/**
 * Roundcube editor js library
 *
 * This file is part of the Roundcube Webmail client
 *
 * @licstart  The following is the entire license notice for the
 * JavaScript code in this file.
 *
 * Copyright (c) The Roundcube Dev Team
 *
 * The JavaScript code in this page is free software: you can
 * redistribute it and/or modify it under the terms of the GNU
 * General Public License (GNU GPL) as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option)
 * any later version.  The code is distributed WITHOUT ANY WARRANTY;
 * without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GNU GPL for more details.
 *
 * As additional permission under GNU GPL version 3 section 7, you
 * may distribute non-source (e.g., minimized or compacted) forms of
 * that code without the copy of the GNU GPL normally required by
 * section 4, provided you include this license notice and a URL
 * through which recipients can access the Corresponding Source.
 *
 * @licend  The above is the entire license notice
 * for the JavaScript code in this file.
 *
 * @author Eric Stadtherr <estadtherr@gmail.com>
 * @author Aleksander Machniak <alec@alec.pl>
 */

/**
 * Roundcube Text Editor Widget class
 * @constructor
 */
function rcube_text_editor(config, id) {
    var ref = this,
        editorElement = $('#' + id),
        abs_url = location.href.replace(/[?#].*$/, '').replace(/\/$/, ''),
        conf = {
            selector: '#' + (editorElement.is('.mce_editor') ? id : 'fake-editor-id'),
            readonly: editorElement.is('[readonly],[disabled]'),
            cache_suffix: 's=5080200',
            theme: 'silver',
            language: config.lang,
            content_css: rcmail.assets_path(config.content_css),
            content_style: config.content_style,
            menubar: false,
            statusbar: false,
            // toolbar_sticky: true, // does not work in scrollable element: https://github.com/tinymce/tinymce/issues/5227
            toolbar_drawer: 'sliding',
            toolbar: 'bold italic underline | alignleft aligncenter alignright alignjustify'
                + ' | $font | forecolor backcolor',
            extended_valid_elements: 'font[face|size|color|style],span[id|class|align|style]',
            // Allow style tag, have to be allowed inside body/div/blockquote (#7088)
            valid_children: '+body[style],+blockquote[style],+div[style]',
            relative_urls: false,
            remove_script_host: false,
            convert_urls: false, // #1486944
            image_description: false,
            paste_webkit_styles: 'color font-size font-family font-weight background-color',
            automatic_uploads: false, // allows to paste images
            paste_data_images: true,
            // Note: We disable contextmenu options specifically for browser_spellcheck:true.
            //       Otherwise user would have to use Right-Click with CTRL to get to
            //       the browser's spellchecker options. Should you disable browser_spellcheck
            //       you can enable other contextmenu options (by removing these options below).
            browser_spellcheck: true,
            contextmenu: 'spellchecker',
            anchor_bottom: false,
            anchor_top: false,
            file_picker_types: 'image media',
            file_picker_callback: function (callback, value, meta) {
                ref.file_picker_callback(callback, value, meta);
            },
            min_height: config.mode == 'identity' ? 100 : 400,
            deprecation_warnings: false,
        };

    // register spellchecker for plain text editor
    this.spellcheck_observer = function () {};
    if (config.spellchecker) {
        this.spellchecker = config.spellchecker;
        if (config.spellcheck_observer) {
            this.spellchecker.spelling_state_observer = this.spellcheck_observer = config.spellcheck_observer;
        }
    }

    // Note: must be registered only once (#1490311)
    if (!tinymce.registered_request_token) {
        tinymce.registered_request_token = true;
        tinymce.util.XHR.on('beforeSend', function (e) {
            // secure spellchecker requests with Roundcube token
            e.xhr.setRequestHeader('X-Roundcube-Request', rcmail.env.request_token);
            // A hacky way of setting spellchecker language (there's no API for this in Tiny)
            if (e.settings && e.settings.data) {
                e.settings.data = e.settings.data.replace(/^(method=[a-zA-Z]+&lang=)([^&]+)/, '$1' + rcmail.env.spell_lang);
            }
        });
    }

