import dbHandler, { holdEventLoop, resolveClient } from "../db-handler";
import { quoteIdentifier } from "../../utils/sql-identifier";
import { QUEUE_NOW_SQL, requireQueueTable } from "./queue-utils";
/**
 * Claim the next available jobs, oldest `queue_available_at` first. Each
 * returned row carries a `queue_lock_token` that must be passed to `ack`,
 * `fail` or `extend`.
 *
 * `FOR UPDATE SKIP LOCKED` lets concurrent workers claim different jobs
 * without blocking on each other or claiming the same job twice.
 */
export default async function QueueClaim({ table, limit = 1, lease_ms, max_attempts, config, }) {
    try {
        const options = requireQueueTable(table);
        const tableSql = quoteIdentifier(table);
        const finalLimit = Math.max(1, Math.floor(Number(limit) || 1));
        const leaseMs = Math.max(0, Math.floor(Number(lease_ms ?? options.lease_ms) || 0));
        const maxAttempts = Math.max(1, Math.floor(Number(max_attempts ?? options.max_attempts) || 1));
        /**
         * Release jobs whose worker died or stalled past its lease: back to
         * `pending`, or `failed` if that was the last attempt.
         */
        const expired_res = await dbHandler({
            query: `UPDATE ${tableSql} SET queue_status = IF(queue_attempts >= ?, 'failed', 'pending'), queue_lease_expires_at = NULL, queue_lock_token = NULL, queue_last_error = 'Lease expired', updated_at = ${QUEUE_NOW_SQL} WHERE queue_status = 'processing' AND queue_lease_expires_at <= ${QUEUE_NOW_SQL}`,
            values: [maxAttempts],
            config,
        });
        if (!expired_res.success) {
            return { ...expired_res, success: false };
        }
        const CLIENT = resolveClient(config);
        if (!CLIENT) {
            throw new Error(`Couldn't grab MariaDB Client.`);
        }
        const lock_token = crypto.randomUUID();
        return await holdEventLoop(() => CLIENT.begin(async (tx) => {
            /**
             * The ORDER BY must match `idx_queue_claim`. A filesort would
             * lock every pending row before LIMIT applies, and SKIP LOCKED
             * would then hide the whole queue from other workers.
             */
            const matched_res = await dbHandler({
                query: `SELECT id FROM ${tableSql} FORCE INDEX (idx_queue_claim) WHERE queue_status = 'pending' AND queue_available_at <= ${QUEUE_NOW_SQL} ORDER BY queue_status, queue_available_at, id LIMIT ? FOR UPDATE SKIP LOCKED`,
                values: [finalLimit],
                client: tx,
            });
            if (!matched_res.success) {
                return {
                    ...matched_res,
                    success: false,
                };
            }
            const ids = (matched_res.payload || []).map((row) => row.id);
            if (ids.length === 0) {
                return { success: true, payload: [] };
            }
            const idPlaceholders = ids.map(() => "?").join(",");
            const update_res = await dbHandler({
                query: `UPDATE ${tableSql} SET queue_status = 'processing', queue_attempts = queue_attempts + 1, queue_lease_expires_at = ${QUEUE_NOW_SQL} + ?, queue_lock_token = ?, updated_at = ${QUEUE_NOW_SQL} WHERE id IN (${idPlaceholders})`,
                values: [leaseMs, lock_token, ...ids],
                client: tx,
            });
            if (!update_res.success) {
                throw new Error(update_res.error || "Queue claim failed");
            }
            return await dbHandler({
                query: `SELECT * FROM ${tableSql} WHERE id IN (${idPlaceholders}) ORDER BY queue_available_at, id`,
                values: ids,
                client: tx,
            });
        }));
    }
    catch (error) {
        return {
            success: false,
            error: error.message,
        };
    }
}