import { Request, Response } from "express";
import { db } from "../databases/databases";
import { DBSegment, SegmentUUID } from "../types/segments.model";

const isValidSegmentUUID = (str: string): boolean => /^([a-f0-9]{64}|[a-f0-9]{8}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{12})/.test(str);

async function getSegmentFromDBByUUID(UUID: SegmentUUID): Promise<DBSegment> {
    try {
        return await db.prepare("get", `SELECT * FROM "sponsorTimes" WHERE "UUID" = ?`, [UUID]);
    } catch (err) {
        return null;
    }
}

async function getSegmentsByUUID(UUIDs: SegmentUUID[]): Promise<DBSegment[]> {
    const DBSegments: DBSegment[] = [];
    for (const UUID of UUIDs) {
        // if UUID is invalid, skip
        if (!isValidSegmentUUID(UUID)) continue;
        DBSegments.push(await getSegmentFromDBByUUID(UUID as SegmentUUID));
    }
    return DBSegments;
}

async function handleGetSegmentInfo(req: Request, res: Response): Promise<DBSegment[]> {
    // If using params instead of JSON, only one UUID can be pulled
    let UUIDs = req.query.UUIDs
        ? JSON.parse(req.query.UUIDs as string)
        : req.query.UUID
            ? Array.isArray(req.query.UUID)
                ? req.query.UUID
                : [req.query.UUID]
            : null;
    // deduplicate with set
    UUIDs = [ ...new Set(UUIDs)];
    // if more than 10 entries, slice
    if (UUIDs.length > 10) UUIDs = UUIDs.slice(0, 10);
    if (!Array.isArray(UUIDs) || !UUIDs) {
        res.status(400).send("UUIDs parameter does not match format requirements.");
        return;
    }
    const DBSegments = await getSegmentsByUUID(UUIDs);
    // all uuids failed lookup
    if (!DBSegments?.length) {
        res.sendStatus(400);
        return;
    }
    // uuids valid but not found
    if (DBSegments[0] === null || DBSegments[0] === undefined) {
        res.sendStatus(400);
        return;
    }
    return DBSegments;
}

async function endpoint(req: Request, res: Response): Promise<Response> {
    try {
        const DBSegments = await handleGetSegmentInfo(req, res);

        // If false, res.send has already been called
        if (DBSegments) {
            //send result
            return res.send(DBSegments);
        }
    } catch (err) {
        if (err instanceof SyntaxError) { // catch JSON.parse error
            return res.status(400).send("UUIDs parameter does not match format requirements.");
        } else return res.sendStatus(500);
    }
}

export {
    getSegmentFromDBByUUID,
    getSegmentsByUUID,
    handleGetSegmentInfo,
    endpoint
};