"""Recursive file discovery with extension filtering.

Discovers files for ingestion by walking directories and filtering
to supported document types.
"""

import logging
from pathlib import Path

logger = logging.getLogger(__name__)

SUPPORTED_EXTENSIONS = {".pdf", ".jpg", ".jpeg", ".png", ".md", ".txt", ".docx"}


def discover_files(path: Path) -> list[Path]:
    """Discover supported files from a path (file or directory).

    Args:
        path: A single file path or a directory to scan recursively.

    Returns:
        Sorted list of Path objects with supported extensions.

    Raises:
        FileNotFoundError: If the path does not exist.
    """
    path = Path(path)

    if not path.exists():
        raise FileNotFoundError(f"Path does not exist: {path}")

    if path.is_file():
        if path.suffix.lower() in SUPPORTED_EXTENSIONS:
            return [path]
        logger.warning("Unsupported file type: %s", path)
        return []

    # Recursive directory traversal
    files: list[Path] = []
    for item in sorted(path.rglob("*")):
        if item.is_file() and item.suffix.lower() in SUPPORTED_EXTENSIONS:
            files.append(item)

    logger.info("Discovered %d supported files in %s", len(files), path)
    return files