#!/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 1a: CSP Compliance on content AFTER edit
 * Simulates the edit and validates the result
 */
function checkCSPComplianceAfterEdit() {
  const oldString = HOOK_INPUT.tool_input.old_string;
  const newString = HOOK_INPUT.tool_input.new_string;

  if (!oldString || newString === undefined) {
    warning('No old_string/new_string in tool input - skipping CSP check');
    return { passed: true };
  }

  // Only check HTML/JS files
  const ext = path.extname(FILE_PATH).toLowerCase();
  if (!['.html', '.js'].includes(ext)) {
    return { passed: true };
  }

  // Exclude scripts/ directory (not served to browsers)
  if (FILE_PATH.includes('/scripts/')) {
    return { passed: true };
  }

  // Read current file content
  if (!fs.existsSync(FILE_PATH)) {
    warning(`File does not exist yet: ${FILE_PATH} - skipping CSP check`);
    return { passed: true };
  }

  let currentContent;
  try {
    currentContent = fs.readFileSync(FILE_PATH, 'utf8');
  } catch (err) {
    warning(`Could not read file: ${err.message} - skipping CSP check`);
    return { passed: true };
  }

  // Simulate the edit
  const contentAfterEdit = currentContent.replace(oldString, newString);

  // Check for CSP violations in the RESULT
  const violations = [];

  const patterns = [
    {
      name: 'Inline event handlers',
      regex: /\son\w+\s*=\s*["'][^"']*["']/gi,
      severity: 'CRITICAL'
    },
    {
      name: 'Inline styles',
      regex: /\sstyle\s*=\s*["'][^"']+["']/gi,
      severity: 'CRITICAL'
    },
    {
      name: 'Inline scripts (without src)',
      regex: /<script(?![^>]*\ssrc=)[^>]*>[\s\S]*?<\/script>/gi,
      severity: 'WARNING',
      filter: (match) => match.replace(/<script[^>]*>|<\/script>/gi, '').trim().length > 0
    },
    {
      name: 'javascript: URLs',
      regex: /href\s*=\s*["']javascript:[^"']*["']/gi,
      severity: 'CRITICAL'
    }
  ];

  patterns.forEach(pattern => {
    const matches = contentAfterEdit.match(pattern.regex);
    if (matches) {
      const filtered = pattern.filter ? matches.filter(pattern.filter) : matches;
      if (filtered.length > 0) {
        violations.push({
          name: pattern.name,
          severity: pattern.severity,
          count: filtered.length,
          samples: filtered.slice(0, 3)
        });
      }
    }
  });

  if (violations.length === 0) {
    return { passed: true };
  }

  // Report violations
  const output = [];
  output.push(`CSP violations detected in content AFTER edit for ${path.basename(FILE_PATH)}:`);
  violations.forEach(v => {
    output.push(`  [${v.severity}] ${v.name} (${v.count} occurrences)`);
    v.samples.forEach((sample, idx) => {
      const truncated = sample.length > 80 ? sample.substring(0, 77) + '...' : sample;
      output.push(`    ${idx + 1}. ${truncated}`);
    });
  });

  return {
    passed: false,
    reason: 'CSP violations in content after edit',
    output: output.join('\n')
  };
}

/**
 * Check 1b: Other pre-action validations (skip CSP, handle separately)
 */
function runOtherPreActionChecks() {
  // Skip pre-action-check.js to avoid catch-22
  // CSP is handled by checkCSPComplianceAfterEdit()
  return { passed: true };
}

/**
 * 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 };
}

/**
 * Check 4: Credential Protection - Prevent unauthorized credential changes
 */
function checkCredentialProtection() {
  try {
    const validatorPath = path.join(__dirname, 'validate-credentials.js');
    if (!fs.existsSync(validatorPath)) {
      warning('Credential validator not found - skipping check');
      return { passed: true };
    }

    const { validate } = require(validatorPath);
    const result = validate(FILE_PATH, 'edit');

    if (!result.valid) {
      return {
        passed: false,
        reason: 'Protected credential change detected',
        output: result.message
      };
    }

    return { passed: true };
  } catch (err) {
    warning(`Credential check error: ${err.message}`);
    return { passed: true };  // Fail open on error
  }
}

/**
 * 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 cspCheck = checkCSPComplianceAfterEdit();
  if (!cspCheck.passed) {
    error(cspCheck.reason);
    if (cspCheck.output) {
      console.log(cspCheck.output);
    }
    logMetrics('blocked', cspCheck.reason);
    process.exit(2);  // Exit code 2 = BLOCK
  }
  success('CSP compliance validated on content after edit');

  // Check 1b: Other pre-action checks
  const otherChecks = runOtherPreActionChecks();
  if (!otherChecks.passed) {
    error(otherChecks.reason);
    if (otherChecks.output) {
      console.log(otherChecks.output);
    }
    logMetrics('blocked', otherChecks.reason);
    process.exit(2);  // Exit code 2 = BLOCK
  }
  success('Other pre-action checks 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');

  // Check 4: Credential Protection
  const credentials = checkCredentialProtection();
  if (!credentials.passed) {
    error(credentials.reason);
    if (credentials.output) {
      console.log(credentials.output);
    }
    logMetrics('blocked', credentials.reason);
    process.exit(2);  // Exit code 2 = BLOCK
  }
  success('No protected credential changes 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
});