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import { Codec, createCodec, metadata } from "../common/mod.ts"import { compact } from "./compact.ts"import { u32 } from "./int.ts"
const compactU32 = compact(u32)
type ArrayOfLength<  T,  L extends number,  A extends T[] = [],> = number extends L ? T[]  : L extends A["length"] ? A  : ArrayOfLength<T, L, [...A, T]>
export function sizedArray<L extends number, I, O>($el: Codec<I, O>, length: L): Codec<  Readonly<ArrayOfLength<I, L>>,  ArrayOfLength<O, L>> {  return createCodec({    _metadata: metadata("$.sizedArray", sizedArray, $el, length),    _staticSize: $el._staticSize * length,    _encode(buffer, value) {      for (let i = 0; i < value.length; i++) {        $el._encode(buffer, value[i]!)      }    },    _decode(buffer) {      const value: O[] = Array(length)      for (let i = 0; i < value.length; i++) {        value[i] = $el._decode(buffer)      }      return value as ArrayOfLength<O, L>    },    _assert(assert) {      assert.instanceof(this, Array)      assert.key(this, "length").equals(this, length)      for (let i = 0; i < length; i++) {        $el._assert(assert.key(this, i))      }    },  })}
export function array<I, O = I>($el: Codec<I, O>): Codec<readonly I[], O[]> {  return createCodec({    _metadata: metadata("$.array", array, $el),    _staticSize: compactU32._staticSize,    _encode(buffer, value) {      compactU32._encode(buffer, value.length)      if (value.length) {        buffer.pushAlloc(value.length * $el._staticSize)        for (let i = 0; i < value.length; i++) {          $el._encode(buffer, value[i]!)        }        buffer.popAlloc()      }    },    _decode(buffer) {      const length = compactU32._decode(buffer)      const value: O[] = Array(length)      for (let i = 0; i < value.length; i++) {        value[i] = $el._decode(buffer)      }      return value    },    _assert(assert) {      assert.instanceof(this, Array)      for (let i = 0; i < (assert.value as unknown[]).length; i++) {        $el._assert(assert.key(this, i))      }    },  })}
export const uint8Array: Codec<Uint8Array> = createCodec({  _metadata: metadata("$.uint8Array"),  _staticSize: compactU32._staticSize,  _encode(buffer, value) {    compactU32._encode(buffer, value.length)    buffer.insertArray(value) // the contents of this will eventually be cloned by buffer  },  _decode(buffer) {    const length = compactU32._decode(buffer)    const value = buffer.array.subarray(buffer.index, buffer.index + length)    buffer.index += length    return value  },  _assert(assert) {    assert.instanceof(this, Uint8Array)  },})
export function sizedUint8Array(length: number): Codec<Uint8Array> {  return createCodec({    _metadata: metadata("$.sizedUint8Array", sizedUint8Array, length),    // We could set `_staticSize` to `length`, but in this case it will usually    // more efficient to insert the array dynamically, rather than manually copy    // the bytes.    _staticSize: 0,    _encode(buffer, value) {      buffer.insertArray(value) // the contents of this will eventually be cloned by buffer    },    _decode(buffer) {      return buffer.array.subarray(buffer.index, buffer.index += length)    },    _assert(assert) {      assert.instanceof(this, Uint8Array)      assert.key(this, "length").equals(this, length)    },  })}