    // minimal editor
    if (config.mode == 'identity' || config.mode == 'response') {
        conf.toolbar += ' | charmap hr link unlink image code $extra';
        $.extend(conf, {
            plugins: 'autolink charmap code hr image link paste tabfocus',
            file_picker_types: 'image',
        });
    }
    // full-featured editor
    else {
        conf.toolbar += ' | bullist numlist outdent indent ltr rtl blockquote'
        + ' | link unlink table | $extra charmap image media | code searchreplace undo redo',
        $.extend(conf, {
            plugins: 'autolink charmap code directionality link lists image media nonbreaking'
                + ' paste table tabfocus searchreplace spellchecker',
            spellchecker_rpc_url: abs_url + '/?_task=utils&_action=spell_html&_remote=1',
            spellchecker_language: rcmail.env.spell_lang,
        });
    }

    // add TinyMCE plugins/buttons from Roundcube plugin
    $.each(config.extra_plugins || [], function () {
        if (conf.plugins.indexOf(this) < 0) {
            conf.plugins = conf.plugins + ' ' + this;
        }
    });
    $.each(config.extra_buttons || [], function () {
        if (conf.toolbar.indexOf(this) < 0) {
            conf.toolbar = conf.toolbar.replace('$extra', '$extra ' + this);
        }
    });

    // disable TinyMCE plugins/buttons from Roundcube plugin
    $.each(config.disabled_plugins || [], function () {
        conf.plugins = conf.plugins.replace(this, '');
    });
    $.each(config.disabled_buttons || [], function () {
        conf.toolbar = conf.toolbar.replace(this, '');
    });

    // font list, convert to TinyMCE format
    var fonts = [];
    $.each(config.font_formats || [], function (key) {
        fonts.push(key + '=' + this.replace(/"/g, '').toLowerCase());
    });
    conf.font_formats = fonts.join('; ');
    if (fonts.length > 1) {
        conf.toolbar = conf.toolbar.replace('$font', 'fontselect $font');
    }

    // font size list
    conf.fontsize_formats = config.fontsize_formats.join(' ');
    if (config.fontsize_formats.length > 1) {
        conf.toolbar = conf.toolbar.replace('$font', 'fontsizeselect $font');
    }

    conf.toolbar = conf.toolbar.replace(/($extra|$font)/, '').replace(/\|\s+\|/g, '|');

    // support external configuration settings e.g. from skin
    if (window.rcmail_editor_settings) {
        $.extend(conf, window.rcmail_editor_settings);
    }

    conf.setup = function (ed) {
        ed.on('init', function () {
            ref.init_callback(ed);
        });
        // add handler for spellcheck button state update
        ed.on('SpellcheckStart SpellcheckEnd', function (args) {
            ref.spellcheck_active = args.type == 'spellcheckstart';
            ref.spellcheck_observer();
        });
        ed.on('keypress', function () {
            rcmail.compose_type_activity++;
        });
        ed.on('PastePostProcess', function (e) {
            $(e.node).find('img').each(function () {
                var id = 'i' + Date.now();

                // No referrer for privacy
                this.referrerPolicy = 'no-referrer';

                // Need an attribute to find the image element after paste
                this.setAttribute('data-img-id', id);

                // Replace the 'src' with data: URI after the image has been loaded
                // This way if we fetch the image again the browser will fetch it from cache
                this.onload = function () {
                    this.onload = null; ref.replace_img_src(this.src, id);
                };
            });
        });
        // make links open on shift-click
        ed.on('click', function (e) {
            var link = $(e.target).closest('a');
            if (link.length && e.shiftKey) {
                window.open(link.get(0).href, '_blank');
                return false;
            }
        });
        ed.on('focus blur', function (e) {
            $(ed.getContainer()).toggleClass('focused');
        });

        if (conf.setup_callback) {
            conf.setup_callback(ed);
        }
    };

    rcmail.triggerEvent('editor-init', { config: conf, ref: ref, id: id });

    // textarea identifier
    this.id = id;
    // reference to active editor (if in HTML mode)
    this.editor = null;

    tinymce.init(conf);

    // react to real individual tinyMCE editor init
    this.init_callback = function (editor) {
        this.editor = editor;

        // Browsers have performance problems with rendering a lot of content in a textarea.
        // To workaround that we create a separate hidden textarea for the content and copy it
        // to the editor after the page is already loaded (#8108)
        var content, editorContentElement = editorElement.data('html-editor-content-element');
        if (editorContentElement && (content = $('#' + editorContentElement).val())) {
            editor.setContent(content);
            $('#' + editorContentElement).remove();
        }

        if (rcmail.env.action == 'compose') {
            var area = $('#' + this.id),
                height = $('div.tox-toolbar__group', area.parent()).first().height();

