Codewalkers/src/events/types.ts

/**
 * Event Bus Types
 *
 * Port interface for the event bus - the backbone of the hexagonal architecture.
 * EventBus is the PORT. Implementations (EventEmitterBus, RabbitMQ, etc.) are ADAPTERS.
 */

/**
 * Base interface for all domain events.
 * Every event in the system extends this.
 */
export interface DomainEvent {
  /** Event type identifier (e.g., 'process:spawned', 'server:started') */
  type: string;
  /** When the event occurred */
  timestamp: Date;
  /** Event-specific data */
  payload: unknown;
}

/**
 * Event Bus Port Interface
 *
 * All modules communicate through this interface.
 * Can be swapped for external systems (RabbitMQ, WebSocket forwarding) later.
 */
// =============================================================================
// Domain Event Types - Typed payloads for each event
// =============================================================================

/**
 * Process Events
 */

export interface ProcessSpawnedEvent extends DomainEvent {
  type: 'process:spawned';
  payload: {
    processId: string;
    pid: number;
    command: string;
  };
}

export interface ProcessStoppedEvent extends DomainEvent {
  type: 'process:stopped';
  payload: {
    processId: string;
    pid: number;
    exitCode: number | null;
  };
}

export interface ProcessCrashedEvent extends DomainEvent {
  type: 'process:crashed';
  payload: {
    processId: string;
    pid: number;
    signal: string | null;
  };
}

/**
 * Server Events
 */

export interface ServerStartedEvent extends DomainEvent {
  type: 'server:started';
  payload: {
    port: number;
    host: string;
    pid: number;
  };
}

export interface ServerStoppedEvent extends DomainEvent {
  type: 'server:stopped';
  payload: {
    uptime: number;
  };
}

/**
 * Log Events
 */

export interface LogEntryEvent extends DomainEvent {
  type: 'log:entry';
  payload: {
    processId: string;
    stream: 'stdout' | 'stderr';
    data: string;
  };
}

/**
 * Git Worktree Events
 */

export interface WorktreeCreatedEvent extends DomainEvent {
  type: 'worktree:created';
  payload: {
    worktreeId: string;
    branch: string;
    path: string;
  };
}

export interface WorktreeRemovedEvent extends DomainEvent {
  type: 'worktree:removed';
  payload: {
    worktreeId: string;
    branch: string;
  };
}

export interface WorktreeMergedEvent extends DomainEvent {
  type: 'worktree:merged';
  payload: {
    worktreeId: string;
    sourceBranch: string;
    targetBranch: string;
  };
}

export interface WorktreeConflictEvent extends DomainEvent {
  type: 'worktree:conflict';
  payload: {
    worktreeId: string;
    sourceBranch: string;
    targetBranch: string;
    conflictingFiles: string[];
  };
}

/**
 * Agent Events
 */

export interface AgentSpawnedEvent extends DomainEvent {
  type: 'agent:spawned';
  payload: {
    agentId: string;
    name: string;
    taskId: string;
    worktreeId: string;
  };
}

export interface AgentStoppedEvent extends DomainEvent {
  type: 'agent:stopped';
  payload: {
    agentId: string;
    name: string;
    taskId: string;
    reason: 'user_requested' | 'task_complete' | 'error' | 'waiting_for_input';
  };
}

export interface AgentCrashedEvent extends DomainEvent {
  type: 'agent:crashed';
  payload: {
    agentId: string;
    name: string;
    taskId: string;
    error: string;
  };
}

export interface AgentResumedEvent extends DomainEvent {
  type: 'agent:resumed';
  payload: {
    agentId: string;
    name: string;
    taskId: string;
    sessionId: string;
  };
}

export interface AgentWaitingEvent extends DomainEvent {
  type: 'agent:waiting';
  payload: {
    agentId: string;
    name: string;
    taskId: string;
    sessionId: string;
    question: string;  // The question being asked
  };
}

/**
 * Union of all domain events - enables type-safe event handling
 */
export type DomainEventMap =
  | ProcessSpawnedEvent
  | ProcessStoppedEvent
  | ProcessCrashedEvent
  | ServerStartedEvent
  | ServerStoppedEvent
  | LogEntryEvent
  | WorktreeCreatedEvent
  | WorktreeRemovedEvent
  | WorktreeMergedEvent
  | WorktreeConflictEvent
  | AgentSpawnedEvent
  | AgentStoppedEvent
  | AgentCrashedEvent
  | AgentResumedEvent
  | AgentWaitingEvent;

/**
 * Event type literal union for type checking
 */
export type DomainEventType = DomainEventMap['type'];

// =============================================================================
// Event Bus Port Interface
// =============================================================================

/**
 * Event Bus Port Interface
 *
 * All modules communicate through this interface.
 * Can be swapped for external systems (RabbitMQ, WebSocket forwarding) later.
 */
export interface EventBus {
  /**
   * Emit an event to all subscribed handlers
   */
  emit<T extends DomainEvent>(event: T): void;

  /**
   * Subscribe to events of a specific type
   */
  on<T extends DomainEvent>(
    eventType: T['type'],
    handler: (event: T) => void
  ): void;

  /**
   * Unsubscribe from events of a specific type
   */
  off<T extends DomainEvent>(
    eventType: T['type'],
    handler: (event: T) => void
  ): void;

  /**
   * Subscribe to a single occurrence of an event type
   */
  once<T extends DomainEvent>(
    eventType: T['type'],
    handler: (event: T) => void
  ): void;
}