// Copyright (c) 2022, 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.

import 'package:_js_interop_checks/src/js_interop.dart' as jsInteropHelper;
import 'package:_js_interop_checks/src/transformations/js_util_wasm_optimizer.dart';
import 'package:_js_interop_checks/src/transformations/static_interop_class_eraser.dart';
import 'package:kernel/ast.dart';
import 'package:kernel/class_hierarchy.dart';
import 'package:kernel/clone.dart';
import 'package:kernel/core_types.dart';
import 'package:kernel/reference_from_index.dart';
import 'package:kernel/target/changed_structure_notifier.dart';
import 'package:kernel/target/targets.dart';
import 'package:vm/transformations/mixin_full_resolution.dart'
    as transformMixins show transformLibraries;
import 'package:vm/transformations/ffi/common.dart' as ffiHelper
    show calculateTransitiveImportsOfDartFfiIfUsed;
import 'package:vm/transformations/ffi/definitions.dart'
    as transformFfiDefinitions show transformLibraries;
import 'package:vm/transformations/ffi/use_sites.dart' as transformFfiUseSites
    show transformLibraries;

import 'package:dart2wasm/transformers.dart' as wasmTrans;

class WasmTarget extends Target {
  Class? _growableList;
  Class? _immutableList;
  Class? _wasmImmutableLinkedHashMap;
  Class? _wasmImmutableLinkedHashSet;
  Class? _compactLinkedCustomHashMap;
  Class? _compactLinkedCustomHashSet;
  Class? _oneByteString;
  Class? _twoByteString;

  @override
  bool get enableNoSuchMethodForwarders => true;

  @override
  ConstantsBackend get constantsBackend => const ConstantsBackend();

  @override
  String get name => 'wasm';

  @override
  TargetFlags get flags => TargetFlags(enableNullSafety: true);

  @override
  List<String> get extraRequiredLibraries => const <String>[
        'dart:async',
        'dart:ffi',
        'dart:_internal',
        'dart:_http',
        'dart:_js_helper',
        'dart:typed_data',
        'dart:nativewrappers',
        'dart:io',
        'dart:js',
        'dart:js_util',
        'dart:wasm',
        'dart:developer',
      ];

  @override
  List<String> get extraIndexedLibraries => const <String>[
        'dart:_js_helper',
        'dart:collection',
        'dart:typed_data',
        'dart:js',
        'dart:js_util',
        'dart:wasm',
      ];

  void _patchHostEndian(CoreTypes coreTypes) {
    // Fix Endian.host to be a const field equal to Endian.little instead of
    // a final field. Wasm is a little-endian platform.
    // Can't use normal patching process for this because CFE does not
    // support patching fields.
    // See http://dartbug.com/32836 for the background.
    final Field host =
        coreTypes.index.getField('dart:typed_data', 'Endian', 'host');
    final Field little =
        coreTypes.index.getField('dart:typed_data', 'Endian', 'little');
    host.isConst = true;
    host.initializer = new CloneVisitorNotMembers().clone(little.initializer!)
      ..parent = host;
  }

  void _performJSInteropTransformations(
      CoreTypes coreTypes,
      ClassHierarchy hierarchy,
      List<Library> interopDependentLibraries,
      ReferenceFromIndex? referenceFromIndex) {
    final jsUtilOptimizer = JsUtilWasmOptimizer(coreTypes, hierarchy);
    final staticInteropClassEraser = StaticInteropClassEraser(
        coreTypes, referenceFromIndex,
        libraryForJavaScriptObject: 'dart:_js_helper',
        classNameOfJavaScriptObject: 'JSValue');
    for (Library library in interopDependentLibraries) {
      jsUtilOptimizer.visitLibrary(library);
      staticInteropClassEraser.visitLibrary(library);
    }
  }

