#!/bin/bash
# Diagnostic logging utility for Shopify AI App Builder container
# Provides comprehensive system and application diagnostics

set -e

# Colors for log output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
NC='\033[0m' # No Color

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

# Logging function with timestamps and levels
diag_log() {
    local level="$1"
    shift
    local message="$*"
    local timestamp=$(date '+%Y-%m-%d %H:%M:%S.%3N')
    local pid=$$

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

    # Log to stderr with colors
    case "$level" in
        ERROR)
            echo -e "${RED}[${timestamp}] [ERROR] ${message}${NC}" >&2
            ;;
        WARN)
            echo -e "${YELLOW}[${timestamp}] [WARN] ${message}${NC}" >&2
            ;;
        INFO)
            echo -e "${GREEN}[${timestamp}] [INFO] ${message}${NC}" >&2
            ;;
        DEBUG)
            echo -e "${BLUE}[${timestamp}] [DEBUG] ${message}${NC}" >&2
            ;;
    esac
}

# System information gathering
log_system_info() {
    diag_log "INFO" "========== SYSTEM DIAGNOSTIC START =========="

    # OS Information
    diag_log "INFO" "=== OS Information ==="
    diag_log "INFO" "Kernel: $(uname -r)"
    diag_log "INFO" "Hostname: $(hostname)"
    diag_log "INFO" "Uptime: $(uptime -p 2>/dev/null || uptime)"

    # CPU Information
    diag_log "INFO" "=== CPU Information ==="
    if [ -f /proc/cpuinfo ]; then
        local cpu_count=$(nproc)
        local cpu_model=$(grep -m1 "model name" /proc/cpuinfo | cut -d':' -f2 | xargs)
        diag_log "INFO" "CPUs: ${cpu_count}"
        diag_log "INFO" "Model: ${cpu_model}"
    fi

    # Memory Information
    diag_log "INFO" "=== Memory Information ==="
    if [ -f /proc/meminfo ]; then
        local total_mem=$(awk '/MemTotal/ {printf "%.2f GB", $2/1024/1024}' /proc/meminfo)
        local free_mem=$(awk '/MemAvailable/ {printf "%.2f GB", $2/1024/1024}' /proc/meminfo)
        local used_mem=$(awk 'BEGIN{printf "%.2f GB", '"${total_mem}"' - '"${free_mem}"'}')
        diag_log "INFO" "Total: ${total_mem}"
        diag_log "INFO" "Used: ${used_mem}"
        diag_log "INFO" "Available: ${free_mem}"
    fi

    # Disk Information
    diag_log "INFO" "=== Disk Information ==="
    df -h / | while read line; do
        diag_log "INFO" "$line"
    done

    # Network Information
    diag_log "INFO" "=== Network Information ==="
    ip -4 addr show | grep -oP '(?<=inet\s)\d+(\.\d+){3}' | while read ip; do
        diag_log "INFO" "IPv4: ${ip}"
    done
}

# Service status checking
check_service_status() {
    local service_name="$1"
    local port="$2"
    local pid="$3"

    diag_log "INFO" "=== Service: ${service_name} ==="

    # Check if process is running
    if [ -n "$pid" ] && kill -0 "$pid" 2>/dev/null; then
        diag_log "INFO" "Process running (PID: ${pid})"

        # Check memory usage
        if [ -f "/proc/${pid}/status" ]; then
            local mem_usage=$(awk '/VmRSS/ {printf "%.2f MB", $2/1024}' "/proc/${pid}/status")
            local cpu_usage=$(awk '/utime|stime/ {sum+=$2} END {printf "%.2f seconds", sum/100}' "/proc/${pid}/status")
            diag_log "INFO" "Memory: ${mem_usage}"
            diag_log "INFO" "CPU Time: ${cpu_usage}"
        fi
    else
        diag_log "WARN" "Process not running (PID: ${pid})"
    fi

