import io
import easyocr
import fitz  # pymupdf
import docx2txt
import numpy as np
from PIL import Image
from typing import Tuple

_reader = None

def get_reader() -> easyocr.Reader:
    global _reader
    if _reader is None:
        _reader = easyocr.Reader(["en"], gpu=False)
    return _reader


def image_bytes_to_array(image_bytes: bytes) -> np.ndarray:
    img = Image.open(io.BytesIO(image_bytes)).convert("RGB")
    return np.array(img)


def ocr_image_array(img_array: np.ndarray) -> str:
    reader = get_reader()
    results = reader.readtext(img_array, detail=0, paragraph=True)
    return "\n".join(results)


def extract_text_from_image(file_bytes: bytes) -> Tuple[str, int]:
    img_array = image_bytes_to_array(file_bytes)
    text = ocr_image_array(img_array)
    return text, 1


def extract_text_from_pdf(file_bytes: bytes) -> Tuple[str, int]:
    doc = fitz.open(stream=file_bytes, filetype="pdf")
    pages_processed = len(doc)
    all_text_parts = []

    for page in doc:
        # Try native text first
        native_text = page.get_text("text").strip()

        if len(native_text) > 50:
            all_text_parts.append(native_text)
        else:
            # Fallback to EasyOCR on rasterised page
            pix = page.get_pixmap(dpi=200)
            img = Image.frombytes("RGB", [pix.width, pix.height], pix.samples)
            img_array = np.array(img)
            ocr_text = ocr_image_array(img_array)
            all_text_parts.append(ocr_text)

    doc.close()
    return "\n\n--- PAGE BREAK ---\n\n".join(all_text_parts), pages_processed


def extract_text_from_docx(file_bytes: bytes) -> Tuple[str, int]:
    text = docx2txt.process(io.BytesIO(file_bytes))
    return text or "", 1


def extract_text_from_file(file_bytes: bytes, ext: str) -> Tuple[str, int]:
    if ext == "pdf":
        return extract_text_from_pdf(file_bytes)
    elif ext == "docx":
        return extract_text_from_docx(file_bytes)
    elif ext in {"png", "jpg", "jpeg", "webp"}:
        return extract_text_from_image(file_bytes)
    else:
        raise ValueError(f"Unsupported extension: {ext}")