// Copyright 2021 The Tint Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef SRC_RESOLVER_RESOLVER_TEST_HELPER_H_
#define SRC_RESOLVER_RESOLVER_TEST_HELPER_H_

#include <memory>
#include <string>
#include <vector>

#include "gtest/gtest.h"
#include "src/program_builder.h"
#include "src/resolver/resolver.h"
#include "src/sem/expression.h"
#include "src/sem/statement.h"
#include "src/sem/variable.h"

namespace tint {
namespace resolver {

/// Helper class for testing
class TestHelper : public ProgramBuilder {
 public:
  /// Constructor
  TestHelper();

  /// Destructor
  ~TestHelper() override;

  /// @return a pointer to the Resolver
  Resolver* r() const { return resolver_.get(); }

  /// Returns the statement that holds the given expression.
  /// @param expr the ast::Expression
  /// @return the ast::Statement of the ast::Expression, or nullptr if the
  /// expression is not owned by a statement.
  const ast::Statement* StmtOf(ast::Expression* expr) {
    auto* sem_stmt = Sem().Get(expr)->Stmt();
    return sem_stmt ? sem_stmt->Declaration() : nullptr;
  }

  /// Returns the BlockStatement that holds the given statement.
  /// @param stmt the ast::Statment
  /// @return the ast::BlockStatement that holds the ast::Statement, or nullptr
  /// if the statement is not owned by a BlockStatement.
  const ast::BlockStatement* BlockOf(ast::Statement* stmt) {
    auto* sem_stmt = Sem().Get(stmt);
    return sem_stmt ? sem_stmt->Block()->Declaration() : nullptr;
  }

  /// Returns the BlockStatement that holds the given expression.
  /// @param expr the ast::Expression
  /// @return the ast::Statement of the ast::Expression, or nullptr if the
  /// expression is not indirectly owned by a BlockStatement.
  const ast::BlockStatement* BlockOf(ast::Expression* expr) {
    auto* sem_stmt = Sem().Get(expr)->Stmt();
    return sem_stmt ? sem_stmt->Block()->Declaration() : nullptr;
  }

  /// Returns the semantic variable for the given identifier expression.
  /// @param expr the identifier expression
  /// @return the resolved sem::Variable of the identifier, or nullptr if
  /// the expression did not resolve to a variable.
  const sem::Variable* VarOf(ast::Expression* expr) {
    auto* sem_ident = Sem().Get(expr);
    auto* var_user = sem_ident ? sem_ident->As<sem::VariableUser>() : nullptr;
    return var_user ? var_user->Variable() : nullptr;
  }

  /// Checks that all the users of the given variable are as expected
  /// @param var the variable to check
  /// @param expected_users the expected users of the variable
  /// @return true if all users are as expected
  bool CheckVarUsers(ast::Variable* var,
                     std::vector<ast::Expression*>&& expected_users) {
    auto& var_users = Sem().Get(var)->Users();
    if (var_users.size() != expected_users.size()) {
      return false;
    }
    for (size_t i = 0; i < var_users.size(); i++) {
      if (var_users[i]->Declaration() != expected_users[i]) {
        return false;
      }
    }
    return true;
  }

  /// @param type a type
  /// @returns the name for `type` that closely resembles how it would be
  /// declared in WGSL.
  std::string FriendlyName(const ast::Type* type) {
    return type->FriendlyName(Symbols());
  }

  /// @param type a type
  /// @returns the name for `type` that closely resembles how it would be
  /// declared in WGSL.
  std::string FriendlyName(const sem::Type* type) {
    return type->FriendlyName(Symbols());
  }

 private:
  std::unique_ptr<Resolver> resolver_;
};

class ResolverTest : public TestHelper, public testing::Test {};

template <typename T>
class ResolverTestWithParam : public TestHelper,
                              public testing::TestWithParam<T> {};

namespace builder {

using i32 = ProgramBuilder::i32;
using u32 = ProgramBuilder::u32;
using f32 = ProgramBuilder::f32;

template <int N, typename T>
struct vec {};

template <typename T>
using vec2 = vec<2, T>;

template <typename T>
using vec3 = vec<3, T>;

template <typename T>
using vec4 = vec<4, T>;

template <int N, int M, typename T>
struct mat {};

template <typename T>
using mat2x2 = mat<2, 2, T>;

template <typename T>
using mat2x3 = mat<2, 3, T>;

