// 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 FUZZERS_TINT_COMMON_FUZZER_H_
#define FUZZERS_TINT_COMMON_FUZZER_H_

#include <cstring>
#include <memory>
#include <string>
#include <utility>
#include <vector>

#include "include/tint/tint.h"

namespace tint {
namespace fuzzers {

class Reader {
 public:
  Reader(const uint8_t* data, size_t size);

  bool failed() { return failed_; }
  const uint8_t* data() { return data_; }
  size_t size() { return size_; }

  template <typename T>
  T read() {
    T out{};
    read(&out, sizeof(T));
    return out;
  }

  std::string string();

  template <typename T>
  std::vector<T> vector() {
    auto count = read<uint8_t>();
    if (failed_ || size_ < count) {
      mark_failed();
      return {};
    }
    std::vector<T> out(count);
    memcpy(out.data(), data_, count * sizeof(T));
    data_ += count * sizeof(T);
    size_ -= count * sizeof(T);
    return out;
  }

  template <typename T>
  std::vector<T> vector(T (*extract)(Reader*)) {
    auto count = read<uint8_t>();
    if (size_ < count) {
      mark_failed();
      return {};
    }
    std::vector<T> out(count);
    for (uint8_t i = 0; i < count; i++) {
      out[i] = extract(this);
    }
    return out;
  }
  template <typename T>
  T enum_class(uint8_t count) {
    auto val = read<uint8_t>();
    return static_cast<T>(val % count);
  }

 private:
  void mark_failed();
  void read(void* out, size_t n);

  const uint8_t* data_;
  size_t size_;
  bool failed_ = false;
};

void ExtractBindingRemapperInputs(Reader* r, tint::transform::DataMap* inputs);
void ExtractFirstIndexOffsetInputs(Reader* r, tint::transform::DataMap* inputs);

void ExtractSingleEntryPointInputs(Reader* r, tint::transform::DataMap* inputs);

void ExtractVertexPullingInputs(Reader* r, tint::transform::DataMap* inputs);

enum class InputFormat { kWGSL, kSpv, kNone };

enum class OutputFormat { kWGSL, kSpv, kHLSL, kMSL, kNone };

class CommonFuzzer {
 public:
  explicit CommonFuzzer(InputFormat input, OutputFormat output);
  ~CommonFuzzer();

  void SetTransformManager(transform::Manager* tm, transform::DataMap inputs) {
    transform_manager_ = tm;
    transform_inputs_ = std::move(inputs);
  }
  void EnableInspector() { inspector_enabled_ = true; }

  int Run(const uint8_t* data, size_t size);

  const writer::Writer* GetWriter() const;

  const std::string& GetErrors() const { return errors_; }

  bool HasErrors() const { return !errors_.empty(); }

 private:
  InputFormat input_;
  OutputFormat output_;
  std::unique_ptr<writer::Writer> writer_;
  transform::Manager* transform_manager_;
  transform::DataMap transform_inputs_;
  bool inspector_enabled_;
  std::string errors_;
};

}  // namespace fuzzers
}  // namespace tint

#endif  // FUZZERS_TINT_COMMON_FUZZER_H_