#!/bin/bash
# ============================================================================
# Aula 17 - Cloud Native PostgreSQL (CNPG)
# ============================================================================
# Instala o CloudNativePG operator e cria um cluster PostgreSQL HA
# com backup automático para Hetzner Object Storage (S3).
#
# Componentes:
#   - CNPG Operator (gerenciamento do ciclo de vida do PostgreSQL)
#   - Cluster PostgreSQL (3 instâncias: 1 primary + 1 sync + 1 async)
#   - Backup S3 (WAL archiving + base backup diário)
#   - App demo (valida conexão com o banco)
#
# Pré-requisitos:
#   - Cluster Kubernetes na Hetzner (aula-08)
#   - Victoria Metrics (aula-12) para métricas
#   - Hetzner Object Storage com bucket criado
#   - kubectl e helm instalados
# ============================================================================

set -e

RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
CYAN='\033[0;36m'
NC='\033[0m'

log_info() { echo -e "${BLUE}[INFO]${NC} $1"; }
log_success() { echo -e "${GREEN}[OK]${NC} $1"; }
log_warn() { echo -e "${YELLOW}[WARN]${NC} $1"; }
log_error() { echo -e "${RED}[ERRO]${NC} $1"; }

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
ENV_FILE="${SCRIPT_DIR}/.env"

# ============================================================================
# Gerenciamento de Configuração
# ============================================================================

load_config() {
    if [[ -f "$ENV_FILE" ]]; then
        source "$ENV_FILE"
        return 0
    fi
    return 1
}

save_config() {
    cat > "$ENV_FILE" << EOF
# Configuração da Aula 17 - CNPG
# Gerado em: $(date)

S3_ACCESS_KEY=${S3_ACCESS_KEY}
S3_SECRET_KEY=${S3_SECRET_KEY}
S3_ENDPOINT=${S3_ENDPOINT}
S3_BUCKET=${S3_BUCKET}
EOF
    log_success "Configuração salva em .env"
}

# ============================================================================
# Verificação de Pré-requisitos
# ============================================================================

check_prerequisites() {
    echo ""
    log_info "Verificando pré-requisitos..."

    local failed=false

    for cmd in kubectl helm; do
        if command -v "$cmd" &> /dev/null; then
            log_success "$cmd encontrado"
        else
            log_error "$cmd não encontrado"
            failed=true
        fi
    done

    if ! kubectl cluster-info &> /dev/null; then
        log_error "Cluster Kubernetes não acessível. Execute a aula-08 primeiro."
        exit 1
    fi
    log_success "Cluster Kubernetes acessível"

    # Verificar Victoria Metrics
    if kubectl get svc -n monitoring vmsingle-monitoring-victoria-metrics-k8s-stack &> /dev/null; then
        log_success "Victoria Metrics encontrado"
    else
        log_warn "Victoria Metrics não encontrado (aula-12). PodMonitor não terá scrape target."
        log_warn "O CNPG funcionará sem métricas, mas recomenda-se instalar a aula-12."
    fi

    if [[ "$failed" == "true" ]]; then
        exit 1
    fi
}

# ============================================================================
# Coleta de Configuração
# ============================================================================

collect_config() {
    echo ""
    echo -e "${CYAN}═══════════════════════════════════════════════════════════${NC}"
    echo -e "${CYAN}  Configuração do CNPG - Hetzner Object Storage${NC}"
    echo -e "${CYAN}═══════════════════════════════════════════════════════════${NC}"
    echo ""
    echo -e "Você precisa de um bucket no Hetzner Object Storage."
    echo -e "Crie em: ${GREEN}https://console.hetzner.cloud/storage/object${NC}"
    echo ""

    if load_config; then
        echo -e "Configuração existente encontrada:"
        echo -e "  Endpoint: ${GREEN}${S3_ENDPOINT}${NC}"
        echo -e "  Bucket:   ${GREEN}${S3_BUCKET}${NC}"
        echo ""
        echo -e "[1] Usar configuração existente"
        echo -e "[2] Inserir nova configuração"
        read -p "Escolha [1/2]: " choice
        if [[ "$choice" == "1" ]]; then
            return 0
        fi
    fi

    echo ""
    echo -e "${YELLOW}Endpoints disponíveis:${NC}"
    echo "  fsn1.your-objectstorage.com  (Frankfurt)"
    echo "  nbg1.your-objectstorage.com  (Nuremberg)"
    echo "  hel1.your-objectstorage.com  (Helsinki)"
    echo ""

