var copy_and_paste = (function () {

var exports = {};

function find_boundary_tr(initial_tr, iterate_row) {
    var j;
    var skip_same_td_check = false;
    var tr = initial_tr;

    // If the selection boundary is somewhere that does not have a
    // parent tr, we should let the browser handle the copy-paste
    // entirely on its own
    if (tr.length === 0) {
        return;
    }

    // If the selection boundary is on a table row that does not have an
    // associated message id (because the user clicked between messages),
    // then scan downwards until we hit a table row with a message id.
    // To ensure we can't enter an infinite loop, bail out (and let the
    // browser handle the copy-paste on its own) if we don't hit what we
    // are looking for within 10 rows.
    for (j = 0; !tr.is('.message_row') && j < 10; j += 1) {
        tr = iterate_row(tr);
    }
    if (j === 10) {
        return;
    } else if (j !== 0) {
        // If we updated tr, then we are not dealing with a selection
        // that is entirely within one td, and we can skip the same td
        // check (In fact, we need to because it won't work correctly
        // in this case)
        skip_same_td_check = true;
    }
    return [rows.id(tr), skip_same_td_check];
}

function construct_recipient_header(message_row) {
    var message_header_content = rows.get_message_recipient_header(message_row)
        .text()
        .replace(/\s+/g, " ")
        .replace(/^\s/, "").replace(/\s$/, "");
    return $('<p>').append($('<strong>').text(message_header_content));
}

function construct_copy_div(div, start_id, end_id) {
    var start_row = current_msg_list.get_row(start_id);
    var start_recipient_row = rows.get_message_recipient_row(start_row);
    var start_recipient_row_id = rows.id_for_recipient_row(start_recipient_row);
    var should_include_start_recipient_header = false;

    var last_recipient_row_id = start_recipient_row_id;
    for (var row = start_row; rows.id(row) <= end_id; row = rows.next_visible(row)) {
        var recipient_row_id = rows.id_for_recipient_row(rows.get_message_recipient_row(row));
        // if we found a message from another recipient,
        // it means that we have messages from several recipients,
        // so we have to add new recipient's bar to final copied message
        // and wouldn't forget to add start_recipient's bar at the beginning of final message
        if (recipient_row_id !== last_recipient_row_id) {
            div.append(construct_recipient_header(row));
            last_recipient_row_id = recipient_row_id;
            should_include_start_recipient_header = true;
        }
        var message = current_msg_list.get(rows.id(row));
        var message_firstp = $(message.content).slice(0, 1);
        message_firstp.prepend(message.sender_full_name + ": ");
        div.append(message_firstp);
        div.append($(message.content).slice(1));
    }

    if (should_include_start_recipient_header) {
        div.prepend(construct_recipient_header(start_row));
    }
}

function copy_handler() {
    var selection = window.getSelection();
    var i;
    var range;
    var ranges = [];
    var startc;
    var endc;
    var initial_end_tr;
    var start_id;
    var end_id;
    var start_data;
    var end_data;
    var skip_same_td_check = false;
    var div = $('<div>');
    for (i = 0; i < selection.rangeCount; i += 1) {
        range = selection.getRangeAt(i);
        ranges.push(range);

        startc = $(range.startContainer);
        start_data = find_boundary_tr($(startc.parents('.selectable_row, .message_header')[0]), function (row) {
            return row.next();
        });
        if (start_data === undefined) {
            return;
        }
        start_id = start_data[0];

        endc = $(range.endContainer);
        // If the selection ends in the bottom whitespace, we should act as
        // though the selection ends on the final message
        // Chrome seems to like selecting the compose_close button
        // when you go off the end of the last message
        if (endc.attr('id') === "bottom_whitespace" || endc.attr('id') === "compose_close") {
            initial_end_tr = $(".message_row:last");
            skip_same_td_check = true;
        } else {
            initial_end_tr = $(endc.parents('.selectable_row')[0]);
        }
        end_data = find_boundary_tr(initial_end_tr, function (row) {
            return row.prev();
        });
        if (end_data === undefined) {
            return;
        }
        end_id = end_data[0];

        if (start_data[1] || end_data[1]) {
            skip_same_td_check = true;
        }

