import { parse } from "csv-parse/sync";
import fs from "fs/promises";
import { NextResponse } from "next/server";
import path from "path";

import { PrismaClient } from "@prismaclient";

// Path to CSV file
const csvFilePath = path.resolve(process.cwd(), "public/scientists.csv");
const prisma = new PrismaClient();

type CsvRow = {
	Name: string;
	Level?: string;
	UserId: string;
	SuperiorId?: string;
};

function normalizeLevel(level: string | undefined): string {
	// Only allow JUNIOR, SENIOR; default JUNIOR
	if (!level || !level.trim()) return "JUNIOR";
	const lv = level.trim().toUpperCase();
	return ["JUNIOR", "SENIOR"].includes(lv) ? lv : "JUNIOR";
}

export async function POST() {
	try {
		// 1. Read the CSV file
		const fileContent = await fs.readFile(csvFilePath, "utf8");

		// 2. Parse the CSV
		const records: CsvRow[] = parse(fileContent, {
			columns: true,
			skip_empty_lines: true,
		});

		// 3. Transform each record for Prisma
		const scientists = records.map((row) => ({
			name: row.Name,
			level: normalizeLevel(row.Level),
			userId: parseInt(row.UserId, 10),
			superiorId: row.SuperiorId && row.SuperiorId.trim() !== "" ? parseInt(row.SuperiorId, 10) : null,
		}));

		// 4. Bulk create scientists in database
		await prisma.scientist.createMany({
			data: scientists,
			skipDuplicates: true, // in case the scientist/userid combo already exists
		});

		return NextResponse.json({ success: true, count: scientists.length });
	} catch (error: any) {
		console.error(error);
		return NextResponse.json({ success: false, error: error.message }, { status: 500 });
	} finally {
		await prisma.$disconnect();
	}
}