            // the editor might be still not fully loaded, making the editing area
            // inaccessible, wait and try again (#1490310)
            if (height > 200 || height > area.height()) {
                return setTimeout(function () {
                    ref.init_callback(editor);
                }, 300);
            }

            var elem = rcube_find_object('_from'),
                fe = rcmail.env.compose_focus_elem;

            if (elem && elem.type == 'select-one') {
                // insert signature (only for the first time)
                if (!rcmail.env.identities_initialized) {
                    rcmail.change_identity(elem);
                }

                // Focus previously focused element
                if (fe && fe.id != this.id && fe.nodeName != 'BODY') {
                    window.focus(); // for WebKit (#1486674)
                    fe.focus();
                    rcmail.env.compose_focus_elem = null;
                }
            }
        }

        rcmail.triggerEvent('editor-load', { config: conf, ref: this });

        // set tabIndex and set focus to element that was focused before
        this.tabindex(this.force_focus || (fe && fe.id == this.id));

        // Trigger resize (needed for proper editor resizing in some browsers)
        $(window).resize();
    };

    // set tabIndex on tinymce editor
    this.tabindex = function (focus) {
        if (rcmail.env.task == 'mail' && this.editor) {
            var textarea = this.editor.getElement(),
                node = this.editor.getContentAreaContainer().childNodes[0];

            if (textarea && node) {
                node.tabIndex = textarea.tabIndex;
            }

            // find :prev and :next elements to get focus when tabbing away
            if (textarea.tabIndex > 0) {
                var x = null,
                    tabfocus_elements = [':prev', ':next'],
                    el = tinymce.DOM.select('*[tabindex=' + textarea.tabIndex + ']:not(iframe)');

                tinymce.each(el, function (e, i) {
                    if (e.id == ref.id) {
                        x = i; return false;
                    }
                });
                if (x !== null) {
                    if (el[x - 1] && el[x - 1].id) {
                        tabfocus_elements[0] = el[x - 1].id;
                    }
                    if (el[x + 1] && el[x + 1].id) {
                        tabfocus_elements[1] = el[x + 1].id;
                    }
                    this.editor.settings.tabfocus_elements = tabfocus_elements.join(',');
                }
            }

            // ContentEditable reset fixes invisible cursor issue in Firefox < 25
            if (bw.mz && bw.vendver < 25) {
                $(this.editor.getBody()).prop('contenteditable', false).prop('contenteditable', true);
            }
        }

        if (focus) {
            this.focus();
        }
    };

    // focus the editor
    this.focus = function () {
        $(this.editor || ('#' + this.id)).focus();
        this.force_focus = false;
    };

    // Returns current editor mode
    this.is_html = function () {
        return !!this.editor;
    };

    // switch html/plain mode
    this.toggle = function (ishtml, noconvert) {
        var curr, content, result,
            // these non-printable chars are not removed on text2html and html2text
            // we can use them as temp signature replacement
            sig_mark = '\u0002\u0003',
            input = $('#' + this.id),
            signature = rcmail.env.identity ? rcmail.env.signatures[rcmail.env.identity] : null,
            is_sig = signature && signature.text && signature.text.length > 1;

        // apply spellcheck changes if spell checker is active
        this.spellcheck_stop();

        if (ishtml) {
            content = input.val();

            // replace current text signature with temp mark
            if (is_sig) {
                content = content.replace(/\r\n/, '\n');
                content = content.replace(signature.text.replace(/\r\n/, '\n'), sig_mark);
            }

            var init_editor = function (data) {
                // replace signature mark with html version of the signature
                if (is_sig) {
                    data = data.replace(sig_mark, '<div id="_rc_sig">' + signature.html + '</div>');
                }

                ref.force_focus = true;
                input.val(data);
                tinymce.execCommand('mceAddEditor', false, ref.id);
            };

