#!/usr/bin/env node

/**
 * Hook Validator: File Edit
 *
 * Runs BEFORE Edit tool execution to enforce governance requirements.
 * This is architectural enforcement - AI cannot bypass this check.
 *
 * Checks:
 * 1. Pre-action validation (CSP, file type restrictions)
 * 2. CrossReferenceValidator (instruction conflicts)
 * 3. BoundaryEnforcer (values decisions)
 *
 * Exit codes:
 * 0 = PASS (allow edit)
 * 1 = FAIL (block edit)
 *
 * Copyright 2025 Tractatus Project
 * Licensed under Apache License 2.0
 */

const fs = require('fs');
const path = require('path');
const { execSync } = require('child_process');

// Hooks receive input via stdin as JSON
let HOOK_INPUT = null;
let FILE_PATH = null;

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

/**
 * Color output
 */
const colors = {
  reset: '\x1b[0m',
  green: '\x1b[32m',
  yellow: '\x1b[33m',
  red: '\x1b[31m',
  cyan: '\x1b[36m'
};

function log(message, color = 'reset') {
  console.log(`${colors[color]}${message}${colors.reset}`);
}

function error(message) {
  log(`  ✗ ${message}`, 'red');
}

function warning(message) {
  log(`  ⚠ ${message}`, 'yellow');
}

function success(message) {
  log(`  ✓ ${message}`, 'green');
}

/**
 * Check 1: Pre-action validation
 */
function runPreActionCheck() {
  try {
    // Determine action type based on file extension
    let actionType = 'file-edit';

    // Run pre-action-check.js
    execSync(
      `node ${path.join(__dirname, '../pre-action-check.js')} ${actionType} "${FILE_PATH}" "Hook validation"`,
      { encoding: 'utf8', stdio: 'pipe' }
    );

    return { passed: true };
  } catch (err) {
    // Pre-action check failed (non-zero exit code)
    return {
      passed: false,
      reason: 'Pre-action check failed (CSP violation or file restriction)',
      output: err.stdout || err.message
    };
  }
}

/**
 * Check 2: CrossReferenceValidator - Check for instruction conflicts
 */
function checkInstructionConflicts() {
  try {
    if (!fs.existsSync(INSTRUCTION_HISTORY_PATH)) {
      return { passed: true, conflicts: [] };
    }

    const history = JSON.parse(fs.readFileSync(INSTRUCTION_HISTORY_PATH, 'utf8'));
    const activeInstructions = history.instructions?.filter(i => i.active) || [];

    // Check if any HIGH persistence instructions might conflict with this file edit
    const highPriorityInstructions = activeInstructions.filter(i => i.persistence === 'HIGH');

    if (highPriorityInstructions.length === 0) {
      return { passed: true, conflicts: [] };
    }

    // Check file path against instruction contexts
    const conflicts = highPriorityInstructions.filter(instruction => {
      // If instruction mentions specific files or paths
      if (instruction.context && typeof instruction.context === 'string') {
        return instruction.context.includes(FILE_PATH) ||
               FILE_PATH.includes(instruction.context);
      }
      return false;
    });

    if (conflicts.length > 0) {
      return {
        passed: false,
        reason: `Conflicts with ${conflicts.length} HIGH persistence instruction(s)`,
        conflicts: conflicts.map(c => ({
          id: c.id,
          instruction: c.instruction,
          quadrant: c.quadrant
        }))
      };
    }

    return { passed: true, conflicts: [] };
  } catch (err) {
    warning(`Could not check instruction conflicts: ${err.message}`);
    return { passed: true, conflicts: [] };  // Fail open on error
  }
}

/**
 * Check 3: BoundaryEnforcer - Values decisions
 */
function checkBoundaryViolation() {
  // Check if file path suggests values content
  const valuesIndicators = [
    '/docs/values/',
    '/docs/ethics/',
    'privacy-policy',
    'code-of-conduct',
    'values.html',
    '/pluralistic-values'
  ];

  const isValuesContent = valuesIndicators.some(indicator =>
    FILE_PATH.toLowerCase().includes(indicator.toLowerCase())
  );

  if (isValuesContent) {
    return {
      passed: false,
      reason: 'File appears to contain values content - requires human approval',
      requiresHumanApproval: true
    };
  }

  return { passed: true };
}

/**
 * Update session state with hook execution
 */
function updateSessionState() {
  try {
    if (fs.existsSync(SESSION_STATE_PATH)) {
      const sessionState = JSON.parse(fs.readFileSync(SESSION_STATE_PATH, 'utf8'));
      sessionState.last_framework_activity = sessionState.last_framework_activity || {};
      sessionState.last_framework_activity.FileEditHook = {
        timestamp: new Date().toISOString(),
        file: FILE_PATH,
        result: 'passed'
      };
      sessionState.last_updated = new Date().toISOString();
      fs.writeFileSync(SESSION_STATE_PATH, JSON.stringify(sessionState, null, 2));
    }
  } catch (err) {
    // Non-critical - don't fail on logging errors
  }
}