template <typename T>
using mat3x2 = mat<3, 2, T>;

template <typename T>
using mat3x3 = mat<3, 3, T>;

template <typename T>
using mat4x4 = mat<4, 4, T>;

template <typename TO, int ID = 0>
struct alias {};

template <typename TO>
using alias1 = alias<TO, 1>;

template <typename TO>
using alias2 = alias<TO, 2>;

template <typename TO>
using alias3 = alias<TO, 3>;

using ast_type_func_ptr = ast::Type* (*)(ProgramBuilder& b);
using ast_expr_func_ptr = ast::Expression* (*)(ProgramBuilder& b,
                                               int elem_value);
using sem_type_func_ptr = sem::Type* (*)(ProgramBuilder& b);

template <typename T>
struct DataType {};

/// Helper for building bool types and expressions
template <>
struct DataType<bool> {
  /// false as bool is not a composite type
  static constexpr bool is_composite = false;

  /// @param b the ProgramBuilder
  /// @return a new AST bool type
  static inline ast::Type* AST(ProgramBuilder& b) { return b.ty.bool_(); }
  /// @param b the ProgramBuilder
  /// @return the semantic bool type
  static inline sem::Type* Sem(ProgramBuilder& b) {
    return b.create<sem::Bool>();
  }
  /// @param b the ProgramBuilder
  /// @param elem_value the b
  /// @return a new AST expression of the bool type
  static inline ast::Expression* Expr(ProgramBuilder& b, int elem_value) {
    return b.Expr(elem_value == 0);
  }
};

/// Helper for building i32 types and expressions
template <>
struct DataType<i32> {
  /// false as i32 is not a composite type
  static constexpr bool is_composite = false;

  /// @param b the ProgramBuilder
  /// @return a new AST i32 type
  static inline ast::Type* AST(ProgramBuilder& b) { return b.ty.i32(); }
  /// @param b the ProgramBuilder
  /// @return the semantic i32 type
  static inline sem::Type* Sem(ProgramBuilder& b) {
    return b.create<sem::I32>();
  }
  /// @param b the ProgramBuilder
  /// @param elem_value the value i32 will be initialized with
  /// @return a new AST i32 literal value expression
  static inline ast::Expression* Expr(ProgramBuilder& b, int elem_value) {
    return b.Expr(static_cast<i32>(elem_value));
  }
};

/// Helper for building u32 types and expressions
template <>
struct DataType<u32> {
  /// false as u32 is not a composite type
  static constexpr bool is_composite = false;

  /// @param b the ProgramBuilder
  /// @return a new AST u32 type
  static inline ast::Type* AST(ProgramBuilder& b) { return b.ty.u32(); }
  /// @param b the ProgramBuilder
  /// @return the semantic u32 type
  static inline sem::Type* Sem(ProgramBuilder& b) {
    return b.create<sem::U32>();
  }
  /// @param b the ProgramBuilder
  /// @param elem_value the value u32 will be initialized with
  /// @return a new AST u32 literal value expression
  static inline ast::Expression* Expr(ProgramBuilder& b, int elem_value) {
    return b.Expr(static_cast<u32>(elem_value));
  }
};

/// Helper for building f32 types and expressions
template <>
struct DataType<f32> {
  /// false as f32 is not a composite type
  static constexpr bool is_composite = false;

  /// @param b the ProgramBuilder
  /// @return a new AST f32 type
  static inline ast::Type* AST(ProgramBuilder& b) { return b.ty.f32(); }
  /// @param b the ProgramBuilder
  /// @return the semantic f32 type
  static inline sem::Type* Sem(ProgramBuilder& b) {
    return b.create<sem::F32>();
  }
  /// @param b the ProgramBuilder
  /// @param elem_value the value f32 will be initialized with
  /// @return a new AST f32 literal value expression
  static inline ast::Expression* Expr(ProgramBuilder& b, int elem_value) {
    return b.Expr(static_cast<f32>(elem_value));
  }
};

/// Helper for building vector types and expressions
template <int N, typename T>
struct DataType<vec<N, T>> {
  /// true as vectors are a composite type
  static constexpr bool is_composite = true;

