#!/bin/bash
#
# Scheduler Monitoring Script
# Checks service health, job status, and system resources
#

set -e

# Configuration
LOG_FILE="${LOG_FILE:-/var/log/scheduler-monitor.log}"
DB_PATH="${DB_PATH:-/opt/scheduler/scheduler.db}"
SERVICE_NAME="${SERVICE_NAME:-scheduler}"
ALERT_EMAIL="${ALERT_EMAIL:-}"
DISK_THRESHOLD=90

# Colors for output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
NC='\033[0m' # No Color

TIMESTAMP=$(date '+%Y-%m-%d %H:%M:%S')
ALERTS=()

echo "=== Scheduler Monitor - $TIMESTAMP ===" | tee -a "$LOG_FILE"

# Check if service is running
check_service() {
    if systemctl is-active --quiet "$SERVICE_NAME" 2>/dev/null; then
        echo -e "${GREEN}✓ Service is running${NC}" | tee -a "$LOG_FILE"
        return 0
    elif docker ps --filter "name=movie_scheduler" --format "{{.Status}}" | grep -q "Up"; then
        echo -e "${GREEN}✓ Docker container is running${NC}" | tee -a "$LOG_FILE"
        return 0
    else
        echo -e "${RED}✗ Service is DOWN${NC}" | tee -a "$LOG_FILE"
        ALERTS+=("Service is DOWN")

        # Try to restart
        echo "Attempting to restart service..." | tee -a "$LOG_FILE"
        systemctl start "$SERVICE_NAME" 2>/dev/null || \
        docker compose -f /opt/scheduler/docker-compose.prod.yml restart 2>/dev/null || true

        return 1
    fi
}

# Check database
check_database() {
    if [ ! -f "$DB_PATH" ]; then
        echo -e "${RED}✗ Database not found${NC}" | tee -a "$LOG_FILE"
        ALERTS+=("Database file not found")
        return 1
    fi

    # Database size
    DB_SIZE=$(du -h "$DB_PATH" | cut -f1)
    echo "Database size: $DB_SIZE" | tee -a "$LOG_FILE"

    # Job counts
    TOTAL=$(sqlite3 "$DB_PATH" "SELECT COUNT(*) FROM jobs;" 2>/dev/null)
    PENDING_PREP=$(sqlite3 "$DB_PATH" "SELECT COUNT(*) FROM jobs WHERE prep_status='pending';" 2>/dev/null)
    PENDING_PLAY=$(sqlite3 "$DB_PATH" "SELECT COUNT(*) FROM jobs WHERE play_status='pending';" 2>/dev/null)
    STREAMING=$(sqlite3 "$DB_PATH" "SELECT COUNT(*) FROM jobs WHERE play_status='streaming';" 2>/dev/null)
    FAILED=$(sqlite3 "$DB_PATH" "SELECT COUNT(*) FROM jobs WHERE prep_status='failed' OR play_status='failed';" 2>/dev/null)

    echo "Jobs - Total: $TOTAL, Pending prep: $PENDING_PREP, Pending play: $PENDING_PLAY, Streaming: $STREAMING, Failed: $FAILED" | tee -a "$LOG_FILE"

    if [ "$FAILED" -gt 0 ]; then
        echo -e "${YELLOW}⚠ Found $FAILED failed job(s)${NC}" | tee -a "$LOG_FILE"
        ALERTS+=("$FAILED failed jobs")
    fi

    if [ "$STREAMING" -gt 0 ]; then
        echo -e "${GREEN}✓ $STREAMING active stream(s)${NC}" | tee -a "$LOG_FILE"
    fi
}

# Check disk space
check_disk() {
    for PATH in "/mnt/storage" "/opt/scheduler" "/"; do
        if [ -d "$PATH" ]; then
            USAGE=$(df "$PATH" 2>/dev/null | tail -1 | awk '{print $5}' | sed 's/%//')
            if [ -n "$USAGE" ]; then
                if [ "$USAGE" -gt "$DISK_THRESHOLD" ]; then
                    echo -e "${RED}✗ Disk usage for $PATH: ${USAGE}%${NC}" | tee -a "$LOG_FILE"
                    ALERTS+=("Disk usage ${USAGE}% on $PATH")
                else
                    echo -e "Disk usage for $PATH: ${USAGE}%" | tee -a "$LOG_FILE"
                fi
            fi
        fi
    done
}

# Check for stuck streams
check_stuck_streams() {
    # Find streams that have been active for more than 4 hours
    STUCK=$(sqlite3 "$DB_PATH" "
        SELECT COUNT(*) FROM jobs
        WHERE play_status='streaming'
        AND datetime(stream_start_time) < datetime('now', '-4 hours')
    " 2>/dev/null)

    if [ "$STUCK" -gt 0 ]; then
        echo -e "${YELLOW}⚠ Found $STUCK stream(s) active for >4 hours${NC}" | tee -a "$LOG_FILE"
        ALERTS+=("$STUCK potentially stuck streams")
    fi
}

# Check recent errors in logs
check_logs() {
    if systemctl is-active --quiet "$SERVICE_NAME" 2>/dev/null; then
        ERROR_COUNT=$(journalctl -u "$SERVICE_NAME" --since "5 minutes ago" 2>/dev/null | grep -i "ERROR" | wc -l)
    else
        ERROR_COUNT=$(docker compose -f /opt/scheduler/docker-compose.prod.yml logs --since 5m 2>/dev/null | grep -i "ERROR" | wc -l || echo "0")
    fi

    if [ "$ERROR_COUNT" -gt 10 ]; then
        echo -e "${YELLOW}⚠ Found $ERROR_COUNT errors in last 5 minutes${NC}" | tee -a "$LOG_FILE"
        ALERTS+=("$ERROR_COUNT recent errors")
    fi
}

# Send alerts
send_alerts() {
    if [ ${#ALERTS[@]} -gt 0 ]; then
        echo "" | tee -a "$LOG_FILE"
        echo -e "${RED}=== ALERTS ===${NC}" | tee -a "$LOG_FILE"
        for alert in "${ALERTS[@]}"; do
            echo "- $alert" | tee -a "$LOG_FILE"
        done

        # Send email if configured
        if [ -n "$ALERT_EMAIL" ] && command -v mail &> /dev/null; then
            {
                echo "Scheduler Monitoring Alert - $TIMESTAMP"
                echo ""
                echo "The following issues were detected:"
                for alert in "${ALERTS[@]}"; do
                    echo "- $alert"
                done
                echo ""
                echo "Check $LOG_FILE for details"
            } | mail -s "Scheduler Alert" "$ALERT_EMAIL"
        fi

        # Could also send to Slack, PagerDuty, etc.
        # Example Slack webhook:
        # if [ -n "$SLACK_WEBHOOK" ]; then
        #     curl -X POST -H 'Content-type: application/json' \
        #     --data "{\"text\":\"Scheduler Alert: ${ALERTS[*]}\"}" \
        #     "$SLACK_WEBHOOK"
        # fi
    fi
}

# Run checks
check_service
check_database
check_disk
check_stuck_streams
check_logs
send_alerts

echo "" | tee -a "$LOG_FILE"

# Exit with error if there are alerts
if [ ${#ALERTS[@]} -gt 0 ]; then
    exit 1
fi

exit 0