"""PDF extractor with optional OCR fallback."""

from pathlib import Path
from typing import List

from src.ingest.models import DocumentChunk, NormalizedDocument


def _extract_with_pymupdf(path: Path) -> tuple[str, List[DocumentChunk]]:
    import fitz  # pymupdf

    doc = fitz.open(str(path))
    chunks: List[DocumentChunk] = []
    parts: List[str] = []
    for page_num, page in enumerate(doc, start=1):
        text = page.get_text("text").strip()
        if text:
            parts.append(f"--- Страница {page_num} ---\n{text}")
            chunks.append(DocumentChunk(text=text, source=path.name, page=page_num))
    doc.close()
    return "\n\n".join(parts).strip(), chunks


def _extract_with_ocr(path: Path) -> tuple[str, List[DocumentChunk]]:
    try:
        import fitz
        import pytesseract
        from PIL import Image
        import io
    except ImportError:
        return "", []

    doc = fitz.open(str(path))
    chunks: List[DocumentChunk] = []
    parts: List[str] = []
    for page_num, page in enumerate(doc, start=1):
        pix = page.get_pixmap(dpi=200)
        img = Image.open(io.BytesIO(pix.tobytes("png")))
        text = pytesseract.image_to_string(img, lang="rus+eng").strip()
        if text:
            parts.append(f"--- Страница {page_num} (OCR) ---\n{text}")
            chunks.append(DocumentChunk(text=text, source=path.name, page=page_num))
    doc.close()
    return "\n\n".join(parts).strip(), chunks


def extract_pdf(path: Path, document_id: str, project: str, doc_type: str, use_ocr: bool = True) -> NormalizedDocument:
    full_text, chunks = _extract_with_pymupdf(path)
    ocr_used = False
    if not full_text and use_ocr:
        full_text, chunks = _extract_with_ocr(path)
        ocr_used = bool(full_text)

    return NormalizedDocument(
        document_id=document_id,
        filename=path.name,
        doc_type=doc_type,
        project=project,
        full_text=full_text,
        chunks=chunks or ([DocumentChunk(text=full_text, source=path.name)] if full_text else []),
        metadata={"format": "pdf", "ocr_used": ocr_used, "pages": len(chunks)},
        mime_hint="application/pdf",
    )