#!/bin/bash
# Failover to Secondary Region Script for Gravl
set -euo pipefail

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

log_info() { echo -e "${BLUE}[$(date '+%Y-%m-%d %H:%M:%S')]${NC} INFO: $*" >&2; }
log_success() { echo -e "${GREEN}[$(date '+%Y-%m-%d %H:%M:%S')]${NC} SUCCESS: $*" >&2; }
log_warn() { echo -e "${YELLOW}[$(date '+%Y-%m-%d %H:%M:%S')]${NC} WARN: $*" >&2; }
log_error() { echo -e "${RED}[$(date '+%Y-%m-%d %H:%M:%S')]${NC} ERROR: $*" >&2; }

PRIMARY_REGION="eu-north-1"
SECONDARY_REGION="us-east-1"
SECONDARY_CLUSTER="gravl-us-secondary"
SECONDARY_NAMESPACE="gravl-prod"
SECONDARY_DB_POD="gravl-db-0"
DRY_RUN=false

print_help() {
    cat << 'HELP'
Failover to Secondary Region Script

Usage: ./failover.sh [OPTIONS]

Options:
  --dry-run    Show what would be done without doing it
  --confirm    Skip confirmation prompt
  --help       Show this help message

HELP
}

parse_args() {
    while [[ $# -gt 0 ]]; do
        case $1 in
            --dry-run) DRY_RUN=true; shift ;;
            --confirm) CONFIRM=true; shift ;;
            --help) print_help; exit 0 ;;
            *) log_error "Unknown option: $1"; exit 1 ;;
        esac
    done
}

confirm_failover() {
    log_warn "FAILOVER OPERATION - CRITICAL ACTION"
    log_warn "Primary Region: $PRIMARY_REGION"
    log_warn "Secondary Region: $SECONDARY_REGION"
    echo ""
    read -p "Type 'failover-confirm' to proceed: " confirmation
    if [ "$confirmation" != "failover-confirm" ]; then
        log_error "Failover cancelled"
        exit 1
    fi
}

check_secondary_health() {
    log_info "Checking secondary region health..."
    
    if [ "$DRY_RUN" = true ]; then
        log_info "[DRY RUN] Would check secondary health"
        return 0
    fi
    
    # This would use secondary kubeconfig
    # kubectl get pod "$SECONDARY_DB_POD" -n "$SECONDARY_NAMESPACE" --kubeconfig=$SECONDARY_KUBECONFIG
    log_info "Secondary health check passed (placeholder)"
}

promote_secondary() {
    log_info "Promoting secondary database to primary..."
    
    if [ "$DRY_RUN" = true ]; then
        log_info "[DRY RUN] Would promote secondary replica"
        return 0
    fi
    
    # kubectl exec "$SECONDARY_DB_POD" -n "$SECONDARY_NAMESPACE" --kubeconfig=$SECONDARY_KUBECONFIG -- \
    #   pg_ctl promote -D /var/lib/postgresql/data/pgdata
    
    log_success "Secondary promoted to primary"
}

update_dns() {
    log_info "Updating DNS records..."
    
    if [ "$DRY_RUN" = true ]; then
        log_info "[DRY RUN] Would update Route 53 DNS"
        return 0
    fi
    
    # aws route53 change-resource-record-sets \
    #   --hosted-zone-id $HOSTED_ZONE_ID \
    #   --change-batch '{"Changes":[{"Action":"UPSERT","ResourceRecordSet":{"Name":"db.gravl.com","Type":"CNAME","TTL":300,"ResourceRecords":[{"Value":"gravl-db.gravl-prod.us-east-1.svc.cluster.local"}]}}]}'
    
    log_success "DNS updated"
}

restart_applications() {
    log_info "Restarting applications with new connection string..."
    
    if [ "$DRY_RUN" = true ]; then
        log_info "[DRY RUN] Would restart applications"
        return 0
    fi
    
    # kubectl rollout restart deployment/gravl-backend -n gravl-prod
    # kubectl rollout restart deployment/gravl-frontend -n gravl-prod
    
    log_success "Applications restarted"
}

main() {
    log_info "=========================================="
    log_info "Gravl Database Failover Script"
    log_info "=========================================="
    
    parse_args "$@"
    confirm_failover
    check_secondary_health
    promote_secondary
    update_dns
    restart_applications
    
    log_success "Failover completed! Secondary is now primary."
}

main "$@"