#!/bin/bash

# Safe Deployment Script for dk0.dev
# Ensures secure, zero-downtime deployments with proper error handling and rollback

set -euo pipefail  # Exit on error, undefined vars, pipe failures

# Configuration
IMAGE_NAME="portfolio-app"
NEW_TAG="latest"
OLD_TAG="previous"
BACKUP_TAG="backup-$(date +%Y%m%d-%H%M%S)"
COMPOSE_FILE="docker-compose.production.yml"
HEALTH_CHECK_URL="http://localhost:3000/api/health"
HEALTH_CHECK_TIMEOUT=180
HEALTH_CHECK_INTERVAL=5
MAX_ROLLBACK_ATTEMPTS=3

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

# Logging functions
log() {
    echo -e "${BLUE}[$(date +'%Y-%m-%d %H:%M:%S')]${NC} $1"
}

error() {
    echo -e "${RED}[ERROR]${NC} $1" >&2
}

success() {
    echo -e "${GREEN}[SUCCESS]${NC} $1"
}

warning() {
    echo -e "${YELLOW}[WARNING]${NC} $1"
}

# Cleanup function
cleanup() {
    local exit_code=$?
    if [ $exit_code -ne 0 ]; then
        error "Deployment failed with exit code $exit_code"
        rollback
    fi
}

# Health check function
check_health() {
    local url=$1
    local max_attempts=$((HEALTH_CHECK_TIMEOUT / HEALTH_CHECK_INTERVAL))
    local attempt=0
    
    log "Performing health check on $url..."
    while [ $attempt -lt $max_attempts ]; do
        if curl -f -s -m 5 "$url" > /dev/null 2>&1; then
            return 0
        fi
        attempt=$((attempt + 1))
        sleep $HEALTH_CHECK_INTERVAL
        echo -n "."
    done
    echo ""
    return 1
}

# Rollback function
rollback() {
    error "Deployment failed. Initiating rollback..."
    
    local rollback_attempt=0
    while [ $rollback_attempt -lt $MAX_ROLLBACK_ATTEMPTS ]; do
        rollback_attempt=$((rollback_attempt + 1))
        log "Rollback attempt $rollback_attempt/$MAX_ROLLBACK_ATTEMPTS"
        
        # Try to restore from backup tag first
        if docker images | grep -q "${IMAGE_NAME}:${OLD_TAG}"; then
            log "Restoring from previous image..."
            docker tag "${IMAGE_NAME}:${OLD_TAG}" "${IMAGE_NAME}:${NEW_TAG}" || {
                warning "Failed to tag previous image"
                continue
            }
        elif docker images | grep -q "${IMAGE_NAME}:${BACKUP_TAG}"; then
            log "Restoring from backup image..."
            docker tag "${IMAGE_NAME}:${BACKUP_TAG}" "${IMAGE_NAME}:${NEW_TAG}" || {
                warning "Failed to tag backup image"
                continue
            }
        else
            error "No backup image found for rollback"
            return 1
        fi
        
        # Restart container with previous image
        log "Restarting container with previous image..."
        docker-compose -f "$COMPOSE_FILE" up -d --force-recreate portfolio || {
            warning "Failed to restart container"
            continue
        }
        
        # Wait for health check
        sleep 10
        if check_health "$HEALTH_CHECK_URL"; then
            success "Rollback successful!"
            return 0
        else
            warning "Rollback attempt $rollback_attempt failed health check"
        fi
    done
    
    error "All rollback attempts failed"
    return 1
}

# Pre-deployment checks
pre_deployment_checks() {
    log "Running pre-deployment checks..."
    
    # Check if running as root
    if [[ $EUID -eq 0 ]]; then
        error "This script should not be run as root"
        exit 1
    fi
    
    # Check if Docker is running
    if ! docker info > /dev/null 2>&1; then
        error "Docker is not running. Please start Docker and try again."
        exit 1
    fi
    
    # Check if docker-compose is available
    if ! command -v docker-compose &> /dev/null && ! docker compose version &> /dev/null; then
        error "docker-compose is not installed"
        exit 1
    fi
    
    # Check if .env file exists
    if [ ! -f .env ]; then
        error ".env file not found. Please create it before deploying."
        exit 1
    fi
    
    # Check if required environment variables are set
    local required_vars=("DATABASE_URL" "NEXT_PUBLIC_BASE_URL")
    for var in "${required_vars[@]}"; do
        if ! grep -q "^${var}=" .env 2>/dev/null; then
            warning "Required environment variable $var not found in .env"
        fi
    done
    
