export declare const make: <Key, Environment, Error, Value>(options: {
  readonly capacity: number
  readonly timeToLive: Duration.DurationInput
  readonly lookup: Lookup<Key, Environment, Error, Value>
}) => Effect.Effect<Environment, never, Cache<Key, Error, Value>>

export declare const makeCacheStats: (options: {
  readonly hits: number
  readonly misses: number
  readonly size: number
}) => CacheStats

export declare const makeEntryStats: (loadedMillis: number) => EntryStats

export declare const makeWith: <Key, Environment, Error, Value>(options: {
  readonly capacity: number
  readonly lookup: Lookup<Key, Environment, Error, Value>
  readonly timeToLive: (exit: Exit.Exit<Error, Value>) => Duration.DurationInput
}) => Effect.Effect<Environment, never, Cache<Key, Error, Value>>

export interface Cache<Key, Error, Value> extends ConsumerCache<Key, Error, Value> {
  /**
   * Retrieves the value associated with the specified key if it exists.
   * Otherwise computes the value with the lookup function, puts it in the
   * cache, and returns it.
   */
  get(key: Key): Effect.Effect<never, Error, Value>

  /**
   * Retrieves the value associated with the specified key if it exists as a left.
   * Otherwise computes the value with the lookup function, puts it in the
   * cache, and returns it as a right.
   */
  getEither(key: Key): Effect.Effect<never, Error, Either<Value, Value>>

  /**
   * Computes the value associated with the specified key, with the lookup
   * function, and puts it in the cache. The difference between this and
   * `get` method is that `refresh` triggers (re)computation of the value
   * without invalidating it in the cache, so any request to the associated
   * key can still be served while the value is being re-computed/retrieved
   * by the lookup function. Additionally, `refresh` always triggers the
   * lookup function, disregarding the last `Error`.
   */
  refresh(key: Key): Effect.Effect<never, Error, void>

  /**
   * Associates the specified value with the specified key in the cache.
   */
  set<Key, Error, Value>(this: Cache<Key, Error, Value>, key: Key, value: Value): Effect.Effect<never, never, void>
}

export interface CacheStats {
  readonly hits: number
  readonly misses: number
  readonly size: number
}

export interface ConsumerCache<Key, Error, Value> extends Cache.Variance<Key, Error, Value> {
  /**
   * Retrieves the value associated with the specified key if it exists.
   * Otherwise returns `Option.none`.
   */
  getOption(key: Key): Effect.Effect<never, Error, Option.Option<Value>>

  /**
   * Retrieves the value associated with the specified key if it exists and the
   * lookup function has completed. Otherwise returns `Option.none`.
   */
  getOptionComplete(key: Key): Effect.Effect<never, never, Option.Option<Value>>

  /**
   * Returns statistics for this cache.
   */
  cacheStats(): Effect.Effect<never, never, CacheStats>

  /**
   * Returns whether a value associated with the specified key exists in the
   * cache.
   */
  contains(key: Key): Effect.Effect<never, never, boolean>

  /**
   * Returns statistics for the specified entry.
   */
  entryStats(key: Key): Effect.Effect<never, never, Option.Option<EntryStats>>

  /**
   * Invalidates the value associated with the specified key.
   */
  invalidate(key: Key): Effect.Effect<never, never, void>

  /**
   * Invalidates the value associated with the specified key if the predicate holds.
   */
  invalidateWhen(key: Key, when: (value: Value) => boolean): Effect.Effect<never, never, void>

  /**
   * Invalidates all values in the cache.
   */
  invalidateAll(): Effect.Effect<never, never, void>

  /**
   * Returns the approximate number of values in the cache.
   */
  size(): Effect.Effect<never, never, number>

  /**
   * Returns an approximation of the values in the cache.
   */
  keys<Key, Error, Value>(this: ConsumerCache<Key, Error, Value>): Effect.Effect<never, never, Array<Key>>

  /**
   * Returns an approximation of the values in the cache.
   */
  values(): Effect.Effect<never, never, Array<Value>>

  /**
   * Returns an approximation of the values in the cache.
   */
  entries<Key, Error, Value>(this: ConsumerCache<Key, Error, Value>): Effect.Effect<never, never, Array<[Key, Value]>>
}

export interface EntryStats {
  readonly loadedMillis: number
}

export type Lookup<Key, Environment, Error, Value> = (key: Key) => Effect.Effect<Environment, Error, Value>

export declare const CacheTypeId: typeof CacheTypeId

export type CacheTypeId = typeof CacheTypeId

export interface Variance<Key, Error, Value> {
  readonly [CacheTypeId]: {
    readonly _Key: (_: Key) => void
    readonly _Error: (_: never) => Error
    readonly _Value: (_: never) => Value
  }
}