import type { RequestHandler } from './$types';
import { db } from '$lib/server/db';
import { dailyCompletions } from '$lib/server/db/schema';
import { and, eq, asc } from 'drizzle-orm';
import { json } from '@sveltejs/kit';
import crypto from 'node:crypto';

export const POST: RequestHandler = async ({ request }) => {
	try {
		const { anonymousId, date, guessCount } = await request.json();

		// Validation
		if (!anonymousId || !date || typeof guessCount !== 'number' || guessCount < 1) {
			return json({ error: 'Invalid data' }, { status: 400 });
		}

		const completedAt = new Date();

		try {
			// Insert with duplicate prevention
			await db.insert(dailyCompletions).values({
				id: crypto.randomUUID(),
				anonymousId,
				date,
				guessCount,
				completedAt,
			});
		} catch (err: any) {
			if (err?.code === 'SQLITE_CONSTRAINT_UNIQUE' || err?.message?.includes('UNIQUE')) {
				return json({ error: 'Already submitted' }, { status: 409 });
			}
			throw err;
		}

		// Calculate statistics
		const allCompletions = await db
			.select()
			.from(dailyCompletions)
			.where(eq(dailyCompletions.date, date))
			.orderBy(asc(dailyCompletions.completedAt));

		const totalSolves = allCompletions.length;

		// Solve rank: position in time-ordered list
		const solveRank = allCompletions.findIndex(c => c.anonymousId === anonymousId) + 1;

		// Guess rank: count how many DISTINCT guess counts are better (grouped ranking)
		const uniqueBetterGuessCounts = new Set(
			allCompletions.filter(c => c.guessCount < guessCount).map(c => c.guessCount)
		);
		const guessRank = uniqueBetterGuessCounts.size + 1;

		// Count ties: how many have the SAME guessCount (excluding self)
		const tiedCount = allCompletions.filter(c => c.guessCount === guessCount && c.anonymousId !== anonymousId).length;

		// Average guesses
		const totalGuesses = allCompletions.reduce((sum, c) => sum + c.guessCount, 0);
		const averageGuesses = Math.round((totalGuesses / totalSolves) * 10) / 10;

		// Percentile: what percentage of people you beat (100 - your rank percentage)
		const betterOrEqualCount = allCompletions.filter(c => c.guessCount <= guessCount).length;
		const percentile = Math.round((betterOrEqualCount / totalSolves) * 100);

		return json({
			success: true,
			stats: { solveRank, guessRank, totalSolves, averageGuesses, tiedCount, percentile }
		});
	} catch (err) {
		console.error('Error submitting completion:', err);
		return json({ error: 'Failed to submit completion' }, { status: 500 });
	}
};



export const GET: RequestHandler = async ({ url }) => {
	try {
		const anonymousId = url.searchParams.get('anonymousId');
		const date = url.searchParams.get('date');

		if (!anonymousId || !date) {
			return json({ error: 'Invalid data' }, { status: 400 });
		}

		const userCompletions = await db
			.select()
			.from(dailyCompletions)
			.where(and(
				eq(dailyCompletions.anonymousId, anonymousId),
				eq(dailyCompletions.date, date)
			))
			.limit(1);

		if (userCompletions.length === 0) {
			return json({ error: 'No completion found' }, { status: 404 });
		}

		const userCompletion = userCompletions[0];
		const guessCount = userCompletion.guessCount;

		// Calculate statistics
		const allCompletions = await db
			.select()
			.from(dailyCompletions)
			.where(eq(dailyCompletions.date, date))
			.orderBy(asc(dailyCompletions.completedAt));

		const totalSolves = allCompletions.length;

		// Solve rank: position in time-ordered list
		const solveRank = allCompletions.findIndex(c => c.anonymousId === anonymousId) + 1;

		// Guess rank: count how many DISTINCT guess counts are better (grouped ranking)
		const uniqueBetterGuessCounts = new Set(
			allCompletions.filter(c => c.guessCount < guessCount).map(c => c.guessCount)
		);
		const guessRank = uniqueBetterGuessCounts.size + 1;

		// Count ties: how many have the SAME guessCount (excluding self)
		const tiedCount = allCompletions.filter(c => c.guessCount === guessCount && c.anonymousId !== anonymousId).length;

		// Average guesses
		const totalGuesses = allCompletions.reduce((sum, c) => sum + c.guessCount, 0);
		const averageGuesses = Math.round((totalGuesses / totalSolves) * 10) / 10;

		// Percentile: what percentage of people you beat (100 - your rank percentage)
		const betterOrEqualCount = allCompletions.filter(c => c.guessCount <= guessCount).length;
		const percentile = Math.round((betterOrEqualCount / totalSolves) * 100);

		return json({
			success: true,
			stats: { solveRank, guessRank, totalSolves, averageGuesses, tiedCount, percentile }
		});
	} catch (err) {
		console.error('Error fetching stats:', err);
		return json({ error: 'Failed to fetch stats' }, { status: 500 });
	}
};