import { CommandDiscoveryService, CommandRegistry } from '../lib/command-discovery';

/**
 * Utility class for working with the command registry
 */
export class CommandRegistryUtil {
  private static instance: CommandRegistryUtil;
  private registry: CommandRegistry | null = null;
  private discoveryService: CommandDiscoveryService;

  private constructor() {
    this.discoveryService = new CommandDiscoveryService();
  }

  public static getInstance(): CommandRegistryUtil {
    if (!CommandRegistryUtil.instance) {
      CommandRegistryUtil.instance = new CommandRegistryUtil();
    }
    return CommandRegistryUtil.instance;
  }

  /**
   * Get the command registry (cached after first call)
   */
  public getRegistry(): CommandRegistry {
    if (!this.registry) {
      this.registry = this.discoveryService.discoverCommands();
    }
    return this.registry;
  }

  /**
   * Get all read-only commands for testing
   */
  public getReadOnlyCommands() {
    return this.getRegistry().readOnlyCommands;
  }

  /**
   * Get all state-changing commands
   */
  public getStateChangingCommands() {
    return this.getRegistry().stateChangingCommands;
  }

  /**
   * Get commands for a specific namespace
   */
  public getCommandsForNamespace(namespace: string) {
    return this.discoveryService.getCommandsForNamespace(namespace);
  }

  /**
   * Get a specific command
   */
  public getCommand(namespace: string, commandName: string) {
    return this.discoveryService.getCommand(namespace, commandName);
  }

  /**
   * Generate command signature for CLI execution
   */
  public generateCommandSignature(namespace: string, commandName: string): string | null {
    const command = this.getCommand(namespace, commandName);
    if (!command) {
      return null;
    }
    return this.discoveryService.generateCommandSignature(command);
  }

  /**
   * Get all available namespaces
   */
  public getNamespaces(): string[] {
    return this.getRegistry().namespaces;
  }

  /**
   * Print registry statistics
   */
  public printStats(): void {
    const registry = this.getRegistry();
    console.log('Command Registry Statistics:');
    console.log(`  Total commands: ${registry.commands.length}`);
    console.log(`  Namespaces: ${registry.namespaces.length} (${registry.namespaces.join(', ')})`);
    console.log(`  Read-only commands: ${registry.readOnlyCommands.length}`);
    console.log(`  State-changing commands: ${registry.stateChangingCommands.length}`);
  }

  /**
   * Refresh the registry (re-discover commands)
   */
  public refresh(): void {
    this.registry = null;
  }
}

// Export a singleton instance for convenience
export const commandRegistry = CommandRegistryUtil.getInstance();