/**
 * @since 2.0.0
 */
import type { Chunk } from "./Chunk.js"
import type { Context } from "./Context.js"
import type { Either } from "./Either.js"
import type { Equal } from "./Equal.js"
import * as Dual from "./Function.js"
import type { HashMap } from "./HashMap.js"
import type { HashSet } from "./HashSet.js"
import * as internal from "./internal/differ.js"
import * as ChunkPatch from "./internal/differ/chunkPatch.js"
import * as ContextPatch from "./internal/differ/contextPatch.js"
import * as HashMapPatch from "./internal/differ/hashMapPatch.js"
import * as HashSetPatch from "./internal/differ/hashSetPatch.js"
import * as OrPatch from "./internal/differ/orPatch.js"
import * as ReadonlyArrayPatch from "./internal/differ/readonlyArrayPatch.js"
import type { Pipeable } from "./Pipeable.js"
import type * as Types from "./Types.js"

/**
 * @since 2.0.0
 * @category symbol
 */
export const TypeId: unique symbol = internal.DifferTypeId as TypeId

/**
 * @since 2.0.0
 * @category symbol
 */
export type TypeId = typeof TypeId

/**
 * A `Differ<Value, Patch>` knows how to compare an old value and new value of
 * type `Value` to produce a patch of type `Patch` that describes the
 * differences between those values. A `Differ` also knows how to apply a patch
 * to an old value to produce a new value that represents the old value updated
 * with the changes described by the patch.
 *
 * A `Differ` can be used to construct a `FiberRef` supporting compositional
 * updates using the `FiberRef.makePatch` constructor.
 *
 * The `Differ` companion object contains constructors for `Differ` values for
 * common data types such as `Chunk`, `HashMap`, and `HashSet``. In addition,
 * `Differ`values can be transformed using the `transform` operator and combined
 * using the `orElseEither` and `zip` operators. This allows creating `Differ`
 * values for arbitrarily complex data types compositionally.
 *
 * @since 2.0.0
 * @category models
 */
export interface Differ<in out Value, in out Patch> extends Pipeable {
  readonly [TypeId]: {
    readonly _V: Types.Invariant<Value>
    readonly _P: Types.Invariant<Patch>
  }
  readonly empty: Patch
  diff(oldValue: Value, newValue: Value): Patch
  combine(first: Patch, second: Patch): Patch
  patch(patch: Patch, oldValue: Value): Value
}

const ChunkPatchTypeId: unique symbol = ChunkPatch.ChunkPatchTypeId as Differ.Chunk.TypeId
const ContextPatchTypeId: unique symbol = ContextPatch.ContextPatchTypeId as Differ.Context.TypeId
const HashMapPatchTypeId: unique symbol = HashMapPatch.HashMapPatchTypeId as Differ.HashMap.TypeId
const HashSetPatchTypeId: unique symbol = HashSetPatch.HashSetPatchTypeId as Differ.HashSet.TypeId
const OrPatchTypeId: unique symbol = OrPatch.OrPatchTypeId as Differ.Or.TypeId
const ReadonlyArrayPatchTypeId: unique symbol = ReadonlyArrayPatch
  .ReadonlyArrayPatchTypeId as Differ.ReadonlyArray.TypeId

/**
 * @since 2.0.0
 */
export declare namespace Differ {
  /**
   * @since 2.0.0
   */
  export namespace Context {
    /**
     * @since 2.0.0
     * @category symbol
     */
    export type TypeId = typeof ContextPatchTypeId
    /**
     * A `Patch<Input, Output>` describes an update that transforms a `Env<Input>`
     * to a `Env<Output>` as a data structure. This allows combining updates to
     * different services in the environment in a compositional way.
     *
     * @since 2.0.0
     * @category models
     */
    export interface Patch<in Input, out Output> extends Equal {
      readonly [ContextPatchTypeId]: {
        readonly _Input: Types.Contravariant<Input>
        readonly _Output: Types.Covariant<Output>
      }
    }
  }

