import os
import shutil
from uuid import uuid4
from fastapi import UploadFile
from typing import Optional
from datetime import datetime
from sqlmodel import Session, select
from app.models.coupon import Coupon

# Use absolute path relative to THIS file's location (app/services/image_handler.py)
# Going up 3 levels: services -> app -> backend -> uploads
_BASE_DIR = os.path.dirname(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
UPLOAD_BASE = os.path.join(_BASE_DIR, "uploads")


def save_image(image: UploadFile, subfolder: str) -> str:
    """Saves an image to the local filesystem and returns its relative URL."""
    upload_dir = os.path.join(UPLOAD_BASE, subfolder)
    os.makedirs(upload_dir, exist_ok=True)

    # Generate unique filename
    ext = os.path.splitext(image.filename or "")[1].lower()
    if not ext or ext not in ['.jpg', '.jpeg', '.png', '.gif', '.webp', '.avif']:
        ext = ".jpg"  # Default extension if missing or invalid

    filename = f"{uuid4()}{ext}"
    path = os.path.join(upload_dir, filename)

    # Reset file pointer to start before reading
    image.file.seek(0)

    # Save file
    with open(path, "wb") as buffer:
        shutil.copyfileobj(image.file, buffer)

    print(f"DEBUG: Saved image to {path}")
    return f"/uploads/{subfolder}/{filename}"


def delete_image(image_url: Optional[str]):
    """Deletes an image from the filesystem if it's stored locally."""
    if not image_url:
        return

    # We only delete if it points to our local uploads folder
    if image_url.startswith("/uploads/"):
        # Build absolute path
        relative = image_url.lstrip("/")  # e.g. "uploads/businesses/uuid.jpg"
        file_path = os.path.join(_BASE_DIR, relative)
        if os.path.exists(file_path):
            try:
                os.remove(file_path)
                print(f"DEBUG: Deleted file {file_path}")
            except Exception as e:
                print(f"ERROR: Failed to delete {file_path}: {e}")
        else:
            print(f"DEBUG: File not found for deletion: {file_path}")


def cleanup_expired_coupons(session: Session):
    """Finds and deletes expired coupons and their associated images."""
    try:
        now = datetime.now()
        # Coupons where valid_until is passed
        statement = select(Coupon).where(Coupon.valid_until < now)
        expired = session.exec(statement).all()

        count = 0
        for coupon in expired:
            if coupon.image_url:
                delete_image(coupon.image_url)
            session.delete(coupon)
            count += 1

        if count > 0:
            session.commit()
            print(f"DEBUG: Cleaned up {count} expired coupons and their images.")
    except Exception as e:
        print(f"ERROR: Cleanup failed: {e}")