import cronjobs from "./cronjobs"
import * as queries from "./queries";
import * as twitch from "./twitch";
import { log, LogLevel } from "./logging"
import db from "./db";
import pg from "pg";

interface CronJob {
	(streamer: twitch.StreamerUserIdTokenPair): Promise<void>
}

function validateJob(job: string) {
	if (!Object.keys(cronjobs).includes(job)) throw new Error("Invalid cronjob " + job);
}

async function runJob(job: string) {
	validateJob(job);
	var streamer = await db.query(queries.getStreamerIdToken).then(
		(result: pg.QueryResult) => result.rows[0]);
	return await (cronjobs as { [key: string]: CronJob })[job](streamer);
}

// Run a specific job on request of streamer
async function request(job: string) {
	validateJob(job);
	// TODO: Rate limiting
	await runJob(job);
}

async function run() {
	// If instance is not yet set up, end processing at this point
	var streamer = await db.query(queries.getStreamerIdToken).then(
		(result: pg.QueryResult) => result.rows[0]);
	if (typeof streamer == 'undefined') {
		log(LogLevel.INFO,"Cron run skipped due to instance not being set up")
		return;
	}
	log(LogLevel.INFO,"Begin cron run")
	for (var job in cronjobs) {
		log(LogLevel.INFO,"cron: Checking job " + job);
		var dbconn = await db.connect();
		await dbconn.query("BEGIN");
		try {
			var needsRun = (await dbconn.query(
				Object.assign(queries.getAndLockCronJob,{values: [job]})
			)).rowCount;
			if (needsRun) {
				log(LogLevel.INFO,`cron: Database says job ${job} needs run; executing`);
				await (cronjobs as { [key: string]: CronJob })[job](streamer)
				log(LogLevel.INFO,`cron: Job ${job} returned without exception; updating lastSuccess`);
				await dbconn.query(Object.assign(queries.updateCronJobLastSuccess,{values: [job]}))
				await dbconn.query("COMMIT");
			} else {
				log(LogLevel.INFO,`cron: Database says job ${job} does not need run; skipping`);
				await dbconn.query("ROLLBACK");
			}
		} catch(e) {
			log(LogLevel.ERROR,`cron: Job ${job} threw exception; rolling back`);
			await dbconn.query("ROLLBACK");
			log(LogLevel.ERROR,`cron: Job ${job} exception message: ${e}`)
		} finally {
			log(LogLevel.DEBUG,`cron: Job ${job} hit finally; releasing dbconn`);
			dbconn.release();
		}
		log(LogLevel.INFO,"cron: Finished job " + job);
	}
	log(LogLevel.INFO,"End cron run")
}

export = {run,validateJob,request}