            // convert to html
            if (!noconvert) {
                result = rcmail.plain2html(content, init_editor);
            } else {
                init_editor(content);
                result = true;
            }
        } else if (this.editor) {
            if (is_sig) {
                // get current version of signature, we'll need it in
                // case of html2text conversion abort
                if (curr = this.editor.dom.get('_rc_sig')) {
                    curr = curr.innerHTML;
                }

                // replace current signature with some non-printable characters
                // we use non-printable characters, because this replacement
                // is visible to the user
                // doing this after getContent() would be hard
                this.editor.dom.setHTML('_rc_sig', sig_mark);
            }

            // get html content
            content = this.editor.getContent();

            var init_plaintext = function (data) {
                tinymce.execCommand('mceRemoveEditor', false, ref.id);
                ref.editor = null;

                // replace signature mark with text version of the signature
                if (is_sig) {
                    data = data.replace(sig_mark, '\n' + signature.text);
                }

                input.val(data).focus().trigger('input');
                rcmail.set_caret_pos(input.get(0), 0);
            };

            // convert html to text
            if (!noconvert) {
                result = rcmail.html2plain(content, init_plaintext);
            } else {
                init_plaintext(input.val());
                result = true;
            }

            // bring back current signature
            if (!result && curr) {
                this.editor.dom.setHTML('_rc_sig', curr);
            }
        }

        return result;
    };

    // start spellchecker
    this.spellcheck_start = function () {
        if (this.editor) {
            tinymce.execCommand('mceSpellCheck', true);
            this.spellcheck_observer();
        } else if (this.spellchecker && this.spellchecker.spellCheck) {
            this.spellchecker.spellCheck();
        }
    };

    // stop spellchecker
    this.spellcheck_stop = function () {
        var ed = this.editor;

        if (ed) {
            if (ed.plugins && ed.plugins.spellchecker && this.spellcheck_active) {
                ed.execCommand('mceSpellCheck', false);
                this.spellcheck_observer();
            }
        } else if (ed = this.spellchecker) {
            if (ed.state && ed.state != 'ready' && ed.state != 'no_error_found') {
                $(ed.spell_span).trigger('click');
            }
        }
    };

    // spellchecker state
    this.spellcheck_state = function () {
        var ed;

        if (this.editor) {
            return this.spellcheck_active;
        }

        if ((ed = this.spellchecker) && ed.state) {
            return ed.state != 'ready' && ed.state != 'no_error_found';
        }
    };

    // resume spellchecking, highlight provided misspellings without a new ajax request
    this.spellcheck_resume = function (data) {
        var ed = this.editor;

        if (ed) {
            ed.plugins.spellchecker.markErrors(data);
        } else if (ed = this.spellchecker) {
            ed.prepare(false, true);
            ed.processData(data);
        }
    };

    // get selected (spellchecker) language
    this.get_language = function () {
        return rcmail.env.spell_lang;
    };

    // set language for spellchecking
    this.set_language = function (lang) {
        var ed = this.editor;

        if (ed) {
            // TODO: this has no effect in recent Tiny versions
            ed.settings.spellchecker_language = lang;
        }
        if (ed = this.spellchecker) {
            ed.setCurrentLanguage(lang);
        }

        rcmail.env.spell_lang = lang;
    };

    // replace selection with text snippet
    // input can be a string or object with 'text' and 'html' properties
    this.replace = function (input) {
        var format, ed = this.editor;

        if (!input) {
            return false;
        }

        // insert into tinymce editor
        if (ed) {
            ed.getWin().focus(); // correct focus in IE & Chrome

            if ($.type(input) == 'object' && ('html' in input)) {
                input = input.html;
                format = 'html';
            } else {
                if ($.type(input) == 'object') {
                    input = input.text || '';
                }

                input = rcmail.quote_html(input).replace(/\r?\n/g, '<br/>');
                format = 'text';
            }

            ed.selection.setContent(input, { format: format });
        }
        // replace selection in compose textarea
        else if (ed = rcube_find_object(this.id)) {
            var selection = rcmail.get_input_selection(ed),
                value = ed.value,
                pre = value.substring(0, selection.start),
                end = value.substring(selection.end, value.length);

            if ($.type(input) == 'object') {
                input = input.text || '';
            }

            // insert response text
            ed.value = pre + input + end;

            // set caret after inserted text
            rcmail.set_caret_pos(ed, selection.start + input.length);
            ed.focus();
        }
    };

