{% load compressed i18n static %}

<script language="javascript">
(function() {

function renderThumbnail(apiPrefix, reviewRequestId) {
    const pdfStatus = '{{pdfStatus|escapejs}}';
    const pdfWorkerURL = '{{pdfWorkerURL|escapejs}}';
    const thumbnailSrc = '{{thumbnailSrc|escapejs}}';
    const isOriginalPDF = {{isOriginalPDF|yesno:"true,false"}};
    const errorTemplate = _.template([
        '<div class="powerpack-c-pdf-thumbnail-placeholder-text">',
        ' <span class="rb-icon rb-icon-warning"></span>',
        ' <%- errorText %>',
        '</div>',
    ].join(''));
    let isDocReviewDefined = false;

    try {
        isDocReviewDefined = (PowerPack.DocReview.instance !== undefined)
    } catch (e) {
        /*
         * PowerPack and/or DocReview is not defined, which means this is a
         * page where Doc Review's static media isn't loaded. For example,
         * we're on the review UI of an image and there's a PDF/Office
         * Document thumbnail in the left and/or right attachment navigation.
         *
         * This will prevent us from rendering the "Download as PDF" file
         * action, but that isn't even needed in these cases anyways.
         */
    }

    /* Display a spinner for now. */
    $('#thumbnail-placeholder-{{pdf.pk}}')
        .html('<span class="djblets-o-spinner"></span>');

    if (thumbnailSrc) {
        /* The thumbnail exists. */
        const thumbnailTemplate = _.template([
            '<div class="file-thumbnail">',
            '<img src="<%- thumbnailSrc %>" srcset="<%- thumbnailSrcset %>"',
            'alt="<%- caption %>" width="300">',
            '</div>',
        ].join(''));

        $('#thumbnail-placeholder-{{pdf.pk}}')
            .replaceWith(thumbnailTemplate({
                caption: '{{caption|escapejs}}',
                thumbnailSrc: thumbnailSrc,
                thumbnailSrcset: '{{thumbnailSrcset|escapejs}}',
            }));

        if (isDocReviewDefined && !isOriginalPDF) {
            /*
            * This is an Office document whose PDF is available. Trigger
            * this to render the download as PDF file action.
            */
            PowerPack.DocReview.instance.trigger('pdfURLAvailable',
                                                '{{downloadURL|escapejs}}',
                                                '{{pdfURL|escapejs}}');
            }

        return;
    } else if (pdfStatus === 'fatal_error' ||
               !pdfWorkerURL ||
               pdfjsLib.GlobalWorkerOptions.workerSrc === undefined) {
        $('#thumbnail-placeholder-{{pdf.pk}}')
            .replaceWith(errorTemplate({
                errorText: gettext("There was an unexpected problem loading the document for review. Try deleting and re-uploading the file, and if that doesn't work contact your administrator."),
            }));
        console.assert(pdfWorkerURL, 'Failed to find PDF worker script.');
        console.assert(pdfjsLib.GlobalWorkerOptions.workerSrc !== undefined,
                       'Unable to find the pdf.js workerSrc attribute.');
        return;
    } else if (pdfStatus === 'not_configured') {
        $('#thumbnail-placeholder-{{pdf.pk}}')
            .replaceWith(errorTemplate({
                errorText: gettext('Document Review has not been configured. Please contact your administrator.'),
            }));
        return;
    }

    if (!RB.UserSession.instance.get('authenticated')) {
        /*
         * If for some reason an anonymous user is viewing a thumbnail
         * that hasn't been set yet, just display an error and bail.
         */
        $('#thumbnail-placeholder-{{pdf.pk}}')
            .replaceWith(errorTemplate({
                errorText: gettext('Failed to display thumbnail.'),
            }));
        return;
    }

    /* Try to create and set the thumbnail. */
    pdfjsLib.GlobalWorkerOptions.workerSrc = pdfWorkerURL;
    const pdfRenderer = new PowerPack.DocReview.PDF({
        fileAttachmentID: {{pdf.pk}},
        isOriginalPDF: isOriginalPDF,
        pdfStatus: pdfStatus,
        pdfURL: '{{pdfURL|escapejs}}',
    });

    pdfRenderer.getPage(1).then(function(page) {
        const viewport = page.getViewport({ scale: 1.0 }),
            $canvas = $('<canvas/>')
            .attr({
                width: viewport.width,
                height: viewport.height
            });

        page.render({
            canvasContext: $canvas[0].getContext('2d'),
            viewport: viewport
        }).promise.then(function() {
            const maxMemorySize = {{DATA_MAX_MEMORY_SIZE}};
            let thumbnail = $canvas[0].toDataURL();

            if (maxMemorySize && thumbnail.length + 314572 >= maxMemorySize) {
                /*
                 * The thumbnail size is within ~0.3MB of the server's
                 * maximum request body size. Reduce the quality of the
                 * thumbnail to avoid hitting the maximum.
                 */
                thumbnail = $canvas[0].toDataURL('image/jpeg', 0.5);
            }

            RB.apiCall({
                type: 'PUT',
                prefix: apiPrefix,
                path: `/review-requests/${reviewRequestId}/file-attachments/{{pdf.pk}}/`,
                data: {
                    thumbnail: thumbnail,
                },
                success: data => {
                    const $placeholder = $('#thumbnail-placeholder-{{pdf.pk}}');
                    const $parent = $placeholder.parent();

                    $placeholder.remove();
                    $parent.append(data.file_attachment.thumbnail);

                    if (isDocReviewDefined && !isOriginalPDF) {
                        /* Trigger to render the download as PDF file action. */
                        PowerPack.DocReview.instance.trigger('pdfURLAvailable',
                                                             '{{downloadURL|escapejs}}',
                                                             '{{pdfURL|escapejs}}');
                    }
                },
                error: () => {
                    $('#thumbnail-placeholder-{{pdf.pk}}')
                    .replaceWith(errorTemplate({
                        errorText: gettext('Failed to generate thumbnail.'),
                    }));
                }
            });
        });
    }).catch((err) => {
        $('#thumbnail-placeholder-{{pdf.pk}}')
            .replaceWith(errorTemplate({
                errorText: gettext("There was an unexpected problem loading the document for review. Try deleting and re-uploading the file, and if that doesn't work contact your administrator."),
            }));
    });
}

$(document).ready(function() {
    RB.PageManager.ready(function(page) {
        renderThumbnail(page.reviewRequest.get('localSitePrefix'),
                        page.reviewRequest.get('id'));
    });
});

}());

</script>
<div id="thumbnail-placeholder-{{pdf.pk}}"></div>