#!/usr/bin/env bash
# install.sh — Instalador inteligente del agente usite-agent
# Se adapta automáticamente al entorno: VPS root, contenedor, usuario sin root, etc.
#
# Uso:
#   curl -sL https://admin.u-site.app/agent/install.sh | bash -s -- --token=TU_TOKEN --url=https://admin.u-site.app
#   bash install.sh --token=TU_TOKEN --url=https://admin.u-site.app [--interval=30] [--dir=/opt/usite-agent]

set -euo pipefail

RED='\033[0;31m'; GREEN='\033[0;32m'; YELLOW='\033[1;33m'; BLUE='\033[0;34m'; NC='\033[0m'
info()    { echo -e "${BLUE}[INFO]${NC}  $*"; }
ok()      { echo -e "${GREEN}[OK]${NC}    $*"; }
warn()    { echo -e "${YELLOW}[WARN]${NC}  $*"; }
error()   { echo -e "${RED}[ERROR]${NC} $*"; exit 1; }

TOKEN=""
API_URL=""
INTERVAL=30
INSTALL_DIR=""
CPU_THRESHOLD=90
RENICE_ENABLED=true
RENICE_CONSECUTIVE=2

for arg in "$@"; do
  case $arg in
    --token=*)             TOKEN="${arg#*=}" ;;
    --url=*)               API_URL="${arg#*=}" ;;
    --interval=*)          INTERVAL="${arg#*=}" ;;
    --dir=*)               INSTALL_DIR="${arg#*=}" ;;
    --cpu-threshold=*)     CPU_THRESHOLD="${arg#*=}" ;;
    --renice=*)            RENICE_ENABLED="${arg#*=}" ;;
    --renice-consecutive=*) RENICE_CONSECUTIVE="${arg#*=}" ;;
  esac
done

[[ -z "$TOKEN" ]]   && error "Falta --token=TU_TOKEN"
[[ -z "$API_URL" ]] && error "Falta --url=https://admin.u-site.app"

OS="$(uname -s | tr '[:upper:]' '[:lower:]')"
ARCH="$(uname -m)"
case $ARCH in
  x86_64)  ARCH="amd64" ;;
  aarch64) ARCH="arm64" ;;
  armv7l)  ARCH="arm" ;;
  *)       error "Arquitectura no soportada: $ARCH" ;;
esac

BINARY_NAME="usite-agent-${OS}-${ARCH}"
DOWNLOAD_URL="${API_URL}/agent/download/${BINARY_NAME}"

IS_ROOT=0
[[ "$(id -u)" == "0" ]] && IS_ROOT=1

# ── Detectar entorno ──────────────────────────────────────────────────────────
ENV_TYPE="vps"
IS_CONTAINER=0
if [[ -f "/run/.containerenv" ]] || [[ -f "/.dockerenv" ]]; then
  IS_CONTAINER=1; ENV_TYPE="contenedor"
fi
if [[ -n "${DOCKER_HOST:-}" ]] || [[ -n "${KUBERNETES_SERVICE_HOST:-}" ]]; then
  IS_CONTAINER=1; ENV_TYPE="contenedor"
fi
if [[ "$IS_ROOT" == 0 ]]; then
  ENV_TYPE="usuario"
fi

# ── Directorio ─────────────────────────────────────────────────────────────────
if [[ -z "$INSTALL_DIR" ]]; then
  if [[ "$IS_ROOT" == 1 ]]; then
    INSTALL_DIR="/opt/usite-agent"
  else
    INSTALL_DIR="${HOME}/.usite-agent"
  fi
fi

info "Entorno: ${ENV_TYPE}${IS_CONTAINER:+(contenedor)}"
info "Sistema: ${OS}/${ARCH}"
info "Directorio: ${INSTALL_DIR}"
info "Intervalo: ${INTERVAL}s"

# ── Instalar binario ──────────────────────────────────────────────────────────
mkdir -p "$INSTALL_DIR" || error "No se pudo crear directorio ${INSTALL_DIR} (¿permisos?)"

# Verificar espacio disponible (necesita al menos 20 MB)
AVAIL_KB=$(df -k "$INSTALL_DIR" 2>/dev/null | awk 'NR==2 {print $4}')
if [[ -n "$AVAIL_KB" && "$AVAIL_KB" -lt 20480 ]]; then
  error "Espacio insuficiente en ${INSTALL_DIR}: solo ${AVAIL_KB} KB disponibles (se necesitan ≥20 MB)"
fi

info "Descargando agente desde ${DOWNLOAD_URL}..."
DEST="${INSTALL_DIR}/usite-agent"
TMP_DEST="/tmp/usite-agent-download-$$"

if command -v curl &>/dev/null; then
  curl -fsSL "$DOWNLOAD_URL" -o "$TMP_DEST" 2>/tmp/curl_err || {
    CURL_ERR=$(cat /tmp/curl_err 2>/dev/null)
    rm -f "$TMP_DEST"
    error "No se pudo descargar: ${CURL_ERR}"
  }
elif command -v wget &>/dev/null; then
  wget -q "$DOWNLOAD_URL" -O "$TMP_DEST" || { rm -f "$TMP_DEST"; error "No se pudo descargar con wget"; }
else
  error "Se requiere curl o wget"
fi

if [[ ! -s "$TMP_DEST" ]]; then
  rm -f "$TMP_DEST"
  error "El archivo descargado está vacío"
fi

mv "$TMP_DEST" "$DEST" || { cp "$TMP_DEST" "$DEST" && rm -f "$TMP_DEST"; } || error "No se pudo mover el binario a ${DEST}"
chmod +x "$DEST"
ok "Binario descargado ($(du -sh "$DEST" | cut -f1))"

