const autosize = require('autosize');

exports.blur_textarea = function () {
    $('.message_comp').find('input, textarea, button').blur();
};

function hide_box() {
    exports.blur_textarea();
    $('#stream-message').hide();
    $('#private-message').hide();
    $(".new_message_textarea").css("min-height", "");
    compose_fade.clear_compose();
    $('.message_comp').hide();
    $("#compose_controls").show();
    compose.clear_preview_area();
}

function get_focus_area(msg_type, opts) {
    // Set focus to "Topic" when narrowed to a stream+topic and "New topic" button clicked.
    if (msg_type === 'stream' && opts.stream && !opts.topic) {
        return '#stream_message_recipient_topic';
    } else if (msg_type === 'stream' && opts.stream
               || msg_type === 'private' && opts.private_message_recipient) {
        if (opts.trigger === "new topic button") {
            return '#stream_message_recipient_topic';
        }
        return '#compose-textarea';
    }

    if (msg_type === 'stream') {
        return '#stream_message_recipient_stream';
    }
    return '#private_message_recipient';
}
// Export for testing
exports._get_focus_area = get_focus_area;

exports.set_focus = function (msg_type, opts) {
    const focus_area = get_focus_area(msg_type, opts);
    if (focus_area === undefined) {
        return;
    }

    if (window.getSelection().toString() === "" ||
         opts.trigger !== "message click") {
        const elt = $(focus_area);
        elt.focus().select();
    }
};


// Show the compose box.
function show_box(msg_type, opts) {
    if (msg_type === "stream") {
        $('#private-message').hide();
        $('#stream-message').show();
        $("#stream_toggle").addClass("active");
        $("#private_message_toggle").removeClass("active");
    } else {
        $('#private-message').show();
        $('#stream-message').hide();
        $("#stream_toggle").removeClass("active");
        $("#private_message_toggle").addClass("active");
    }
    $("#compose-send-status").removeClass(common.status_classes).hide();
    $('#compose').css({visibility: "visible"});
    // When changing this, edit the 42px in _maybe_autoscroll
    $(".new_message_textarea").css("min-height", "3em");

    exports.set_focus(msg_type, opts);
}

exports.clear_textarea = function () {
    $("#compose").find('input[type=text], textarea').val('');
};

function clear_box() {
    compose.clear_invites();

    // TODO: Better encapsulate at-mention warnings.
    compose.clear_all_everyone_warnings();
    compose.clear_announce_warnings();
    compose.clear_private_stream_alert();
    compose.reset_user_acknowledged_all_everyone_flag();
    compose.reset_user_acknowledged_announce_flag();

    exports.clear_textarea();
    $("#compose-textarea").removeData("draft-id");
    compose_ui.autosize_textarea();
    $("#compose-send-status").hide(0);
}

exports.autosize_message_content = function () {
    autosize($("#compose-textarea"), {
        callback: function () {
            exports.maybe_scroll_up_selected_message();
        },
    });
};

exports.expand_compose_box = function () {
    $("#compose_close").show();
    $("#compose_controls").hide();
    $('.message_comp').show();
};

exports.complete_starting_tasks = function (msg_type, opts) {
    // This is sort of a kitchen sink function, and it's called only
    // by compose.start() for now.  Having this as a separate function
    // makes testing a bit easier.

    exports.maybe_scroll_up_selected_message();
    ui_util.change_tab_to("#home");
    compose_fade.start_compose(msg_type);
    ui_util.decorate_stream_bar(opts.stream, $("#stream-message .message_header_stream"), true);
    $(document).trigger($.Event('compose_started.zulip', opts));
    exports.update_placeholder_text(opts);
};

exports.maybe_scroll_up_selected_message = function () {
    // If the compose box is obscuring the currently selected message,
    // scroll up until the message is no longer occluded.
    if (current_msg_list.selected_id() === -1) {
        // If there's no selected message, there's no need to
        // scroll the compose box to avoid it.
        return;
    }
    const selected_row = current_msg_list.selected_row();

    if (selected_row.height() > message_viewport.height() - 100) {
        // For very tall messages whose height is close to the entire
        // height of the viewport, don't auto-scroll the viewport to
        // the end of the message (since that makes it feel annoying
        // to work with very tall messages).  See #8941 for details.
        return;
    }

    const cover = selected_row.offset().top + selected_row.height()
        - $("#compose").offset().top;
    if (cover > 0) {
        message_viewport.user_initiated_animate_scroll(cover + 20);
    }
};

function fill_in_opts_from_current_narrowed_view(msg_type, opts) {
    return {
        message_type: msg_type,
        stream: '',
        topic: '',
        private_message_recipient: '',
        trigger: 'unknown',

        // Set default parameters based on the current narrowed view.
        ...narrow_state.set_compose_defaults(),

