import React, { PropsWithChildren } from "react";
import { IFlags } from "flagsmith";

export interface Flagsmith {
  /**
   * Denotes if Flagsmith is fully initialised and ready
   */
  isLoading: boolean;

  /**
   * Denotes if Flagsmith is in an errored state
   */
  isError: boolean;

  /**
   * Denotes if Flagsmith is evaluating flags for a specific user
   */
  isIdentified: boolean;

  /**
   * Denotes if Flagsmith is listening for changes
   */
  isListening: boolean;

  /**
   * Identify user, triggers a call to get flags if flagsmith.init has been called
   */
  identify: (userId: string, traits?: Record<string, string|number|boolean>) => Promise<IFlags | undefined>;

  /**
   * Clears the identity, triggers a call to getFlags
   */
  logout: () => Promise<IFlags>;

  /**
   * Polls the flagsmith API, specify interval in ms
   */
  startListening: (interval?: number) => void;

  /**
   * Stops polling
   */
  stopListening: () => void;

  /**
   * Determine whether a flag is enabled e.g. flagsmith.hasFeature("powerUserFeature")
   */
  hasFeature: (key: string) => boolean;

  /**
   * Get the value of a particular remote config e.g. flagsmith.getValue("font_size")
   */
  getValue: (key: string) => string | number | boolean;

  /**
   * Attach a callback function that is notified whenever the Flagsmith state
   * changes (i.e. new flag evaluations are available)
   */
  subscribe: (callback: Function) => void;

  /**
   * Force a re-evaluation and fetch of flags
   */
  getFlags: () => Promise<IFlags>;

  /**
   * Get the value of a specific trait for the currently identified user
   */
  getTrait: (key: string) => string | number | boolean;

  /**
   * Set the value of a trait for the current user. Triggers a fetch of the flags
   */
  setTrait: (key: string, value: string | number | boolean) => Promise<IFlags>;

  /**
   * Increment the value of a trait for the current user. Triggers a fetch of the flags
   */
  incrementTrait: (key: string, incrementBy: number) => Promise<IFlags>;

  /**
   * Set a key value set of traits for a given user, triggers a fetch of the flags
   */
  setTraits: (
    traits: Record<string, string | number | boolean>
  ) => Promise<IFlags>;
}

/**
 * Hook function to access Flagsmith functionality
 */
export function useFlagsmith(): Flagsmith;

export declare type FlagsmithProviderProps = PropsWithChildren<{
  environmentId: string; // Flagsmith environmentId
  flagsmith?: Object; // Optional Flagsmith implementation
  asyncStorage?: Object; // Async storage implementation
  cacheFlags?: boolean; // Cache flags locally
  defaultFlags?: IFlags; // Default flags
  preventFetch?: boolean; // Prevent flags from being fetched
  api?: string; // Flagsmith api url
}>

export declare function FlagsmithProvider({}: FlagsmithProviderProps): React.ReactElement;