// Exported for unit testing
exports.is_using_input_method = false;

exports.narrow_or_search_for_term = function (search_string) {
    const search_query_box = $("#search_query");
    if (exports.is_using_input_method) {
        // Neither narrow nor search when using input tools as
        // `updater` is also triggered when 'enter' is triggered
        // while using input tool
        return search_query_box.val();
    }
    ui_util.change_tab_to('#home');

    let operators;
    if (page_params.search_pills_enabled) {
        // We have to take care to append the new pill before calling this
        // function, so that the base_query includes the suggestion selected
        // along with query corresponding to the existing pills.
        const base_query = search_pill.get_search_string_for_current_filter(
            search_pill_widget.widget);
        operators = Filter.parse(base_query);
    } else {
        operators = Filter.parse(search_string);
    }
    narrow.activate(operators, {trigger: 'search'});

    // 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.
    if (!page_params.search_pills_enabled) {
        search_query_box.blur();
    }
    return search_query_box.val();
};

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

    // Show buttons iff the search input is focused, or has non-empty contents,
    // or we are narrowed.
    if (focused
        || search_query_box.val()
        || narrow_state.active()) {
        $('.search_button').prop('disabled', false);
    }
}

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

exports.initialize = function () {
    const search_query_box = $('#search_query');
    const searchbox_form = $('#searchbox_form');
    const searchbox = $('#searchbox');

    // Data storage for the typeahead.
    // This maps a search string to an object with a "description" field.
    // (It's a bit of legacy that we have an object with only one important
    // field.  There's also a "search_string" field on each element that actually
    // just represents the key of the hash, so it's redundant.)
    let search_map = new Map();

    search_query_box.typeahead({
        source: function (query) {
            let base_query = '';
            if (page_params.search_pills_enabled) {
                base_query = search_pill.get_search_string_for_current_filter(
                    search_pill_widget.widget);
            }
            const suggestions = search_suggestion.get_suggestions(base_query, query);
            // Update our global search_map hash
            search_map = suggestions.lookup_table;
            return suggestions.strings;
        },
        fixed: true,
        items: search_suggestion.max_num_of_search_results,
        helpOnEmptyStrings: true,
        naturalSearch: true,
        highlighter: function (item) {
            const obj = search_map.get(item);
            return obj.description;
        },
        matcher: function () {
            return true;
        },
        updater: function (search_string) {
            if (page_params.search_pills_enabled) {
                search_pill.append_search_string(search_string,
                                                 search_pill_widget.widget);
                if (search_query_box.is(':focus')) {
                    // We usually allow the user to continue
                    // typing until the enter key is pressed.
                    // But we narrow when the user clicks on a
                    // typeahead suggestion. This change in behaviour
                    // is a workaround to be able to display the
                    // navbar every time search_query_box loses focus.
                    return search_query_box.val();
                }
            }
            return exports.narrow_or_search_for_term(search_string);
        },
        sorter: function (items) {
            return items;
        },
        stopAdvance: page_params.search_pills_enabled,
        advanceKeyCodes: [8],

        on_move: function () {
            if (page_params.search_pills_enabled) {
                ui_util.place_caret_at_end(search_query_box[0]);
                return true;
            }
        },
        // Use our custom typeahead `on_escape` hook to exit
        // the search bar as soon as the user hits Esc.
        on_escape: tab_bar.exit_search,
    });

    searchbox_form.on('compositionend', () => {
        // Set `is_using_input_method` to true if enter is pressed to exit
        // the input tool popover and get the text in the search bar. Then
        // we suppress searching triggered by this enter key by checking
        // `is_using_input_method` before searching.
        // More details in the commit message that added this line.
        exports.is_using_input_method = true;
    });

    searchbox_form.keydown((e) => {
        exports.update_button_visibility();
        const code = e.which;
        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.
            return false;
        }
    }).keyup((e) => {
        if (exports.is_using_input_method) {
            exports.is_using_input_method = false;
            return;
        }
        const code = e.which;
        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)

            // Pill is already added during keydown event of input pills.
            exports.narrow_or_search_for_term(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_query_box.on('focus', exports.focus_search);
    search_query_box.on('blur', (e) => {
        // The search query box is a visual cue as to
        // whether search or narrowing is active.  If
        // the user blurs the search box, then we should
        // update the search string to reflect the current
        // narrow (or lack of narrow).
        //
        // But we can't do this right away, because
        // selecting something in the typeahead menu causes
        // the box to lose focus a moment before.
        //
        // The workaround is to check 300ms 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).

        if (page_params.search_pills_enabled) {
            const pill_id = $(e.relatedTarget).closest(".pill").data('id');
            const search_pill = search_pill_widget.widget.getByID(pill_id);
            if (search_pill) {
                // The searchbox loses focus while the search
                // pill element gains focus.
                // We do not consider the searchbox to actually
                // lose focus when a pill inside it gets selected
                // or deleted by a click.
                return;
            }
        }
        setTimeout(() => {
            exports.update_button_visibility();
            tab_bar.close_search_bar_and_open_narrow_description();
            searchbox.css({"box-shadow": "unset"});
        }, 300);
    });
};

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

exports.initiate_search = function () {
    tab_bar.open_search_bar_and_close_narrow_description();
    $('#searchbox').css({"box-shadow": "inset 0px 0px 0px 2px hsl(204, 20%, 74%)"});
    $('#search_query').typeahead('lookup').select();
    if (page_params.search_pills_enabled) {
        $('#search_query').focus();
        ui_util.place_caret_at_end($('#search_query')[0]);
    }
};

exports.clear_search_form = function () {
    $('#search_query').val('');
    $('#search_query').blur();
    $('.search_button').prop('disabled', true);
};

window.search = exports;