        ...opts,
    };
}

function same_recipient_as_before(msg_type, opts) {
    return compose_state.get_message_type() === msg_type &&
            (msg_type === "stream" &&
              opts.stream === compose_state.stream_name() &&
              opts.topic === compose_state.topic() ||
             msg_type === "private" &&
              opts.private_message_recipient === compose_state.private_message_recipient());
}

exports.update_placeholder_text = function (opts) {
    const placeholder_text = compose_ui.compute_placeholder_text(opts);
    $('#compose-textarea').attr('placeholder', placeholder_text);
};

exports.start = function (msg_type, opts) {
    exports.autosize_message_content();

    if (reload_state.is_in_progress()) {
        return;
    }
    notifications.clear_compose_notifications();
    exports.expand_compose_box();

    opts = fill_in_opts_from_current_narrowed_view(msg_type, opts);
    // If we are invoked by a compose hotkey (c or x) or new topic
    // button, do not assume that we know what the message's topic or
    // PM recipient should be.
    if (opts.trigger === "compose_hotkey" ||
        opts.trigger === "new topic button") {
        opts.topic = '';
        opts.private_message_recipient = '';
    }

    const subbed_streams = stream_data.subscribed_subs();
    if (subbed_streams.length === 1 && (opts.trigger === "new topic button" || opts.trigger === "compose_hotkey" && msg_type === "stream")) {
        opts.stream = subbed_streams[0].name;
    }

    if (compose_state.composing() && !same_recipient_as_before(msg_type, opts)) {
        // Clear the compose box if the existing message is to a different recipient
        clear_box();
    }

    // We set the stream/topic/private_message_recipient
    // unconditionally here, which assumes the caller will have passed
    // '' or undefined for these values if they are not appropriate
    // for this message.
    //
    // TODO: Move these into a conditional on message_type, using an
    // explicit "clear" function for compose_state.
    compose_state.stream_name(opts.stream);
    compose_state.topic(opts.topic);

    // Set the recipients with a space after each comma, so it looks nice.
    compose_state.private_message_recipient(opts.private_message_recipient.replace(/,\s*/g, ", "));

    // If the user opens the compose box, types some text, and then clicks on a
    // different stream/topic, we want to keep the text in the compose box
    if (opts.content !== undefined) {
        compose_state.message_content(opts.content);
    }

    compose_state.set_message_type(msg_type);

    // Show either stream/topic fields or "You and" field.
    show_box(msg_type, opts);

    exports.complete_starting_tasks(msg_type, opts);
};

exports.cancel = function () {
    $("#compose-textarea").height(40 + "px");

    if (page_params.narrow !== undefined) {
        // Never close the compose box in narrow embedded windows, but
        // at least clear the topic and unfade.
        compose_fade.clear_compose();
        if (page_params.narrow_topic !== undefined) {
            compose_state.topic(page_params.narrow_topic);
        } else {
            compose_state.topic("");
        }
        return;
    }
    hide_box();
    $("#compose_close").hide();
    clear_box();
    notifications.clear_compose_notifications();
    compose.abort_xhr();
    compose_state.set_message_type(false);
    compose_pm_pill.clear();
    $(document).trigger($.Event('compose_canceled.zulip'));
};

exports.respond_to_message = function (opts) {
    let msg_type;
    // Before initiating a reply to a message, if there's an
    // in-progress composition, snapshot it.
    drafts.update_draft();

    const message = current_msg_list.selected_message();

    if (message === undefined) { // empty narrow implementation
        if (!narrow_state.narrowed_by_pm_reply() &&
            !narrow_state.narrowed_by_stream_reply() &&
            !narrow_state.narrowed_by_topic_reply()) {
            compose.nonexistent_stream_reply_error();
            return;
        }
        const current_filter = narrow_state.filter();
        const first_term = current_filter.operators()[0];
        const first_operator = first_term.operator;
        const first_operand = first_term.operand;

        if (first_operator === "stream" && !stream_data.is_subscribed(first_operand)) {
            compose.nonexistent_stream_reply_error();
            return;
        }

        // Set msg_type to stream by default in the case of an empty
        // home view.
        msg_type = 'stream';
        if (narrow_state.narrowed_by_pm_reply()) {
            msg_type = 'private';
        }

        const new_opts = fill_in_opts_from_current_narrowed_view(msg_type, opts);
        exports.start(new_opts.message_type, new_opts);
        return;
    }

    if (current_msg_list.can_mark_messages_read()) {
        unread_ops.notify_server_message_read(message);
    }

    // Important note: A reply_type of 'personal' is for the R hotkey
    // (replying to a message's sender with a private message).  All
    // other replies can just copy message.type.
    if (opts.reply_type === 'personal' || message.type === 'private') {
        msg_type = 'private';
    } else {
        msg_type = message.type;
    }

    let stream = '';
    let topic = '';
    let pm_recipient = '';
    if (msg_type === "stream") {
        stream = message.stream;
        topic = message.topic;
    } else {
        pm_recipient = message.reply_to;
        if (opts.reply_type === "personal") {
            // reply_to for private messages is everyone involved, so for
            // personals replies we need to set the private message
            // recipient to just the sender
            pm_recipient = people.get_by_user_id(message.sender_id).email;
        } else {
            pm_recipient = people.pm_reply_to(message);
        }
    }

    exports.start(msg_type, {stream: stream, topic: topic,
                             private_message_recipient: pm_recipient,
                             trigger: opts.trigger});

