        }
        let data = Object.assign(Object.create(null), this.fieldData);
        data['fileSize'] = fileSize;

        freezeFieldData(data);
        this._updateUI();
      });
    });
  }

  /**
   * Close the document properties overlay.
   */
  close() {
    this.overlayManager.close(this.overlayName);
  }

  /**
   * Set a reference to the PDF document and the URL in order
   * to populate the overlay fields with the document properties.
   * Note that the overlay will contain no information if this method
   * is not called.
   *
   * @param {Object} pdfDocument - A reference to the PDF document.
   * @param {string} url - The URL of the document.
   */
  setDocument(pdfDocument, url) {
    if (this.pdfDocument) {
      this._reset();
      this._updateUI(true);
    }
    if (!pdfDocument) {
      return;
    }
    this.pdfDocument = pdfDocument;
    this.url = url;

    this._dataAvailableCapability.resolve();
  }

  /**
   * Set the file size of the PDF document. This method is used to
   * update the file size in the document properties overlay once it
   * is known so we do not have to wait until the entire file is loaded.
   *
   * @param {number} fileSize - The file size of the PDF document.
   */
  setFileSize(fileSize) {
    if (Number.isInteger(fileSize) && fileSize > 0) {
      this.maybeFileSize = fileSize;
    }
  }

  /**
   * @private
   */
  _reset() {
    this.pdfDocument = null;
    this.url = null;

    this.maybeFileSize = 0;
    delete this.fieldData;
    this._dataAvailableCapability = createPromiseCapability();
    this._currentPageNumber = 1;
    this._pagesRotation = 0;
  }

  /**
   * Always updates all of the dialog fields, to prevent inconsistent UI state.
   * NOTE: If the contents of a particular field is neither a non-empty string,
   *       nor a number, it will fall back to `DEFAULT_FIELD_CONTENT`.
   * @private
   */
  _updateUI(reset = false) {
    if (reset || !this.fieldData) {
      for (let id in this.fields) {
        this.fields[id].textContent = DEFAULT_FIELD_CONTENT;
      }
      return;
    }
    if (this.overlayManager.active !== this.overlayName) {
      // Don't bother updating the dialog if has already been closed,
      // since it will be updated the next time `this.open` is called.
      return;
    }
    for (let id in this.fields) {
      let content = this.fieldData[id];
      this.fields[id].textContent = (content || content === 0) ?
                                    content : DEFAULT_FIELD_CONTENT;
    }
  }

  /**
   * @private
   */
  _parseFileSize(fileSize = 0) {
    let kb = fileSize / 1024;
    if (!kb) {
      return Promise.resolve(undefined);
    } else if (kb < 1024) {
      return this.l10n.get('document_properties_kb', {
        size_kb: (+kb.toPrecision(3)).toLocaleString(),
        size_b: fileSize.toLocaleString(),
      }, '{{size_kb}} KB ({{size_b}} bytes)');
    }
    return this.l10n.get('document_properties_mb', {
      size_mb: (+(kb / 1024).toPrecision(3)).toLocaleString(),
      size_b: fileSize.toLocaleString(),
    }, '{{size_mb}} MB ({{size_b}} bytes)');
  }

  /**
   * @private
   */
  _parsePageSize(pageSizeInches, pagesRotation) {
    if (!pageSizeInches) {
      return Promise.resolve(undefined);
    }
    // Take the viewer rotation into account as well; compare with Adobe Reader.
    if (pagesRotation % 180 !== 0) {
      pageSizeInches = {
        width: pageSizeInches.height,
        height: pageSizeInches.width,
      };
    }
    const isPortrait = isPortraitOrientation(pageSizeInches);

    let sizeInches = {
      width: Math.round(pageSizeInches.width * 100) / 100,
      height: Math.round(pageSizeInches.height * 100) / 100,
    };
    // 1in == 25.4mm; no need to round to 2 decimals for millimeters.
    let sizeMillimeters = {
      width: Math.round(pageSizeInches.width * 25.4 * 10) / 10,
      height: Math.round(pageSizeInches.height * 25.4 * 10) / 10,
    };

    let pageName = null;
    let name = getPageName(sizeInches, isPortrait, US_PAGE_NAMES) ||
               getPageName(sizeMillimeters, isPortrait, METRIC_PAGE_NAMES);

    if (!name && !(Number.isInteger(sizeMillimeters.width) &&
                   Number.isInteger(sizeMillimeters.height))) {
      // Attempt to improve the page name detection by falling back to fuzzy
      // matching of the metric dimensions, to account for e.g. rounding errors
      // and/or PDF files that define the page sizes in an imprecise manner.
      const exactMillimeters = {
        width: pageSizeInches.width * 25.4,
        height: pageSizeInches.height * 25.4,
      };
      const intMillimeters = {
        width: Math.round(sizeMillimeters.width),
        height: Math.round(sizeMillimeters.height),
      };

