export type ChatToolSurface = 'site' | 'web' | 'internal';
export type ChatActivityState = 'running' | 'done' | 'error';

export interface ChatActivity {
  id: string;
  requestId?: string;
  name: string;
  surface: ChatToolSurface;
  state: ChatActivityState;
  label: string;
  target?: string;
  summary?: string;
  batchId?: string;
}

export interface ChatApprovalState {
  state: 'needed';
  tool: string;
  target?: string;
}

export type ThinkingTimelineEntry =
  | { id: string; kind: 'work_step'; label: string; state: ChatActivityState; source?: 'reasoning_summary' | 'tool' | 'approval' | 'preamble' }
  | { id: string; kind: 'tool'; name?: string; label: string; state: ChatActivityState; target?: string };

export interface FinalizedThinkingSummary {
  durationMs: number;
  activities: ChatActivity[];
  approvalState?: ChatApprovalState;
  timeline: ThinkingTimelineEntry[];
}

export type ChatBackendStreamEvent =
  | { type: 'work_step'; id: string; label: string; state?: 'done'; source?: 'reasoning_summary' }
  | { type: 'message_delta'; text: string }
  | { type: 'error'; message: string };

export type ChatRuntimeUiEvent =
  | { type: 'tool_start'; id: string; name: string; surface: ChatToolSurface; target?: string; batchId?: string; label?: string }
  | { type: 'tool_end'; id: string; ok: boolean; summary?: string; batchId?: string }
  | { type: 'approval'; id: string; state: 'needed' | 'granted' | 'rejected'; tool: string; target?: string; batchId?: string };