import {z} from "zod";

import * as blueslip from "./blueslip";
import * as channel from "./channel";
import type {MessageList} from "./message_lists";
import * as message_store from "./message_store";
import type {Message} from "./message_store";
import * as widgetize from "./widgetize";

export type Submessage = {
    id: number;
    sender_id: number;
    message_id: number;
    content: string;
    msg_type: string;
};

export const zform_widget_extra_data_schema = z
    .object({
        choices: z.array(
            z.object({
                type: z.string(),
                long_name: z.string(),
                reply: z.string(),
                short_name: z.string(),
            }),
        ),
        heading: z.string(),
        type: z.literal("choices"),
    })
    .nullable();

const poll_widget_extra_data_schema = z
    .object({
        question: z.string().optional(),
        options: z.array(z.string()).optional(),
    })
    .nullable();

export const todo_widget_extra_data_schema = z
    .object({
        task_list_title: z.string().optional(),
        tasks: z.array(z.object({task: z.string(), desc: z.string()})).optional(),
    })
    .nullable();

const widget_data_event_schema = z.object({
    sender_id: z.number(),
    data: z.discriminatedUnion("widget_type", [
        z.object({widget_type: z.literal("poll"), extra_data: poll_widget_extra_data_schema}),
        z.object({widget_type: z.literal("zform"), extra_data: zform_widget_extra_data_schema}),
        z.object({
            widget_type: z.literal("todo"),
            extra_data: todo_widget_extra_data_schema,
        }),
    ]),
});

const inbound_data_event_schema = z.object({
    sender_id: z.number(),
    data: z.intersection(
        z.object({
            type: z.string(),
        }),
        z.record(z.string(), z.unknown()),
    ),
});

const submessages_event_schema = z
    .tuple([widget_data_event_schema])
    .rest(inbound_data_event_schema);

type SubmessageEvents = z.infer<typeof submessages_event_schema>;

export function get_message_events(message: Message): SubmessageEvents | undefined {
    if (message.locally_echoed) {
        return undefined;
    }

    if (!message.submessages) {
        return undefined;
    }

    if (message.submessages.length === 0) {
        return undefined;
    }

    message.submessages.sort((m1, m2) => m1.id - m2.id);

    const events = message.submessages.map((obj): {sender_id: number; data: unknown} => ({
        sender_id: obj.sender_id,
        data: JSON.parse(obj.content),
    }));
    const clean_events = submessages_event_schema.parse(events);
    return clean_events;
}

export function process_widget_rows_in_list(list: MessageList | undefined): void {
    for (const message_id of widgetize.widget_event_handlers.keys()) {
        const $row = list?.get_row(message_id);
        if ($row && $row.length !== 0) {
            process_submessages({message_id, $row});
        }
    }
}

export function process_submessages(in_opts: {$row: JQuery; message_id: number}): void {
    // This happens in our rendering path, so we try to limit any
    // damage that may be triggered by one rogue message.
    try {
        do_process_submessages(in_opts);
        return;
    } catch (error) {
        blueslip.error("Failed to do_process_submessages", undefined, error);
        return;
    }
}

export function do_process_submessages(in_opts: {$row: JQuery; message_id: number}): void {
    const message_id = in_opts.message_id;
    const message = message_store.get(message_id);

    if (!message) {
        return;
    }

    const events = get_message_events(message);

    if (!events) {
        return;
    }
    const [widget_event, ...inbound_events] = events;

    if (widget_event.sender_id !== message.sender_id) {
        blueslip.warn(`User ${widget_event.sender_id} tried to hijack message ${message.id}`);
        return;
    }

    const $row = in_opts.$row;

    // Right now, our only use of submessages is widgets.

    const data = widget_event.data;

    if (data === undefined) {
        return;
    }

    const widget_type = data.widget_type;

    if (widget_type === undefined) {
        return;
    }

    const post_to_server = make_server_callback(message_id);

    widgetize.activate({
        widget_type,
        extra_data: data.extra_data,
        events: inbound_events,
        $row,
        message,
        post_to_server,
    });
}

export function update_message(submsg: Submessage): void {
    const message = message_store.get(submsg.message_id);

    if (message === undefined) {
        // This is generally not a problem--the server
        // can send us events without us having received
        // the original message, since the server doesn't
        // track that.
        return;
    }

    if (message.submessages === undefined) {
        message.submessages = [];
    }

    const existing = message.submessages.find((sm) => sm.id === submsg.id);

    if (existing !== undefined) {
        blueslip.warn("Got submessage multiple times: " + submsg.id);
        return;
    }

    message.submessages.push(submsg);
}

export function handle_event(submsg: Submessage): void {
    // Update message.submessages in case we haven't actually
    // activated the widget yet, so that when the message does
    // come in view, the data will be complete.
    update_message(submsg);

    // Right now, our only use of submessages is widgets.
    const msg_type = submsg.msg_type;

    if (msg_type !== "widget") {
        blueslip.warn("unknown msg_type: " + msg_type);
        return;
    }

    let data: unknown;

    try {
        data = JSON.parse(submsg.content);
    } catch {
        blueslip.warn("server sent us invalid json in handle_event: " + submsg.content);
        return;
    }

    widgetize.handle_event({
        sender_id: submsg.sender_id,
        message_id: submsg.message_id,
        data,
    });
}

export function make_server_callback(
    message_id: number,
): (opts: {msg_type: string; data: string}) => void {
    return function (opts: {msg_type: string; data: string}) {
        const url = "/json/submessage";

        void channel.post({
            url,
            data: {
                message_id,
                msg_type: opts.msg_type,
                content: JSON.stringify(opts.data),
            },
        });
    };
}