#!/bin/bash
set -e

# ============================================================================
# Rollback Deployment Script
# ============================================================================
# Restores previous deployment from backup
# Based on rollback logic from Gitea workflows
# ============================================================================

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

# Usage function
usage() {
    echo "Usage: $0 <environment> [backup_name]"
    echo ""
    echo "Arguments:"
    echo "  environment    staging or production"
    echo "  backup_name    (optional) specific backup to restore"
    echo "                 If not specified, restores latest backup"
    echo ""
    echo "Examples:"
    echo "  $0 staging                           # Restore latest staging backup"
    echo "  $0 production                        # Restore latest production backup"
    echo "  $0 production backup_20250124_143022 # Restore specific backup"
    echo ""
    exit 1
}

# Validate arguments
if [ $# -lt 1 ]; then
    usage
fi

ENVIRONMENT="$1"
SPECIFIC_BACKUP="${2:-}"

# Validate environment
if [ "$ENVIRONMENT" != "staging" ] && [ "$ENVIRONMENT" != "production" ]; then
    echo -e "${RED}❌ Error: Invalid environment '${ENVIRONMENT}'${NC}"
    echo "Must be 'staging' or 'production'"
    usage
fi

# Set environment-specific variables
if [ "$ENVIRONMENT" = "staging" ]; then
    REMOTE_USER="${STAGING_USER:-deploy}"
    REMOTE_HOST="${STAGING_HOST:-staging.michaelschiemer.de}"
    REMOTE_PORT="${STAGING_SSH_PORT:-22}"
    REMOTE_PATH="/opt/framework-staging"
    COMPOSE_FILES="docker-compose.base.yml -f docker-compose.staging.yml"
else
    REMOTE_USER="${PRODUCTION_USER:-deploy}"
    REMOTE_HOST="${PRODUCTION_HOST:-michaelschiemer.de}"
    REMOTE_PORT="${PRODUCTION_SSH_PORT:-22}"
    REMOTE_PATH="/opt/framework-production"
    COMPOSE_FILES="docker-compose.base.yml -f docker-compose.prod.yml"
fi

# Validation
if [ -z "$REMOTE_HOST" ]; then
    echo -e "${RED}❌ Error: ${ENVIRONMENT^^}_HOST environment variable is required${NC}"
    echo "Export ${ENVIRONMENT^^}_HOST before running this script"
    exit 1
fi

echo "=================================================="
echo "🔄 Starting Rollback: ${ENVIRONMENT}"
echo "=================================================="
echo "Remote: ${REMOTE_USER}@${REMOTE_HOST}:${REMOTE_PORT}"
echo "Path: ${REMOTE_PATH}"
if [ -n "$SPECIFIC_BACKUP" ]; then
    echo "Target Backup: ${SPECIFIC_BACKUP}"
else
    echo "Target Backup: Latest available"
fi
echo ""

# Confirm rollback
echo -e "${YELLOW}⚠️  WARNING: This will rollback the ${ENVIRONMENT} deployment${NC}"
echo -e "${YELLOW}   Current deployment will be stopped and replaced with backup${NC}"
echo ""
read -p "Are you sure you want to continue? (yes/no): " CONFIRM

if [ "$CONFIRM" != "yes" ]; then
    echo "Rollback cancelled"
    exit 0
fi

# Step 1: List available backups
echo -e "${GREEN}[1/5] Listing available backups...${NC}"
ssh -p "${REMOTE_PORT}" "${REMOTE_USER}@${REMOTE_HOST}" "
    cd ${REMOTE_PATH}

    echo 'Available backups:'
    ls -dt backup_* 2>/dev/null || {
        echo '❌ No backups found'
        exit 1
    }
"

if [ $? -ne 0 ]; then
    echo -e "${RED}❌ No backups available for rollback${NC}"
    exit 1
fi

# Step 2: Determine which backup to restore
echo -e "${GREEN}[2/5] Determining backup to restore...${NC}"
if [ -n "$SPECIFIC_BACKUP" ]; then
    BACKUP_TO_RESTORE="$SPECIFIC_BACKUP"
    echo "Using specified backup: ${BACKUP_TO_RESTORE}"
else
    BACKUP_TO_RESTORE=$(ssh -p "${REMOTE_PORT}" "${REMOTE_USER}@${REMOTE_HOST}" "
        cd ${REMOTE_PATH}
        ls -dt backup_* 2>/dev/null | head -n1
    ")
    echo "Using latest backup: ${BACKUP_TO_RESTORE}"
fi