/**
 * Log metrics for hook execution
 */
function logMetrics(result, reason = null) {
  try {
    const METRICS_PATH = path.join(__dirname, '../../.claude/metrics/hooks-metrics.json');
    const METRICS_DIR = path.dirname(METRICS_PATH);

    // Ensure directory exists
    if (!fs.existsSync(METRICS_DIR)) {
      fs.mkdirSync(METRICS_DIR, { recursive: true });
    }

    // Load existing metrics
    let metrics = { hook_executions: [], blocks: [], session_stats: {} };
    if (fs.existsSync(METRICS_PATH)) {
      metrics = JSON.parse(fs.readFileSync(METRICS_PATH, 'utf8'));
    }

    // Log execution
    metrics.hook_executions.push({
      hook: 'validate-file-edit',
      timestamp: new Date().toISOString(),
      file: FILE_PATH,
      result: result,
      reason: reason
    });

    // Log block if failed
    if (result === 'blocked') {
      metrics.blocks.push({
        hook: 'validate-file-edit',
        timestamp: new Date().toISOString(),
        file: FILE_PATH,
        reason: reason
      });
    }

    // Update session stats
    metrics.session_stats.total_edit_hooks = (metrics.session_stats.total_edit_hooks || 0) + 1;
    metrics.session_stats.total_edit_blocks = (metrics.session_stats.total_edit_blocks || 0) + (result === 'blocked' ? 1 : 0);
    metrics.session_stats.last_updated = new Date().toISOString();

    // Keep only last 1000 executions
    if (metrics.hook_executions.length > 1000) {
      metrics.hook_executions = metrics.hook_executions.slice(-1000);
    }

    // Keep only last 500 blocks
    if (metrics.blocks.length > 500) {
      metrics.blocks = metrics.blocks.slice(-500);
    }

    // Write metrics
    fs.writeFileSync(METRICS_PATH, JSON.stringify(metrics, null, 2));
  } catch (err) {
    // Non-critical - don't fail on metrics logging
  }
}

/**
 * Read hook input from stdin
 */
function readHookInput() {
  return new Promise((resolve) => {
    let data = '';
    process.stdin.on('data', chunk => {
      data += chunk;
    });
    process.stdin.on('end', () => {
      try {
        resolve(JSON.parse(data));
      } catch (err) {
        resolve(null);
      }
    });
  });
}

/**
 * Main validation
 */
async function main() {
  // Read input from stdin
  HOOK_INPUT = await readHookInput();

  if (!HOOK_INPUT || !HOOK_INPUT.tool_input || !HOOK_INPUT.tool_input.file_path) {
    error('No file path provided in hook input');
    logMetrics('error', 'No file path in input');
    process.exit(2);  // Exit code 2 = BLOCK
  }

  FILE_PATH = HOOK_INPUT.tool_input.file_path;
  log(`\n🔍 Hook: Validating file edit: ${FILE_PATH}`, 'cyan');

  // Check 1: Pre-action validation
  const preCheck = runPreActionCheck();
  if (!preCheck.passed) {
    error(preCheck.reason);
    if (preCheck.output) {
      console.log(preCheck.output);
    }
    logMetrics('blocked', preCheck.reason);
    process.exit(2);  // Exit code 2 = BLOCK
  }
  success('Pre-action check passed');

  // Check 2: CrossReferenceValidator
  const conflicts = checkInstructionConflicts();
  if (!conflicts.passed) {
    error(conflicts.reason);
    conflicts.conflicts.forEach(c => {
      log(`    • ${c.id}: ${c.instruction} [${c.quadrant}]`, 'yellow');
    });
    logMetrics('blocked', conflicts.reason);
    process.exit(2);  // Exit code 2 = BLOCK
  }
  success('No instruction conflicts detected');

  // Check 3: BoundaryEnforcer
  const boundary = checkBoundaryViolation();
  if (!boundary.passed) {
    error(boundary.reason);
    logMetrics('blocked', boundary.reason);
    process.exit(2);  // Exit code 2 = BLOCK
  }
  success('No boundary violations detected');

  // Update session state
  updateSessionState();

  // Log successful execution
  logMetrics('passed');

  success('File edit validation complete\n');
  process.exit(0);
}

main().catch(err => {
  error(`Hook validation error: ${err.message}`);
  logMetrics('error', err.message);
  process.exit(2);  // Exit code 2 = BLOCK
});