#!/bin/bash
set -e

# Rollback Application Deployment
# This script rolls back to a previous deployment using Ansible

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
DEPLOYMENT_DIR="$(dirname "$SCRIPT_DIR")"
ANSIBLE_DIR="$DEPLOYMENT_DIR/ansible"

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

# Function to print colored messages
print_success() {
    echo -e "${GREEN}✅ $1${NC}"
}

print_error() {
    echo -e "${RED}❌ $1${NC}"
}

print_warning() {
    echo -e "${YELLOW}⚠️  $1${NC}"
}

print_info() {
    echo -e "${BLUE}ℹ️  $1${NC}"
}

# Show usage
usage() {
    echo "Usage: $0 [version] [options]"
    echo ""
    echo "Arguments:"
    echo "  version                Backup version to rollback to (e.g., 2025-01-28T15-30-00)"
    echo "                         If not provided, will rollback to previous version"
    echo ""
    echo "Options:"
    echo "  --list                 List available backup versions"
    echo "  --dry-run              Run in check mode without making changes"
    echo "  --help                 Show this help message"
    echo ""
    echo "Examples:"
    echo "  $0                                    # Rollback to previous version"
    echo "  $0 2025-01-28T15-30-00               # Rollback to specific version"
    echo "  $0 --list                            # List available backups"
    echo "  $0 2025-01-28T15-30-00 --dry-run    # Test rollback"
    exit 1
}

# Parse arguments
ROLLBACK_VERSION=""
LIST_BACKUPS=false
DRY_RUN=""

while [[ $# -gt 0 ]]; do
    case $1 in
        --list)
            LIST_BACKUPS=true
            shift
            ;;
        --dry-run)
            DRY_RUN="--check"
            shift
            ;;
        --help)
            usage
            ;;
        *)
            if [ -z "$ROLLBACK_VERSION" ]; then
                ROLLBACK_VERSION="$1"
                shift
            else
                print_error "Unknown argument: $1"
                usage
            fi
            ;;
    esac
done

echo ""
echo "🔄 Rollback Application Deployment"
echo "==================================="
echo ""

# Check if running from correct directory
if [ ! -f "$ANSIBLE_DIR/ansible.cfg" ]; then
    print_error "Error: Must run from deployment/scripts directory"
    exit 1
fi

cd "$ANSIBLE_DIR"

SSH_KEY="$HOME/.ssh/production"
DEPLOY_USER="deploy"
DEPLOY_HOST="94.16.110.151"

# List available backups
list_backups() {
    print_info "Fetching available backups from production server..."
    echo ""

    if ! ssh -i "$SSH_KEY" "$DEPLOY_USER@$DEPLOY_HOST" \
        "ls -lt /home/deploy/backups/ 2>/dev/null" | tail -n +2; then
        print_error "Failed to list backups"
        print_info "Make sure backups exist on production server: /home/deploy/backups/"
        exit 1
    fi

    echo ""
    print_info "To rollback to a specific version, run:"
    echo "  $0 <version>"
    echo ""
    print_info "To rollback to previous version, run:"
    echo "  $0"
    exit 0
}

# Check Prerequisites
check_prerequisites() {
    echo "Checking Prerequisites..."
    echo "------------------------"

    # Check Ansible
    if ! command -v ansible &> /dev/null; then
        print_error "Ansible is not installed"
        exit 1
    fi
    print_success "Ansible installed"

    # Check vault password
    if [ ! -f "$ANSIBLE_DIR/secrets/.vault_pass" ]; then
        print_error "Vault password file not found"
        exit 1
    fi
    print_success "Vault password file found"

    # Check playbook
    if [ ! -f "$ANSIBLE_DIR/playbooks/rollback.yml" ]; then
        print_error "Rollback playbook not found"
        exit 1
    fi
    print_success "Rollback playbook found"

    # Test connection
    print_info "Testing connection to production..."
    if ansible production -m ping > /dev/null 2>&1; then
        print_success "Connection successful"
    else
        print_error "Connection to production failed"
        exit 1
    fi

    echo ""
}

# Get current deployment info
get_current_deployment() {
    print_info "Fetching current deployment information..."

    CURRENT_IMAGE=$(ssh -i "$SSH_KEY" "$DEPLOY_USER@$DEPLOY_HOST" \
        "docker service inspect app_app --format '{{.Spec.TaskTemplate.ContainerSpec.Image}}' 2>/dev/null" || echo "unknown")

    if [ "$CURRENT_IMAGE" != "unknown" ]; then
        print_info "Current deployment: $CURRENT_IMAGE"
    else
        print_warning "Could not determine current deployment"
    fi

    echo ""
}

# Main logic
if [ "$LIST_BACKUPS" = true ]; then
    list_backups
fi

check_prerequisites
get_current_deployment

# Show available backups
echo "Available Backups"
echo "----------------"
ssh -i "$SSH_KEY" "$DEPLOY_USER@$DEPLOY_HOST" \
    "ls -lt /home/deploy/backups/ 2>/dev/null | tail -n +2 | head -10" || {
    print_warning "No backups found on production server"
    echo ""
    print_info "Backups are created automatically during deployments"
    print_info "You need at least one previous deployment to rollback"
    exit 1
}
echo ""