  /**
   * @since 2.0.0
   */
  export namespace Chunk {
    /**
     * @since 2.0.0
     * @category symbol
     */
    export type TypeId = typeof ChunkPatchTypeId
    /**
     * A patch which describes updates to a chunk of values.
     *
     * @since 2.0.0
     * @category models
     */
    export interface Patch<in out Value, in out Patch> extends Equal {
      readonly [ChunkPatchTypeId]: {
        readonly _Value: Types.Invariant<Value>
        readonly _Patch: Types.Invariant<Patch>
      }
    }
  }

  /**
   * @since 2.0.0
   */
  export namespace HashMap {
    /**
     * @since 2.0.0
     * @category symbol
     */
    export type TypeId = typeof HashMapPatchTypeId
    /**
     * A patch which describes updates to a map of keys and values.
     *
     * @since 2.0.0
     * @category models
     */
    export interface Patch<in out Key, in out Value, in out Patch> extends Equal {
      readonly [HashMapPatchTypeId]: {
        readonly _Key: Types.Invariant<Key>
        readonly _Value: Types.Invariant<Value>
        readonly _Patch: Types.Invariant<Patch>
      }
    }
  }

  /**
   * @since 2.0.0
   */
  export namespace HashSet {
    /**
     * @since 2.0.0
     * @category symbol
     */
    export type TypeId = typeof HashSetPatchTypeId
    /**
     * A patch which describes updates to a set of values.
     *
     * @since 2.0.0
     * @category models
     */
    export interface Patch<in out Value> extends Equal {
      readonly [HashSetPatchTypeId]: {
        readonly _Value: Types.Invariant<Value>
      }
    }
  }

  /**
   * @since 2.0.0
   */
  export namespace Or {
    /**
     * @since 2.0.0
     * @category symbol
     */
    export type TypeId = typeof OrPatchTypeId
    /**
     * A patch which describes updates to either one value or another.
     *
     * @since 2.0.0
     * @category models
     */
    export interface Patch<in out Value, in out Value2, in out Patch, in out Patch2> extends Equal {
      readonly [OrPatchTypeId]: {
        readonly _Value: Types.Invariant<Value>
        readonly _Value2: Types.Invariant<Value2>
        readonly _Patch: Types.Invariant<Patch>
        readonly _Patch2: Types.Invariant<Patch2>
      }
    }
  }

  /**
   * @since 2.0.0
   */
  export namespace ReadonlyArray {
    /**
     * @since 2.0.0
     * @category symbol
     */
    export type TypeId = typeof ReadonlyArrayPatchTypeId
    /**
     * A patch which describes updates to a ReadonlyArray of values.
     *
     * @since 2.0.0
     * @category models
     */
    export interface Patch<in out Value, in out Patch> extends Equal {
      readonly [ReadonlyArrayPatchTypeId]: {
        readonly _Value: Types.Invariant<Value>
        readonly _Patch: Types.Invariant<Patch>
      }
    }
  }
}

/**
 * An empty patch that describes no changes.
 *
 * @since 2.0.0
 * @category patch
 */
export const empty: <Value, Patch>(self: Differ<Value, Patch>) => Patch = (
  self
) => self.empty

/**
 * @since 2.0.0
 * @category patch
 */
export const diff: {
  /**
   * @since 2.0.0
   * @category patch
   */
  <Value>(oldValue: Value, newValue: Value): <Patch>(
    self: Differ<Value, Patch>
  ) => Patch
  /**
   * @since 2.0.0
   * @category patch
   */
  <Value, Patch>(self: Differ<Value, Patch>, oldValue: Value, newValue: Value): Patch
} = Dual.dual(
  3,
  <Value, Patch>(
    self: Differ<Value, Patch>,
    oldValue: Value,
    newValue: Value
  ): Patch => self.diff(oldValue, newValue)
)

