import os
import uuid
import tempfile
import requests
from minio import Minio
from pdf2image import convert_from_path
import pytesseract
import concurrent.futures
import PyPDF2

# ================= CONFIG =================
MINIO_ENDPOINT = "192.168.10.76:9000"
MINIO_ACCESS = "minioadmin"
MINIO_SECRET = "Admin@!@2025"
BUCKET_NAME = "pdf-storage"

POPPLER_PATH = r"C:\Program Files\poppler\Library\bin"  # Ubuntu = None
MAX_FILE_SIZE_MB = 20

# ================= INIT MINIO =================
minio_client = Minio(
    MINIO_ENDPOINT,
    access_key=MINIO_ACCESS,
    secret_key=MINIO_SECRET,
    secure=False
)

if not minio_client.bucket_exists(BUCKET_NAME):
    minio_client.make_bucket(BUCKET_NAME)


# ================= HELPERS =================

def pdf_has_text(file_path):
    reader = PyPDF2.PdfReader(file_path)
    for page in reader.pages:
        if page.extract_text():
            return True
    return False


def ocr_page(page):
    return pytesseract.image_to_string(page, config="--psm 6")


def process_pdf(url):
    response = requests.get(url, timeout=30)

    if response.status_code != 200:
        raise Exception("Download failed")

    if "application/pdf" not in response.headers.get("Content-Type", ""):
        raise Exception("Not a valid PDF")

    if len(response.content) > MAX_FILE_SIZE_MB * 1024 * 1024:
        raise Exception("File too large")

    return _process_bytes(response.content)


def process_uploaded_pdf(file_bytes):
    return _process_bytes(file_bytes)


def _process_bytes(file_bytes):
    file_id = str(uuid.uuid4())

    with tempfile.NamedTemporaryFile(delete=False, suffix=".pdf") as tmp:
        tmp.write(file_bytes)
        local_pdf = tmp.name

    # Upload PDF
    minio_client.fput_object(
        BUCKET_NAME,
        f"{file_id}.pdf",
        local_pdf,
        content_type="application/pdf"
    )

    # Detect digital PDF
    if pdf_has_text(local_pdf):
        reader = PyPDF2.PdfReader(local_pdf)
        full_text = ""
        for page in reader.pages:
            full_text += page.extract_text() or ""
        source_type = "digital_pdf"
    else:
        pages = convert_from_path(
            local_pdf,
            dpi=300,
            poppler_path=POPPLER_PATH
        )

        with concurrent.futures.ThreadPoolExecutor() as executor:
            results = executor.map(ocr_page, pages)

        full_text = "\n".join(results)
        source_type = "scanned_pdf"

    os.remove(local_pdf)

    return {
        "file_id": file_id,
        "type": source_type,
        "text_length": len(full_text),
        "text": full_text
    }