#!/bin/bash

#######################################
# SIAX Agent - Script de Despliegue
# Instalación automática production-ready
#######################################

set -e  # Salir si hay errores

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

# Variables
INSTALL_DIR="/opt/siax-agent"
SERVICE_USER="siax-agent"
BACKUP_DIR="/tmp/siax-agent-backup-$(date +%s)"

#######################################
# Funciones
#######################################

print_header() {
    echo -e "${BLUE}"
    echo "============================================"
    echo "  SIAX Agent - Deployment Script"
    echo "============================================"
    echo -e "${NC}"
}

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}"
}

check_root() {
    if [ "$EUID" -ne 0 ]; then
        print_error "Este script debe ejecutarse como root"
        echo "Usa: sudo ./desplegar_agent.sh"
        exit 1
    fi
}

check_dependencies() {
    print_info "Verificando dependencias..."

    local deps=("systemctl" "cargo" "rustc")
    local missing=()

    for dep in "${deps[@]}"; do
        if ! command -v $dep &> /dev/null; then
            missing+=($dep)
        fi
    done

    if [ ${#missing[@]} -ne 0 ]; then
        print_error "Faltan dependencias: ${missing[*]}"
        echo ""
        echo "Instalación de Rust:"
        echo "  curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh"
        echo ""
        echo "Instalación de systemd (debería estar instalado por defecto):"
        echo "  sudo apt-get install systemd  # Debian/Ubuntu"
        echo "  sudo yum install systemd       # RedHat/CentOS"
        exit 1
    fi

    print_success "Todas las dependencias están instaladas"
}

backup_existing() {
    if [ -d "$INSTALL_DIR" ]; then
        print_warning "Instalación existente detectada"
        print_info "Creando backup en: $BACKUP_DIR"
        mkdir -p "$BACKUP_DIR"
        cp -r "$INSTALL_DIR" "$BACKUP_DIR/"
        print_success "Backup creado"
    fi
}

compile_release() {
    print_info "Compilando SIAX Agent en modo release..."

    if cargo build --release; then
        print_success "Compilación exitosa"
    else
        print_error "Error en la compilación"
        rollback
        exit 1
    fi
}

create_user() {
    if id "$SERVICE_USER" &>/dev/null; then
        print_info "Usuario $SERVICE_USER ya existe"
    else
        print_info "Creando usuario del sistema: $SERVICE_USER"
        useradd --system --no-create-home --shell /bin/false "$SERVICE_USER"
        print_success "Usuario creado"
    fi
}

install_binary() {
    print_info "Instalando binario en $INSTALL_DIR..."

    mkdir -p "$INSTALL_DIR"
    mkdir -p "$INSTALL_DIR/config"
    mkdir -p "$INSTALL_DIR/logs"

    cp target/release/siax_monitor "$INSTALL_DIR/siax-agent"
    chmod +x "$INSTALL_DIR/siax-agent"

    # Copiar archivos de configuración si existen
    if [ -f "config/monitored_apps.json" ]; then
        cp config/monitored_apps.json "$INSTALL_DIR/config/"
    fi

    # Copiar archivos web
    if [ -d "web" ]; then
        cp -r web "$INSTALL_DIR/"
    fi

    # Permisos
    chown -R $SERVICE_USER:$SERVICE_USER "$INSTALL_DIR"

    print_success "Binario instalado"
}

configure_sudoers() {
    print_info "Configurando permisos sudo para systemctl..."

    local sudoers_file="/etc/sudoers.d/siax-agent"

    cat > "$sudoers_file" << EOF
# SIAX Agent - Permisos para gestionar servicios systemd
$SERVICE_USER ALL=(ALL) NOPASSWD: /bin/systemctl start *
$SERVICE_USER ALL=(ALL) NOPASSWD: /bin/systemctl stop *
$SERVICE_USER ALL=(ALL) NOPASSWD: /bin/systemctl restart *
$SERVICE_USER ALL=(ALL) NOPASSWD: /bin/systemctl status *
$SERVICE_USER ALL=(ALL) NOPASSWD: /bin/systemctl enable *
$SERVICE_USER ALL=(ALL) NOPASSWD: /bin/systemctl disable *
$SERVICE_USER ALL=(ALL) NOPASSWD: /bin/systemctl daemon-reload
$SERVICE_USER ALL=(ALL) NOPASSWD: /bin/systemctl is-active *
$SERVICE_USER ALL=(ALL) NOPASSWD: /bin/systemctl list-unit-files *
$SERVICE_USER ALL=(ALL) NOPASSWD: /bin/journalctl *
EOF

    chmod 0440 "$sudoers_file"

    # Validar sintaxis
    if visudo -c -f "$sudoers_file" &>/dev/null; then
        print_success "Configuración de sudoers creada"
    else
        print_error "Error en configuración de sudoers"
        rm -f "$sudoers_file"
        exit 1
    fi
}

create_systemd_service() {
    print_info "Creando servicio systemd para SIAX Agent..."

