#!/usr/bin/env python3
"""
MusicGen Music Generation Service

OpenAI-compatible music generation using Meta's MusicGen Medium model.
Provides /v1/audio/generations endpoint.
"""

import base64
import io
import os
import tempfile
from typing import Optional

import torch
import torchaudio
from audiocraft.models import MusicGen
from fastapi import HTTPException
from pydantic import BaseModel, Field

# Import base service class
import sys
sys.path.insert(0, os.path.join(os.path.dirname(__file__), '../..'))
from core.base_service import GPUService


class AudioGenerationRequest(BaseModel):
    """Music generation request"""
    model: str = Field(default="musicgen-medium", description="Model name")
    prompt: str = Field(..., description="Text description of the music to generate")
    duration: float = Field(default=30.0, ge=1.0, le=30.0, description="Duration in seconds")
    temperature: float = Field(default=1.0, ge=0.1, le=2.0, description="Sampling temperature")
    top_k: int = Field(default=250, ge=0, le=500, description="Top-k sampling")
    top_p: float = Field(default=0.0, ge=0.0, le=1.0, description="Top-p (nucleus) sampling")
    cfg_coef: float = Field(default=3.0, ge=1.0, le=15.0, description="Classifier-free guidance coefficient")
    response_format: str = Field(default="wav", description="Audio format (wav or mp3)")


class AudioGenerationResponse(BaseModel):
    """Music generation response"""
    audio: str = Field(..., description="Base64-encoded audio data")
    format: str = Field(..., description="Audio format (wav or mp3)")
    duration: float = Field(..., description="Duration in seconds")
    sample_rate: int = Field(..., description="Sample rate in Hz")


class MusicGenService(GPUService):
    """MusicGen music generation service"""

    def __init__(self):
        # Get port from environment or use default
        port = int(os.getenv("PORT", "8003"))
        super().__init__(name="musicgen-medium", port=port)

        # Service-specific attributes
        self.model: Optional[MusicGen] = None
        self.model_name = os.getenv("MODEL_NAME", "facebook/musicgen-medium")

    async def initialize(self):
        """Initialize MusicGen model"""
        await super().initialize()

        self.logger.info(f"Loading MusicGen model: {self.model_name}")

        # Load model
        device = "cuda" if torch.cuda.is_available() else "cpu"
        self.model = MusicGen.get_pretrained(self.model_name, device=device)

        self.logger.info(f"MusicGen model loaded successfully")
        self.logger.info(f"Max duration: 30 seconds at {self.model.sample_rate}Hz")

    async def cleanup(self):
        """Cleanup resources"""
        await super().cleanup()
        if self.model:
            self.logger.info("MusicGen model cleanup")
            self.model = None

    def create_app(self):
        """Create FastAPI routes"""

        @self.app.get("/")
        async def root():
            """Root endpoint"""
            return {
                "service": "MusicGen API Server",
                "model": self.model_name,
                "max_duration": 30.0,
                "sample_rate": self.model.sample_rate if self.model else 32000
            }

        @self.app.get("/v1/models")
        async def list_models():
            """List available models (OpenAI-compatible)"""
            return {
                "object": "list",
                "data": [
                    {
                        "id": "musicgen-medium",
                        "object": "model",
                        "created": 1234567890,
                        "owned_by": "meta",
                        "permission": [],
                        "root": self.model_name,
                        "parent": None,
                    }
                ]
            }

        @self.app.post("/v1/audio/generations")
        async def generate_audio(request: AudioGenerationRequest) -> AudioGenerationResponse:
            """Generate music from text prompt"""
            if not self.model:
                raise HTTPException(status_code=503, detail="Model not initialized")

            self.logger.info(f"Generating music: {request.prompt[:100]}...")
            self.logger.info(f"Duration: {request.duration}s, Temperature: {request.temperature}")

            try:
                # Set generation parameters
                self.model.set_generation_params(
                    duration=request.duration,
                    temperature=request.temperature,
                    top_k=request.top_k,
                    top_p=request.top_p,
                    cfg_coef=request.cfg_coef,
                )

                # Generate audio
                descriptions = [request.prompt]
                with torch.no_grad():
                    wav = self.model.generate(descriptions)

                # wav shape: [batch_size, channels, samples]
                # Extract first batch item
                audio_data = wav[0].cpu()  # [channels, samples]

                # Get sample rate
                sample_rate = self.model.sample_rate

                # Save to temporary file
                with tempfile.NamedTemporaryFile(suffix=".wav", delete=False) as temp_file:
                    temp_path = temp_file.name
                    torchaudio.save(temp_path, audio_data, sample_rate)

                # Read audio file and encode to base64
                with open(temp_path, 'rb') as f:
                    audio_bytes = f.read()

                # Clean up temporary file
                os.unlink(temp_path)

                # Encode to base64
                audio_base64 = base64.b64encode(audio_bytes).decode('utf-8')

                self.logger.info(f"Generated {request.duration}s of audio")

                return AudioGenerationResponse(
                    audio=audio_base64,
                    format="wav",
                    duration=request.duration,
                    sample_rate=sample_rate
                )

            except Exception as e:
                self.logger.error(f"Error generating audio: {e}")
                raise HTTPException(status_code=500, detail=str(e))


if __name__ == "__main__":
    service = MusicGenService()
    service.run()