#!/bin/bash

#######################################
# SIAX Agent - Script de Instalación Remota
# Descarga e instala SIAX Agent desde servidor central
#######################################

set -e  # Salir si hay errores

# Variables (CONFIGURAR AQUÍ)
CENTRAL_SERVER="${SIAX_SERVER:-localhost:8080}"  # Servidor central
INSTALL_DIR="/opt/siax-agent"
SERVICE_USER="siax-agent"
BACKUP_DIR="/tmp/siax-agent-backup-$(date +%s)"
DOWNLOAD_DIR="/tmp/siax-agent-download-$(date +%s)"

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

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

print_header() {
    echo -e "${BLUE}"
    echo "============================================"
    echo "  SIAX Agent - Remote Installation"
    echo "  Server: $CENTRAL_SERVER"
    echo "============================================"
    echo -e "${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 [ "$EUID" -ne 0 ]; then
        print_error "Este script debe ejecutarse como root"
        echo "Usa: curl -sSL http://$CENTRAL_SERVER/install.sh | sudo bash"
        echo "O con variable: curl -sSL http://$CENTRAL_SERVER/install.sh | sudo SIAX_SERVER=tu-servidor:8080 bash"
        exit 1
    fi
}

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

    local deps=("systemctl" "curl")
    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 en Debian/Ubuntu:"
        echo "  sudo apt-get update && sudo apt-get install -y curl systemd"
        echo ""
        echo "Instalación en RedHat/CentOS:"
        echo "  sudo yum install -y curl systemd"
        exit 1
    fi

    print_success "Todas las dependencias están instaladas"
}

download_binary() {
    print_info "Descargando binario desde $CENTRAL_SERVER..."

    mkdir -p "$DOWNLOAD_DIR"

    # Intentar descargar el binario pre-compilado
    if curl -f -L -o "$DOWNLOAD_DIR/siax-agent" "http://$CENTRAL_SERVER/static/binary/siax-agent"; then
        chmod +x "$DOWNLOAD_DIR/siax-agent"
        print_success "Binario descargado"
    else
        print_error "No se pudo descargar el binario desde http://$CENTRAL_SERVER/static/binary/siax-agent"
        echo ""
        echo "Asegúrate de que:"
        echo "  1. El servidor $CENTRAL_SERVER está accesible"
        echo "  2. El binario está en web/static/binary/siax-agent"
        echo "  3. Compilaste con: cargo build --release && cp target/release/siax_monitor web/static/binary/siax-agent"
        rm -rf "$DOWNLOAD_DIR"
        exit 1
    fi
}

download_web_files() {
    print_info "Descargando archivos web..."

    mkdir -p "$DOWNLOAD_DIR/web"

    # Descargar archivos HTML principales (opcional, solo si quieres que cada agente tenga su propia interfaz)
    # Para agentes worker, probablemente no necesites esto
    print_info "Archivos web no necesarios para worker nodes (omitiendo)"
}

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
}

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 "$INSTALL_DIR/logs"
    mkdir -p "$INSTALL_DIR/web/static"

    # Copiar binario
    cp "$DOWNLOAD_DIR/siax-agent" "$INSTALL_DIR/siax-agent"
    chmod +x "$INSTALL_DIR/siax-agent"

    # Crear configuración inicial vacía si no existe
    if [ ! -f "$INSTALL_DIR/config/monitored_apps.json" ]; then
        echo '{"apps":[]}' > "$INSTALL_DIR/config/monitored_apps.json"
    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
siax-agent ALL=(ALL) NOPASSWD: /bin/systemctl start *
siax-agent ALL=(ALL) NOPASSWD: /bin/systemctl stop *
siax-agent ALL=(ALL) NOPASSWD: /bin/systemctl restart *
siax-agent ALL=(ALL) NOPASSWD: /bin/systemctl status *
siax-agent ALL=(ALL) NOPASSWD: /bin/systemctl enable *
siax-agent ALL=(ALL) NOPASSWD: /bin/systemctl disable *
siax-agent ALL=(ALL) NOPASSWD: /bin/systemctl daemon-reload
siax-agent ALL=(ALL) NOPASSWD: /bin/systemctl is-active *
siax-agent ALL=(ALL) NOPASSWD: /bin/systemctl list-unit-files *
siax-agent ALL=(ALL) NOPASSWD: /bin/journalctl *
siax-agent ALL=(ALL) NOPASSWD: /usr/bin/systemctl start *
siax-agent ALL=(ALL) NOPASSWD: /usr/bin/systemctl stop *
siax-agent ALL=(ALL) NOPASSWD: /usr/bin/systemctl restart *
siax-agent ALL=(ALL) NOPASSWD: /usr/bin/systemctl status *
siax-agent ALL=(ALL) NOPASSWD: /usr/bin/systemctl enable *
siax-agent ALL=(ALL) NOPASSWD: /usr/bin/systemctl disable *
siax-agent ALL=(ALL) NOPASSWD: /usr/bin/systemctl daemon-reload
siax-agent ALL=(ALL) NOPASSWD: /usr/bin/systemctl is-active *
siax-agent ALL=(ALL) NOPASSWD: /usr/bin/systemctl list-unit-files *
siax-agent ALL=(ALL) NOPASSWD: /usr/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"
}

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
}

cleanup() {
    print_info "Limpiando archivos temporales..."
    rm -rf "$DOWNLOAD_DIR"
    print_success "Limpieza completada"
}

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:8080/api"
    echo "📡 WebSocket:     ws://localhost:8080/api/apps/:name/logs"
    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 ""
    echo "🌐 Servidor Central: $CENTRAL_SERVER"
    echo ""
}

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

main() {
    print_header

    check_root
    check_dependencies
    backup_existing
    download_binary
    create_user
    install_binary
    configure_sudoers
    create_systemd_service

    if start_service; then
        cleanup
        print_summary
        exit 0
    else
        print_error "El servicio no pudo iniciarse correctamente"
        print_info "Revisa los logs: journalctl -u siax-agent -n 50"
        cleanup
        exit 1
    fi
}

main