#!/usr/bin/env node
/**
 * Auto-Compact Event Recorder
 *
 * Records observable metrics when an auto-compact (context window compression)
 * occurs in Claude Code sessions. This helps build empirical understanding of
 * what triggers compaction since we cannot directly measure Claude's internal
 * context window consumption.
 *
 * Usage:
 *   node scripts/record-auto-compact.js [options]
 *
 * Options:
 *   --tokens <current>/<budget>   Token count from system reminder (e.g., 89195/200000)
 *   --messages <count>            Message count from system reminder
 *   --note "message"              Optional note about what was happening
 *   --auto                        Automatic detection (no prompts)
 *
 * This script should be run IMMEDIATELY AFTER noticing a compact event:
 * - Session summary message appears
 * - Context seems to reset
 * - Previous conversation details become unavailable
 *
 * The goal is to build a dataset correlating observable metrics with actual
 * compact events, which can later inform heuristic warnings.
 */

const fs = require('fs');
const path = require('path');
const readline = require('readline');

const SESSION_STATE_PATH = path.join(__dirname, '../.claude/session-state.json');

// Parse command line arguments
function parseArgs() {
  const args = process.argv.slice(2);
  const options = {
    tokens: null,
    budget: null,
    messages: null,
    note: null,
    auto: false
  };

  for (let i = 0; i < args.length; i++) {
    switch (args[i]) {
      case '--tokens':
        const [current, budget] = args[++i].split('/').map(s => parseInt(s.trim()));
        options.tokens = current;
        options.budget = budget;
        break;
      case '--messages':
        options.messages = parseInt(args[++i]);
        break;
      case '--note':
        options.note = args[++i];
        break;
      case '--auto':
        options.auto = true;
        break;
      case '--help':
        console.log(`
Auto-Compact Event Recorder - Tractatus Framework

This tool records observable metrics when Claude Code auto-compaction occurs.
Run IMMEDIATELY after noticing a compact event to capture accurate data.

Usage:
  node scripts/record-auto-compact.js [options]

Options:
  --tokens <current>/<budget>   Token usage (e.g., 89195/200000)
  --messages <count>            Message count
  --note "message"              What were you doing when compact occurred
  --auto                        Non-interactive mode
  --help                        Show this help

Examples:
  # Interactive mode (prompts for missing values)
  node scripts/record-auto-compact.js --tokens 150000/200000

  # Fully specified
  node scripts/record-auto-compact.js --tokens 145000/200000 --messages 45 --note "Large file reads"

  # Automatic mode (use current session state)
  node scripts/record-auto-compact.js --auto
        `);
        process.exit(0);
    }
  }

  return options;
}

// Load session state
function loadSessionState() {
  if (!fs.existsSync(SESSION_STATE_PATH)) {
    console.error(`Error: Session state not found at ${SESSION_STATE_PATH}`);
    console.error('Run: node scripts/session-init.js');
    process.exit(1);
  }

  return JSON.parse(fs.readFileSync(SESSION_STATE_PATH, 'utf8'));
}

// Save session state
function saveSessionState(state) {
  fs.writeFileSync(SESSION_STATE_PATH, JSON.stringify(state, null, 2));
}

// Prompt user for input
async function promptFor(question, defaultValue = null) {
  const rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout
  });

  return new Promise((resolve) => {
    const prompt = defaultValue ? `${question} [${defaultValue}]: ` : `${question}: `;
    rl.question(prompt, (answer) => {
      rl.close();
      resolve(answer.trim() || defaultValue);
    });
  });
}

// Calculate session duration
function calculateDuration(startTime) {
  const start = new Date(startTime);
  const now = new Date();
  const diffMs = now - start;
  const hours = Math.floor(diffMs / (1000 * 60 * 60));
  const minutes = Math.floor((diffMs % (1000 * 60 * 60)) / (1000 * 60));
  return { hours, minutes, totalMinutes: Math.floor(diffMs / (1000 * 60)) };
}

// Main recording function
async function recordCompactEvent(options) {
  console.log('\n╔════════════════════════════════════════════════════════════════╗');
  console.log('║         Auto-Compact Event Recorder                            ║');
  console.log('╚════════════════════════════════════════════════════════════════╝\n');

  // Load current session state
  const sessionState = loadSessionState();
  console.log(`Session ID: ${sessionState.session_id}`);
  console.log(`Started: ${new Date(sessionState.started).toLocaleString()}\n`);

  // Initialize auto_compact_events array if not present
  if (!sessionState.auto_compact_events) {
    sessionState.auto_compact_events = [];
  }

