import { NextResponse } from 'next/server';
import { PrismaClient } from '@prisma/client';
import { getTodayISOString } from '@/lib/dateUtils';

const prisma = new PrismaClient();

export async function GET() {
    try {
        const today = getTodayISOString();

        let dailyPuzzle = await prisma.dailyPuzzle.findUnique({
            where: { date: today },
            include: { song: true },
        });

        console.log(`[Daily Puzzle] Date: ${today}, Found existing: ${!!dailyPuzzle}`);

        if (!dailyPuzzle) {
            // Get all songs with their usage count
            const allSongs = await prisma.song.findMany({
                include: {
                    puzzles: true,
                },
            });

            if (allSongs.length === 0) {
                return NextResponse.json({ error: 'No songs available' }, { status: 404 });
            }

            // Calculate weights: songs never used get weight 1.0, 
            // songs used once get 0.5, twice 0.33, etc.
            const weightedSongs = allSongs.map(song => ({
                song,
                weight: 1.0 / (song.puzzles.length + 1),
            }));

            // Calculate total weight
            const totalWeight = weightedSongs.reduce((sum, item) => sum + item.weight, 0);

            // Pick a random song based on weights
            let random = Math.random() * totalWeight;
            let selectedSong = weightedSongs[0].song;

            for (const item of weightedSongs) {
                random -= item.weight;
                if (random <= 0) {
                    selectedSong = item.song;
                    break;
                }
            }

            // Create the daily puzzle
            dailyPuzzle = await prisma.dailyPuzzle.create({
                data: {
                    date: today,
                    songId: selectedSong.id,
                },
                include: { song: true },
            });

            console.log(`[Daily Puzzle] Created new puzzle for ${today} with song: ${selectedSong.title} (ID: ${selectedSong.id})`);
        }

        if (!dailyPuzzle) {
            return NextResponse.json({ error: 'Failed to create puzzle' }, { status: 500 });
        }

        return NextResponse.json({
            id: dailyPuzzle.id,
            audioUrl: `/uploads/${dailyPuzzle.song.filename}`,
            songId: dailyPuzzle.songId,
            title: dailyPuzzle.song.title,
            artist: dailyPuzzle.song.artist,
            coverImage: dailyPuzzle.song.coverImage ? `/uploads/covers/${dailyPuzzle.song.coverImage}` : null,
        });

    } catch (error) {
        console.error('Error fetching daily puzzle:', error);
        return NextResponse.json({ error: 'Internal Server Error' }, { status: 500 });
    }
}