    // Fill the editor with specified content
    // TODO: support format conversion
    this.set_content = function (content) {
        if (this.editor) {
            this.editor.setContent(content);
            this.editor.getWin().focus();
        } else if (ed = rcube_find_object(this.id)) {
            $(ed).val(content).focus();
        }
    };

    // get selected text (if no selection returns all text) from the editor
    this.get_content = function (args) {
        var sigstart, ed = this.editor, text = '', strip = false,
            defaults = {
                refresh: true, selection: false, nosig: false, format: 'html',
            };

        if (!args) {
            args = defaults;
        } else {
            args = $.extend(defaults, args);
        }

        // apply spellcheck changes if spell checker is active
        if (args.refresh) {
            this.spellcheck_stop();
        }

        // get selected text from tinymce editor
        if (ed) {
            if (args.selection) {
                text = ed.selection.getContent({ format: args.format });
            }

            if (!text) {
                text = ed.getContent({ format: args.format });
                // @todo: strip signature in html mode
                strip = args.format == 'text';
            }
        }
        // get selected text from compose textarea
        else if (ed = rcube_find_object(this.id)) {
            if (args.selection) {
                text = rcmail.get_input_selection(ed).text;
            }

            if (!text) {
                text = ed.value;
                strip = true;
            }
        }

        // strip off signature
        // @todo: make this optional
        if (strip && args.nosig) {
            sigstart = text.indexOf('-- \n');
            if (sigstart > 0) {
                text = text.substring(0, sigstart);
            }
        }

        return text;
    };

    // change user signature text
    this.change_signature = function (id, show_sig) {
        var position_element, cursor_pos, p = -1,
            input_message = $('#' + this.id),
            message = input_message.val(),
            sig = rcmail.env.identity;

        if (!this.editor) { // plain text mode
            // remove the 'old' signature
            if (show_sig && sig && rcmail.env.signatures && rcmail.env.signatures[sig]) {
                sig = rcmail.env.signatures[sig].text;
                sig = sig.replace(/\r\n/g, '\n');

                p = rcmail.env.top_posting ? message.indexOf(sig) : message.lastIndexOf(sig);
                if (p >= 0) {
                    message = message.substring(0, p) + message.substring(p + sig.length, message.length);
                }
            }

            // add the new signature string
            if (show_sig && rcmail.env.signatures && rcmail.env.signatures[id]) {
                sig = rcmail.env.signatures[id].text;
                sig = sig.replace(/\r\n/g, '\n');

                // in place of removed signature
                if (p >= 0) {
                    message = message.substring(0, p) + sig + message.substring(p, message.length);
                    cursor_pos = p - 1;
                }
                // empty message or new-message mode
                else if (!message || !rcmail.env.compose_mode) {
                    cursor_pos = message.length;
                    message += '\n\n' + sig;
                } else if (rcmail.env.top_posting && !rcmail.env.sig_below) {
                    // at cursor position
                    if (pos = rcmail.get_caret_pos(input_message.get(0))) {
                        message = message.substring(0, pos) + '\n' + sig + '\n\n' + message.substring(pos, message.length);
                        cursor_pos = pos;
                    }
                    // on top
                    else {
                        message = '\n\n' + sig + '\n\n' + message.replace(/^[\r\n]+/, '');
                        cursor_pos = 0;
                    }
                } else {
                    message = message.replace(/[\r\n]+$/, '');
                    cursor_pos = !rcmail.env.top_posting && message.length ? message.length + 1 : 0;
                    message += '\n\n' + sig;
                }
            } else {
                cursor_pos = rcmail.env.top_posting ? 0 : message.length;
            }

            input_message.val(message);

            // move cursor before the signature
            rcmail.set_caret_pos(input_message.get(0), cursor_pos);
        } else if (show_sig && rcmail.env.signatures) { // html
            var sigElem = this.editor.dom.get('_rc_sig');

            // Append the signature as a div within the body
            if (!sigElem) {
                var body = this.editor.getBody();

                sigElem = $('<div id="_rc_sig"></div>').get(0);

                // insert at start or at cursor position in top-posting mode
                // (but not if the content is empty and not in new-message mode)
                if (rcmail.env.top_posting && !rcmail.env.sig_below
                    && rcmail.env.compose_mode && (body.childNodes.length > 1 || $(body).text())
                ) {
                    this.editor.getWin().focus(); // correct focus in IE & Chrome

                    var node = this.editor.selection.getNode();

