var emoji = (function () {

var exports = {};

// `emojis_by_name` is the central data source that is supposed to be
// used by every widget in the webapp for gathering data for displaying
// emojis. Emoji picker uses this data to derive data for its own use.
exports.emojis_by_name = {};

exports.emojis = [];
exports.all_realm_emojis = {};
exports.active_realm_emojis = {};
exports.default_emoji_aliases = {};

// Unfortunately, this list does not currently match on
// alias names like party_popper, simple_smile, and
// hammer_and_wrench. But thumbs_up sorts to the top
// for some other reason.
exports.frequently_used_emojis_list = [
    '1f44d',    // +1
    '1f389',    // tada
    '1f642',    // slight_smile
    '2764',     // heart
    '1f6e0',    // working_on_it
    '1f419',    // octopus
];

var default_emojis = [];

var zulip_emoji = {
    id: 'zulip',
    emoji_name: 'zulip',
    emoji_url: '/static/generated/emoji/images/emoji/unicode/zulip.png',
    is_realm_emoji: true,
    deactivated: false,
};

exports.update_emojis = function update_emojis(realm_emojis) {
    // exports.all_realm_emojis is emptied before adding the realm-specific emoji
    // to it. This makes sure that in case of deletion, the deleted realm_emojis
    // don't persist in exports.active_realm_emojis.
    exports.all_realm_emojis = {};
    exports.active_realm_emojis = {};

    // Copy the default emoji list and add realm-specific emoji to it
    exports.emojis = default_emojis.slice(0);
    _.each(realm_emojis, function (data) {
        exports.all_realm_emojis[data.id] = {id: data.id,
                                             emoji_name: data.name,
                                             emoji_url: data.source_url,
                                             deactivated: data.deactivated};
        if (data.deactivated !== true) {
            // export.emojis are used in composebox autocomplete. This condition makes sure
            // that deactivated emojis don't appear in the autocomplete.
            exports.emojis.push({emoji_name: data.name,
                                 emoji_url: data.source_url,
                                 is_realm_emoji: true});
            exports.active_realm_emojis[data.name] = {id: data.id,
                                                      emoji_name: data.name,
                                                      emoji_url: data.source_url};
        }
    });
    // Add the Zulip emoji to the realm emojis list
    exports.emojis.push(zulip_emoji);
    exports.all_realm_emojis.zulip = zulip_emoji;
    exports.active_realm_emojis.zulip = zulip_emoji;

    exports.build_emoji_data(exports.active_realm_emojis);
};

exports.initialize = function initialize() {

    _.each(emoji_codes.names, function (value) {
        var base_name = emoji_codes.name_to_codepoint[value];
        default_emojis.push({emoji_name: value,
                             codepoint: emoji_codes.name_to_codepoint[value]});

        if (exports.default_emoji_aliases.hasOwnProperty(base_name)) {
            exports.default_emoji_aliases[base_name].push(value);
        } else {
            exports.default_emoji_aliases[base_name] = [value];
        }
    });

    exports.update_emojis(page_params.realm_emoji);

    var emojiset = page_params.emojiset;
    if (page_params.emojiset === 'text') {
        // If the current emojiset is `text`, then we fallback to the
        // `google` emojiset on the backend (see zerver/views/home.py)
        // for displaying emojis in emoji picker and composebox
        // typeahead. This logic ensures that we do sprite sheet
        // prefetching for that case.
        emojiset = 'google';
    }
    // Load the sprite image and octopus image in the background, so
    // that the browser will cache it for later use.
    var sprite = new Image();
    sprite.src = '/static/generated/emoji/sheet-' + emojiset + '-64.png';
    var octopus_image = new Image();
    octopus_image.src = '/static/generated/emoji/images-' + emojiset + '-64/1f419.png';
};

exports.build_emoji_data = function (realm_emojis) {
    exports.emojis_by_name = {};
    var emoji_dict;
    _.each(realm_emojis, function (realm_emoji, realm_emoji_name) {
        emoji_dict = {
            name: realm_emoji_name,
            aliases: [realm_emoji_name],
            is_realm_emoji: true,
            url: realm_emoji.emoji_url,
            has_reacted: false,
        };
        exports.emojis_by_name[realm_emoji_name] = emoji_dict;
    });

    _.each(emoji_codes.emoji_catalog, function (codepoints) {
        _.each(codepoints, function (codepoint) {
            if (emoji_codes.codepoint_to_name.hasOwnProperty(codepoint)) {
                var emoji_name = emoji_codes.codepoint_to_name[codepoint];
                if (!exports.emojis_by_name.hasOwnProperty(emoji_name)) {
                    emoji_dict = {
                        name: emoji_name,
                        aliases: emoji.default_emoji_aliases[codepoint],
                        is_realm_emoji: false,
                        emoji_code: codepoint,
                        has_reacted: false,
                    };
                    exports.emojis_by_name[emoji_name] = emoji_dict;
                }
            }
        });
    });
};

exports.build_emoji_upload_widget = function () {

    var get_file_input = function () {
        return $('#emoji_file_input');
    };

    var file_name_field = $('#emoji-file-name');
    var input_error = $('#emoji_file_input_error');
    var clear_button = $('#emoji_image_clear_button');
    var upload_button = $('#emoji_upload_button');

    return upload_widget.build_widget(
        get_file_input,
        file_name_field,
        input_error,
        clear_button,
        upload_button
    );
};

exports.get_canonical_name = function (emoji_name) {
    if (exports.active_realm_emojis.hasOwnProperty(emoji_name)) {
        return emoji_name;
    }
    if (!emoji_codes.name_to_codepoint.hasOwnProperty(emoji_name)) {
        blueslip.error("Invalid emoji name: " + emoji_name);
        return;
    }
    var codepoint = emoji_codes.name_to_codepoint[emoji_name];

    return emoji_codes.codepoint_to_name[codepoint];
};

// Translates emoticons in a string to their colon syntax.
exports.translate_emoticons_to_names = function translate_emoticons_to_names(text) {
    var translated = text;
    var replacement_text;
    var terminal_symbols = ',.;?!()[] "\'\n\t'; // From composebox_typeahead
    var symbols_except_space = terminal_symbols.replace(' ', '');

    var emoticon_replacer = function (match, g1, offset, str) {
        var prev_char = str[offset - 1];
        var next_char = str[offset + match.length];

        var symbol_at_start = terminal_symbols.indexOf(prev_char) !== -1;
        var symbol_at_end = terminal_symbols.indexOf(next_char) !== -1;
        var non_space_at_start = symbols_except_space.indexOf(prev_char) !== -1;
        var non_space_at_end = symbols_except_space.indexOf(next_char) !== -1;
        var valid_start = symbol_at_start || offset === 0;
        var valid_end = symbol_at_end || offset === str.length - match.length;

        if (non_space_at_start && non_space_at_end) { // Hello!:)?
            return match;
        }
        if (valid_start && valid_end) {
            return replacement_text;
        }
        return match;
    };

    for (var emoticon in emoji_codes.emoticon_conversions) {
        if (emoji_codes.emoticon_conversions.hasOwnProperty(emoticon)) {
            replacement_text = emoji_codes.emoticon_conversions[emoticon];
            var emoticon_regex = new RegExp('(' + util.escape_regexp(emoticon) + ')', 'g');
            translated = translated.replace(emoticon_regex, emoticon_replacer);
        }
    }

    return translated;
};

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