#!/bin/bash
# Enhanced health check script for Shopify AI App Builder container
# Checks chat service (port 4500)
# Provides detailed diagnostics for debugging

set -e

# Colors for output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
NC='\033[0m'

# Diagnostic log location
DIAG_LOG_DIR="/var/log/shopify-ai"
DIAG_LOG_FILE="${DIAG_LOG_DIR}/healthcheck.log"
mkdir -p "$DIAG_LOG_DIR"

# Health check logging
health_log() {
    local level="$1"
    shift
    local message="$*"
    local timestamp=$(date '+%Y-%m-%d %H:%M:%S')

    # Log to file
    echo "[${timestamp}] [${level}] ${message}" >> "$DIAG_LOG_FILE"

    # Log to stdout for Docker health check
    echo "${message}"
}

# Port checking function
check_port() {
    local port="$1"
    local service="$2"

    health_log "INFO" "Checking ${service} on port ${port}..."

    # Check using ss (modern alternative to netstat)
    if command -v ss &>/dev/null; then
        if ss -tuln 2>/dev/null | grep -q ":${port} "; then
            health_log "INFO" "✓ ${service} is listening on port ${port}"
        else
            health_log "ERROR" "✗ ${service} is NOT listening on port ${port}"
            return 1
        fi
    # Fallback to netstat if ss not available
    elif command -v netstat &>/dev/null; then
        if netstat -tuln 2>/dev/null | grep -q ":${port} "; then
            health_log "INFO" "✓ ${service} is listening on port ${port}"
        else
            health_log "ERROR" "✗ ${service} is NOT listening on port ${port}"
            return 1
        fi
    else
        health_log "WARN" "Neither ss nor netstat available for port checking"
        return 1
    fi
}

# HTTP endpoint checking function
check_http() {
    local url="$1"
    local service="$2"
    local timeout="${3:-3}"

    health_log "INFO" "Checking ${service} HTTP endpoint: ${url}"

    if command -v timeout &>/dev/null; then
        if timeout "${timeout}" curl -s -o /dev/null -w "%{http_code}" "${url}" 2>&1 | grep -q "200\|302"; then
            health_log "INFO" "✓ ${service} HTTP endpoint responding (HTTP 200/302)"
            return 0
        else
            health_log "ERROR" "✗ ${service} HTTP endpoint NOT responding (timeout: ${timeout}s)"
            return 1
        fi
    else
        health_log "WARN" "timeout command not available for HTTP check"
        return 1
    fi
}

# Process checking function
check_process() {
    local service="$1"
    local port="$2"

    health_log "INFO" "Checking ${service} process..."

    # Find process listening on port
    local pid=""
    if command -v ss &>/dev/null; then
        pid=$(ss -tulnp 2>/dev/null | grep ":${port} " | awk '{print $7}' | cut -d',' -f1)
    elif command -v lsof &>/dev/null; then
        pid=$(lsof -ti ":${port}" 2>/dev/null)
    fi

    if [ -n "$pid" ]; then
        health_log "INFO" "✓ ${service} process running (PID: ${pid})"

        # Check process memory usage
        if [ -f "/proc/${pid}/status" ]; then
            local mem_mb=$(awk '/VmRSS/ {printf "%.2f MB", $2/1024}' "/proc/${pid}/status")
            health_log "INFO" "  Memory usage: ${mem_mb}"

            local cpu_time=$(awk '/utime|stime/ {sum+=$2} END {printf "%.2f seconds", sum/100}' "/proc/${pid}/status")
            health_log "INFO" "  CPU time: ${cpu_time}"
        fi
        return 0
    else
        health_log "ERROR" "✗ ${service} process NOT found"
        return 1
    fi
}

# System resource check
check_resources() {
    health_log "INFO" "=== System Resources ==="

    # Memory
    if command -v free &>/dev/null; then
        local mem_total=$(free -m | awk '/Mem:/ {print $2}')
        local mem_used=$(free -m | awk '/Mem:/ {print $3}')
        local mem_percent=$(( (mem_used * 100) / mem_total ))
        health_log "INFO" "Memory: ${mem_used}MB / ${mem_total}MB (${mem_percent}%)"

        if [ $mem_percent -gt 90 ]; then
            health_log "WARN" "⚠ High memory usage: ${mem_percent}%"
        fi
    fi

