/**
 * Migrates the 13 Factfulness quiz cards from type=basic (A/B/C embedded in
 * front text) to type=multiple-choice with proper field structure.
 * Also sets the deck to visibility=public.
 *
 * Run from repo root: bun --cwd apps/api run ../../scripts/migrate-factfulness-to-mc.ts
 */

import postgres from 'postgres';

const DECK_ID = '01KR96NH892HBP1TV5M3XJTB39';
const DB_URL = 'postgresql://cards:cards@localhost:5435/cards';

const sql = postgres(DB_URL);

interface CardRow {
	id: string;
	fields: { front?: string; back?: string };
}

function parseQuizCard(front: string, back: string): {
	question: string;
	answer: string;
	distractorPool: string;
	explanation: string;
} | null {
	// front: "<question>\n\nA: opt1\nB: opt2\nC: opt3"
	const splitIdx = front.indexOf('\n\nA:');
	if (splitIdx === -1) return null;

	const question = front.slice(0, splitIdx).trim();
	const optionsBlock = front.slice(splitIdx + 2).trim(); // starts with "A: …"

	const options: Record<string, string> = {};
	for (const line of optionsBlock.split('\n')) {
		const m = line.match(/^([A-D]):\s*(.+)$/);
		if (m) options[m[1]] = m[2].trim();
	}

	// back: "LETTER — answer_text\n\nexplanation"
	const backMatch = back.match(/^([A-D])\s*[—–-]+\s*(.+?)(?:\n\n([\s\S]*))?$/);
	if (!backMatch) return null;

	const correctLetter = backMatch[1];
	const answer = options[correctLetter] ?? backMatch[2].trim();
	const explanation = (backMatch[3] ?? '').trim();

	const distractorPool = Object.entries(options)
		.filter(([l]) => l !== correctLetter)
		.map(([, v]) => v)
		.join('\n');

	return { question, answer, distractorPool, explanation };
}

async function run() {
	console.log('Fetching basic cards from Factfulness deck…\n');

	const rows = await sql<CardRow[]>`
		SELECT id, fields
		FROM cards.cards
		WHERE deck_id = ${DECK_ID}
		  AND type = 'basic'
	`;

	let migrated = 0;
	let skipped = 0;

	for (const row of rows) {
		const front = row.fields.front ?? '';
		const back = row.fields.back ?? '';

		if (!front.includes('\n\nA:')) {
			skipped++;
			continue;
		}

		const parsed = parseQuizCard(front, back);
		if (!parsed) {
			console.warn(`  ⚠ Cannot parse ${row.id.slice(-8)}: "${front.slice(0, 60)}"`);
			skipped++;
			continue;
		}

		const { question, answer, distractorPool, explanation } = parsed;

		const newFields: Record<string, string> = { front: question, answer };
		if (distractorPool) newFields.distractor_pool = distractorPool;
		if (explanation) newFields.explanation = explanation;

		await sql`
			UPDATE cards.cards
			SET type = 'multiple-choice',
			    fields = ${sql.json(newFields)}
			WHERE id = ${row.id}
		`;

		console.log(`  ✓ ${row.id.slice(-8)}  Q: "${question.slice(0, 55)}…"`);
		migrated++;
	}

	await sql`
		UPDATE cards.decks
		SET visibility = 'public'
		WHERE id = ${DECK_ID}
	`;
	console.log(`\n  ✓ Deck → visibility=public`);

	console.log(`\nDone: ${migrated} migrated, ${skipped} basic cards kept as-is.`);
	await sql.end();
}

run().catch((e) => {
	console.error(e);
	process.exit(1);
});