                    $(sigElem).insertBefore(node.nodeName == 'BODY' ? body.firstChild : node.nextSibling);
                    $('<p>').append($('<br>')).insertBefore(sigElem);
                } else {
                    body.appendChild(sigElem);
                    position_element = rcmail.env.top_posting && rcmail.env.compose_mode ? body.firstChild : $(sigElem).prev();
                }
            }

            sigElem.innerHTML = rcmail.env.signatures[id] ? rcmail.env.signatures[id].html : '';
        } else if (!rcmail.env.top_posting) {
            position_element = $(this.editor.getBody()).children().last();
        }

        // put cursor before signature and scroll the window
        if (this.editor && position_element && position_element.length) {
            this.editor.selection.setCursorLocation(position_element.get(0));
            this.editor.getWin().scroll(0, position_element.offset().top);
        }
    };

    // trigger content save
    this.save = function () {
        if (this.editor) {
            this.editor.save();
        }
    };

    // focus the editing area
    this.focus = function () {
        (this.editor || rcube_find_object(this.id)).focus();
    };

    // image selector
    this.file_picker_callback = function (callback, value, meta) {
        var i, button, elem, cancel, dialog, fn, hint, list = [],
            type = meta.filetype,
            form = $('.upload-form').clone();

        // open image selector dialog
        this.editor.windowManager.open({
            title: rcmail.get_label('select' + type),
            body: {
                type: 'panel',
                items: [{
                    type: 'htmlpanel',
                    html: '<div id="image-selector" class="image-selector file-upload"><ul id="image-selector-list" class="attachmentslist"></ul></div>',
                }],
            },
            buttons: [{
                type: 'cancel',
                text: rcmail.get_label('close'),
                onclick: function () {
                    ref.file_picker_close();
                },
            }],
        });

        rcmail.env.file_picker_callback = callback;
        rcmail.env.file_picker_type = type;

        dialog = $('#image-selector');

        if (!form.length) {
            form = this.file_upload_form(rcmail.gui_objects.uploadform);
        } else {
            form.find('button,a.button').slice(1).remove();
        } // need only the first button

        button = dialog.prepend(form).find('button,a.button')
            .text(rcmail.get_label('add' + type))
            .focus();

        if (!button.is('.btn')) {
            button.addClass('tox-button');
        }

        // fill images list with available images
        for (i in rcmail.env.attachments) {
            if (elem = ref.file_picker_entry(i, rcmail.env.attachments[i])) {
                list.push(elem);
            }
        }

        cancel = dialog.parents('.tox-dialog').find('button').last();

        // Add custom Tab key handlers, tabindex does not work
        list = $('#image-selector-list').append(list).on('keydown', 'li', function (e) {
            if (e.which == 9) {
                if (rcube_event.get_modifier(e) == SHIFT_KEY) {
                    if (!$(this).prev().focus().length) {
                        button.focus();
                    }
                } else if (!$(this).next().focus().length) {
                    cancel.focus();
                }

                return false;
            }
        });

        button.keydown(function (e) {
            if (e.which == 9) { // Tab
                if (rcube_event.get_modifier(e) == SHIFT_KEY || !list.find('li').first().focus().length) {
                    cancel.focus();
                }

                return false;
            }

            if (e.which == 13) { // Enter
                this.click();
            }
        });

        cancel.keydown(function (e) {
            if (e.which == 9) {
                if (rcube_event.get_modifier(e) != SHIFT_KEY || !list.find('li').last().focus().length) {
                    button.focus();
                }

                return false;
            }
        });

        // enable drag-n-drop area
        if (window.FormData) {
            if (!rcmail.env.filedrop) {
                rcmail.env.filedrop = {};
            }
            if (rcmail.gui_objects.filedrop) {
                rcmail.env.old_file_drop = rcmail.gui_objects.filedrop;
            }

            rcmail.gui_objects.filedrop = $('#image-selector');
            rcmail.gui_objects.filedrop.addClass('droptarget')
                .on('dragover dragleave', function (e) {
                    e.preventDefault();
                    e.stopPropagation();
                    $(this)[(e.type == 'dragover' ? 'addClass' : 'removeClass')]('hover');
                })
                .get(0).addEventListener('drop', function (e) {
                    return rcmail.file_dropped(e);
                }, false);
        }