      // Try to avoid false positives, by only considering "small" differences.
      if (Math.abs(exactMillimeters.width - intMillimeters.width) < 0.1 &&
          Math.abs(exactMillimeters.height - intMillimeters.height) < 0.1) {

        name = getPageName(intMillimeters, isPortrait, METRIC_PAGE_NAMES);
        if (name) {
          // Update *both* sizes, computed above, to ensure that the displayed
          // dimensions always correspond to the detected page name.
          sizeInches = {
            width: Math.round(intMillimeters.width / 25.4 * 100) / 100,
            height: Math.round(intMillimeters.height / 25.4 * 100) / 100,
          };
          sizeMillimeters = intMillimeters;
        }
      }
    }
    if (name) {
      pageName = this.l10n.get('document_properties_page_size_name_' +
                               name.toLowerCase(), null, name);
    }

    return Promise.all([
      (this._isNonMetricLocale ? sizeInches : sizeMillimeters),
      this.l10n.get('document_properties_page_size_unit_' +
                    (this._isNonMetricLocale ? 'inches' : 'millimeters'), null,
                    this._isNonMetricLocale ? 'in' : 'mm'),
      pageName,
      this.l10n.get('document_properties_page_size_orientation_' +
                    (isPortrait ? 'portrait' : 'landscape'), null,
                    isPortrait ? 'portrait' : 'landscape'),
    ]).then(([{ width, height, }, unit, name, orientation]) => {
      return this.l10n.get('document_properties_page_size_dimension_' +
                           (name ? 'name_' : '') + 'string', {
          width: width.toLocaleString(),
          height: height.toLocaleString(),
          unit,
          name,
          orientation,
        }, '{{width}} × {{height}} {{unit}} (' +
           (name ? '{{name}}, ' : '') + '{{orientation}})');
    });
  }

  /**
   * @private
   */
  _parseDate(inputDate) {
    if (!inputDate) {
      return;
    }
    // This is implemented according to the PDF specification, but note that
    // Adobe Reader doesn't handle changing the date to universal time
    // and doesn't use the user's time zone (they're effectively ignoring
    // the HH' and mm' parts of the date string).
    let dateToParse = inputDate;

    // Remove the D: prefix if it is available.
    if (dateToParse.substring(0, 2) === 'D:') {
      dateToParse = dateToParse.substring(2);
    }

    // Get all elements from the PDF date string.
    // JavaScript's `Date` object expects the month to be between
    // 0 and 11 instead of 1 and 12, so we're correcting for this.
    let year = parseInt(dateToParse.substring(0, 4), 10);
    let month = parseInt(dateToParse.substring(4, 6), 10) - 1;
    let day = parseInt(dateToParse.substring(6, 8), 10);
    let hours = parseInt(dateToParse.substring(8, 10), 10);
    let minutes = parseInt(dateToParse.substring(10, 12), 10);
    let seconds = parseInt(dateToParse.substring(12, 14), 10);
    let utRel = dateToParse.substring(14, 15);
    let offsetHours = parseInt(dateToParse.substring(15, 17), 10);
    let offsetMinutes = parseInt(dateToParse.substring(18, 20), 10);

    // As per spec, utRel = 'Z' means equal to universal time.
    // The other cases ('-' and '+') have to be handled here.
    if (utRel === '-') {
      hours += offsetHours;
      minutes += offsetMinutes;
    } else if (utRel === '+') {
      hours -= offsetHours;
      minutes -= offsetMinutes;
    }

    // Return the new date format from the user's locale.
    let date = new Date(Date.UTC(year, month, day, hours, minutes, seconds));
    let dateString = date.toLocaleDateString();
    let timeString = date.toLocaleTimeString();
    return this.l10n.get('document_properties_date_string',
                         { date: dateString, time: timeString, },
                         '{{date}}, {{time}}');
  }
}

export {
  PDFDocumentProperties,
};