# Rollback Summary
echo "Rollback Summary"
echo "---------------"
if [ -n "$ROLLBACK_VERSION" ]; then
    echo "  Target Version:  $ROLLBACK_VERSION"
    echo "  Current Image:   $CURRENT_IMAGE"
else
    echo "  Target Version:  Previous deployment (most recent backup)"
    echo "  Current Image:   $CURRENT_IMAGE"
fi
if [ -n "$DRY_RUN" ]; then
    echo "  Mode:            DRY RUN (no changes will be made)"
else
    echo "  Mode:            PRODUCTION ROLLBACK"
fi
echo ""

# Confirmation
if [ -z "$DRY_RUN" ]; then
    print_warning "⚠️  WARNING: This will rollback your production deployment!"
    echo ""
    read -p "Are you sure you want to proceed with rollback? (y/N): " -n 1 -r
    echo
    if [[ ! $REPLY =~ ^[Yy]$ ]]; then
        print_warning "Rollback cancelled"
        exit 0
    fi
fi

echo ""

# Build ansible-playbook command
ANSIBLE_CMD="ansible-playbook $ANSIBLE_DIR/playbooks/rollback.yml"
ANSIBLE_CMD="$ANSIBLE_CMD --vault-password-file $ANSIBLE_DIR/secrets/.vault_pass"

# Add version if specified
if [ -n "$ROLLBACK_VERSION" ]; then
    ANSIBLE_CMD="$ANSIBLE_CMD -e rollback_to_version=$ROLLBACK_VERSION"
fi

# Add dry-run flag if set
if [ -n "$DRY_RUN" ]; then
    ANSIBLE_CMD="$ANSIBLE_CMD $DRY_RUN"
fi

# Execute rollback
print_info "Starting rollback..."
echo ""

if eval "$ANSIBLE_CMD"; then
    echo ""
    if [ -z "$DRY_RUN" ]; then
        print_success "Rollback completed successfully!"
    else
        print_success "Dry run completed successfully!"
    fi
else
    echo ""
    print_error "Rollback failed!"
    echo ""
    print_info "Check the Ansible output above for error details"
    exit 1
fi

echo ""

# Post-rollback checks
if [ -z "$DRY_RUN" ]; then
    echo "Post-Rollback Checks"
    echo "-------------------"

    # Check service status
    print_info "Checking service status..."
    ssh -i "$SSH_KEY" "$DEPLOY_USER@$DEPLOY_HOST" "docker service ls --filter name=app_" || true
    echo ""

    # Get new image
    NEW_IMAGE=$(ssh -i "$SSH_KEY" "$DEPLOY_USER@$DEPLOY_HOST" \
        "docker service inspect app_app --format '{{.Spec.TaskTemplate.ContainerSpec.Image}}' 2>/dev/null" || echo "unknown")

    if [ "$NEW_IMAGE" != "unknown" ]; then
        print_info "Rolled back to: $NEW_IMAGE"
    fi
    echo ""

    # Show recent logs
    print_info "Recent application logs:"
    ssh -i "$SSH_KEY" "$DEPLOY_USER@$DEPLOY_HOST" "docker service logs --tail 20 app_app" || true
    echo ""

    # Summary
    echo "✅ Rollback Complete!"
    echo "===================="
    echo ""
    echo "Rollback Details:"
    echo "  From:  $CURRENT_IMAGE"
    echo "  To:    $NEW_IMAGE"
    if [ -n "$ROLLBACK_VERSION" ]; then
        echo "  Version: $ROLLBACK_VERSION"
    else
        echo "  Version: Previous deployment"
    fi
    echo ""
    echo "Next Steps:"
    echo ""
    echo "1. Monitor application:"
    echo "   ssh -i $SSH_KEY $DEPLOY_USER@$DEPLOY_HOST 'docker service logs -f app_app'"
    echo ""
    echo "2. Check service status:"
    echo "   ssh -i $SSH_KEY $DEPLOY_USER@$DEPLOY_HOST 'docker service ps app_app'"
    echo ""
    echo "3. Test application:"
    echo "   curl https://michaelschiemer.de/health"
    echo ""
    echo "4. If rollback didn't fix the issue, check available backups:"
    echo "   $0 --list"
    echo ""
else
    echo "Dry Run Summary"
    echo "==============="
    echo ""
    echo "This was a dry run. No changes were made to production."
    echo ""
    if [ -n "$ROLLBACK_VERSION" ]; then
        echo "To rollback for real, run:"
        echo "  $0 $ROLLBACK_VERSION"
    else
        echo "To rollback for real, run:"
        echo "  $0"
    fi
    echo ""
fi