// Copyright (c) 2020, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

/* <GEN_DOC> */

import 'dart:convert';
import 'dart:ffi';
import 'dart:typed_data';

// wasm_valkind_enum
const int WasmerValKindI32 = 0;
const int WasmerValKindI64 = 1;
const int WasmerValKindF32 = 2;
const int WasmerValKindF64 = 3;
// The void tag is not part of the C API. It's used to represent the return type
// of a void function.
const int WasmerValKindVoid = -1;

// wasm_externkind_enum
const int WasmerExternKindFunction = 0;
const int WasmerExternKindGlobal = 1;
const int WasmerExternKindTable = 2;
const int WasmerExternKindMemory = 3;

String wasmerExternKindName(int kind) {
  switch (kind) {
    case WasmerExternKindFunction:
      return "function";
    case WasmerExternKindGlobal:
      return "global";
    case WasmerExternKindTable:
      return "table";
    case WasmerExternKindMemory:
      return "memory";
    default:
      return "unknown";
  }
}

String wasmerValKindName(int kind) {
  switch (kind) {
    case WasmerValKindI32:
      return "int32";
    case WasmerValKindI64:
      return "int64";
    case WasmerValKindF32:
      return "float32";
    case WasmerValKindF64:
      return "float64";
    case WasmerValKindVoid:
      return "void";
    default:
      return "unknown";
  }
}

// wasm_val_t
class WasmerVal extends Struct {
  // wasm_valkind_t
  @Uint8()
  external int kind;

  // This is a union of int32_t, int64_t, float, and double. The kind determines
  // which type it is. It's declared as an int64_t because that's large enough
  // to hold all the types. We use ByteData to get the other types.
  @Int64()
  external int value;

  int get _off32 => Endian.host == Endian.little ? 0 : 4;
  int get i64 => value;
  ByteData get _getterBytes => ByteData(8)..setInt64(0, value, Endian.host);
  int get i32 => _getterBytes.getInt32(_off32, Endian.host);
  double get f32 => _getterBytes.getFloat32(_off32, Endian.host);
  double get f64 => _getterBytes.getFloat64(0, Endian.host);

  set i64(int val) => value = val;
  set _val(ByteData bytes) => value = bytes.getInt64(0, Endian.host);
  set i32(int val) => _val = ByteData(8)..setInt32(_off32, val, Endian.host);
  set f32(num val) =>
      _val = ByteData(8)..setFloat32(_off32, val as double, Endian.host);
  set f64(num val) =>
      _val = ByteData(8)..setFloat64(0, val as double, Endian.host);

  bool get isI32 => kind == WasmerValKindI32;
  bool get isI64 => kind == WasmerValKindI64;
  bool get isF32 => kind == WasmerValKindF32;
  bool get isF64 => kind == WasmerValKindF64;

  dynamic get toDynamic {
    switch (kind) {
      case WasmerValKindI32:
        return i32;
      case WasmerValKindI64:
        return i64;
      case WasmerValKindF32:
        return f32;
      case WasmerValKindF64:
        return f64;
    }
  }
}

// wasmer_limits_t
class WasmerLimits extends Struct {
  @Uint32()
  external int min;

  @Uint32()
  external int max;
}

// Default maximum, which indicates no upper limit.
const int wasm_limits_max_default = 0xffffffff;

/* <WASMER_API> */