/**
 * Combines two patches to produce a new patch that describes the updates of
 * the first patch and then the updates of the second patch. The combine
 * operation should be associative. In addition, if the combine operation is
 * commutative then joining multiple fibers concurrently will result in
 * deterministic `FiberRef` values.
 *
 * @since 2.0.0
 * @category patch
 */
export const combine: {
  /**
   * Combines two patches to produce a new patch that describes the updates of
   * the first patch and then the updates of the second patch. The combine
   * operation should be associative. In addition, if the combine operation is
   * commutative then joining multiple fibers concurrently will result in
   * deterministic `FiberRef` values.
   *
   * @since 2.0.0
   * @category patch
   */
  <Patch>(first: Patch, second: Patch): <Value>(
    self: Differ<Value, Patch>
  ) => Patch
  /**
   * Combines two patches to produce a new patch that describes the updates of
   * the first patch and then the updates of the second patch. The combine
   * operation should be associative. In addition, if the combine operation is
   * commutative then joining multiple fibers concurrently will result in
   * deterministic `FiberRef` values.
   *
   * @since 2.0.0
   * @category patch
   */
  <Value, Patch>(self: Differ<Value, Patch>, first: Patch, second: Patch): Patch
} = Dual.dual(
  3,
  <Value, Patch>(
    self: Differ<Value, Patch>,
    first: Patch,
    second: Patch
  ): Patch => self.combine(first, second)
)

/**
 * Applies a patch to an old value to produce a new value that is equal to the
 * old value with the updates described by the patch.
 *
 * @since 2.0.0
 * @category patch
 */
export const patch: {
  /**
   * Applies a patch to an old value to produce a new value that is equal to the
   * old value with the updates described by the patch.
   *
   * @since 2.0.0
   * @category patch
   */
  <Patch, Value>(patch: Patch, oldValue: Value): (
    self: Differ<Value, Patch>
  ) => Value
  /**
   * Applies a patch to an old value to produce a new value that is equal to the
   * old value with the updates described by the patch.
   *
   * @since 2.0.0
   * @category patch
   */
  <Patch, Value>(self: Differ<Value, Patch>, patch: Patch, oldValue: Value): Value
} = Dual.dual(
  3,
  <Patch, Value>(
    self: Differ<Value, Patch>,
    patch: Patch,
    oldValue: Value
  ): Value => self.patch(patch, oldValue)
)

/**
 * Constructs a new `Differ`.
 *
 * @since 2.0.0
 * @category constructors
 */
export const make: <Value, Patch>(params: {
  readonly empty: Patch
  readonly diff: (oldValue: Value, newValue: Value) => Patch
  readonly combine: (first: Patch, second: Patch) => Patch
  readonly patch: (patch: Patch, oldValue: Value) => Value
}) => Differ<Value, Patch> = internal.make

/**
 * Constructs a differ that knows how to diff `Env` values.
 *
 * @since 2.0.0
 * @category constructors
 */
export const environment: <A>() => Differ<
  Context<A>,
  Differ.Context.Patch<A, A>
> = internal.environment

/**
 * Constructs a differ that knows how to diff a `Chunk` of values given a
 * differ that knows how to diff the values.
 *
 * @since 2.0.0
 * @category constructors
 */
export const chunk: <Value, Patch>(
  differ: Differ<Value, Patch>
) => Differ<Chunk<Value>, Differ.Chunk.Patch<Value, Patch>> = internal.chunk

/**
 * Constructs a differ that knows how to diff a `HashMap` of keys and values given
 * a differ that knows how to diff the values.
 *
 * @since 2.0.0
 * @category constructors
 */
export const hashMap: <Key, Value, Patch>(
  differ: Differ<Value, Patch>
) => Differ<HashMap<Key, Value>, Differ.HashMap.Patch<Key, Value, Patch>> = internal.hashMap

/**
 * Constructs a differ that knows how to diff a `HashSet` of values.
 *
 * @since 2.0.0
 * @category constructors
 */
export const hashSet: <Value>() => Differ<
  HashSet<Value>,
  Differ.HashSet.Patch<Value>
> = internal.hashSet

