'use server';

import { PrismaClient } from '@prisma/client';

const prisma = new PrismaClient();

const OPENROUTER_API_KEY = process.env.OPENROUTER_API_KEY;
const OPENROUTER_MODEL = 'anthropic/claude-3.5-haiku';
const BATCH_SIZE = 20; // Process 20 songs at a time to avoid timeouts

interface CategorizeResult {
    songId: number;
    title: string;
    artist: string;
    assignedGenres: string[];
}

export async function POST(request: Request) {
    try {
        if (!OPENROUTER_API_KEY) {
            return Response.json(
                { error: 'OPENROUTER_API_KEY not configured' },
                { status: 500 }
            );
        }

        // Get offset from request body (for batch processing)
        const body = await request.json().catch(() => ({}));
        const offset = body.offset || 0;

        // Fetch all songs without genres
        const totalUncategorized = await prisma.song.count({
            where: {
                genres: {
                    none: {}
                }
            }
        });

        if (totalUncategorized === 0) {
            return Response.json({
                message: 'No uncategorized songs found',
                results: [],
                hasMore: false,
                totalUncategorized: 0,
                processed: 0
            });
        }

        // Fetch batch of songs
        const uncategorizedSongs = await prisma.song.findMany({
            where: {
                genres: {
                    none: {}
                }
            },
            include: {
                genres: true
            },
            take: BATCH_SIZE,
            skip: offset
        });

        // Fetch all available genres
        const allGenres = await prisma.genre.findMany({
            orderBy: { name: 'asc' }
        });

        if (allGenres.length === 0) {
            return Response.json(
                { error: 'No genres available. Please create genres first.' },
                { status: 400 }
            );
        }

        const results: CategorizeResult[] = [];

        // Process each song in this batch
        for (const song of uncategorizedSongs) {
            try {
                const genreNames = allGenres.map(g => g.name);

                const prompt = `You are a music genre categorization assistant. Given a song title and artist, categorize it into 0-3 of the available genres.

Song: "${song.title}" by ${song.artist}
Available genres: ${genreNames.join(', ')}

Rules:
- Select 0-3 genres that best match this song
- Only use genres from the available list
- Respond with ONLY a JSON array of genre names, nothing else
- If no genres match well, return an empty array []

Example response: ["Rock", "Alternative"]

Your response:`;

                const response = await fetch('https://openrouter.ai/api/v1/chat/completions', {
                    method: 'POST',
                    headers: {
                        'Authorization': `Bearer ${OPENROUTER_API_KEY}`,
                        'Content-Type': 'application/json',
                        'HTTP-Referer': 'https://hoerdle.elpatron.me',
                        'X-Title': 'Hördle Genre Categorization'
                    },
                    body: JSON.stringify({
                        model: OPENROUTER_MODEL,
                        messages: [
                            {
                                role: 'user',
                                content: prompt
                            }
                        ],
                        temperature: 0.3,
                        max_tokens: 100
                    })
                });

                if (!response.ok) {
                    console.error(`OpenRouter API error for song ${song.id}:`, await response.text());
                    continue;
                }

                const data = await response.json();
                const aiResponse = data.choices?.[0]?.message?.content?.trim() || '[]';

                // Parse AI response
                let suggestedGenreNames: string[] = [];
                try {
                    suggestedGenreNames = JSON.parse(aiResponse);
                } catch (e) {
                    console.error(`Failed to parse AI response for song ${song.id}:`, aiResponse);
                    continue;
                }

                // Filter to only valid genres and get their IDs
                const genreIds = allGenres
                    .filter(g => suggestedGenreNames.includes(g.name))
                    .map(g => g.id)
                    .slice(0, 3); // Max 3 genres

                if (genreIds.length > 0) {
                    // Update song with genres
                    await prisma.song.update({
                        where: { id: song.id },
                        data: {
                            genres: {
                                connect: genreIds.map(id => ({ id }))
                            }
                        }
                    });

                    results.push({
                        songId: song.id,
                        title: song.title,
                        artist: song.artist,
                        assignedGenres: suggestedGenreNames.filter(name =>
                            allGenres.some(g => g.name === name)
                        )
                    });
                }

            } catch (error) {
                console.error(`Error processing song ${song.id}:`, error);
                continue;
            }
        }

        const newOffset = offset + BATCH_SIZE;
        const hasMore = newOffset < totalUncategorized;

        return Response.json({
            message: `Processed ${uncategorizedSongs.length} songs in this batch, categorized ${results.length}`,
            totalUncategorized,
            processed: Math.min(newOffset, totalUncategorized),
            hasMore,
            nextOffset: hasMore ? newOffset : null,
            results
        });

    } catch (error) {
        console.error('Categorization error:', error);
        return Response.json(
            { error: 'Failed to categorize songs' },
            { status: 500 }
        );
    }
}