# Verify backup exists
ssh -p "${REMOTE_PORT}" "${REMOTE_USER}@${REMOTE_HOST}" "
    cd ${REMOTE_PATH}
    if [ ! -d '${BACKUP_TO_RESTORE}' ]; then
        echo '❌ Backup ${BACKUP_TO_RESTORE} not found'
        exit 1
    fi
    echo '✅ Backup ${BACKUP_TO_RESTORE} verified'
"

if [ $? -ne 0 ]; then
    echo -e "${RED}❌ Backup verification failed${NC}"
    exit 1
fi

# Step 3: Stop current deployment
echo -e "${GREEN}[3/5] Stopping current deployment...${NC}"
ssh -p "${REMOTE_PORT}" "${REMOTE_USER}@${REMOTE_HOST}" "
    cd ${REMOTE_PATH}/current

    echo 'Stopping containers...'
    docker-compose -f ${COMPOSE_FILES} down 2>/dev/null || {
        echo '⚠️  Some containers may not have stopped cleanly'
    }

    echo '✅ Current deployment stopped'
"

# Step 4: Restore backup
echo -e "${GREEN}[4/5] Restoring backup...${NC}"
ssh -p "${REMOTE_PORT}" "${REMOTE_USER}@${REMOTE_HOST}" "
    cd ${REMOTE_PATH}

    # Backup current (failed) deployment for investigation
    if [ -d 'current' ]; then
        failed_backup=\"failed_\$(date +%Y%m%d_%H%M%S)\"
        echo \"Archiving failed deployment as \${failed_backup}...\"
        mv current \"\${failed_backup}\"
    fi

    # Restore backup
    echo 'Restoring backup ${BACKUP_TO_RESTORE}...'
    cp -r '${BACKUP_TO_RESTORE}' current

    echo '✅ Backup restored'
"

if [ $? -ne 0 ]; then
    echo -e "${RED}❌ Backup restoration failed${NC}"
    exit 1
fi

# Step 5: Start restored deployment
echo -e "${GREEN}[5/5] Starting restored deployment...${NC}"
ssh -p "${REMOTE_PORT}" "${REMOTE_USER}@${REMOTE_HOST}" "
    cd ${REMOTE_PATH}/current

    echo 'Starting containers...'
    docker-compose -f ${COMPOSE_FILES} up -d

    # Wait for services
    echo 'Waiting for services to start...'
    sleep 30

    # Verify deployment
    echo 'Verifying deployment...'
    docker-compose -f ${COMPOSE_FILES} ps

    echo '✅ Restored deployment is running'
"

if [ $? -ne 0 ]; then
    echo -e "${RED}❌ Failed to start restored deployment${NC}"
    exit 1
fi

# Health check
echo ""
echo -e "${GREEN}Performing health check...${NC}"
ssh -p "${REMOTE_PORT}" "${REMOTE_USER}@${REMOTE_HOST}" "
    cd ${REMOTE_PATH}/current

    # Wait a bit more for full initialization
    sleep 10

    # Check container health
    healthy_containers=\$(docker-compose -f ${COMPOSE_FILES} ps --filter 'status=running' | wc -l)
    echo \"Healthy containers: \${healthy_containers}\"

    if [ \"\${healthy_containers}\" -gt 0 ]; then
        echo '✅ Containers are running'
    else
        echo '⚠️  No containers running - manual investigation required'
    fi
"

echo ""
echo "=================================================="
echo -e "${GREEN}✅ Rollback Complete${NC}"
echo "=================================================="
echo "Environment: ${ENVIRONMENT}"
echo "Restored: ${BACKUP_TO_RESTORE}"
echo "Completed at: $(date)"
echo ""
echo "Next steps:"
echo "  - Verify application: https://${REMOTE_HOST}"
echo "  - Monitor logs: ssh ${REMOTE_USER}@${REMOTE_HOST} 'cd ${REMOTE_PATH}/current && docker-compose logs -f'"
echo "  - Check status: ssh ${REMOTE_USER}@${REMOTE_HOST} 'cd ${REMOTE_PATH}/current && docker-compose ps'"
echo ""
echo "Failed deployment archived as: failed_YYYYMMDD_HHMMSS (if applicable)"
echo "You can investigate the failure by SSH'ing to the server and examining:"
echo "  ${REMOTE_PATH}/failed_*"
echo ""