"""
Memory Usage Detector
Monitors RAM usage and reports to the aggregator when thresholds are exceeded.

Environment variables:
    AGGREGATOR_URL      - URL of the aggregator (default: http://localhost:5000)
    CHECK_INTERVAL      - Seconds between checks (default: 30)
    THRESHOLD_CRITICAL  - Percent usage for critical alert (default: 95)
    THRESHOLD_WARNING   - Percent usage for warning alert (default: 85)
"""

import os
import time
import psutil
import requests

# Configuration from environment
AGGREGATOR_URL = os.environ.get("AGGREGATOR_URL", "http://localhost:5000")
CHECK_INTERVAL = int(os.environ.get("CHECK_INTERVAL", 30))
THRESHOLD_CRITICAL = int(os.environ.get("THRESHOLD_CRITICAL", 95))
THRESHOLD_WARNING = int(os.environ.get("THRESHOLD_WARNING", 85))

EVENT_ID = "memory_usage"


def send_event(priority, message):
    """Send an event to the aggregator with heartbeat TTL."""
    ttl = CHECK_INTERVAL * 2
    try:
        response = requests.post(
            f"{AGGREGATOR_URL}/event",
            json={"id": EVENT_ID, "priority": priority, "message": message, "ttl": ttl},
            timeout=5
        )
        print(f"[EVENT] {message} (priority {priority}, ttl {ttl}s) -> {response.status_code}")
    except requests.RequestException as e:
        print(f"[ERROR] Failed to send event: {e}")


def clear_event():
    """Clear the event from the aggregator."""
    try:
        response = requests.post(
            f"{AGGREGATOR_URL}/clear",
            json={"id": EVENT_ID},
            timeout=5
        )
        if response.status_code == 200:
            print(f"[CLEAR] {EVENT_ID}")
    except requests.RequestException as e:
        print(f"[ERROR] Failed to clear event: {e}")


def main():
    print(f"Memory Usage Detector started")
    print(f"  Aggregator: {AGGREGATOR_URL}")
    print(f"  Interval: {CHECK_INTERVAL}s")
    print(f"  Thresholds: Warning={THRESHOLD_WARNING}%, Critical={THRESHOLD_CRITICAL}%")
    print()

    alert_active = False

    while True:
        mem = psutil.virtual_memory()
        mem_percent = mem.percent
        used_gb = mem.used / (1024 ** 3)
        total_gb = mem.total / (1024 ** 3)

        if mem_percent >= THRESHOLD_CRITICAL:
            send_event(1, f"Memory at {mem_percent:.0f}% ({used_gb:.1f}/{total_gb:.1f} GB)")
            alert_active = True
        elif mem_percent >= THRESHOLD_WARNING:
            send_event(2, f"Memory at {mem_percent:.0f}% ({used_gb:.1f}/{total_gb:.1f} GB)")
            alert_active = True
        else:
            print(f"[OK] Memory: {mem_percent:.0f}% ({used_gb:.1f}/{total_gb:.1f} GB)")
            if alert_active:
                clear_event()
                alert_active = False

        time.sleep(CHECK_INTERVAL)


if __name__ == "__main__":
    main()