import { z } from "zod";
import type { BUN_SQLITE_COBBLE_COMPUTERS } from "@/db/types/db";
import enqueueBotJob from "@/src/functions/backend/db/bots-queue/enqueue-bot-job";
import countComputerTaskJobs from "@/src/functions/backend/db/bots-queue/count-computer-task-jobs";
import grabOpenBotTask from "@/src/functions/backend/db/bots-queue/grab-open-bot-task";
import type { HarnessTool } from "../../types";

type Params = {
    user_id: number | string;
    bot_id: number | string;
    /**
     * The session the task is started from; its result is posted there.
     */
    session_id: number | string;
    /**
     * The bot's computers, the current one first (`grabBotComputers`).
     */
    computers: BUN_SQLITE_COBBLE_COMPUTERS[];
    /**
     * The user message that asked for the work.
     */
    message_id?: number | string;
};

type Args = {
    title: string;
    instructions: string;
    computer_id?: number;
    separate?: boolean;
};

/**
 * Lets a bot queue long-running work for itself. The task runs in the
 * background with the computer's tools and posts its result to the chat.
 * It's a run in the queue (`bots_queue`), not a task on the to-do list
 * (`tasks`), so it's called a run: told "Task #52", bots and users look
 * for it in `list_tasks` and don't find it. While a run is open in the
 * session on that computer a new one is refused unless it's separate
 * work, since it would only wait behind it (one task per computer).
 */
export default function startTaskTool({
    user_id,
    bot_id,
    session_id,
    computers,
    message_id,
}: Params): HarnessTool<Args> {
    const listed = computers
        .map((computer) => `${computer.id} (${computer.name || computer.kind})`)
        .join(", ");

    return {
        name: "start_task",
        description: `Queue work that takes a while or needs a computer. It runs in the background and its result is posted in this chat. It's a run, not a task on the to-do list: list_tasks never shows it, so don't send the user there to find it. Write the instructions as a full brief for yourself: what to do, where, and how you'll know it's done. Tasks run one at a time per computer, so while one of yours is open here, a new one only waits behind it: don't start the same work again with another title. ${
            computers.length
                ? `Computers you can use: ${listed}. Defaults to ${computers[0]!.id}, the one you're on.`
                : `You have no computer, so the task can't run commands or browse.`
        }`,
        schema: z.object({
            title: z.string().min(1).max(80).describe("A short label, e.g. \"Check the backup logs\""),
            instructions: z.string().min(1).max(8000),
            computer_id: z.number().int().optional(),
            separate: z
                .boolean()
                .optional()
                .describe("Only for different work while another run of yours is open here on that computer, never to retry or redo it."),
        }),
        run: async ({ args }) => {
            const same = await grabOpenBotTask({ bot_id, session_id, title: args.title });

            if (same) {
                throw new Error(
                    `Run #${same.id} "${args.title}" is already ${same.status == "pending" ? "queued" : "under way"}. Don't start it again; its result will be posted here.`,
                );
            }

            const computer_id = args.computer_id ?? computers[0]?.id ?? undefined;

            const open = args.separate ? null : await grabOpenBotTask({ bot_id, session_id, computer_id });

            if (open) {
                throw new Error(
                    `Run #${open.id} "${open.title || "Task"}" is still ${open.status == "pending" ? "queued" : "under way"} here on that computer, and a new one would only wait behind it. If this is the same work, don't start it again: its result will be posted here (the user can Stop it to start over). Only for different work, call start_task again with separate.`,
                );
            }

            const job_id = await enqueueBotJob({
                user_id,
                bot_id,
                session_id,
                title: args.title,
                instructions: args.instructions,
                message_id,
                computer_id: computer_id || undefined,
            });

            const ahead = computer_id ? await countComputerTaskJobs({ computer_id, except_job_id: job_id }) : 0;

            return `Run #${job_id} queued; you'll work on it yourself in the background. It's not on the task list (list_tasks), so never tell the user to look for it there. ${
                ahead
                    ? `The computer has ${ahead} other ${ahead == 1 ? "run" : "runs"} queued or working (they go one at a time), so it waits for ${ahead == 1 ? "it" : "them"} first: tell the user it's queued behind other work, not that it's running. `
                    : ""
            }Tell the user in one sentence, in the first person, what you're doing (e.g. "I'm checking your inbox now. I'll report back when I'm done."); the result will be posted here when it's done.`;
        },
    };
}