    if [[ -z "$S3_ENDPOINT" ]]; then
        S3_ENDPOINT="nbg1.your-objectstorage.com"
    fi
    read -r -p "Endpoint (${GREEN}${S3_ENDPOINT}${NC}): " input < /dev/tty
    [[ -n "$input" ]] && S3_ENDPOINT="$input"

    if [[ -z "$S3_BUCKET" ]]; then
        S3_BUCKET="cnpg-backups"
    fi
    read -r -p "Bucket name (${GREEN}${S3_BUCKET}${NC}): " input < /dev/tty
    [[ -n "$input" ]] && S3_BUCKET="$input"

    read -r -p "Access Key ID: " S3_ACCESS_KEY < /dev/tty
    if [[ -z "$S3_ACCESS_KEY" ]]; then
        log_error "Access Key é obrigatória"
        exit 1
    fi

    read -rs -p "Secret Access Key: " S3_SECRET_KEY < /dev/tty
    echo ""
    if [[ -z "$S3_SECRET_KEY" ]]; then
        log_error "Secret Key é obrigatória"
        exit 1
    fi

    save_config
}

# ============================================================================
# Instalação do CNPG Operator
# ============================================================================

install_cnpg_operator() {
    echo ""
    echo -e "${CYAN}═══════════════════════════════════════════════════════════${NC}"
    echo -e "${CYAN}  Instalando CNPG Operator${NC}"
    echo -e "${CYAN}═══════════════════════════════════════════════════════════${NC}"

    helm repo add cnpg https://cloudnative-pg.github.io/charts 2>/dev/null || true
    helm repo update cnpg

    log_info "Instalando CNPG operator no namespace cnpg-system..."
    if helm status cnpg -n cnpg-system &> /dev/null; then
        helm upgrade cnpg cnpg/cloudnative-pg \
            -n cnpg-system \
            --wait
    else
        helm install cnpg cnpg/cloudnative-pg \
            -n cnpg-system \
            --create-namespace \
            --wait
    fi
    log_success "CNPG operator instalado"

    log_info "Aguardando operator ficar ready..."
    kubectl wait --for=condition=available deployment/cnpg-cloudnative-pg -n cnpg-system --timeout=120s
    log_success "CNPG operator pronto"
}

# ============================================================================
# Criar Namespace e Secrets
# ============================================================================

setup_namespace_and_secrets() {
    echo ""
    echo -e "${CYAN}═══════════════════════════════════════════════════════════${NC}"
    echo -e "${CYAN}  Criando namespace e secrets${NC}"
    echo -e "${CYAN}═══════════════════════════════════════════════════════════${NC}"

    if kubectl get namespace cnpg &>/dev/null; then
        NS_PHASE=$(kubectl get namespace cnpg -o jsonpath='{.status.phase}' 2>/dev/null)
        if [[ "$NS_PHASE" == "Terminating" ]]; then
            log_info "Namespace cnpg em Terminating, forçando remoção..."
            kubectl get namespace cnpg -o json | \
                python3 -c "import sys,json; d=json.load(sys.stdin); d['metadata'].pop('finalizers',None); json.dump(d,sys.stdout)" | \
                kubectl replace --raw /api/v1/namespaces/cnpg/finalize -f - 2>/dev/null || true
            kubectl wait --for=delete namespace cnpg --timeout=60s 2>/dev/null || sleep 5
        fi
    fi
    kubectl create namespace cnpg --dry-run=client -o yaml | kubectl apply -f -

    log_info "Criando secret de credenciais S3..."
    kubectl create secret generic cnpg-backup-credentials \
        -n cnpg \
        --from-literal=ACCESS_KEY_ID="$S3_ACCESS_KEY" \
        --from-literal=ACCESS_SECRET_KEY="$S3_SECRET_KEY" \
        --dry-run=client -o yaml | kubectl apply -f -
    log_success "Secret criado"
}

# ============================================================================
# Criar Cluster PostgreSQL
# ============================================================================

create_cluster() {
    echo ""
    echo -e "${CYAN}═══════════════════════════════════════════════════════════${NC}"
    echo -e "${CYAN}  Criando Cluster PostgreSQL${NC}"
    echo -e "${CYAN}═══════════════════════════════════════════════════════════${NC}"

    log_info "Gerando cluster.yaml com suas configurações..."
    sed -e "s|CHANGE_BUCKET_NAME|${S3_BUCKET}|g" \
        -e "s|CHANGE_ENDPOINT|${S3_ENDPOINT}|g" \
        "${SCRIPT_DIR}/cnpg/cluster.yaml" | kubectl apply -f -

    log_success "Cluster aplicado"

    log_info "Aplicando backup agendado..."
    kubectl apply -f "${SCRIPT_DIR}/cnpg/scheduled-backup.yaml"
    log_success "Backup agendado aplicado"

    log_info "Aguardando cluster ficar ready (pode levar 2-5 minutos)..."
    kubectl wait --for=condition=Ready cluster/shared-postgres -n cnpg --timeout=600s
    log_success "Cluster PostgreSQL pronto!"
}

