/**
 * Type definitions for @geepers/chat
 */

// ========== Provider ==========

export type Provider =
  | 'xai'
  | 'anthropic'
  | 'openai'
  | 'cohere'
  | 'mistral'
  | 'perplexity'
  | 'huggingface'
  | 'gemini'
  | 'ollama';

export interface ProviderConfig {
  /** Model identifier string sent to the API Gateway */
  model: string;
  /** Human-readable display label */
  label: string;
}

// ========== Messages ==========

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

export interface Message {
  /** Unique message identifier */
  id: string;
  /** Sender role */
  role: MessageRole;
  /** Message text content */
  content: string;
  /** Unix timestamp (ms) when message was created */
  timestamp: number;
  /** Provider that generated this message (assistant only) */
  provider?: Provider;
}

// ========== Conversations ==========

export interface ConversationRecord {
  /** Unique conversation identifier (UUID v4) */
  id: string;
  /** Title derived from first user message */
  title: string;
  /** Ordered message history (excludes system prompt) */
  messages: Message[];
  /** Active provider when conversation was saved */
  provider: Provider;
  /** System prompt for this conversation (may be empty) */
  systemPrompt: string;
  /** Unix timestamp (ms) when conversation was created */
  createdAt: number;
  /** Unix timestamp (ms) when conversation was last modified */
  updatedAt: number;
}

// ========== Events ==========

export type ChatEventType =
  | 'message'
  | 'stream-chunk'
  | 'stream-start'
  | 'stream-end'
  | 'error'
  | 'conversation-change';

export interface MessageEvent {
  type: 'message';
  message: Message;
}

export interface StreamChunkEvent {
  type: 'stream-chunk';
  chunk: string;
  accumulated: string;
  messageId: string;
}

export interface StreamStartEvent {
  type: 'stream-start';
  messageId: string;
}

export interface StreamEndEvent {
  type: 'stream-end';
  message: Message;
}

export interface ErrorEvent {
  type: 'error';
  error: Error;
}

export interface ConversationChangeEvent {
  type: 'conversation-change';
  conversationId: string | null;
}

export type ChatEvent =
  | MessageEvent
  | StreamChunkEvent
  | StreamStartEvent
  | StreamEndEvent
  | ErrorEvent
  | ConversationChangeEvent;

export type ChatEventHandler<T extends ChatEvent = ChatEvent> = (event: T) => void;

// ========== Configuration ==========

export interface WelcomeHint {
  /** Short label shown on the hint chip button */
  label: string;
  /** Full text sent as the message when the hint is clicked */
  prompt: string;
}

export type ThemeMode = 'light' | 'dark' | 'auto';

export interface ChatConfig {
  /**
   * API Gateway base URL.
   * Defaults to 'https://api.dr.eamer.dev/v1' if not provided.
   */
  gateway?: string;

  /** API key sent as X-API-Key header. Falls back to localStorage 'api_key' if not set. */
  apiKey?: string;

  /** Initial provider selection. Defaults to 'xai'. */
  provider?: Provider;

  /** Initial model override. If omitted the default from MODELS[provider] is used. */
  model?: string;

  /** System prompt prepended to every conversation. */
  systemPrompt?: string;

  /** Initial conversation ID to restore. Loads from localStorage if found. */
  conversationId?: string;

  /** Theme preference. Defaults to 'auto' (respects OS preference). */
  theme?: ThemeMode;

  /**
   * Hint chips shown on the welcome screen.
   * Pass an empty array to disable the welcome screen entirely.
   */
  welcomeHints?: WelcomeHint[];

  /**
   * localStorage key prefix for conversation persistence.
   * Defaults to 'gchat_conversations'. Override to namespace multiple instances.
   */
  storageKey?: string;

  // ---- Lifecycle callbacks ----

  /** Called when an assistant message finishes streaming. */
  onMessage?: (message: Message) => void;

  /** Called when an error occurs (network, API, or parsing). */
  onError?: (error: Error) => void;

  /** Called immediately when a stream begins. */
  onStreamStart?: (messageId: string) => void;

  /** Called when a stream finishes (including aborted streams). */
  onStreamEnd?: (message: Message) => void;
}