import logging
import os
import time
from logging.handlers import RotatingFileHandler

import requests

# =========================
# Configuration
# =========================

PRODUCT_URL = f"{os.environ["PRODUCT_URL"]}.js"
TARGET_VARIANT_ID = os.environ["TARGET_VARIANT_ID"]
DISCORD_WEBHOOK_URL = os.environ["DISCORD_WEBHOOK_URL"]

CHECK_INTERVAL_SECONDS = 30
POST_DETECTION_COOLDOWN_SECONDS = 600

# =========================
# Logging Setup
# =========================

logger = logging.getLogger("FormDStockMonitor")
logger.setLevel(logging.INFO)

log_format = logging.Formatter("%(asctime)s - %(levelname)s - %(message)s", datefmt="%Y-%m-%d %H:%M:%S")

# Write logs to a rotating file so disk space is not exhausted
file_handler = RotatingFileHandler("formd_monitor.log", maxBytes=5 * 1024 * 1024, backupCount=2)
file_handler.setFormatter(log_format)
logger.addHandler(file_handler)

# Also show logs directly in the terminal
console_handler = logging.StreamHandler()
console_handler.setFormatter(log_format)
logger.addHandler(console_handler)


# =========================
# Discord Notification
# =========================

def send_discord_notification(product_name, variant_name, checkout_link):
    """
    Sends a stock alert to Discord using a webhook.
    """

    logger.critical("Stock detected! Sending Discord notification.")

    payload = {"content": ("🚨 **RESTOCK ALERT** 🚨\n\n"
                           f"**{product_name}**\n"
                           f"Variant: {variant_name}\n\n"
                           f"👉 [ONE-CLICK CHECKOUT]({checkout_link})")}

    try:
        response = requests.post(DISCORD_WEBHOOK_URL, json=payload)

        if response.status_code == 204:
            logger.info("Discord notification sent successfully.")
        else:
            logger.error("Discord notification failed. "
                         f"HTTP status code: {response.status_code}")

    except Exception as exception:
        logger.error("Failed to send Discord notification due to an exception.", exc_info=exception)


# =========================
# Stock Monitoring Logic
# =========================

def check_stock_continuously():
    """
    Continuously checks the product JSON endpoint to see if the target
    variant is available for purchase.
    """

    logger.info(f"Stock monitor started. Watching variant ID: {TARGET_VARIANT_ID}")

    request_headers = {"User-Agent": ("Mozilla/5.0 (Windows NT 10.0; Win64; x64) "
                                      "AppleWebKit/537.36 (KHTML, like Gecko) "
                                      "Chrome/120.0.0.0 Safari/537.36"), "Accept": "application/json"}

    while True:
        try:
            response = requests.get(PRODUCT_URL, headers=request_headers, timeout=10)

            if response.status_code != 200:
                logger.error(f"HTTP request failed. Status code: {response.status_code}")
                time.sleep(CHECK_INTERVAL_SECONDS)
                continue

            product_data = response.json()
            product_name = product_data.get("title", "FormD T1")
            variants = product_data.get("variants", [])

            target_variant = next((variant for variant in variants if variant.get("id") == TARGET_VARIANT_ID), None)

            if not target_variant:
                logger.error(f"Variant ID {TARGET_VARIANT_ID} was not found in the product data.")
                time.sleep(CHECK_INTERVAL_SECONDS)
                continue

            variant_name = target_variant.get("title", "Unknown Variant")
            is_in_stock = target_variant.get("available", False)

            if is_in_stock:
                logger.warning(f"Stock available! Variant detected: {variant_name}")

                checkout_link = (f"https://formdt1.com/cart/{TARGET_VARIANT_ID}:1")

                send_discord_notification(product_name, variant_name, checkout_link)

                logger.info("Cooldown started to prevent duplicate alerts.")
                time.sleep(POST_DETECTION_COOLDOWN_SECONDS)

            else:
                logger.info(f"Out of stock. Checked variant: {variant_name}")

        except requests.exceptions.ConnectionError:
            logger.error("Network connection error. Unable to reach the product server.")

        except requests.exceptions.Timeout:
            logger.warning("Request timed out. The server may be slow or blocking requests.")

        except Exception as exception:
            logger.exception("An unexpected error occurred during the stock check.")

        time.sleep(CHECK_INTERVAL_SECONDS)


# =========================
# Application Entry Point
# =========================

if __name__ == "__main__":
    check_stock_continuously()