"""
VoiceVerse AI — Utility helpers.

Provides temp file management and error formatting
used across the pipeline.
"""

import os
import tempfile
import logging

logging.basicConfig(
    level=logging.INFO,
    format="%(asctime)s [%(levelname)s] %(name)s: %(message)s",
)
logger = logging.getLogger("voiceverse")


def get_temp_filepath(suffix: str = ".wav") -> str:
    """Return a path to a new temporary file that won't be auto-deleted."""
    fd, path = tempfile.mkstemp(suffix=suffix)
    os.close(fd)
    return path


def format_error(stage: str, error: Exception) -> str:
    """
    Return a user-friendly error string.
    Hides raw tracebacks; logs the full error for debugging.
    """
    logger.error("Error in %s: %s", stage, error, exc_info=True)
    friendly_messages = {
        "upload": "Could not read the uploaded file. Please try a different PDF or TXT file.",
        "rag": "Failed to process the document text. The file may be empty or corrupted.",
        "script": "Could not generate the audio script. Please check your HF_TOKEN and try again.",
        "tts": "Audio generation failed. The system will retry with a fallback voice.",
    }
    return friendly_messages.get(stage, f"An unexpected error occurred: {stage}")


def validate_file(file_path: str) -> tuple[bool, str]:
    """
    Validate an uploaded file. Returns (is_valid, message).
    """
    if file_path is None:
        return False, "Please upload a PDF or TXT file first."

    if not os.path.exists(file_path):
        return False, "The uploaded file could not be found. Please try again."

    ext = os.path.splitext(file_path)[1].lower()
    if ext not in (".pdf", ".txt"):
        return False, f"Unsupported file format '{ext}'. Please upload a PDF or TXT file."

    size = os.path.getsize(file_path)
    if size == 0:
        return False, "The uploaded file is empty. Please upload a file with content."

    if size > 20 * 1024 * 1024:  # 20 MB limit
        return False, "File is too large (>20 MB). Please upload a smaller document."

    return True, "File is valid."