  // Calculate session duration
  const duration = calculateDuration(sessionState.started);
  console.log(`Session Duration: ${duration.hours}h ${duration.minutes}m\n`);

  // Gather metrics (prompt if not provided)
  let tokens = options.tokens;
  let budget = options.budget;
  let messages = options.messages;
  let note = options.note;

  if (!options.auto) {
    if (tokens === null) {
      const tokenInput = await promptFor('Token usage (format: current/budget)',
        `${sessionState.token_estimate}/${sessionState.staleness_thresholds.tokens || 200000}`);
      [tokens, budget] = tokenInput.split('/').map(s => parseInt(s.trim()));
    }

    if (messages === null) {
      const messageInput = await promptFor('Message count', sessionState.message_count);
      messages = parseInt(messageInput);
    }

    if (note === null) {
      note = await promptFor('What were you doing? (optional)', null);
    }
  } else {
    // Auto mode: use session state
    tokens = sessionState.token_estimate || 0;
    budget = 200000; // Default budget
    messages = sessionState.message_count || 0;
    note = 'Auto-detected compact';
  }

  // Get pressure score from last monitoring activity
  const lastPressure = sessionState.last_framework_activity?.ContextPressureMonitor;
  const pressureLevel = lastPressure?.last_level || 'UNKNOWN';
  const pressureScore = lastPressure?.last_score || null;

  // Build compact event record
  const compactEvent = {
    timestamp: new Date().toISOString(),
    session_id: sessionState.session_id,
    metrics: {
      tokens_at_compact: tokens,
      token_budget: budget,
      token_percentage: budget > 0 ? ((tokens / budget) * 100).toFixed(1) : null,
      messages: messages,
      action_count: sessionState.action_count || 0,
      session_duration_minutes: duration.totalMinutes,
      pressure_level: pressureLevel,
      pressure_score: pressureScore
    },
    framework_activity: {
      cross_reference_validations: sessionState.framework_components?.CrossReferenceValidator?.validations_performed || 0,
      bash_command_validations: sessionState.framework_components?.BashCommandValidator?.validations_performed || 0,
      bash_blocks_issued: sessionState.framework_components?.BashCommandValidator?.blocks_issued || 0
    },
    note: note || null
  };

  // Add to history
  sessionState.auto_compact_events.push(compactEvent);

  // Save updated state
  saveSessionState(sessionState);

  // Display summary
  console.log('✅ Compact event recorded!\n');
  console.log('Metrics Captured:');
  console.log(`  Tokens:          ${compactEvent.metrics.tokens_at_compact} / ${compactEvent.metrics.token_budget} (${compactEvent.metrics.token_percentage}%)`);
  console.log(`  Messages:        ${compactEvent.metrics.messages}`);
  console.log(`  Actions:         ${compactEvent.metrics.action_count}`);
  console.log(`  Duration:        ${duration.hours}h ${duration.minutes}m`);
  console.log(`  Pressure Level:  ${compactEvent.metrics.pressure_level}`);
  if (compactEvent.metrics.pressure_score !== null) {
    console.log(`  Pressure Score:  ${(compactEvent.metrics.pressure_score * 100).toFixed(1)}%`);
  }
  console.log(`\nTotal Compacts:  ${sessionState.auto_compact_events.length}\n`);

  // Show compact frequency
  if (sessionState.auto_compact_events.length > 1) {
    const allTokens = sessionState.auto_compact_events.map(e => e.metrics.tokens_at_compact);
    const avgTokens = allTokens.reduce((a, b) => a + b, 0) / allTokens.length;

    const allMessages = sessionState.auto_compact_events.map(e => e.metrics.messages);
    const avgMessages = allMessages.reduce((a, b) => a + b, 0) / allMessages.length;

    console.log('Historical Averages:');
    console.log(`  Avg Tokens at Compact:   ${avgTokens.toFixed(0)}`);
    console.log(`  Avg Messages at Compact: ${avgMessages.toFixed(1)}`);
    console.log();
  }

  console.log('Data saved to:', SESSION_STATE_PATH);
  console.log('\nRun: node scripts/check-session-pressure.js --tokens <current>/<budget>');
  console.log('     to see compact statistics and predictions\n');
}

// Run if called directly
if (require.main === module) {
  const options = parseArgs();
  recordCompactEvent(options).catch(err => {
    console.error('Error:', err.message);
    process.exit(1);
  });
}

module.exports = { recordCompactEvent, loadSessionState };