#!/usr/bin/env bash
# Append a run heartbeat for long agent dispatches.
# Binding: wiki/process/agent-scale.md slice G.
#
# Usage:
#   tools/heartbeat.sh start <id> [--worktree path] [--phase text]
#   tools/heartbeat.sh phase <id> <phase text>
#   tools/heartbeat.sh end <id> [--status ok|fail]
#
# Writes machine-local (gitignored) files under .agents/runs/<id>/.
set -euo pipefail

script_root=$(cd "$(dirname "$0")/.." && pwd)
root=$script_root
if [ -f "$script_root/.git" ]; then
  common=$(git -C "$script_root" rev-parse --path-format=absolute --git-common-dir)
  case "$common" in
    */.git) root=${common%/.git} ;;
  esac
fi
RUNS_DIR=${MISALIGNED_RUNS_DIR:-"$root/.agents/runs"}

usage() {
  sed -n '2,12p' "$0" | sed 's/^# \{0,1\}//'
  exit 2
}

run_dir() {
  local id="$1"
  case "$id" in
    ""|*/*|*..*) echo "FAIL: bad run id" >&2; exit 2 ;;
  esac
  printf '%s/%s\n' "$RUNS_DIR" "$id"
}

now() { date -u +"%Y-%m-%dT%H:%M:%SZ"; }

cmd_start() {
  local id="${1:-}"; shift || true
  [ -n "$id" ] || usage
  local worktree="" phase="start"
  while [ $# -gt 0 ]; do
    case "$1" in
      --worktree) shift; worktree="${1:-}"; shift || true ;;
      --phase) shift; phase="${1:-start}"; shift || true ;;
      *) usage ;;
    esac
  done
  local dir
  dir=$(run_dir "$id")
  mkdir -p "$dir"
  cat > "$dir/status.json" <<EOF
{"id":"$id","pid":$$,"worktree":"$worktree","phase":"$phase","started_at":"$(now)","updated_at":"$(now)","status":"running"}
EOF
  printf '%s start phase=%s pid=%s\n' "$(now)" "$phase" "$$" >> "$dir/events.ndjson"
  echo "heartbeat: started $id -> $dir"
}

cmd_phase() {
  local id="${1:-}" phase="${2:-}"
  [ -n "$id" ] && [ -n "$phase" ] || usage
  local dir
  dir=$(run_dir "$id")
  mkdir -p "$dir"
  local started
  if [ -f "$dir/status.json" ]; then
    started=$(grep -o '"started_at":"[^"]*"' "$dir/status.json" | head -1 | sed 's/.*"started_at":"//;s/"$//')
  fi
  started=${started:-$(now)}
  cat > "$dir/status.json" <<EOF
{"id":"$id","pid":$$,"phase":"$phase","started_at":"$started","updated_at":"$(now)","status":"running"}
EOF
  printf '%s phase=%s\n' "$(now)" "$phase" >> "$dir/events.ndjson"
  echo "heartbeat: $id -> $phase"
}

cmd_end() {
  local id="${1:-}"; shift || true
  [ -n "$id" ] || usage
  local status=ok
  while [ $# -gt 0 ]; do
    case "$1" in
      --status) shift; status="${1:-ok}"; shift || true ;;
      *) usage ;;
    esac
  done
  local dir
  dir=$(run_dir "$id")
  mkdir -p "$dir"
  local started phase
  started=$(now); phase=end
  if [ -f "$dir/status.json" ]; then
    started=$(grep -o '"started_at":"[^"]*"' "$dir/status.json" | head -1 | sed 's/.*"started_at":"//;s/"$//' || echo "$started")
    phase=$(grep -o '"phase":"[^"]*"' "$dir/status.json" | head -1 | sed 's/.*"phase":"//;s/"$//' || echo end)
  fi
  cat > "$dir/status.json" <<EOF
{"id":"$id","pid":$$,"phase":"$phase","started_at":"$started","updated_at":"$(now)","status":"$status"}
EOF
  printf '%s end status=%s\n' "$(now)" "$status" >> "$dir/events.ndjson"
  echo "heartbeat: ended $id ($status)"
}

cmd="${1:-}"; shift || true
case "$cmd" in
  start) cmd_start "$@" ;;
  phase) cmd_phase "$@" ;;
  end) cmd_end "$@" ;;
  *) usage ;;
esac