/** Provider-neutral types used by the chat engine, router and UI. */

export type Provider = "openai" | "anthropic" | "local";

export type Capability = "text" | "vision" | "audioInput" | "audioOutput" | "imageGeneration" | "reasoning" | "tools" | "structuredOutput" | "streaming" | "longContext";
export type CapValue = boolean | "unknown";

export interface AIModel {
  id: string;
  provider: Provider;
  displayName: string;
  kind: string;
  api?: "responses" | "chat" | "messages" | null;
  status: "verified" | "unavailable" | "unsupported" | "untested";
  available: boolean;
  tested: boolean;
  unavailableReason?: string | null;
  capabilities: Partial<Record<Capability, CapValue>>;
  contextWindow?: number | null;
  maxOutputTokens?: number | null;
  pricing?: { input?: number; cachedInput?: number; output?: number; notes?: string; [k: string]: unknown } | null;
  benchmark?: {
    tests: number; passed: number; qualityScore: number | null; p50LatencyMs: number | null; p50TtftMs: number | null;
    totalCostUsd: number; avgOutputTokens: number | null; perTest: Record<string, "pass" | "fail" | "error">; errors: string[];
  } | null;
  hidden: boolean;
  favorite: boolean;
  lastVerifiedAt?: string | null;
}

// ---------------------------------------------------------------- message parts (stored in messages.parts)
export type Part =
  | { type: "text"; text: string }
  | { type: "reasoning"; text: string; summarized?: boolean }
  | { type: "image"; attachmentId: string; mime: string; name?: string; url?: string }
  | { type: "file"; attachmentId: string; mime: string; name: string; size?: number; pages?: number }
  | { type: "tool_call"; id: string; name: string; input: unknown; status: "pending_approval" | "running" | "ok" | "error" | "denied"; output?: unknown; durationMs?: number; error?: string }
  | { type: "artifact"; artifactId: string; title: string; artifactType: string; language?: string }
  | { type: "citation"; url: string; title?: string; snippet?: string }
  | { type: "generated_image"; attachmentId: string; prompt: string; model: string };

export type Role = "user" | "assistant" | "system" | "tool";

export interface UnifiedMessage { role: Role; parts: Part[]; id?: string }

export interface ToolDef {
  name: string;
  description: string;
  inputSchema: Record<string, unknown>; // JSON schema object
}

export interface ChatSettings {
  effort?: "low" | "medium" | "high" | "xhigh" | "max";
  maxOutputTokens?: number;
  temperature?: number; // only honoured where the provider still accepts it
  reasoningSummary?: boolean;
  toolsEnabled?: string[];
}

export interface ChatRequest {
  model: AIModel;
  system?: string;
  messages: UnifiedMessage[];
  tools?: ToolDef[];
  settings?: ChatSettings;
  signal?: AbortSignal;
  /** resolver for attachments referenced in parts → {bytes, mime} */
  loadAttachment: (id: string) => Promise<{ data: Buffer; mime: string; name: string; text?: string | null } | null>;
}

export interface Usage { input: number; output: number; cached?: number; reasoning?: number }

export type StreamEvent =
  | { type: "text"; delta: string }
  | { type: "reasoning"; delta: string }
  | { type: "tool_call"; id: string; name: string; input: unknown }
  | { type: "usage"; usage: Usage }
  | { type: "stop"; reason: string; details?: unknown }
  | { type: "error"; message: string; status?: number; retryable?: boolean }
  | { type: "meta"; data: Record<string, unknown> };

export interface ProviderAdapter {
  provider: Provider;
  stream(req: ChatRequest): AsyncGenerator<StreamEvent, void, void>;
}