# ============================================================================
# Deploy App Demo
# ============================================================================

deploy_demo() {
    echo ""
    echo -e "${CYAN}═══════════════════════════════════════════════════════════${NC}"
    echo -e "${CYAN}  Deploy App Demo${NC}"
    echo -e "${CYAN}═══════════════════════════════════════════════════════════${NC}"

    log_info "Deployando app de demonstração..."
    kubectl apply -f "${SCRIPT_DIR}/app-demo/deployment.yaml"
    kubectl apply -f "${SCRIPT_DIR}/app-demo/service.yaml"

    log_info "Aguardando app demo..."
    kubectl wait --for=condition=available deployment/pg-demo -n cnpg --timeout=120s 2>/dev/null || true

    # Mostrar resultado
    sleep 3
    echo ""
    log_info "Resultado da conexão do app demo:"
    kubectl logs deployment/pg-demo -n cnpg --tail=20 2>/dev/null || log_warn "Aguardando logs..."
    log_success "App demo deployado"
}

# ============================================================================
# Resumo
# ============================================================================

show_summary() {
    echo ""
    echo -e "${CYAN}═══════════════════════════════════════════════════════════${NC}"
    echo -e "${CYAN}  Instalação Concluída${NC}"
    echo -e "${CYAN}═══════════════════════════════════════════════════════════${NC}"
    echo ""
    echo -e "${GREEN}Componentes instalados:${NC}"
    echo "  - CNPG Operator (namespace: cnpg-system)"
    echo "  - Cluster PostgreSQL 3 instâncias (namespace: cnpg)"
    echo "  - Backup diário às 03:00 → Hetzner Object Storage"
    echo "  - App demo (valida conexão)"
    echo ""

    # Status do cluster
    echo -e "${GREEN}Status do cluster:${NC}"
    kubectl get cluster -n cnpg
    echo ""

    echo -e "${GREEN}Instâncias:${NC}"
    kubectl get pods -n cnpg -l cnpg.io/cluster=shared-postgres
    echo ""

    echo -e "${GREEN}Serviços criados pelo CNPG:${NC}"
    kubectl get svc -n cnpg -l cnpg.io/cluster=shared-postgres
    echo ""

    echo -e "${GREEN}Comandos essenciais:${NC}"
    echo ""
    echo "  # Status do cluster"
    echo "  kubectl get cluster -n cnpg"
    echo ""
    echo "  # Ver instâncias (primary vs replica)"
    echo "  kubectl get pods -n cnpg -l cnpg.io/cluster=shared-postgres -o wide"
    echo ""
    echo "  # Failover manual (promover replica)"
    echo "  kubectl cnpg promote shared-postgres <instance-name> -n cnpg"
    echo ""
    echo "  # Trigger backup manual"
    echo "  kubectl cnpg backup shared-postgres -n cnpg"
    echo ""
    echo "  # Listar backups"
    echo "  kubectl get backups -n cnpg"
    echo ""
    echo "  # Logs do app demo"
    echo "  kubectl logs -f deployment/pg-demo -n cnpg"
    echo ""
    echo -e "${YELLOW}Próximos passos:${NC}"
    echo "  - Conecte sua app ao service: shared-postgres-rw.cnpg.svc:5432"
    echo "  - O backup automático roda às 03:00 diariamente"
    echo "  - Para recovery/PITR, consulte o README"
    echo ""
}

# ============================================================================
# Execução
# ============================================================================

main() {
    echo ""
    echo -e "${CYAN}╔═══════════════════════════════════════════════════════════╗${NC}"
    echo -e "${CYAN}║  Aula 17 - Cloud Native PostgreSQL (CNPG)                ║${NC}"
    echo -e "${CYAN}╚═══════════════════════════════════════════════════════════╝${NC}"

    check_prerequisites
    collect_config
    install_cnpg_operator
    setup_namespace_and_secrets
    create_cluster
    deploy_demo
    show_summary
}

main "$@"