"""
hume_api.py

This file defines the interaction with the Hume TTS API, focusing on converting text to audio.
It includes functionality for input validation, API request handling, and processing API responses.

Key Features:
- Encapsulates all logic related to the Hume TTS API.
- Implements retry logic for handling transient API errors.
- Handles received audio and processes it for playback on the web.
- Provides detailed logging for debugging and error tracking.

Classes:
- HumeConfig: Immutable configuration for interacting with the TTS API.
- HumeException: Custom exception for TTS API-related errors.

Functions:
- text_to_speech_with_hume: Converts text to speech using the Hume TTS API with input validation and retry logic.
"""

# Standard Library Imports
from dataclasses import dataclass
import logging
import random
from typing import List, Optional
# Third-Party Library Imports
import requests
from tenacity import retry, stop_after_attempt, wait_fixed, before_log, after_log
# Local Application Imports
from src.config import logger
from src.utils import validate_env_var, truncate_text


@dataclass(frozen=True)
class HumeConfig:
    """Immutable configuration for interacting with the Hume TTS API."""
    tts_endpoint_url: str = 'https://api.hume.ai/v0/tts'
    api_key: str = validate_env_var('HUME_API_KEY')
    voices: List[str] = ('ITO', 'KORA', 'STELLA')  # List of available Hume voices
    audio_format: str = 'wav'
    headers: dict = None  # Headers for the API requests

    def __post_init__(self):
        # Validate required attributes
        if not self.api_key:
            raise ValueError('Hume API key is not set.')
        if not self.voices:
            raise ValueError('Hume voices list is empty. Please provide at least one voice.')
        if not self.audio_format:
            raise ValueError('Hume audio format is not set.')

        # Set headers dynamically after validation
        object.__setattr__(self, 'headers', {
            'X-Hume-Api-Key': f'{self.api_key}',
            'Content-Type': 'application/json',
        })

    @property
    def random_voice(self) -> str:
        """
        Randomly selects a voice from the available voices.

        Returns:
            str: A randomly chosen voice name.
        """
        return random.choice(self.voices)


class HumeException(Exception):
    """Custom exception for errors related to the Hume TTS API."""
    def __init__(self, message: str, original_exception: Optional[Exception] = None):
        super().__init__(message)
        self.original_exception = original_exception


# Initialize the Hume client
hume_config = HumeConfig()


@retry(
    stop=stop_after_attempt(3),
    wait=wait_fixed(2),
    before=before_log(logger, logging.DEBUG),
    after=after_log(logger, logging.DEBUG),
)
def text_to_speech_with_hume(prompt: str, text: str) -> bytes:
    """
    Converts text to speech using the Hume TTS API and processes raw binary audio data.

    Args:
        prompt (str): The original user prompt (for debugging).
        text (str): The generated text to be converted to speech.

    Returns:
        bytes: The raw binary audio data for playback.

    Raises:
        HumeException: If there is an error communicating with the Hume TTS API.
    """
    logger.debug(f'Processing TTS with Hume. Prompt length: {len(prompt)} characters. Text length: {len(text)} characters.')

    request_body = {
        'text': text,
        'voice': {'name': hume_config.random_voice},
    }

    try:
        response = requests.post(
            url=hume_config.tts_endpoint_url,
            headers=hume_config.headers,
            json=request_body,
        )

        # Validate response
        if response.status_code != 200:
            logger.error(f'Hume TTS API Error: {response.status_code} - {response.text[:200]}... (truncated)')
            raise HumeException(f'Hume TTS API responded with status {response.status_code}: {response.text}')

        # Process audio response
        if response.headers.get('Content-Type', '').startswith('audio/'):
            audio_data = response.content  # Raw binary audio data
            logger.info(f'Received audio data from Hume ({len(response.content)} bytes).')
            return audio_data

        # Unexpected content type
        raise HumeException(f'Unexpected Content-Type: {response.headers.get("Content-Type", "Unknown")}')

    except requests.exceptions.RequestException as e:
        logger.exception('Request to Hume TTS API failed.')
        raise HumeException(
            message=f'Failed to communicate with Hume TTS API: {e}',
            original_exception=e,
        )
    except Exception as e:
        logger.exception('Request to Hume TTS API failed.')
        raise HumeException(
            message=f"Unexpected error while processing the Hume TTS response: {e}",
            original_exception=e,
        )