import type { ObservableInput } from 'rxjs';
import type { QueryClientOptions } from './QueryClient';

/**
 * Represents a request made by the QueryClient with its status, transaction details, arguments, options, and metadata.
 * @template TArgs The type of the arguments passed to the query function. Defaults to unknown.
 */
export type QueryClientRequest<TArgs = unknown> = {
  /** The current status of the request. */
  status: 'idle' | 'active' | 'failed' | 'complete';
  /** A unique identifier for the transaction. */
  transaction: string;
  /** Arguments passed to the query function. */
  args: TArgs;
  /** Optional configuration options for the query. */
  options?: QueryClientOptions;
  /** Timestamp when the request was created. */
  created: number;
  /** An array of timestamps marking the execution points of the request. */
  execution: Array<number>;
  /** An array of errors encountered during the request's lifecycle. */
  errors: Array<unknown>;
  /** An optional reference identifier. */
  ref?: string;
};

/**
 * Represents the result of a completed query, including the value returned and metadata.
 * @template TValue The type of the value returned by the query. Defaults to unknown.
 * @template TArgs The type of the arguments passed to the query function. Defaults to unknown.
 */
export type QueryClientResult<TValue = unknown, TArgs = unknown> = Omit<
  QueryClientRequest<TArgs>,
  'status'
> & {
  /** Status set to 'complete' to indicate the request has finished. */
  status: 'complete';
  /** Timestamp when the request was completed. */
  completed: number;
  /** Timestamp when the request was created. */
  created: number;
  /** The value returned by the query. */
  value: TValue;
};

/**
 * Represents the state of queries managed by the QueryClient, indexed by a unique key.
 * @template TArgs The type of the arguments passed to the query function. Defaults to unknown.
 */
export type QueryClientState<TArgs = unknown> = Record<string, QueryClientRequest<TArgs>>;

/**
 * Configuration options for retrying failed queries.
 */
export type RetryOptions = {
  /** The number of retry attempts. */
  count: number;
  /** The delay between retries, either as a fixed number of milliseconds or a function returning an ObservableInput. */
  delay: number | ((error: unknown) => ObservableInput<void>);
};

/**
 * Defines the function signature for a query function that the QueryClient can execute.
 * @template TType The expected return type of the query function. Defaults to unknown.
 * @template TArgs The type of the arguments passed to the query function. Defaults to unknown.
 * @param args Arguments to pass to the query function.
 * @param signal An optional AbortSignal to cancel the request.
 * @returns An ObservableInput of the expected return type.
 */
export type QueryFn<TType = unknown, TArgs = unknown> = (
  args: TArgs,
  signal?: AbortSignal,
) => ObservableInput<TType>;