    # Check disk space (at least 2GB free)
    local available_space=$(df -BG . | tail -1 | awk '{print $4}' | sed 's/G//')
    if [ "$available_space" -lt 2 ]; then
        error "Insufficient disk space. At least 2GB required, but only ${available_space}GB available."
        exit 1
    fi
    
    success "Pre-deployment checks passed"
}

# Build application
build_application() {
    log "Building application..."
    
    # Build Next.js application
    log "Building Next.js application..."
    npm ci --prefer-offline --no-audit || {
        error "npm install failed"
        exit 1
    }
    
    npm run build || {
        error "Build failed"
        exit 1
    }
    
    success "Application built successfully"
}

# Build Docker image
build_docker_image() {
    log "Building Docker image..."
    
    # Backup current image if it exists
    if docker images | grep -q "${IMAGE_NAME}:${NEW_TAG}"; then
        log "Backing up current image..."
        docker tag "${IMAGE_NAME}:${NEW_TAG}" "${IMAGE_NAME}:${OLD_TAG}" || {
            warning "Could not backup current image (this might be the first deployment)"
        }
        docker tag "${IMAGE_NAME}:${NEW_TAG}" "${IMAGE_NAME}:${BACKUP_TAG}" || true
    fi
    
    # Build new image
    docker build -t "${IMAGE_NAME}:${NEW_TAG}" . || {
        error "Failed to build Docker image"
        exit 1
    }
    
    # Verify new image
    if ! docker images | grep -q "${IMAGE_NAME}:${NEW_TAG}"; then
        error "New image not found after build"
        exit 1
    fi
    
    success "Docker image built successfully"
}

# Deploy application
deploy_application() {
    log "Deploying application..."
    
    # Start new container
    if command -v docker-compose &> /dev/null; then
        docker-compose -f "$COMPOSE_FILE" up -d --force-recreate portfolio || {
            error "Failed to start new container"
            exit 1
        }
    else
        docker compose -f "$COMPOSE_FILE" up -d --force-recreate portfolio || {
            error "Failed to start new container"
            exit 1
        }
    fi
    
    # Wait for container to start
    log "Waiting for container to start..."
    sleep 15
    
    # Check if container is running
    if ! docker ps | grep -q "portfolio-app"; then
        error "Container failed to start"
        log "Container logs:"
        docker logs portfolio-app --tail=50
        exit 1
    fi
    
    success "Container started successfully"
}

# Run database migrations
run_migrations() {
    log "Running database migrations..."
    
    # Wait for database to be ready
    local db_ready=false
    for i in {1..30}; do
        if docker exec portfolio-app npx prisma db push --skip-generate --accept-data-loss 2>&1 | grep -q "Database.*ready\|Everything is in sync"; then
            db_ready=true
            break
        fi
        sleep 2
    done
    
    if [ "$db_ready" = false ]; then
        warning "Database might not be ready, but continuing..."
    fi
    
    # Run migrations
    docker exec portfolio-app npx prisma db push --skip-generate || {
        warning "Database migration had issues, but continuing..."
    }
    
    success "Database migrations completed"
}

# Verify deployment
verify_deployment() {
    log "Verifying deployment..."
    
    # Health check
    if ! check_health "$HEALTH_CHECK_URL"; then
        error "Health check failed"
        log "Container logs:"
        docker logs portfolio-app --tail=100
        return 1
    fi
    
    # Test main page
    if ! curl -f -s -m 10 "http://localhost:3000/" > /dev/null 2>&1; then
        error "Main page is not accessible"
        return 1
    fi
    
    # Test API endpoint
    if ! curl -f -s -m 10 "http://localhost:3000/api/health" > /dev/null 2>&1; then
        error "API health endpoint is not accessible"
        return 1
    fi
    
    success "Deployment verification successful"
}

# Cleanup old images
cleanup_old_images() {
    log "Cleaning up old images..."
    
    # Keep last 5 versions
    docker images "${IMAGE_NAME}" --format "{{.Tag}}" | \
        grep -E "^(backup-|previous|failed-)" | \
        sort -r | \
        tail -n +6 | \
        while read -r tag; do
            docker rmi "${IMAGE_NAME}:${tag}" 2>/dev/null || true
        done
    
    success "Cleanup completed"
}

# Main deployment flow
main() {
    log "Starting safe deployment for dk0.dev..."
    
    # Set up error handling
    trap cleanup ERR
    
    # Run deployment steps
    pre_deployment_checks
    build_application
    build_docker_image
    deploy_application
    run_migrations
    
    # Verify deployment
    if verify_deployment; then
        cleanup_old_images
        
        # Show deployment info
        log "Deployment completed successfully!"
        log "Container status:"
        if command -v docker-compose &> /dev/null; then
            docker-compose -f "$COMPOSE_FILE" ps
        else
            docker compose -f "$COMPOSE_FILE" ps
        fi
        
        log "Resource usage:"
        docker stats --no-stream --format "table {{.Container}}\t{{.CPUPerc}}\t{{.MemUsage}}" portfolio-app
        
        success "Application is available at: http://localhost:3000/"
        success "Health check endpoint: $HEALTH_CHECK_URL"
        
        # Disable error trap (deployment successful)
        trap - ERR
    else
        error "Deployment verification failed"
        exit 1
    fi
}

# Run main function
main "$@"