// For simplicity, we use a list for our internal
// data, since that matches what the server sends us.
let my_alert_words = [];

exports.set_words = function (words) {
    my_alert_words = words;
};

exports.get_word_list = function () {
    // People usually only have a couple alert
    // words, so it's cheap to be defensive
    // here and give a copy of the list to
    // our caller (in case they want to sort it
    // or something).
    return [...my_alert_words];
};

exports.has_alert_word = function (word) {
    return my_alert_words.includes(word);
};

// escape_user_regex taken from jquery-ui/autocomplete.js,
// licensed under MIT license.
function escape_user_regex(value) {
    return value.replace(/[-[\]{}()*+?.,\\^$|#\s]/g, "\\$&");
}

exports.process_message = function (message) {
    // Parsing for alert words is expensive, so we rely on the host
    // to tell us there any alert words to even look for.
    if (!message.alerted) {
        return;
    }

    for (const word of my_alert_words) {
        const clean = escape_user_regex(word);
        const before_punctuation = "\\s|^|>|[\\(\\\".,';\\[]";
        const after_punctuation = "\\s|$|<|[\\)\\\"\\?!:.,';\\]!]";

        const regex = new RegExp(
            "(" + before_punctuation + ")" + "(" + clean + ")" + "(" + after_punctuation + ")",
            "ig",
        );
        message.content = message.content.replace(
            regex,
            (match, before, word, after, offset, content) => {
                // Logic for ensuring that we don't muck up rendered HTML.
                const pre_match = content.substring(0, offset);
                // We want to find the position of the `<` and `>` only in the
                // match and the string before it. So, don't include the last
                // character of match in `check_string`. This covers the corner
                // case when there is an alert word just before `<` or `>`.
                const check_string = pre_match + match.substring(0, match.length - 1);
                const in_tag = check_string.lastIndexOf("<") > check_string.lastIndexOf(">");
                // Matched word is inside a HTML tag so don't perform any highlighting.
                if (in_tag === true) {
                    return before + word + after;
                }
                return before + "<span class='alert-word'>" + word + "</span>" + after;
            },
        );
    }
};

exports.notifies = function (message) {
    // We exclude ourselves from notifications when we type one of our own
    // alert words into a message, just because that can be annoying for
    // certain types of workflows where everybody on your team, including
    // yourself, sets up an alert word to effectively mention the team.
    return !people.is_current_user(message.sender_email) && message.alerted;
};

exports.initialize = (params) => {
    my_alert_words = params.alert_words;
};

window.alert_words = exports;