BookStackApp/BookStack

/**
 * Handle alignment for embed (iframe/video) content.
 * TinyMCE built-in handling doesn't work well for these when classes are used for
 * alignment, since the editor wraps these elements in a non-editable preview span
 * which looses tracking and setting of alignment options.
 * Here we manually manage these properties and formatting events, by effectively
 * syncing the alignment classes to the parent preview span.
 * @param {Editor} editor
 */
export function handleEmbedAlignmentChanges(editor) {
    function updateClassesForPreview(previewElem) {
        const mediaTarget = previewElem.querySelector('iframe, video');
        if (!mediaTarget) {
            return;
        }

        const alignmentClasses = [...mediaTarget.classList.values()].filter(c => c.startsWith('align-'));
        const previewAlignClasses = [...previewElem.classList.values()].filter(c => c.startsWith('align-'));
        previewElem.classList.remove(...previewAlignClasses);
        previewElem.classList.add(...alignmentClasses);
    }

    editor.on('SetContent', () => {
        const previewElems = editor.dom.select('span.mce-preview-object');
        for (const previewElem of previewElems) {
            updateClassesForPreview(previewElem);
        }
    });

    editor.on('FormatApply', event => {
        const isAlignment = event.format.startsWith('align');
        const isElement = event.node instanceof editor.dom.doc.defaultView.HTMLElement;
        if (!isElement || !isAlignment || !event.node.matches('.mce-preview-object')) {
            return;
        }

        const realTarget = event.node.querySelector('iframe, video');
        if (realTarget) {
            const className = (editor.formatter.get(event.format)[0]?.classes || [])[0];
            const toAdd = !realTarget.classList.contains(className);

            const wrapperClasses = (event.node.getAttribute('data-mce-p-class') || '').split(' ');
            const wrapperClassesFiltered = wrapperClasses.filter(c => !c.startsWith('align-'));
            if (toAdd) {
                wrapperClassesFiltered.push(className);
            }

            const classesToApply = wrapperClassesFiltered.join(' ');
            event.node.setAttribute('data-mce-p-class', classesToApply);

            realTarget.setAttribute('class', classesToApply);
            editor.formatter.apply(event.format, {}, realTarget);
            updateClassesForPreview(event.node);
        }
    });
}

/**
 * Cleans up and removes text-alignment specific properties on all child elements.
 * @param {HTMLElement} element
 */
function cleanChildAlignment(element) {
    const alignedChildren = element.querySelectorAll('[align],[style*="text-align"],.align-center,.align-left,.align-right');
    for (const child of alignedChildren) {
        child.removeAttribute('align');
        child.style.textAlign = null;
        child.classList.remove('align-center', 'align-right', 'align-left');
    }
}

/**
 * Cleans up the direction property for an element.
 * Removes all inline direction control from child elements.
 * Removes non "dir" attribute direction control from provided element.
 * @param {HTMLElement} element
 */
function cleanElementDirection(element) {
    const directionChildren = element.querySelectorAll('[dir],[style*="direction"]');
    for (const child of directionChildren) {
        child.removeAttribute('dir');
        child.style.direction = null;
    }

    cleanChildAlignment(element);
    element.style.direction = null;
    element.style.textAlign = null;
    element.removeAttribute('align');
}

/**
 * @typedef {Function} TableCellHandler
 * @param {HTMLTableCellElement} cell
 */

/**
 * This tracks table cell range selection, so we can apply custom handling where
 * required to actions applied to such selections.
 * The events used don't seem to be advertised by TinyMCE.
 * Found at https://github.com/tinymce/tinymce/blob/6.8.3/modules/tinymce/src/models/dom/main/ts/table/api/Events.ts
 * @param {Editor} editor
 */
export function handleTableCellRangeEvents(editor) {
    /** @var {HTMLTableCellElement[]} * */
    let selectedCells = [];

    editor.on('TableSelectionChange', event => {
        selectedCells = (event.cells || []).map(cell => cell.dom);
    });
    editor.on('TableSelectionClear', () => {
        selectedCells = [];
    });

    /**
     * @type {Object<String, TableCellHandler>}
     */
    const actionByCommand = {
        // TinyMCE does not seem to do a great job on clearing styles in complex
        // scenarios (like copied word content) when a range of table cells
        // are selected. Here we watch for clear formatting events, so some manual
        // cleanup can be performed.
        RemoveFormat: cell => {
            const attrsToRemove = ['class', 'style', 'width', 'height', 'align'];
            for (const attr of attrsToRemove) {
                cell.removeAttribute(attr);
            }
        },

        // TinyMCE does not apply direction events to table cell range selections
        // so here we hastily patch in that ability by setting the direction ourselves
        // when a direction event is fired.
        mceDirectionLTR: cell => {
            cell.setAttribute('dir', 'ltr');
            cleanElementDirection(cell);
        },
        mceDirectionRTL: cell => {
            cell.setAttribute('dir', 'rtl');
            cleanElementDirection(cell);
        },

        // The "align" attribute can exist on table elements so this clears
        // the attribute, and also clears common child alignment properties,
        // when a text direction action is made for a table cell range.
        JustifyLeft: cell => {
            cell.removeAttribute('align');
            cleanChildAlignment(cell);
        },
    };

    // Copy justify left action to other alignment actions
    actionByCommand.JustifyRight = actionByCommand.JustifyLeft;
    actionByCommand.JustifyCenter = actionByCommand.JustifyLeft;
    actionByCommand.JustifyFull = actionByCommand.JustifyLeft;

    editor.on('ExecCommand', event => {
        const action = actionByCommand[event.command];
        if (action) {
            for (const cell of selectedCells) {
                action(cell);
            }
        }
    });
}

/**
 * Direction control might not work if there are other unexpected direction-handling styles
 * or attributes involved nearby. This watches for direction change events to clean
 * up direction controls, removing non-dir-attr direction controls, while removing
 * directions from child elements that may be involved.
 * @param {Editor} editor
 */
export function handleTextDirectionCleaning(editor) {
    editor.on('ExecCommand', event => {
        const command = event.command;
        if (command !== 'mceDirectionLTR' && command !== 'mceDirectionRTL') {
            return;
        }

        const blocks = editor.selection.getSelectedBlocks();
        for (const block of blocks) {
            cleanElementDirection(block);
        }
    });
}