#!/usr/bin/env bash
#
# health-check.sh — Probe the Zopu execution plane.
#
# Checks (TCP/process-level; no assumed HTTP health routes):
#   1. zopu-daemon systemd unit is active
#   2. zopu-agent systemd unit is active
#   3. RivetKit engine TCP port (RIVET_ENDPOINT, default 6420) accepts connections
#   4. Flue agent TCP port (PORT, default 3583) accepts connections
#   5. Docker daemon is reachable
#
# Flue does not expose a health endpoint by design. RivetKit's health route
# is internal to the registry runtime. We use TCP connection checks only.
#
# Usage:
#   health-check.sh           # print results
#   health-check.sh --quiet   # suppress output, exit 0 only if all healthy
#
# Exit codes: 0 = all healthy, 1 = one or more unhealthy

set -euo pipefail

QUIET=false
[[ "${1:-}" == "--quiet" ]] && QUIET=true

GREEN='\033[0;32m'
RED='\033[0;31m'
NC='\033[0m'

pass() { $QUIET || echo -e "  ${GREEN}PASS${NC} $*"; }
fail() { echo -e "  ${RED}FAIL${NC} $*" >&2; FAILURES=$((FAILURES + 1)); }

FAILURES=0

# ---------------------------------------------------------------------------
# Load environment
# ---------------------------------------------------------------------------
ENV_FILE="${ENV_FILE:-/opt/zopu/.env}"
if [[ -f "$ENV_FILE" ]]; then
  # shellcheck source=/dev/null
  set -a
  . "$ENV_FILE"
  set +a
fi

RIVET_PORT="6420"
if [[ -n "${RIVET_ENDPOINT:-}" ]]; then
  RIVET_PORT=$(echo "$RIVET_ENDPOINT" | sed -n 's|.*://[^:]*:\([0-9]*\).*|\1|p')
  [[ -z "$RIVET_PORT" ]] && RIVET_PORT="6420"
fi

AGENT_PORT="${PORT:-3583}"

# ---------------------------------------------------------------------------
# TCP probe helper: works on Debian (nc from netcat-openbsd) and macOS.
# Falls back to bash /dev/tcp if nc is unavailable.
# ---------------------------------------------------------------------------
tcp_probe() {
  local host="$1" port="$2"
  if command -v nc &>/dev/null; then
    nc -z -w 5 "$host" "$port" 2>/dev/null
  else
    timeout 5 bash -c "echo > /dev/tcp/${host}/${port}" 2>/dev/null
  fi
}

# ---------------------------------------------------------------------------
# 1. Daemon systemd unit
# ---------------------------------------------------------------------------
if systemctl is-active --quiet zopu-daemon 2>/dev/null; then
  pass "zopu-daemon service is active"
else
  fail "zopu-daemon service is not active"
fi

# ---------------------------------------------------------------------------
# 2. Agent systemd unit
# ---------------------------------------------------------------------------
if systemctl is-active --quiet zopu-agent 2>/dev/null; then
  pass "zopu-agent service is active"
else
  fail "zopu-agent service is not active"
fi

# ---------------------------------------------------------------------------
# 3. RivetKit engine TCP port
# ---------------------------------------------------------------------------
if tcp_probe localhost "$RIVET_PORT"; then
  pass "RivetKit engine port ${RIVET_PORT} is accepting connections"
else
  fail "RivetKit engine port ${RIVET_PORT} is not accepting connections"
fi

# ---------------------------------------------------------------------------
# 4. Flue agent TCP port
# ---------------------------------------------------------------------------
if tcp_probe localhost "$AGENT_PORT"; then
  pass "Flue agent port ${AGENT_PORT} is accepting connections"
else
  fail "Flue agent port ${AGENT_PORT} is not accepting connections"
fi

# ---------------------------------------------------------------------------
# 5. Docker daemon
# ---------------------------------------------------------------------------
if docker info &>/dev/null; then
  pass "Docker daemon is reachable"
else
  fail "Docker daemon is not reachable"
fi

# ---------------------------------------------------------------------------
# Summary
# ---------------------------------------------------------------------------
$QUIET || echo ""
if [[ "$FAILURES" -eq 0 ]]; then
  $QUIET || echo -e "${GREEN}All checks passed.${NC}"
  exit 0
else
  echo -e "${RED}${FAILURES} check(s) failed.${NC}" >&2
  exit 1
fi