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


# =========================
# 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()