// Copyright 2020 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.

#include "src/tint/transform/manager.h"

/// If set to 1 then the transform::Manager will dump the WGSL of the program
/// before and after each transform. Helpful for debugging bad output.
#define TINT_PRINT_PROGRAM_FOR_EACH_TRANSFORM 0

#if TINT_PRINT_PROGRAM_FOR_EACH_TRANSFORM
#define TINT_IF_PRINT_PROGRAM(x) x
#else  // TINT_PRINT_PROGRAM_FOR_EACH_TRANSFORM
#define TINT_IF_PRINT_PROGRAM(x)
#endif  // TINT_PRINT_PROGRAM_FOR_EACH_TRANSFORM

TINT_INSTANTIATE_TYPEINFO(tint::transform::Manager);

namespace tint::transform {

Manager::Manager() = default;
Manager::~Manager() = default;

Transform::ApplyResult Manager::Apply(const Program* program,
                                      const DataMap& inputs,
                                      DataMap& outputs) const {
#if TINT_PRINT_PROGRAM_FOR_EACH_TRANSFORM
    auto print_program = [&](const char* msg, const Transform* transform) {
        auto wgsl = Program::printer(program);
        std::cout << "---------------------------------------------------------" << std::endl;
        std::cout << "-- " << msg << " " << transform->TypeInfo().name << ":" << std::endl;
        std::cout << "---------------------------------------------------------" << std::endl;
        std::cout << wgsl << std::endl;
        std::cout << "---------------------------------------------------------" << std::endl
                  << std::endl;
    };
#endif

    std::optional<Program> output;

    for (const auto& transform : transforms_) {
        TINT_IF_PRINT_PROGRAM(print_program("Input to", transform.get()));

        if (auto result = transform->Apply(program, inputs, outputs)) {
            output.emplace(std::move(result.value()));
            program = &output.value();

            if (!program->IsValid()) {
                TINT_IF_PRINT_PROGRAM(print_program("Invalid output of", transform.get()));
                break;
            }

            if (transform == transforms_.back()) {
                TINT_IF_PRINT_PROGRAM(print_program("Output of", transform.get()));
            }
        } else {
            TINT_IF_PRINT_PROGRAM(std::cout << "Skipped " << transform->TypeInfo().name
                                            << std::endl);
        }
    }

    return output;
}

}  // namespace tint::transform