  @override
  void performPreConstantEvaluationTransformations(
      Component component,
      CoreTypes coreTypes,
      List<Library> libraries,
      DiagnosticReporter diagnosticReporter,
      {void Function(String msg)? logger,
      ChangedStructureNotifier? changedStructureNotifier}) {
    _patchHostEndian(coreTypes);
  }

  @override
  void performModularTransformationsOnLibraries(
      Component component,
      CoreTypes coreTypes,
      ClassHierarchy hierarchy,
      List<Library> libraries,
      Map<String, String>? environmentDefines,
      DiagnosticReporter diagnosticReporter,
      ReferenceFromIndex? referenceFromIndex,
      {void logger(String msg)?,
      ChangedStructureNotifier? changedStructureNotifier}) {
    List<Library> transitiveImportingJSInterop = [
      ...?jsInteropHelper.calculateTransitiveImportsOfJsInteropIfUsed(
          component, Uri.parse("package:js/js.dart")),
      ...?jsInteropHelper.calculateTransitiveImportsOfJsInteropIfUsed(
          component, Uri.parse("dart:_js_annotations"))
    ];
    if (transitiveImportingJSInterop.isEmpty) {
      logger?.call("Skipped JS interop transformations");
    } else {
      _performJSInteropTransformations(coreTypes, hierarchy,
          transitiveImportingJSInterop, referenceFromIndex);
      logger?.call("Transformed JS interop classes");
    }
    transformMixins.transformLibraries(
        this, coreTypes, hierarchy, libraries, referenceFromIndex);
    logger?.call("Transformed mixin applications");

    List<Library>? transitiveImportingDartFfi = ffiHelper
        .calculateTransitiveImportsOfDartFfiIfUsed(component, libraries);
    if (transitiveImportingDartFfi == null) {
      logger?.call("Skipped ffi transformation");
    } else {
      transformFfiDefinitions.transformLibraries(
          component,
          coreTypes,
          hierarchy,
          transitiveImportingDartFfi,
          diagnosticReporter,
          referenceFromIndex,
          changedStructureNotifier);
      transformFfiUseSites.transformLibraries(component, coreTypes, hierarchy,
          transitiveImportingDartFfi, diagnosticReporter, referenceFromIndex);
      logger?.call("Transformed ffi annotations");
    }

    wasmTrans.transformLibraries(libraries, coreTypes, hierarchy);
  }

  @override
  void performTransformationsOnProcedure(
      CoreTypes coreTypes,
      ClassHierarchy hierarchy,
      Procedure procedure,
      Map<String, String>? environmentDefines,
      {void logger(String msg)?}) {
    wasmTrans.transformProcedure(procedure, coreTypes, hierarchy);
  }

  Expression _instantiateInvocation(
      CoreTypes coreTypes, String name, Arguments arguments) {
    if (name.startsWith("set:")) {
      name = name.substring(4);
      Procedure invocationSetter = coreTypes.invocationClass.procedures
          .firstWhere((c) => c.name.text == "setter");
      return StaticInvocation(invocationSetter,
          Arguments([SymbolLiteral(name), arguments.positional.single]));
    } else if (name.startsWith("get:")) {
      Procedure invocationGetter = coreTypes.invocationClass.procedures
          .firstWhere((c) => c.name.text == "getter");
      return StaticInvocation(
          invocationGetter, Arguments([SymbolLiteral(name)]));
    } else if (arguments.types.isEmpty) {
      Procedure invocationMethod = coreTypes.invocationClass.procedures
          .firstWhere((c) => c.name.text == "method");
      return StaticInvocation(
          invocationMethod,
          Arguments([
            SymbolLiteral(name),
            ListLiteral(arguments.positional),
            MapLiteral(List<MapLiteralEntry>.from(
                arguments.named.map((NamedExpression arg) {
              return MapLiteralEntry(SymbolLiteral(arg.name), arg.value);
            })), keyType: coreTypes.symbolNonNullableRawType)
              ..isConst = (arguments.named.isEmpty)
          ]));
    } else {
      Procedure invocationGenericMethod = coreTypes.invocationClass.procedures
          .firstWhere((c) => c.name.text == "genericMethod");
      return StaticInvocation(
          invocationGenericMethod,
          Arguments([
            SymbolLiteral(name),
            ListLiteral(arguments.types.map((t) => TypeLiteral(t)).toList()),
            ListLiteral(arguments.positional),
            MapLiteral(List<MapLiteralEntry>.from(
                arguments.named.map((NamedExpression arg) {
              return new MapLiteralEntry(SymbolLiteral(arg.name), arg.value);
            })), keyType: coreTypes.symbolNonNullableRawType)
              ..isConst = (arguments.named.isEmpty)
          ]));
    }
  }