};

exports.reply_with_mention = function (opts) {
    exports.respond_to_message(opts);
    const message = current_msg_list.selected_message();
    const mention = people.get_mention_syntax(message.sender_full_name, message.sender_id);
    compose_ui.insert_syntax_and_focus(mention);
};

exports.on_topic_narrow = function () {
    if (!compose_state.composing()) {
        // If our compose box is closed, then just
        // leave it closed, assuming that the user is
        // catching up on their feed and not actively
        // composing.
        return;
    }

    if (compose_state.stream_name() !== narrow_state.stream()) {
        // If we changed streams, then we only leave the
        // compose box open if there is content.
        if (compose_state.has_message_content()) {
            compose_fade.update_message_list();
            return;
        }

        // Otherwise, avoid a mix.
        exports.cancel();
        return;
    }

    if (compose_state.topic() && compose_state.has_message_content()) {
        // If the user has written something to a different topic,
        // they probably want that content, so leave compose open.
        //
        // This effectively uses the heuristic of whether there is
        // content in compose to determine whether the user had firmly
        // decided to compose to the old topic or is just looking to
        // reply to what they see.
        compose_fade.update_message_list();
        return;
    }

    // If we got this far, then the compose box has the correct stream
    // filled in, and either compose is empty or no topic was set, so
    // we should update the compose topic to match the new narrow.
    // See #3300 for context--a couple users specifically asked for
    // this convenience.
    compose_state.topic(narrow_state.topic());
    compose_fade.set_focused_recipient("stream");
    compose_fade.update_message_list();
    $('#compose-textarea').focus().select();
};

exports.quote_and_reply = function (opts) {
    const textarea = $("#compose-textarea");
    const message_id = current_msg_list.selected_id();
    const message = current_msg_list.selected_message();

    if (compose_state.has_message_content()) {
        // The user already started typing a message,
        // so we won't re-open the compose box.
        // (If you did re-open the compose box, you
        // are prone to glitches where you select the
        // text, plus it's a complicated codepath that
        // can have other unintended consequences.)
        //
        // Note also that we always put the quoted text
        // above the current text, which explains us
        // moving the caret below.  I think this is what
        // most users will want, and it's consistent with
        // the behavior we had on FF before this change
        // (which may have been an accident of
        // implementation).  If we change this decision,
        // we'll need to make `insert_syntax_and_focus`
        // smarter about newlines.
        textarea.caret(0);
    } else {
        exports.respond_to_message(opts);
    }

    compose_ui.insert_syntax_and_focus("[Quoting…]\n", textarea);

    function replace_content(message) {
        // Final message looks like:
        //     @_**Iago|5** [said](link to message):
        //     ```quote
        //     message content
        //     ```
        let content = `@_**${message.sender_full_name}|${message.sender_id}** `;
        content += `[said](${hash_util.by_conversation_and_time_uri(message)}):\n`;
        const fence = fenced_code.get_unused_fence(message.raw_content);
        content += `${fence}quote\n${message.raw_content}\n${fence}`;
        compose_ui.replace_syntax('[Quoting…]', content, textarea);
        autosize.update($('#compose-textarea'));
    }

    if (message && message.raw_content) {
        replace_content(message);
        return;
    }

    channel.get({
        url: '/json/messages/' + message_id,
        idempotent: true,
        success: function (data) {
            message.raw_content = data.raw_content;
            replace_content(message);
        },
    });
};

exports.on_narrow = function (opts) {
    // We use force_close when jumping between PM narrows with the "p" key,
    // so that we don't have an open compose box that makes it difficult
    // to cycle quickly through unread messages.
    if (opts.force_close) {
        // This closes the compose box if it was already open, and it is
        // basically a noop otherwise.
        exports.cancel();
        return;
    }

    if (opts.trigger === "narrow_to_compose_target") {
        compose_fade.update_message_list();
        return;
    }

    if (narrow_state.narrowed_by_topic_reply()) {
        exports.on_topic_narrow();
        return;
    }

    if (compose_state.has_message_content()) {
        compose_fade.update_message_list();
        return;
    }

    if (narrow_state.narrowed_by_pm_reply()) {
        opts = fill_in_opts_from_current_narrowed_view('private', opts);
        // Do not open compose box if triggered by search and invalid recipient
        // is present.
        if (opts.trigger === "search" && !opts.private_message_recipient) {
            return;
        }
        exports.start('private');
        return;
    }

    // If we got this far, then we assume the user is now in "reading"
    // mode, so we close the compose box to make it easier to use navigation
    // hotkeys and to provide more screen real estate for messages.
    exports.cancel();
};

window.compose_actions = exports;