#!/usr/bin/env node

/**
 * Context Monitor Hook - UserPromptSubmit hook
 * Monitors context usage and triggers backups when needed
 */

const fs = require('fs-extra');
const path = require('path');

// Add lib directory to require path
const libPath = path.join(__dirname, '..', 'lib');

const { ContextMonitor } = require(path.join(libPath, 'context-monitor'));
const { BackupManager } = require(path.join(libPath, 'backup-manager'));
const { SessionStateManager } = require(path.join(libPath, 'session-state'));

async function main() {
  try {
    // Read input from Claude Code
    let inputData = '';
    
    // Handle stdin input
    if (process.stdin.isTTY) {
      // If called directly for testing
      inputData = JSON.stringify({ prompt: 'test prompt', context_size: 1000 });
    } else {
      // Read from stdin
      process.stdin.setEncoding('utf8');
      
      for await (const chunk of process.stdin) {
        inputData += chunk;
      }
    }
    
    const input = JSON.parse(inputData);
    
    // Initialize components
    const contextMonitor = new ContextMonitor();
    const backupManager = new BackupManager();
    const sessionManager = new SessionStateManager();
    
    // Update context estimates from prompt
    contextMonitor.updateFromPrompt(input);
    
    // Check if backup should be triggered
    const backupDecision = contextMonitor.checkBackupTriggers('UserPromptSubmit', input);
    
    let message;
    
    if (backupDecision.shouldBackup) {
      // Execute backup
      const sessionState = await sessionManager.getSessionSummary();
      const backupResult = await backupManager.executeBackup(backupDecision, sessionState);
      
      // Record backup in session
      await sessionManager.addBackup(backupResult.backupId, {
        reason: backupDecision.reason,
        success: backupResult.success
      });
      
      // Add context snapshot
      await sessionManager.addContextSnapshot({
        usageRatio: contextMonitor.getContextUsageRatio(),
        promptCount: contextMonitor.promptCount,
        toolExecutions: contextMonitor.toolExecutions
      });
      
      // Notify about backup
      if (backupResult.success) {
        message = `Auto-backup created: ${backupDecision.reason} (usage: ${(contextMonitor.getContextUsageRatio() * 100).toFixed(1)}%)`;
      } else {
        message = `Backup attempted but failed: ${backupResult.error}`;
      }
    } else {
      message = `Context usage: ${(contextMonitor.getContextUsageRatio() * 100).toFixed(1)}%`;
    }
    
    // Always allow operation (this is a monitoring hook)
    const response = {
      allow: true,
      message
    };
    
    console.log(JSON.stringify(response));
    process.exit(0);
    
  } catch (error) {
    // Never block on errors - always allow operation
    const response = {
      allow: true,
      message: `Context monitor error: ${error.message}`
    };
    console.log(JSON.stringify(response));
    process.exit(0);
  }
}

// Handle unhandled promise rejections
process.on('unhandledRejection', (error) => {
  const response = {
    allow: true,
    message: `Context monitor error: ${error.message}`
  };
  console.log(JSON.stringify(response));
  process.exit(0);
});

main();