  @override
  Expression instantiateInvocation(CoreTypes coreTypes, Expression receiver,
      String name, Arguments arguments, int offset, bool isSuper) {
    return _instantiateInvocation(coreTypes, name, arguments);
  }

  Expression instantiateNoSuchMethodError(CoreTypes coreTypes,
      Expression receiver, String name, Arguments arguments, int offset,
      {bool isMethod: false,
      bool isGetter: false,
      bool isSetter: false,
      bool isField: false,
      bool isLocalVariable: false,
      bool isDynamic: false,
      bool isSuper: false,
      bool isStatic: false,
      bool isConstructor: false,
      bool isTopLevel: false}) {
    return ConstructorInvocation(
        coreTypes.noSuchMethodErrorDefaultConstructor,
        Arguments(
            [receiver, _instantiateInvocation(coreTypes, name, arguments)]));
  }

  @override
  bool get supportsSetLiterals => true;

  @override
  int get enabledLateLowerings => LateLowering.all;

  @override
  int get enabledConstructorTearOffLowerings => ConstructorTearOffLowering.all;

  @override
  bool get supportsExplicitGetterCalls => true;

  @override
  bool get supportsLateLoweringSentinel => false;

  @override
  bool get useStaticFieldLowering => false;

  @override
  bool enableNative(Uri uri) => true;

  @override
  Class concreteListLiteralClass(CoreTypes coreTypes) {
    return _growableList ??=
        coreTypes.index.getClass('dart:core', '_GrowableList');
  }

  @override
  Class concreteConstListLiteralClass(CoreTypes coreTypes) {
    return _immutableList ??=
        coreTypes.index.getClass('dart:core', '_ImmutableList');
  }

  @override
  Class concreteMapLiteralClass(CoreTypes coreTypes) {
    return _compactLinkedCustomHashMap ??= coreTypes.index
        .getClass('dart:collection', '_CompactLinkedCustomHashMap');
  }

  @override
  Class concreteConstMapLiteralClass(CoreTypes coreTypes) {
    return _wasmImmutableLinkedHashMap ??= coreTypes.index
        .getClass('dart:collection', '_WasmImmutableLinkedHashMap');
  }

  @override
  Class concreteSetLiteralClass(CoreTypes coreTypes) {
    return _compactLinkedCustomHashSet ??= coreTypes.index
        .getClass('dart:collection', '_CompactLinkedCustomHashSet');
  }

  @override
  Class concreteConstSetLiteralClass(CoreTypes coreTypes) {
    return _wasmImmutableLinkedHashSet ??= coreTypes.index
        .getClass('dart:collection', '_WasmImmutableLinkedHashSet');
  }

  @override
  Class concreteStringLiteralClass(CoreTypes coreTypes, String value) {
    const int maxLatin1 = 0xff;
    for (int i = 0; i < value.length; ++i) {
      if (value.codeUnitAt(i) > maxLatin1) {
        return _twoByteString ??=
            coreTypes.index.getClass('dart:core', '_TwoByteString');
      }
    }
    return _oneByteString ??=
        coreTypes.index.getClass('dart:core', '_OneByteString');
  }

  @override
  bool isSupportedPragma(String pragmaName) => pragmaName.startsWith("wasm:");
}