var search = (function () {

var exports = {};

var cached_term = "";
var cached_matches = [];
var cached_index;
var cached_table = $('table.focused_table');
var current_search_term;

// Data storage for the typeahead -- to go from object to string representation and vice versa.
var labels = [];
var mapped = {};

function get_query(obj) {
    return obj.query;
}

function get_person(obj) {
    return typeahead_helper.render_person(obj.query);
}

function render_object_in_parts(obj) {
    // N.B. action is *not* escaped by the caller
    switch (obj.action) {
    case 'stream':
        return {prefix: 'Narrow to stream', query: get_query(obj), suffix: ''};

    case 'private_message':
        return {prefix: 'Narrow to private messages with',
                query: get_person(obj),
                suffix: ''};

    case 'sender':
        return {prefix: 'Narrow to messages sent by',
                query: get_person(obj),
                suffix: ''};

    case 'operators':
        // HACK: This label needs to be distinct from the above, because of the
        // way we identify action objects by their labels.  Using two spaces
        // after 'Narrow to' ensures this, and is invisible with standard HTML
        // whitespace handling.
        return {prefix: '',
                query: narrow.describe(obj.operators),
                suffix: ''};
    }
    return {prefix: 'Error', query: 'Error', suffix: 'Error'};
}

function render_object(obj) {
    var parts = render_object_in_parts(obj);
    return parts.prefix + " " + parts.query + " " + parts.suffix;
}

exports.update_typeahead = function () {
    var streams = $.map(subs.subscribed_streams(), function(elt,idx) {
        return {action: 'stream', query: elt};
    });
    var people = $.map(page_params.people_list, function(elt,idx) {
        return {action: 'private_message', query: elt};
    });
    var senders = $.map(page_params.people_list, function(elt,idx) {
        return {action: 'sender', query: elt};
    });
    var options = streams.concat(people).concat(senders);
    // The first slot is reserved for "search for x".
    // (this is updated in the source function for our typeahead as well)
    options.unshift({action: 'operators', query: '', operators: []});

    mapped = {};
    labels = [];
    $.each(options, function (i, obj) {
        var label = render_object(obj);
        mapped[label] = obj;
        labels.push(label);
    });
};

function narrow_or_search_for_term(item) {
    var search_query_box = $("#search_query");
    var obj = mapped[item];
    ui.change_tab_to('#home');
    switch (obj.action) {
    case 'search':
        return obj.query;

    case 'stream':
        narrow.by('stream', obj.query);
        // It's sort of annoying that this is not in a position to
        // blur the search box, because it means that Esc won't
        // unnarrow, it'll leave the searchbox.

        // Narrowing will have already put some operators in the search box,
        // so leave the current text in.
        search_query_box.blur();
        return search_query_box.val();

    case 'private_message':
        narrow.by('pm-with', obj.query.email);
        search_query_box.blur();
        return search_query_box.val();

    case 'sender':
        narrow.by('sender', obj.query.email);
        search_query_box.blur();
        return search_query_box.val();

    case 'operators':
        narrow.activate(obj.operators);
        search_query_box.blur();
        return search_query_box.val();
    }
    return item;
}

function searchbox_sorter(items) {
    var objects_by_action = {};
    var result = [];

    $.each(items, function (idx, elt) {
        var obj = mapped[elt];
        if (objects_by_action[obj.action] === undefined)
            objects_by_action[obj.action] = [];
        objects_by_action[obj.action].push(obj);
    });

    var query = this.query;
    $.each(['operators', 'stream', 'private_message', 'sender', 'search'], function (idx, action) {
        var objs = objects_by_action[action];
        if (!objs)
            return;
        // Get the first object in sorted order.
        var obj = typeahead_helper.sorter(query, objs,
                (action === 'private_message' || action === 'sender') ? get_person : get_query)
            .shift();
        if (obj)
            result.push(render_object(obj));
    });

    return result;
}

function update_buttons_with_focus(focused) {
    var search_query = $('#search_query');

    // Show buttons iff the search input is focused, or has non-empty contents,
    // or we are narrowed.
    if (focused
        || search_query.val()
        || narrow.active()) {
        $('.search_button').removeAttr('disabled');
    } else {
        $('.search_button').attr('disabled', 'disabled');
    }
}

exports.update_button_visibility = function () {
    update_buttons_with_focus($('#search_query').is(':focus'));
};

exports.initialize = function () {
    $( "#search_query" ).typeahead({
        source: function (query, process) {
            // Delete our old search queries (one for find-in-page, one for operators)
            delete mapped[labels.shift()]; // Operators

