export type Brand<T, Name extends string> = T & { readonly __brand: Name };

export type UserId = Brand<string, 'UserId'>;
export type HotelId = Brand<string, 'HotelId'>;
export type ConversationId = Brand<string, 'ConversationId'>;
export type MessageId = Brand<string, 'MessageId'>;
export type SkillId = Brand<string, 'SkillId'>;
export type TaskId = Brand<string, 'TaskId'>;
export type ExecutionId = Brand<string, 'ExecutionId'>;

export interface User {
  id: UserId;
  name: string;
  avatar?: string;
  email?: string;
  phone?: string;
  hotels: HotelMembership[];
}

export interface HotelMembership {
  hotelId: HotelId;
  role: 'owner' | 'manager' | 'staff' | 'viewer';
}

export interface Hotel {
  id: HotelId;
  name: string;
  brand?: string;
  city: string;
  ota: HotelOTABinding[];
}

export interface HotelOTABinding {
  ota: 'ctrip' | 'meituan' | 'booking' | 'agoda' | 'qunar' | string;
  externalId: string;
  enabled: boolean;
}

export type MessageRole = 'user' | 'assistant' | 'system' | 'tool';

export interface Message {
  id: MessageId;
  conversationId: ConversationId;
  role: MessageRole;
  blocks: ContentBlock[];
  createdAt: number;
}

export type ContentBlock =
  | TextBlock
  | ToolCallBlock
  | ToolResultBlock
  | ArtifactBlock
  | ReasoningBlock;

export interface TextBlock {
  type: 'text';
  text: string;
}

export interface ReasoningBlock {
  type: 'reasoning';
  text: string;
}

export interface ToolCallBlock {
  type: 'tool_call';
  toolCallId: string;
  name: string;
  input: Record<string, unknown>;
}

export interface ToolResultBlock {
  type: 'tool_result';
  toolCallId: string;
  status: 'success' | 'failed';
  output: unknown;
  error?: KernelError;
}

export interface ArtifactBlock {
  type: 'artifact';
  artifact: Artifact;
}

export type Artifact =
  | { kind: 'markdown'; id: string; title?: string; content: string }
  | { kind: 'table'; id: string; title?: string; columns: string[]; rows: unknown[][] }
  | { kind: 'chart'; id: string; title?: string; spec: unknown }
  | { kind: 'image'; id: string; title?: string; url: string }
  | { kind: 'file'; id: string; title?: string; url: string; mime: string };

export interface KernelError {
  code: KernelErrorCode;
  message: string;
  retryable: boolean;
  cause?: unknown;
}

export type KernelErrorCode =
  | 'kernel_unavailable'
  | 'kernel_timeout'
  | 'kernel_aborted'
  | 'auth_required'
  | 'permission_denied'
  | 'skill_not_found'
  | 'skill_execution_failed'
  | 'invalid_input'
  | 'rate_limited'
  | 'unknown';

export interface Conversation {
  id: ConversationId;
  title: string;
  hotelId: HotelId;
  createdAt: number;
  updatedAt: number;
  messageCount: number;
}

export interface CreateConversationInput {
  hotelId: HotelId;
  title?: string;
}

export interface SendMessageInput {
  conversationId: ConversationId;
  content: TextBlock | { type: 'invoke_skill'; skillId: SkillId; input: Record<string, unknown> };
}

export type ConversationStreamEvent =
  | { type: 'message_start'; message: Pick<Message, 'id' | 'role' | 'createdAt'> }
  | { type: 'text_delta'; messageId: MessageId; delta: string }
  | { type: 'reasoning_delta'; messageId: MessageId; delta: string }
  | { type: 'tool_call'; messageId: MessageId; block: ToolCallBlock }
  | { type: 'tool_result'; messageId: MessageId; block: ToolResultBlock }
  | { type: 'artifact'; messageId: MessageId; artifact: Artifact }
  | { type: 'message_complete'; messageId: MessageId; message: Message }
  | { type: 'error'; error: KernelError };

export interface ConversationPort {
  list(query?: { hotelId?: HotelId; limit?: number }): Promise<Conversation[]>;
  get(id: ConversationId): Promise<Conversation>;
  create(input: CreateConversationInput): Promise<Conversation>;
  delete(id: ConversationId): Promise<void>;
  send(input: SendMessageInput): AsyncIterable<ConversationStreamEvent>;
  abort(conversationId: ConversationId): Promise<void>;
  history(conversationId: ConversationId, opts?: { before?: MessageId; limit?: number }): Promise<Message[]>;
}

export interface Adapter {
  readonly info: { name: string; kernelVersion: string };
  connect(): Promise<void>;
  disconnect(): Promise<void>;
  health(): Promise<{ ready: boolean; details?: Record<string, unknown> }>;
  readonly conversation: ConversationPort;
}

export type AdapterFactory<Config> = (config: Config) => Adapter;