    # Check if port is listening
    if ss -tuln 2>/dev/null | grep -q ":${port}"; then
        diag_log "INFO" "Port ${port} listening"
    else
        diag_log "ERROR" "Port ${port} NOT listening"
    fi

    # Check if service responds to HTTP requests
    if [ "$port" = "4500" ]; then
        if timeout 3 curl -s http://localhost:${port}/api/health > /dev/null 2>&1; then
            diag_log "INFO" "HTTP endpoint responding"
        else
            diag_log "ERROR" "HTTP endpoint NOT responding"
        fi
    fi
}

# Resource monitoring (can be called periodically)
monitor_resources() {
    local timestamp=$(date '+%Y-%m-%d %H:%M:%S')

    # CPU usage
    local cpu_usage=$(top -bn1 | grep "Cpu(s)" | sed "s/.*, *\([0-9.]*\)%* id.*/\1/" | awk '{print $1}')

    # Memory usage
    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 ))

    # Disk usage
    local disk_usage=$(df / | tail -1 | awk '{print $5}')

    # Load average
    local load_avg=$(uptime | awk -F'load average:' '{print $2}')

    diag_log "INFO" "[MONITOR] CPU: ${cpu_usage}% | MEM: ${mem_percent}% (${mem_used}MB/${mem_total}MB) | DISK: ${disk_usage} | LOAD: ${load_avg}"
}

# Environment variable validation
validate_environment() {
    diag_log "INFO" "=== Environment Validation ==="

    local critical_vars=(
        "OPENCODE_API_KEY"
        "SESSION_SECRET"
        "ACCESS_PASSWORD"
    )

    local optional_vars=(
        "OPENROUTER_API_KEY"
        "MISTRAL_API_KEY"
        "GROQ_API_KEY"
        "GOOGLE_API_KEY"
        "DODO_PAYMENTS_API_KEY"
        "ADMIN_USER"
        "ADMIN_PASSWORD"
        "REPO_URL"
        "REPO_BRANCH"
    )

    # Check critical variables
    for var in "${critical_vars[@]}"; do
        if [ -z "${!var}" ]; then
            diag_log "ERROR" "Missing critical variable: ${var}"
        else
            diag_log "INFO" "✓ ${var}: SET"
        fi
    done

    # Check optional variables
    for var in "${optional_vars[@]}"; do
        if [ -n "${!var}" ]; then
            diag_log "INFO" "✓ ${var}: SET"
        else
            diag_log "DEBUG" "${var}: NOT SET (optional)"
        fi
    done

    # Check filesystem permissions
    diag_log "INFO" "=== Filesystem Permissions ==="
    local data_dir="/home/web/data"
    if [ -d "$data_dir" ]; then
        local perms=$(stat -c "%a" "$data_dir")
        local owner=$(stat -c "%U:%G" "$data_dir")
        diag_log "INFO" "${data_dir}: ${perms} (${owner})"
    else
        diag_log "WARN" "${data_dir}: NOT FOUND"
    fi
}

# Log rotation
rotate_logs() {
    local max_size=$(( 10 * 1024 * 1024 )) # 10 MB
    if [ -f "$DIAG_LOG_FILE" ]; then
        local file_size=$(stat -f%z "$DIAG_LOG_FILE" 2>/dev/null || stat -c%s "$DIAG_LOG_FILE" 2>/dev/null || echo 0)
        if [ "$file_size" -gt "$max_size" ]; then
            local backup_file="${DIAG_LOG_FILE}.$(date '+%Y%m%d_%H%M%S').bak"
            mv "$DIAG_LOG_FILE" "$backup_file"
            diag_log "INFO" "Log rotated to ${backup_file}"
        fi
    fi
}

# Export functions for use in other scripts
export -f diag_log
export -f log_system_info
export -f check_service_status
export -f monitor_resources
export -f validate_environment
export -f rotate_logs
export DIAG_LOG_DIR
export DIAG_LOG_FILE