"""Document text extraction utilities (PDF, DOCX, TXT, etc.)."""
import os
from PyPDF2 import PdfReader
from docx import Document


def extract_text_from_pdf(file_path: str) -> str:
    """Extract text from a PDF file."""
    reader = PdfReader(file_path)
    text_parts = []
    for page in reader.pages:
        text = page.extract_text()
        if text:
            text_parts.append(text)
    return "\n\n".join(text_parts)


def extract_text_from_docx(file_path: str) -> str:
    """Extract text from a DOCX file."""
    doc = Document(file_path)
    text_parts = []
    for para in doc.paragraphs:
        if para.text.strip():
            text_parts.append(para.text)
    # Also extract tables
    for table in doc.tables:
        for row in table.rows:
            row_text = " | ".join(cell.text.strip() for cell in row.cells)
            if row_text.strip():
                text_parts.append(row_text)
    return "\n".join(text_parts)


def extract_text_from_txt(file_path: str) -> str:
    """Read a plain text file."""
    with open(file_path, "r", encoding="utf-8", errors="replace") as f:
        return f.read()


def extract_text(file_path: str) -> str:
    """Extract text from a file based on its extension."""
    ext = os.path.splitext(file_path)[1].lower()
    
    if ext == ".pdf":
        return extract_text_from_pdf(file_path)
    elif ext == ".docx":
        return extract_text_from_docx(file_path)
    elif ext in (".txt", ".md", ".rtf"):
        return extract_text_from_txt(file_path)
    elif ext == ".doc":
        # Old .doc format — try reading as text (best effort)
        try:
            return extract_text_from_txt(file_path)
        except Exception:
            return f"[Could not extract text from .doc file: {file_path}]"
    else:
        # Try reading as text
        try:
            return extract_text_from_txt(file_path)
        except Exception:
            return f"[Unsupported file format: {ext}]"