            // Add an entry for narrow by operators.
            var operators = narrow.parse(query);
            var obj = {action: 'operators', query: query, operators: operators};
            var label = render_object(obj);
            mapped[label] = obj;
            labels.unshift(label);

            return labels;
        },
        items: 4,
        highlighter: function (item) {
            var query = this.query;
            var parts = render_object_in_parts(mapped[item]);
            // We provide action, not the user, so this should
            // be fine from a not-needing-escaping perspective.
            return parts.prefix + " " +
                typeahead_helper.highlight_with_escaping(query, parts.query)
                + " " + parts.suffix;
        },
        matcher: function (item) {
            var obj = mapped[item];
            if (obj.disabled)
                return false;
            var actual_search_term = obj.query;
            if (obj.action === 'private_message' || obj.action === "sender") {
                actual_search_term = obj.query.full_name + ' <' + obj.query.email + '>';
            }
            // Case-insensitive (from Bootstrap's default matcher).
            return (actual_search_term.toLowerCase().indexOf(this.query.toLowerCase()) !== -1);
        },
        updater: narrow_or_search_for_term,
        sorter: searchbox_sorter
    });

    $("#searchbox_form").keydown(function (e) {
        exports.update_button_visibility();
        var code = e.which;
        var search_query_box = $("#search_query");
        if (code === 13 && search_query_box.is(":focus")) {
            // Don't submit the form so that the typeahead can instead
            // handle our Enter keypress. Any searching that needs
            // to be done will be handled in the keyup.
            e.preventDefault();
            return false;
        }
    }).keyup(function (e) {
        var code = e.which;
        var search_query_box = $("#search_query");
        if (code === 13 && search_query_box.is(":focus")) {
            // We just pressed enter and the box had focus, which
            // means we didn't use the typeahead at all.  In that
            // case, we should act as though we're searching by
            // operators.  (The reason the other actions don't call
            // this codepath is that they first all blur the box to
            // indicate that they've done what they need to do)
            if (search_query_box.val()) {
                narrow.activate(narrow.parse(search_query_box.val()));
            }
            search_query_box.blur();
            update_buttons_with_focus(false);
        }
    });

    // Some of these functions don't actually need to be exported,
    // but the code was moved here from elsewhere, and it would be
    // more work to re-order everything and make them private.
    $('#search_exit' ).on('click', exports.clear_search);

    var query = $('#search_query');
    query.on('focus', exports.focus_search)
         .on('blur' , function () {

        // The search query box is a visual cue as to
        // whether search or narrowing is active.  If
        // neither is active, we should clear the box on
        // blur.
        //
        // But we can't do this right away, because
        // selecting something in the typeahead menu causes
        // the box to lose focus a moment before.  We would
        // clear the thing we're about to search for.
        //
        // The workaround is to check 100ms later -- long
        // enough for the search to have gone through, but
        // short enough that the user won't notice (though
        // really it would be OK if they did).

        setTimeout(function () {
            if (!(narrow.active())) {
                query.val('');
            }
            exports.update_button_visibility();
        }, 100);
    });
};

function match_on_visible_text(row, search_term) {
    // You can't select on :visible, since that includes hidden elements that
    // take up space.
    return row.find(".message_content, .message_header")
              .text().toLowerCase().indexOf(search_term) !== -1;
}

exports.update_highlighting = function(search_term) {
    if (current_search_term !== undefined) {
        exports.clear_highlighting();
    }
    current_search_term = search_term;
    if (search_term === undefined) {
        return;
    }

    var focused_table = $('table.focused_table');
    focused_table.find('.message_row').each(function (index, row) {
        row = $(row);
        exports.maybe_highlight_message(row);
    });
};

exports.maybe_highlight_message = function(row) {
    row.find('.message_content').highlight(current_search_term);
    if (current_msg_list.get(rows.id(row)).type === "stream") {
        row = row.prev('.recipient_row');
        row.find('.message_label_clickable').highlight(current_search_term);
    }
};

exports.clear_highlighting = function () {
    current_search_term = undefined;
    return $(".message_content .message_label_clickable").removeHighlight();
};

exports.focus_search = function () {
    // The search bar is not focused yet, but will be.
    update_buttons_with_focus(true);
};

exports.initiate_search = function () {
    $('#search_query').select();
};

exports.clear_search = function () {
    narrow.deactivate();

    $('table tr').removeHighlight();
    $('#search_query').blur();
    exports.update_button_visibility();
};

return exports;

}());