from flask import Flask, request, jsonify
from flask_cors import CORS
import cv2
import numpy as np
import base64
import io
from pyzbar.pyzbar import decode
from PIL import Image
import os
import logging
import requests

# ================== INITIALISATION ==================
app = Flask(__name__)
CORS(app, resources={r"/api/*": {"origins": "*"}})

HF_SPACE = os.environ.get("SPACE_ID") is not None
PORT = 7860 if HF_SPACE else int(os.environ.get("PORT", 5000))

logging.basicConfig(level=logging.INFO)
logger = logging.getLogger("barcode-api")

# ================== UTILS ==================

def safe_b64decode(data: str) -> bytes:
    """Base64 decode safe (Flutter/Web compatible)"""
    return base64.b64decode(data + "=" * (-len(data) % 4))


def decode_barcode(image_bytes: bytes) -> dict:
    """Decode barcode using PIL then OpenCV"""
    try:
        # --- PIL first ---
        try:
            pil_image = Image.open(io.BytesIO(image_bytes))
            barcodes = decode(pil_image)
            if barcodes:
                b = barcodes[0]
                return {
                    "success": True,
                    "barcode": b.data.decode("utf-8"),
                    "type": b.type,
                    "method": "pil"
                }
        except Exception as e:
            logger.debug(f"PIL failed: {e}")

        # --- OpenCV fallback ---
        try:
            nparr = np.frombuffer(image_bytes, np.uint8)
            img = cv2.imdecode(nparr, cv2.IMREAD_GRAYSCALE)
            if img is not None:
                barcodes = decode(img)
                if barcodes:
                    b = barcodes[0]
                    return {
                        "success": True,
                        "barcode": b.data.decode("utf-8"),
                        "type": b.type,
                        "method": "opencv"
                    }

                # Contrast enhancement
                clahe = cv2.createCLAHE(2.0, (8, 8))
                enhanced = clahe.apply(img)
                barcodes = decode(enhanced)
                if barcodes:
                    b = barcodes[0]
                    return {
                        "success": True,
                        "barcode": b.data.decode("utf-8"),
                        "type": b.type,
                        "method": "enhanced"
                    }
        except Exception as e:
            logger.debug(f"OpenCV failed: {e}")

        return {"success": False, "error": "No barcode detected"}

    except Exception as e:
        logger.error(e)
        return {"success": False, "error": str(e)}

# ================== FLUTTER API ==================

@app.route("/api/decode-barcode", methods=["POST"])
def api_decode_barcode():
    if not request.is_json:
        return jsonify({"success": False, "error": "JSON required"}), 400

    data = request.get_json()
    image_data = data.get("image")
    if not image_data:
        return jsonify({"success": False, "error": "Image missing"}), 400

    if "," in image_data:
        image_data = image_data.split(",")[1]

    if len(image_data) > 3 * 1024 * 1024:
        return jsonify({"success": False, "error": "Image too large"}), 400

    image_bytes = safe_b64decode(image_data)
    result = decode_barcode(image_bytes)
    return jsonify(result)


@app.route("/api/product-info/<barcode>", methods=["GET"])
def api_product_info(barcode):
    local_db = {
        "3017620422003": {
            "name": "Nutella",
            "brand": "Ferrero",
            "category": "Food",
            "price": 4.99,
            "description": "Hazelnut spread"
        },
        "5901234123457": {
            "name": "Milk UHT",
            "brand": "Candia",
            "category": "Food",
            "price": 1.20,
            "description": "UHT milk"
        }
    }

    if barcode in local_db:
        return jsonify({"success": True, "product": local_db[barcode], "source": "local"})

    # OpenFoodFacts fallback
    try:
        r = requests.get(
            f"https://world.openfoodfacts.org/api/v0/product/{barcode}.json",
            timeout=4
        )
        if r.status_code == 200:
            data = r.json()
            if data.get("status") == 1:
                p = data["product"]
                return jsonify({
                    "success": True,
                    "source": "openfoodfacts",
                    "product": {
                        "name": p.get("product_name"),
                        "brand": p.get("brands"),
                        "category": p.get("categories"),
                        "description": p.get("generic_name"),
                        "image": p.get("image_url")
                    }
                })
    except Exception as e:
        logger.debug(e)

    return jsonify({"success": False, "error": "Product not found"}), 404

# ================== WEB SCAN ==================

@app.route("/api/scan", methods=["POST"])
def api_scan():
    if not request.is_json:
        return jsonify({"success": False, "error": "JSON required"}), 400

    image_data = request.json.get("image")
    if not image_data:
        return jsonify({"success": False, "error": "Image missing"}), 400

    if "," in image_data:
        image_data = image_data.split(",")[1]

    image_bytes = safe_b64decode(image_data)
    return jsonify(decode_barcode(image_bytes))

# ================== HEALTH ==================

@app.route("/api/health")
def health():
    return jsonify({
        "status": "ok",
        "service": "Barcode Scanner API",
        "platform": "HuggingFace" if HF_SPACE else "Local",
        "endpoints": [
            "/api/decode-barcode",
            "/api/product-info/<barcode>",
            "/api/scan",
            "/api/health"
        ]
    })

@app.route("/")
def home():
    return jsonify({
        "message": "Barcode Scanner API",
        "use": "/api/decode-barcode (POST)"
    })

# ================== MAIN ==================

if __name__ == "__main__":
    app.run(host="0.0.0.0", port=PORT, debug=False)