        // we should let the browser handle the copy-paste entirely on its own
        // (In this case, there is no need for our special copy code)
        if (!skip_same_td_check &&
            startc.parents('.selectable_row>div')[0] === endc.parents('.selectable_row>div')[0]) {
            return;
        }

        // Construct a div for what we want to copy (div)
        construct_copy_div(div, start_id, end_id);
    }

    // Select div so that the browser will copy it
    // instead of copying the original selection
    div.css({position: 'absolute', left: '-99999px'})
        .attr('id', 'copytempdiv');
    $('body').append(div);
    selection.selectAllChildren(div[0]);

    /*
    The techniques we use in this code date back to
    2013 and may be obsolete today (and may not have
    been even the best workaround back then).

    https://github.com/zulip/zulip/commit/fc0b7c00f16316a554349f0ad58c6517ebdd7ac4

    The idea is that we build a temp div, return from
    this function, let jQuery process the selection,
    then restore the selection on a zero-second timer
    back to the original selection.

    Do not be afraid to change this code if you understand
    how modern browsers deal with copy/paste.  Just test
    your changes carefully.
    */

    window.setTimeout(function () {
        selection = window.getSelection();
        selection.removeAllRanges();
        _.each(ranges, function (range) {
            selection.addRange(range);
        });
        $('#copytempdiv').remove();
    }, 0);
}

exports.paste_handler_converter = function (paste_html) {
    var converters = {
        converters: [
            {
                filter: ['h1', 'h2', 'h3', 'h4', 'h5', 'h6'],
                replacement: function (content) {
                    return content;
                },
            },

            {
                filter: ['em', 'i'],
                replacement: function (content) {
                    return '*' + content + '*';
                },
            },
            {
                // Checks for raw links without custom text or title.
                filter: function (node) {
                    return node.nodeName === "A" &&
                      node.href === node.innerHTML &&
                      node.href === node.title;
                },
                replacement: function (content) {
                    return content;
                },
            },
            {
                // Checks for escaped ordered list syntax.
                filter: function (node) {
                    return /(\d+)\\\. /.test(node.innerHTML);
                },
                replacement: function (content) {
                    return content.replace(/(\d+)\\\. /g, '$1. ');
                },
            },
        ],
    };
    var markdown_html = toMarkdown(paste_html, converters);

    // Now that we've done the main conversion, we want to remove
    // any HTML tags that weren't converted to markdown-style
    // text, since Bugdown doesn't support those.
    var div = document.createElement("div");
    div.innerHTML = markdown_html;
    // Using textContent for modern browsers, innerText works for Internet Explorer
    var markdown_text = div.textContent || div.innerText || "";
    markdown_text = markdown_text.trim();
    // Removes newlines before the start of a list and between list elements.
    markdown_text = markdown_text.replace(/\n+([*+-])/g, '\n$1');
    return markdown_text;
};

exports.paste_handler = function (event) {
    var clipboardData = event.originalEvent.clipboardData;
    if (!clipboardData) {
        // On IE11, ClipboardData isn't defined.  One can instead
        // access it with `window.clipboardData`, but even that
        // doesn't support text/html, so this code path couldn't do
        // anything special anyway.  So we instead just let the
        // default paste handler run on IE11.
        return;
    }

    if (clipboardData.getData) {
        var paste_html = clipboardData.getData('text/html');
        if (paste_html && page_params.development_environment) {
            var text = exports.paste_handler_converter(paste_html);
            var mdImageRegex = /^!\[.*\]\(.*\)$/;
            if (text.match(mdImageRegex)) {
                // This block catches cases where we are pasting an
                // image into Zulip, which should be handled by the
                // jQuery filedrop library, not this code path.
                return;
            }
            event.preventDefault();
            event.stopPropagation();
            compose_ui.insert_syntax_and_focus(text);
        }
    }
};

exports.initialize = function () {
    $(document).on('copy', copy_handler);
    $("#compose-textarea").bind('paste', exports.paste_handler);
    $('body').on('paste', '#message_edit_form', exports.paste_handler);
};

return exports;
}());

if (typeof module !== 'undefined') {
    module.exports = copy_and_paste;
}
window.copy_and_paste = copy_and_paste;