  /// @param b the ProgramBuilder
  /// @return a new AST vector type
  static inline ast::Type* AST(ProgramBuilder& b) {
    return b.ty.vec(DataType<T>::AST(b), N);
  }
  /// @param b the ProgramBuilder
  /// @return the semantic vector type
  static inline sem::Type* Sem(ProgramBuilder& b) {
    return b.create<sem::Vector>(DataType<T>::Sem(b), N);
  }
  /// @param b the ProgramBuilder
  /// @param elem_value the value each element in the vector will be initialized
  /// with
  /// @return a new AST vector value expression
  static inline ast::Expression* Expr(ProgramBuilder& b, int elem_value) {
    return b.Construct(AST(b), ExprArgs(b, elem_value));
  }

  /// @param b the ProgramBuilder
  /// @param elem_value the value each element will be initialized with
  /// @return the list of expressions that are used to construct the vector
  static inline ast::ExpressionList ExprArgs(ProgramBuilder& b,
                                             int elem_value) {
    ast::ExpressionList args;
    for (int i = 0; i < N; i++) {
      args.emplace_back(DataType<T>::Expr(b, elem_value));
    }
    return args;
  }
};

/// Helper for building matrix types and expressions
template <int N, int M, typename T>
struct DataType<mat<N, M, T>> {
  /// true as matrices are a composite type
  static constexpr bool is_composite = true;

  /// @param b the ProgramBuilder
  /// @return a new AST matrix type
  static inline ast::Type* AST(ProgramBuilder& b) {
    return b.ty.mat(DataType<T>::AST(b), N, M);
  }
  /// @param b the ProgramBuilder
  /// @return the semantic matrix type
  static inline sem::Type* Sem(ProgramBuilder& b) {
    auto* column_type = b.create<sem::Vector>(DataType<T>::Sem(b), M);
    return b.create<sem::Matrix>(column_type, N);
  }
  /// @param b the ProgramBuilder
  /// @param elem_value the value each element in the matrix will be initialized
  /// with
  /// @return a new AST matrix value expression
  static inline ast::Expression* Expr(ProgramBuilder& b, int elem_value) {
    return b.Construct(AST(b), ExprArgs(b, elem_value));
  }

  /// @param b the ProgramBuilder
  /// @param elem_value the value each element will be initialized with
  /// @return the list of expressions that are used to construct the matrix
  static inline ast::ExpressionList ExprArgs(ProgramBuilder& b,
                                             int elem_value) {
    ast::ExpressionList args;
    for (int i = 0; i < N; i++) {
      args.emplace_back(DataType<vec<M, T>>::Expr(b, elem_value));
    }
    return args;
  }
};

/// Helper for building alias types and expressions
template <typename T, int ID>
struct DataType<alias<T, ID>> {
  /// true if the aliased type is a composite type
  static constexpr bool is_composite = DataType<T>::is_composite;

  /// @param b the ProgramBuilder
  /// @return a new AST alias type
  static inline ast::Type* AST(ProgramBuilder& b) {
    auto name = b.Symbols().Register("alias_" + std::to_string(ID));
    if (!b.AST().LookupType(name)) {
      auto* type = DataType<T>::AST(b);
      b.AST().AddTypeDecl(b.ty.alias(name, type));
    }
    return b.create<ast::TypeName>(name);
  }
  /// @param b the ProgramBuilder
  /// @return the semantic aliased type
  static inline sem::Type* Sem(ProgramBuilder& b) {
    return DataType<T>::Sem(b);
  }

  /// @param b the ProgramBuilder
  /// @param elem_value the value nested elements will be initialized with
  /// @return a new AST expression of the alias type
  template <bool IS_COMPOSITE = is_composite>
  static inline traits::EnableIf<!IS_COMPOSITE, ast::Expression*> Expr(
      ProgramBuilder& b,
      int elem_value) {
    // Cast
    return b.Construct(AST(b), DataType<T>::Expr(b, elem_value));
  }

  /// @param b the ProgramBuilder
  /// @param elem_value the value nested elements will be initialized with
  /// @return a new AST expression of the alias type
  template <bool IS_COMPOSITE = is_composite>
  static inline traits::EnableIf<IS_COMPOSITE, ast::Expression*> Expr(
      ProgramBuilder& b,
      int elem_value) {
    // Construct
    return b.Construct(AST(b), DataType<T>::ExprArgs(b, elem_value));
  }
};

}  // namespace builder

}  // namespace resolver
}  // namespace tint

#endif  // SRC_RESOLVER_RESOLVER_TEST_HELPER_H_