/**
 * PDF.js extension that extracts highlighted text and annotations from pdf files.
 * Based on modified version of pdf.js available here https://github.com/jlegewie/pdf.js
 * (see various extract branches). See 'PDF Reference Manual 1.7' section 8.4 for details on 
 * annotations in pdf files.
 */

'use strict';

/**
 * @return {Promise} A promise that is resolved with an Object
 * that includes elements for path, time, and annotations.
 */
PDFJS.getPDFAnnotations = function(url, removeHyphens, progress, debug) {
    // set default values
    removeHyphens = typeof removeHyphens !== 'undefined' ? removeHyphens : true;
    progress = typeof progress !== 'undefined' ? progress : function(x, y) {};
    debug = typeof debug !== 'undefined' ? debug : false;
    var legacyPromise = PDFJS.Promise!==undefined;
    // Return a new promise (with support for legacy pdf.js promises)
    /* http://www.html5rocks.com/en/tutorials/es6/promises*/
    var extract = function(resolve, reject) {
       // var SUPPORTED_ANNOTS = ['Text','Highlight','Underline'],
           var SUPPORTED_ANNOTS = ['Highlight'],
            obj = {annotations: [],
                time:null,
                url: typeof url=='string' ? url : ''
            };
        // Fetch the PDF document from the URL using promices
        PDFJS.getDocument(url).then(function(pdf) {
            var n_annos = 0,
                numPages = pdf.numPages,
                time_start = performance.now();

            // function to handle page (render and extract annotations)
            var getAnnotationsFromPage = function(page) {
                var scale = 1;
                var viewport = page.getViewport(scale);
                // Prepare canvas using PDF page dimensions
                var canvas = document.getElementById('the-canvas');
                var context = canvas.getContext('2d');
                canvas.height = viewport.height;
                canvas.width = viewport.width;
              //  console.log(canvas.height);
                // Render PDF page into canvas context
                var renderContext = {
                    canvasContext: context,
                    viewport: viewport
                };
                // error handler
                var errorHandler = function(error) {
                    progress(page.pageNumber, numPages);
                    console.log(error);
                    // continue with next page
                    if(numPages>page.pageNumber)
                        pdf.getPage(page.pageNumber+1).then(
                          getAnnotationsFromPage,
                          function(err) {legacyPromise ? promise.reject(obj) : reject(err);});
                    else {
                        var end = performance.now();
                        obj.time = end-time_start;
                        legacyPromise ? promise.resolve(obj) : resolve(obj);
                    }
                };
                // function to convert deviceRGB to RGB
                var convertDeviceRGBtoRGB = function(dr, dg, db) {
                    var r = Math.round(dr*255);
                    var g = Math.round(dg*255);
                    var b = Math.round(db*255);
                    return [r, g, b];
                };
                // get annotations
                page.getAnnotations().then(function extractAnno(annos) {
                    // compatibility for old pdf.js version and filter for supported annotations
                    annos = annos
                        .map(function(anno) {
                            if (anno.subtype===undefined) anno.subtype=anno.type;
                            return anno;
                        })
                        .filter(function(anno) {
                            return SUPPORTED_ANNOTS.indexOf(anno.subtype) >= 0;
                        });
                    // skip page if there is nothing interesting
                    if (annos.length===0) {
                        progress(page.pageNumber,numPages);
                        if(numPages>page.pageNumber)
                            pdf.getPage(page.pageNumber+1).then(
                              getAnnotationsFromPage,
                              function(err) {legacyPromise ? promise.reject(obj) : reject(err);});
                        else {
                            var end = performance.now();
                            obj.time = end-time_start;
                            legacyPromise ? promise.resolve(obj) : resolve(obj);
                        }
                        return;
                    }
                    // render page
                    var render = page.render(renderContext, annos);
                    if (render.promise!==undefined) render = render.promise;
                    render.then(function() {
                        // clean markup
                        annos = annos.map(function(anno) {
                            anno.page = page.pageNumber;
                            if('color' in anno)
                                anno.color = convertDeviceRGBtoRGB(anno.color[0],anno.color[1],anno.color[2]);
                            // clean markup
                            if(anno.markup) {
                                anno.markup = anno.markup
                                  .map(function(part) {return part.trim();})
                                  .join(' ').trim()
                                  // translate ligatures (e.g. 'fi')
                                  .replace('\ufb00','ff').replace('\ufb01','fi').replace('\ufb02','fl')
                                  .replace(/\ufb03/g,'ffi').replace(/\ufb04/g,'ffl').replace(/\ufb05/g,'ft')
                                  .replace(/\ufb06/g,'st').replace(/\uFB00/g,'ff').replace(/\uFB01/g,'fi')
                                  .replace(/\uFB02/g,'fl').replace(/\u201D/g,'"').replace(/\u201C/g,'"')
                                  .replace(/\u2019/g,"'").replace(/\u2018/g,"'").replace(/\u2013/g,'-').
                                  replace(/''/g,'"').replace(/`/g,"'");
                                if(removeHyphens)
                                    anno.markup = anno.markup.replace(/([a-zA-Z])- ([a-zA-Z])/g, '$1$2');
                            }
                            // clean anno
                            if(!debug) {
                                delete anno.annotationFlags;
                                delete anno.borderWidth;
                                delete anno.chars;
                                delete anno.hasAppearance;
                                delete anno.markupGeom;
                                delete anno.quadPoints;
                                delete anno.rect;
                                delete anno.rect;
                                delete anno.spaceSize;
                                delete anno.name;
                            }
                            // return
                            return anno;
                        });
                        // add annotations to return object
                        obj.annotations.push.apply(obj.annotations, annos);

                        // render next page
                        progress(page.pageNumber, numPages);
                        if(numPages>page.pageNumber)
                            pdf.getPage(page.pageNumber+1).then(
                              getAnnotationsFromPage,
                              function(err) {legacyPromise ? promise.reject(obj) : reject(err);} );
                        else {
                            var end = performance.now();
                            obj.time = end-time_start;
                            legacyPromise ? promise.resolve(obj) : resolve(obj);
                        }
                    }, errorHandler);
                }, errorHandler);
            };

            // Using promise to fetch the page
            pdf.getPage(1).then(
              getAnnotationsFromPage,
              function(err) {console.log('error getting the page:' + err);}
            );

        },
        function(err) {
            console.log('unable to open pdf: ' + err);
            legacyPromise ? promise.reject(obj) : reject(err);
        });
    };
    if (legacyPromise) {
        var promise = new PDFJS.Promise();
        extract();
        return promise;
    }
    else
        return new Promise(extract);
};