"""Plain text and markdown file extractor.

Handles .md and .txt files. Reads as UTF-8 by default, with fallback
charset detection for non-UTF-8 encoded files.
"""

import logging
from pathlib import Path

from .base import ExtractionResult

logger = logging.getLogger(__name__)

SUPPORTED_EXTENSIONS = {".md", ".txt"}


class PlainTextExtractor:
    """Extracts text from plain text and markdown files."""

    def can_handle(self, file_path: Path) -> bool:
        """Return True for .md and .txt files."""
        return file_path.suffix.lower() in SUPPORTED_EXTENSIONS

    def extract(self, file_path: Path) -> ExtractionResult:
        """Read file as UTF-8, falling back to charset detection."""
        text = self._read_with_fallback(file_path)
        return ExtractionResult(
            text=text,
            source_file=file_path,
            extraction_method="direct",
            metadata={"encoding": "utf-8"},
        )

    def _read_with_fallback(self, file_path: Path) -> str:
        """Try UTF-8 first, then attempt charset detection."""
        try:
            return file_path.read_text(encoding="utf-8")
        except UnicodeDecodeError:
            logger.warning(
                "UTF-8 decode failed for %s, attempting charset detection", file_path
            )
            return self._read_with_detection(file_path)

    def _read_with_detection(self, file_path: Path) -> str:
        """Detect encoding and read file."""
        raw = file_path.read_bytes()

        # Try common encodings before giving up
        for encoding in ("latin-1", "cp1252", "iso-8859-1"):
            try:
                return raw.decode(encoding)
            except (UnicodeDecodeError, LookupError):
                continue

        # Last resort: decode with replacement characters
        logger.warning("Could not detect encoding for %s, using replacement", file_path)
        return raw.decode("utf-8", errors="replace")