    # Disk
    if command -v df &>/dev/null; then
        local disk_usage=$(df / | tail -1 | awk '{print $5}' | sed 's/%//')
        health_log "INFO" "Disk: ${disk_usage}% used"

        if [ "$disk_usage" -gt 80 ]; then
            health_log "WARN" "⚠ High disk usage: ${disk_usage}%"
        fi
    fi

    # Load average
    if command -v uptime &>/dev/null; then
        local load_avg=$(uptime | awk -F'load average:' '{print $2}' | xargs)
        health_log "INFO" "Load average: ${load_avg}"
    fi
}

# Main health check sequence
main() {
    local exit_code=0

    health_log "INFO" "========== HEALTH CHECK START =========="
    health_log "INFO" "Timestamp: $(date '+%Y-%m-%d %H:%M:%S %Z')"

    # Check system resources
    check_resources

    # Check chat service (port 4500)
    health_log "INFO" "=== Chat Service (port 4500) ==="
    if ! check_port 4500 "chat service"; then
        exit_code=1
    fi

    if ! check_http "http://localhost:4500/api/health" "chat service" 3; then
        exit_code=1
    fi

    if ! check_process "chat service" 4500; then
        exit_code=1
    fi

    # Check OpenSMTPD service (ports 25, 587, 465)
    health_log "INFO" "=== OpenSMTPD Service ==="
    REPO_DIR="${REPO_DIR:-/home/web/data}"
    OPENSMTPD_INSTALL_ROOT="/workspace/src/backend/app/opensmtpd/install"
    if [ -d "${REPO_DIR}/backend/app/opensmtpd" ]; then
        OPENSMTPD_INSTALL_ROOT="${REPO_DIR}/backend/app/opensmtpd/install"
    fi
    OPENSMTPD_CUSTOM_BINARY="${OPENSMTPD_INSTALL_ROOT}/sbin/smtpd"
    OPENSMTPD_SYSTEM_BINARY="/usr/sbin/smtpd"

    # Determine which binary to use (prefer custom, fallback to system)
    OPENSMTPD_BINARY=""
    if [ -x "$OPENSMTPD_CUSTOM_BINARY" ]; then
        OPENSMTPD_BINARY="$OPENSMTPD_CUSTOM_BINARY"
    elif [ -x "$OPENSMTPD_SYSTEM_BINARY" ]; then
        OPENSMTPD_BINARY="$OPENSMTPD_SYSTEM_BINARY"
    elif command -v smtpd &>/dev/null; then
        OPENSMTPD_BINARY="$(command -v smtpd)"
    fi

    if [ -n "$OPENSMTPD_BINARY" ]; then
        # Check SMTP port 25
        if check_port 25 "SMTP"; then
            health_log "INFO" "✓ SMTP port 25 is listening"
        else
            health_log "WARN" "⚠ SMTP port 25 is not listening (may be normal if not using inbound email)"
        fi

        # Check SMTP submission port 587
        if check_port 587 "SMTP Submission"; then
            health_log "INFO" "✓ SMTP submission port 587 is listening"
        else
            health_log "WARN" "⚠ SMTP submission port 587 is not listening"
        fi

        # Check SMTPS port 465
        if check_port 465 "SMTPS"; then
            health_log "INFO" "✓ SMTPS port 465 is listening"
        else
            health_log "WARN" "⚠ SMTPS port 465 is not listening"
        fi

        # Check OpenSMTPD process
        if pgrep -f "smtpd" > /dev/null; then
            local smtpd_pid=$(pgrep -f "smtpd" | head -1)
            health_log "INFO" "✓ OpenSMTPD process running (PID: ${smtpd_pid})"
        else
            health_log "WARN" "⚠ OpenSMTPD process not found (may be disabled)"
        fi
    else
        health_log "INFO" "OpenSMTPD not installed (checked: $OPENSMTPD_CUSTOM_BINARY, $OPENSMTPD_SYSTEM_BINARY, PATH), skipping SMTP checks"
    fi

    # ttyd service has been removed, no longer checking port 4501

    health_log "INFO" "========== HEALTH CHECK END ==========="

    if [ $exit_code -eq 0 ]; then
        health_log "INFO" "✓ Health check PASSED"
    else
        health_log "ERROR" "✗ Health check FAILED"
    fi

    return $exit_code
}

# Run main function
main "$@"