/**
 * Combines this differ and the specified differ to produce a differ that
 * knows how to diff the sum of their values.
 *
 * @since 2.0.0
 */
export const orElseEither: {
  /**
   * Combines this differ and the specified differ to produce a differ that
   * knows how to diff the sum of their values.
   *
   * @since 2.0.0
   */
  <Value2, Patch2>(that: Differ<Value2, Patch2>): <Value, Patch>(
    self: Differ<Value, Patch>
  ) => Differ<
    Either<Value2, Value>,
    Differ.Or.Patch<Value, Value2, Patch, Patch2>
  >
  /**
   * Combines this differ and the specified differ to produce a differ that
   * knows how to diff the sum of their values.
   *
   * @since 2.0.0
   */
  <Value, Patch, Value2, Patch2>(self: Differ<Value, Patch>, that: Differ<Value2, Patch2>): Differ<
    Either<Value2, Value>,
    Differ.Or.Patch<Value, Value2, Patch, Patch2>
  >
} = internal.orElseEither

/**
 * Constructs a differ that knows how to diff a `ReadonlyArray` of values.
 *
 * @since 2.0.0
 * @category constructors
 */
export const readonlyArray: <Value, Patch>(
  differ: Differ<Value, Patch>
) => Differ<ReadonlyArray<Value>, Differ.ReadonlyArray.Patch<Value, Patch>> = internal.readonlyArray

/**
 * Transforms the type of values that this differ knows how to differ using
 * the specified functions that map the new and old value types to each other.
 *
 * @since 2.0.0
 */
export const transform: {
  /**
   * Transforms the type of values that this differ knows how to differ using
   * the specified functions that map the new and old value types to each other.
   *
   * @since 2.0.0
   */
  <Value, Value2>(
    options: {
      readonly toNew: (value: Value) => Value2
      readonly toOld: (value: Value2) => Value
    }
  ): <Patch>(self: Differ<Value, Patch>) => Differ<Value2, Patch>
  /**
   * Transforms the type of values that this differ knows how to differ using
   * the specified functions that map the new and old value types to each other.
   *
   * @since 2.0.0
   */
  <Value, Patch, Value2>(
    self: Differ<Value, Patch>,
    options: {
      readonly toNew: (value: Value) => Value2
      readonly toOld: (value: Value2) => Value
    }
  ): Differ<Value2, Patch>
} = internal.transform

/**
 * Constructs a differ that just diffs two values by returning a function that
 * sets the value to the new value. This differ does not support combining
 * multiple updates to the value compositionally and should only be used when
 * there is no compositional way to update them.
 *
 * @since 2.0.0
 */
export const update: <A>() => Differ<A, (a: A) => A> = internal.update

/**
 * A variant of `update` that allows specifying the function that will be used
 * to combine old values with new values.
 *
 * @since 2.0.0
 */
export const updateWith: <A>(f: (x: A, y: A) => A) => Differ<A, (a: A) => A> = internal.updateWith

/**
 * Combines this differ and the specified differ to produce a new differ that
 * knows how to diff the product of their values.
 *
 * @since 2.0.0
 */
export const zip: {
  /**
   * Combines this differ and the specified differ to produce a new differ that
   * knows how to diff the product of their values.
   *
   * @since 2.0.0
   */
  <Value2, Patch2>(that: Differ<Value2, Patch2>): <Value, Patch>(
    self: Differ<Value, Patch>
  ) => Differ<
    readonly [Value, Value2], // readonly because invariant
    readonly [Patch, Patch2] // readonly because invariant
  >
  /**
   * Combines this differ and the specified differ to produce a new differ that
   * knows how to diff the product of their values.
   *
   * @since 2.0.0
   */
  <Value, Patch, Value2, Patch2>(self: Differ<Value, Patch>, that: Differ<Value2, Patch2>): Differ<
    readonly [Value, Value2], // readonly because invariant
    readonly [Patch, Patch2] // readonly because invariant
  >
} = internal.zip