    cat > /etc/systemd/system/siax-agent.service << EOF
[Unit]
Description=SIAX Agent - Process Monitor and Manager
After=network.target

[Service]
Type=simple
User=$SERVICE_USER
WorkingDirectory=$INSTALL_DIR
ExecStart=$INSTALL_DIR/siax-agent
Restart=always
RestartSec=10
StandardOutput=journal
StandardError=journal

# Security hardening
NoNewPrivileges=true
PrivateTmp=true
ProtectSystem=strict
ReadWritePaths=$INSTALL_DIR/config $INSTALL_DIR/logs /etc/systemd/system
ProtectHome=true

[Install]
WantedBy=multi-user.target
EOF

    systemctl daemon-reload
    systemctl enable siax-agent.service

    print_success "Servicio systemd creado y habilitado"
}

verify_installation() {
    print_info "Verificando instalación..."

    local errors=0

    # Verificar binario
    if [ ! -f "$INSTALL_DIR/siax-agent" ]; then
        print_error "Binario no encontrado"
        ((errors++))
    fi

    # Verificar permisos
    if [ ! -r "$INSTALL_DIR/siax-agent" ]; then
        print_error "Permisos incorrectos en binario"
        ((errors++))
    fi

    # Verificar servicio
    if ! systemctl is-enabled siax-agent.service &>/dev/null; then
        print_error "Servicio no habilitado"
        ((errors++))
    fi

    # Verificar sudoers
    if [ ! -f "/etc/sudoers.d/siax-agent" ]; then
        print_warning "Configuración de sudoers no encontrada"
        echo "          El agente podría tener problemas para gestionar servicios"
    fi

    if [ $errors -eq 0 ]; then
        print_success "Verificación exitosa"
        return 0
    else
        print_error "Verificación falló con $errors errores"
        return 1
    fi
}

start_service() {
    print_info "Iniciando SIAX Agent..."

    if systemctl start siax-agent.service; then
        sleep 2
        if systemctl is-active siax-agent.service &>/dev/null; then
            print_success "SIAX Agent iniciado correctamente"
            return 0
        else
            print_error "SIAX Agent no pudo iniciarse"
            echo ""
            echo "Ver logs con: journalctl -u siax-agent.service -n 50"
            return 1
        fi
    else
        print_error "Error al iniciar el servicio"
        return 1
    fi
}

rollback() {
    print_warning "Ejecutando rollback..."

    systemctl stop siax-agent.service 2>/dev/null || true
    systemctl disable siax-agent.service 2>/dev/null || true

    if [ -d "$BACKUP_DIR" ]; then
        rm -rf "$INSTALL_DIR"
        cp -r "$BACKUP_DIR/siax-agent" "$INSTALL_DIR"
        systemctl start siax-agent.service 2>/dev/null || true
        print_success "Rollback completado"
    else
        print_warning "No hay backup disponible para rollback"
    fi
}

print_summary() {
    echo ""
    echo -e "${GREEN}============================================${NC}"
    echo -e "${GREEN}  ✅ SIAX Agent instalado exitosamente${NC}"
    echo -e "${GREEN}============================================${NC}"
    echo ""
    echo "📊 Interface Web: http://localhost:8080"
    echo "🔌 API REST:      http://localhost:8081/api"
    echo "📡 WebSocket:     ws://localhost:8081/ws/logs/:app_name"
    echo ""
    echo "Comandos útiles:"
    echo "  Estado:    sudo systemctl status siax-agent"
    echo "  Logs:      sudo journalctl -u siax-agent -f"
    echo "  Reiniciar: sudo systemctl restart siax-agent"
    echo "  Detener:   sudo systemctl stop siax-agent"
    echo ""
    echo "Directorio de instalación: $INSTALL_DIR"
    echo "Configuración: $INSTALL_DIR/config/monitored_apps.json"
    echo ""
}

#######################################
# Main
#######################################

main() {
    print_header

    check_root
    check_dependencies
    backup_existing
    compile_release
    create_user
    install_binary
    configure_sudoers
    create_systemd_service

    if verify_installation; then
        if start_service; then
            print_summary
            exit 0
        else
            print_error "El servicio no pudo iniciarse correctamente"
            print_info "Revisa los logs: journalctl -u siax-agent -n 50"
            echo ""
            echo "¿Deseas hacer rollback? (y/n)"
            read -r response
            if [[ "$response" =~ ^[Yy]$ ]]; then
                rollback
            fi
            exit 1
        fi
    else
        print_error "La verificación falló"
        echo ""
        echo "¿Deseas hacer rollback? (y/n)"
        read -r response
        if [[ "$response" =~ ^[Yy]$ ]]; then
            rollback
        fi
        exit 1
    fi
}

main