#!/usr/bin/env bash
# Test, build, and swap the Go MCP binary on ns1.
# Does not restart verae-timestamping-svc or forgejo-runner, and does not read secret files.
set -euo pipefail

LOCK="${LOCK:-/tmp/verae-mcp-go-deploy.lock}"
DEST="${DEST:-/opt/verae/verae-mcp-timestamping-server-go/bin/verae-mcp-timestamping-server}"
SERVICE="${SERVICE:-verae-mcp-timestamping.service}"
PROBE="${PROBE:-http://127.0.0.1:8000/mcp}"
GO_ROOT="${GO_ROOT:-/usr/local/lib/go1.26.9}"
GO_TARBALL="${GO_TARBALL:-go1.26.9.linux-amd64.tar.gz}"
GO_SHA256="${GO_SHA256:-42d158b4d8f7b61ac0a830567c940a86098fb7aac52e467a5ebec03ef5cc2f8d}"
ROOT="$(cd "$(dirname "$0")/.." && pwd)"

mkdir -p "$(dirname "$LOCK")"
exec 9>"$LOCK"
if ! flock -n 9; then
  echo "another mcp deploy holds the lock" >&2
  exit 1
fi

ensure_go() {
  if [[ -x "$GO_ROOT/bin/go" ]] && "$GO_ROOT/bin/go" version | grep -q 'go1.26.9 '; then
    export PATH="$GO_ROOT/bin:$PATH"
    return
  fi
  local tmp
  tmp="$(mktemp -d)"
  curl -fsSL -o "$tmp/go.tgz" "https://go.dev/dl/${GO_TARBALL}"
  echo "${GO_SHA256}  ${tmp}/go.tgz" | sha256sum -c -
  tar -C "$tmp" -xzf "$tmp/go.tgz"
  sudo rm -rf "$GO_ROOT"
  sudo mv "$tmp/go" "$GO_ROOT"
  rm -rf "$tmp"
  export PATH="$GO_ROOT/bin:$PATH"
}

probe_ok() {
  local code
  code="$(curl -s -o /dev/null -w '%{http_code}' --max-time 5 "$PROBE" || true)"
  [[ -n "$code" && "$code" != "000" ]]
}

wait_probe() {
  local i
  for i in 1 2 3 4 5 6 7 8; do
    if probe_ok; then
      return 0
    fi
    sleep 1
  done
  return 1
}

swap_binary() {
  local src="$1"
  sudo systemctl stop "$SERVICE" || true
  local n=0
  while (( n < 5 )); do
    if sudo cp "$src" "$DEST"; then
      sudo chown verae-mcp:verae-mcp "$DEST"
      sudo chmod 755 "$DEST"
      sudo systemctl start "$SERVICE"
      return 0
    fi
    n=$((n + 1))
    sleep 1
    sudo systemctl stop "$SERVICE" || true
  done
  echo "could not replace $DEST" >&2
  sudo systemctl start "$SERVICE" || true
  return 1
}

rollback() {
  local latest
  latest="$(ls -1t "${DEST}.bak-"* 2>/dev/null | head -1 || true)"
  if [[ -z "$latest" ]]; then
    echo "no backup to roll back to" >&2
    sudo systemctl start "$SERVICE" || true
    exit 1
  fi
  swap_binary "$latest"
  if wait_probe; then
    echo "rolled back to $latest (probe ok)"
    return 0
  fi
  echo "rollback probe still failing" >&2
  return 1
}

if [[ "${1:-}" == "--rollback" ]]; then
  rollback
  exit $?
fi

ensure_go
cd "$ROOT"
go test ./... -count=1
go build -o /tmp/verae-mcp-timestamping-server-new ./cmd/verae-mcp-timestamping-server
if ! grep -a -q 'verae-meta-git/1' /tmp/verae-mcp-timestamping-server-new; then
  echo "built binary is missing verae-meta-git/1" >&2
  exit 1
fi

if [[ "${1:-}" == "--test-only" ]]; then
  echo "tests ok"
  exit 0
fi

ts="$(date -u +%Y%m%dT%H%M%SZ)"
sudo cp -a "$DEST" "${DEST}.bak-${ts}"
if ! swap_binary /tmp/verae-mcp-timestamping-server-new; then
  rollback || true
  exit 1
fi
if ! wait_probe; then
  echo "new binary failed probe; rolling back" >&2
  rollback || true
  exit 1
fi
echo "deployed ${ts} probe ok"