        // register handler for successful file upload
        if (!rcmail.env['file_dialog_event_' + type]) {
            rcmail.env['file_dialog_event+' + type] = true;
            rcmail.addEventListener('fileuploaded', function (attr) {
                var elem;
                if (elem = ref.file_picker_entry(attr.name, attr.attachment)) {
                    list.prepend(elem);
                    elem.focus();
                }
            });
        }

    // @todo: upload progress indicator
    };

    // close file browser window
    this.file_picker_close = function (url) {
        this.editor.windowManager.close();

        if (url) {
            rcmail.env.file_picker_callback(url);
        }

        if (rcmail.env.old_file_drop) {
            rcmail.gui_objects.filedrop = rcmail.env.old_file_drop;
        }
    };

    // creates file browser entry
    this.file_picker_entry = function (file_id, file) {
        if (!file.complete || !file.mimetype) {
            return;
        }

        if (rcmail.file_upload_id) {
            rcmail.set_busy(false, null, rcmail.file_upload_id);
        }

        var rx, img_src;

        switch (rcmail.env.file_picker_type) {
            case 'image':
                rx = /^image\//i;

                break;
            case 'media':
                rx = /^video\//i;
                img_src = rcmail.assets_path('program/resources/tinymce/video.png');

                break;
            default:
                return;
        }

        if (rx.test(file.mimetype)) {
            var path = rcmail.env.comm_path + '&_from=' + rcmail.env.action,
                action = rcmail.env.compose_id ? '&_id=' + rcmail.env.compose_id + '&_action=display-attachment' : '&_action=upload-display',
                href = path + action + '&_file=' + file_id,
                img = $('<img>').attr({ title: file.name, src: img_src ? img_src : href + '&_thumbnail=1' });

            return $('<li>').attr({ tabindex: 0 })
                .data('url', href)
                .append($('<span class="img">').append(img))
                .append($('<span class="name">').text(file.name))
                .click(function () {
                    ref.file_picker_close($(this).data('url'));
                })
                .keydown(function (e) {
                    if (e.which == 13) {
                        ref.file_picker_close($(this).data('url'));
                    }
                });
        }
    };

    this.file_upload_form = function (clone_form) {
        var hint = clone_form ? $(clone_form).find('.hint').text() : '',
            form = $('<form id="imageuploadform">').attr({ method: 'post', enctype: 'multipart/form-data' });
        file = $('<input>').attr({
            name: '_file[]', type: 'file', multiple: true, style: 'opacity:0;height:1px;width:1px',
        })
            .change(function () {
                rcmail.upload_file(form, 'upload');
            }),
        wrapper = $('<div class="upload-form">')
            .append($('<button>').attr({ class: 'btn btn-secondary attach', href: '#', onclick: "rcmail.upload_input('imageuploadform')" }));

        if (hint) {
            wrapper.prepend($('<div class="hint">').text(hint));
        }

        // clone existing upload form
        if (clone_form) {
            file.attr('name', $('input[type="file"]', clone_form).attr('name'));
            form.attr('action', $(clone_form).attr('action'));
        }

        form.append(file).append($('<input>').attr({ type: 'hidden', name: '_token', value: rcmail.env.request_token }));

        return wrapper.append(form);
    };

    // Replace pasted image src location with data: URI
    this.replace_img_src = function (src, id) {
        if (!window.fetch || !src || !src.match(/^https?:\/\//)) {
            return;
        }

        var fetch_params = {
            referrerPolicy: 'no-referrer',
        };

        fetch(src, fetch_params).then(function (response) {
            response.arrayBuffer().then(function (body) {
                var url, ctype = response.headers.get('content-type'),
                    u8Buf = new Uint8Array(body),
                    latinBuf = '';

                u8Buf.forEach(function (byte) {
                    latinBuf += String.fromCharCode(byte);
                });

                if (ctype && latinBuf) {
                    url = 'data:' + ctype + ';base64,' + btoa(latinBuf);
                    $(ref.editor.getBody()).find('img[data-img-id="' + id + '"]').attr({
                        src: url,
                        'data-mce-src': url,
                        'data-img-id': null,
                    });
                }
            });
        });
    };
}