export type Provider = "openai-codex" | "zai" | "anthropic";

export type UsageUnit = "percent" | "tokens" | "requests" | "usd" | "minutes" | "bytes" | "unknown";

export type UsageStatus = "ok" | "warning" | "exhausted" | "unknown";

export interface UsageWindow {
  id: string;
  label: string;
  durationMs?: number;
  resetsAt?: number;
}

export interface UsageAmount {
  used?: number;
  limit?: number;
  remaining?: number;
  usedFraction?: number;
  remainingFraction?: number;
  unit: UsageUnit;
}

export interface UsageScope {
  provider: Provider;
  accountId?: string;
  projectId?: string;
  orgId?: string;
  modelId?: string;
  tier?: string;
  windowId?: string;
  shared?: boolean;
}

export interface UsageLimit {
  id: string;
  label: string;
  scope: UsageScope;
  window?: UsageWindow;
  amount: UsageAmount;
  status?: UsageStatus;
  notes?: string[];
}

export interface UsageReport {
  provider: Provider;
  fetchedAt: number;
  limits: UsageLimit[];
  metadata?: Record<string, unknown>;
  raw?: unknown;
}

export interface UsageLogger {
  debug(message: string, meta?: Record<string, unknown>): void;
  warn(message: string, meta?: Record<string, unknown>): void;
}

export interface UsageCredential {
  type: "api_key" | "oauth";
  apiKey?: string;
  accessToken?: string;
  refreshToken?: string;
  expiresAt?: number;
  accountId?: string;
  projectId?: string;
  email?: string;
  enterpriseUrl?: string;
  metadata?: Record<string, unknown>;
}

export interface UsageFetchParams {
  provider: Provider;
  credential: UsageCredential;
  baseUrl?: string;
  signal?: AbortSignal;
}

export interface UsageFetchContext {
  fetch: typeof fetch;
  logger?: UsageLogger;
}

export interface UsageProvider {
  id: Provider;
  fetchUsage(params: UsageFetchParams, ctx: UsageFetchContext): Promise<UsageReport | null>;
  supports?(params: UsageFetchParams): boolean;
}

export interface CredentialRankingStrategy {
  findWindowLimits(report: UsageReport): {
    primary?: UsageLimit;
    secondary?: UsageLimit;
  };
  windowDefaults: {
    primaryMs: number;
    secondaryMs: number;
  };
  hasPriorityBoost?(primary: UsageLimit | undefined): boolean;
}