from pdf2image import convert_from_path
import pytesseract
from PyPDF2 import PdfReader
import tempfile
import os

def extract_text_simple(pdf_path: str) -> str:
    """使用 PyPDF2 直接提取 PDF 純文字"""
    try:
        with open(pdf_path, "rb") as f:
            reader = PdfReader(f)
            return "\n\n".join(page.extract_text() or "" for page in reader.pages)
    except Exception as e:
        return f"❌ PDF 讀取錯誤: {e}"

def extract_text_ocr(pdf_path: str) -> str:
    """使用 OCR 擷取 PDF 的圖片並辨識成文字"""
    try:
        images = convert_from_path(pdf_path, dpi=300)
        text = ""
        for i, img in enumerate(images):
            gray = img.convert('L')
            page_text = pytesseract.image_to_string(gray, lang='chi_tra')
            text += f"\n\n--- Page {i+1} ---\n\n" + page_text
        return text
    except Exception as e:
        return f"❌ OCR 擷取失敗: {e}"

def extract_text(pdf_path: str, mode: str = "simple") -> str:
    """依模式選擇擷取方式：simple 或 ocr"""
    if mode == "ocr":
        return extract_text_ocr(pdf_path)
    return extract_text_simple(pdf_path)