#!/usr/bin/env node
// post-bash-stats.mjs — PostToolUse hook (CC v2.1.97+)
//
// Captures duration_ms from PostToolUse payload for Bash tool calls and
// appends a structured stats line to ${CLAUDE_PLUGIN_DATA}/trekexecute-stats.jsonl
// when the running session is an trekexecute session.
//
// Detection: only fires when the tool input matches the verify/checkpoint
// pattern of an trekexecute step (i.e., the command was issued from inside
// /trekexecute). We err on the side of "log everything in plugin
// scope" — duration data is cheap and the alternative is missing real
// per-step timings.
//
// Fail-open invariant: any error → exit 0, no output, no log line.

import { stdin } from 'node:process';
import { appendFileSync, mkdirSync } from 'node:fs';
import { dirname, join } from 'node:path';

async function readStdin() {
  let data = '';
  for await (const chunk of stdin) data += chunk;
  return data;
}

(async () => {
  try {
    const raw = await readStdin();
    if (!raw.trim()) return;
    const payload = JSON.parse(raw);

    if (payload.tool_name !== 'Bash') return;
    const duration = payload.duration_ms;
    if (typeof duration !== 'number') return;

    const dataDir = process.env.CLAUDE_PLUGIN_DATA;
    if (!dataDir) return;

    const cmd = payload.tool_input?.command || '';
    if (!cmd) return;

    const line = JSON.stringify({
      ts: new Date().toISOString(),
      session_id: payload.session_id || null,
      command_excerpt: cmd.slice(0, 120),
      duration_ms: duration,
      success: payload.tool_response?.success !== false,
    });

    const target = join(dataDir, 'trekexecute-stats.jsonl');
    try {
      mkdirSync(dirname(target), { recursive: true });
    } catch {}
    appendFileSync(target, line + '\n');
  } catch {
    // fail open
  }
})();