# ── Configuración ─────────────────────────────────────────────────────────────
cat > "${INSTALL_DIR}/agent.yml" <<EOF
api_url: ${API_URL}
token: ${TOKEN}
interval: ${INTERVAL}
debug: false
cpu_threshold: ${CPU_THRESHOLD}
renice_enabled: ${RENICE_ENABLED}
renice_consecutive: ${RENICE_CONSECUTIVE}
EOF
ok "Configuración creada en ${INSTALL_DIR}/agent.yml"

# ── Auto-arranque inteligente ─────────────────────────────────────────────────
STARTED=0

# 1) systemd (VPS con root)
if [[ "$IS_ROOT" == 1 ]] && command -v systemctl &>/dev/null; then
  cat > /etc/systemd/system/usite-agent.service <<EOF
[Unit]
Description=u-site Server Monitoring Agent
After=network.target
Wants=network-online.target

[Service]
Type=simple
ExecStart=${INSTALL_DIR}/usite-agent --config=${INSTALL_DIR}/agent.yml
WorkingDirectory=${INSTALL_DIR}
Restart=always
RestartSec=10
StandardOutput=journal
StandardError=journal
SyslogIdentifier=usite-agent

[Install]
WantedBy=multi-user.target
EOF
  systemctl daemon-reload
  systemctl enable usite-agent
  if systemctl is-active --quiet usite-agent; then
    systemctl restart usite-agent
    ok "Servicio systemd 'usite-agent' reiniciado con nueva configuración"
  else
    systemctl start usite-agent
    ok "Servicio systemd 'usite-agent' instalado y activo"
  fi
  STARTED=1

# 2) openrc (Alpine, algunos VPS)
elif [[ "$IS_ROOT" == 1 ]] && command -v rc-update &>/dev/null; then
  cat > /etc/init.d/usite-agent <<EOF
#!/sbin/openrc-run
description="u-site Server Monitoring Agent"
command="${INSTALL_DIR}/usite-agent"
command_args="--config=${INSTALL_DIR}/agent.yml"
command_background=true
pidfile="/run/usite-agent.pid"
EOF
  chmod +x /etc/init.d/usite-agent
  rc-update add usite-agent default
  rc-service usite-agent start
  ok "Servicio openrc 'usite-agent' instalado y activo"
  STARTED=1

# 3) Docker / contenedor — ejecución en foreground con restart automático
elif [[ "$IS_CONTAINER" == 1 ]]; then
  warn "Entorno contenedor detectado. El agente se ejecutará en primer plano."
  warn "Agrega al entrypoint de tu contenedor:"
  warn "  ${INSTALL_DIR}/usite-agent --config=${INSTALL_DIR}/agent.yml &"
  STARTED=1

# 4) Usuario sin root — crontab para auto-arranque
else
  CRON_JOB="@reboot ${INSTALL_DIR}/usite-agent --config=${INSTALL_DIR}/agent.yml >/dev/null 2>&1 &"
  if crontab -l 2>/dev/null | grep -q "usite-agent"; then
    warn "Crontab ya tiene una entrada para usite-agent, se omite"
  else
    (crontab -l 2>/dev/null || true; echo "$CRON_JOB") | crontab -
    ok "Entrada @reboot agregada al crontab"
  fi
  nohup "${INSTALL_DIR}/usite-agent" --config="${INSTALL_DIR}/agent.yml" >/dev/null 2>&1 &
  ok "Agente iniciado en background (PID $!)"
  STARTED=1
fi

# ── Resumen ────────────────────────────────────────────────────────────────────
echo ""
if [[ "$STARTED" == 1 ]]; then
  ok "usite-agent instalado correctamente en ${INSTALL_DIR}"
  info "El agente reportará métricas a ${API_URL} cada ${INTERVAL}s"
  info ""
  info "Comandos útiles:"
  if [[ "$IS_ROOT" == 1 ]] && command -v systemctl &>/dev/null; then
    info "  systemctl status usite-agent"
    info "  journalctl -u usite-agent -f"
  fi
  info "  ${INSTALL_DIR}/usite-agent --config=${INSTALL_DIR}/agent.yml (ejecutar manual)"
  info ""
  info "Para desinstalar:"
  if [[ "$IS_ROOT" == 1 ]] && command -v systemctl &>/dev/null; then
    info "  systemctl disable usite-agent && rm /etc/systemd/system/usite-agent.service && rm -rf ${INSTALL_DIR}"
  elif [[ "$IS_ROOT" == 1 ]] && command -v rc-update &>/dev/null; then
    info "  rc-update del usite-agent && rm /etc/init.d/usite-agent && rm -rf ${INSTALL_DIR}"
  else
    info "  crontab -l | grep -v usite-agent | crontab - && rm -rf ${INSTALL_DIR}"
  fi
else
  warn "No se pudo configurar auto-arranque. Ejecuta manualmente:"
  warn "  ${INSTALL_DIR}/usite-agent --config=${INSTALL_DIR}/agent.yml &"
fi