// =================================================================================================
// This file is part of the CLBlast project. The project is licensed under Apache Version 2.0. This
// project loosely follows the Google C++ styleguide and uses a tab-size of two spaces and a max-
// width of 100 characters per line.
//
// Author(s):
//   Cedric Nugteren <www.cedricnugteren.nl>
//
// This file implements the generic CLBlast auto-tuner (inspired by CLTune). This is only used for
//  the optional and stand-alone tuner binaries and not part of the core of CLBlast.
//
// =================================================================================================

#include <vector>
#include <string>
#include <random>
#include <utility>
#include <algorithm>
#include <cstdio>

#include "utilities/utilities.hpp"
#include "tuning/tuning.hpp"

namespace clblast {
// =================================================================================================

void PrintTimingsToFileAsJSON(const std::string &filename,
                              const Device& device, const Platform& platform,
                              const std::vector<std::pair<std::string,std::string>> &metadata,
                              const std::vector<TuningResult>& tuning_results) {
  auto num_results = tuning_results.size();
  printf("* Writing a total of %zu results to '%s'\n", num_results, filename.c_str());

  auto file = fopen(filename.c_str(), "w");
  fprintf(file, "{\n");
  for (auto &datum: metadata) {
    fprintf(file, "  \"%s\": \"%s\",\n", datum.first.c_str(), datum.second.c_str());
  }
  fprintf(file, "  \"clblast_device_type\": \"%s\",\n", GetDeviceType(device).c_str());
  fprintf(file, "  \"clblast_device_vendor\": \"%s\",\n", GetDeviceVendor(device).c_str());
  fprintf(file, "  \"clblast_device_architecture\": \"%s\",\n", GetDeviceArchitecture(device).c_str());
  fprintf(file, "  \"clblast_device_name\": \"%s\",\n", GetDeviceName(device).c_str());
  fprintf(file, "  \"device\": \"%s\",\n", device.Name().c_str());
  fprintf(file, "  \"platform_vendor\": \"%s\",\n", platform.Vendor().c_str());
  fprintf(file, "  \"platform_version\": \"%s\",\n", platform.Version().c_str());
  fprintf(file, "  \"device_vendor\": \"%s\",\n", device.Vendor().c_str());
  fprintf(file, "  \"device_type\": \"%s\",\n", device.Type().c_str());
  fprintf(file, "  \"device_core_clock\": \"%zu\",\n", device.CoreClock());
  fprintf(file, "  \"device_compute_units\": \"%zu\",\n", device.ComputeUnits());
  fprintf(file, "  \"device_extra_info\": \"%s\",\n", device.GetExtraInfo().c_str());
  fprintf(file, "  \"results\": [\n");

  // Loops over all results
  for (auto r = size_t{0}; r < num_results; ++r) {
    auto result = tuning_results[r];
    fprintf(file, "    {\n");
    fprintf(file, "      \"kernel\": \"%s\",\n", result.name.c_str());
    fprintf(file, "      \"time\": %.3lf,\n", result.score);

    // Loops over all the parameters for this result
    fprintf(file, "      \"parameters\": {");
    auto num_configs = result.config.size();
    auto p = size_t{0};
    for (const auto& parameter : result.config) {
      fprintf(file, "\"%s\": %zu", parameter.first.c_str(), parameter.second);
      if (p < num_configs -1 ) { fprintf(file, ","); }
      ++p;
    }
    fprintf(file, "}\n");

    // The footer
    fprintf(file, "    }");
    if (r < num_results - 1) { fprintf(file, ","); }
    fprintf(file, "\n");
  }
  fprintf(file, "  ]\n");
  fprintf(file, "}\n");
  fclose(file);
}

void print_separator(const size_t parameters_size) {
  printf("x------x-------x");
  for (auto i = size_t{0}; i < parameters_size; ++i) { printf("-----"); }
  printf("-x-----------------x-----------------x----------------x--------------x--------x-------------------x\n");
}

// =================================================================================================

template <typename T>
void Tuner(int argc, char* argv[], const int V,
           GetTunerDefaultsFunc GetTunerDefaults,
           GetTunerSettingsFunc<T> GetTunerSettings,
           TestValidArgumentsFunc<T> TestValidArguments,
           SetConstraintsFunc SetConstraints,
           ComputeLocalMemSizeFunc<T> ComputeLocalMemSize,
           SetArgumentsFunc<T> SetArguments) {
  constexpr auto kSeed = 42; // fixed seed for reproducibility

  // Constants holding start and end strings for terminal-output in colour
  #if defined(_WIN32)
    const std::string kPrintError = "";
    const std::string kPrintSuccess = "";
    const std::string kPrintMessage = "";
    const std::string kPrintEnd = "";
  #else
    const std::string kPrintError = "\x1b[31m";
    const std::string kPrintSuccess = "\x1b[32m";
    const std::string kPrintMessage = "\x1b[1m";
    const std::string kPrintEnd = "\x1b[0m";
  #endif

  // Sets the parameters and platform/device for which to tune (command-line options)
  const TunerDefaults defaults = GetTunerDefaults(V);
  auto command_line_args = RetrieveCommandLineArguments(argc, argv);
  auto help = std::string{"* Options given/available:\n"};
  auto args = Arguments<T>{};
  args.platform_id = GetArgument(command_line_args, help, kArgPlatform, ConvertArgument(std::getenv("CLBLAST_PLATFORM"), size_t{0}));
  args.device_id   = GetArgument(command_line_args, help, kArgDevice, ConvertArgument(std::getenv("CLBLAST_DEVICE"), size_t{0}));
  args.precision   = GetArgument(command_line_args, help, kArgPrecision, Precision::kSingle);
  for (auto &o: defaults.options) {
    if (o == kArgM)        { args.m        = GetArgument(command_line_args, help, kArgM, defaults.default_m); }
    if (o == kArgN)        { args.n        = GetArgument(command_line_args, help, kArgN, defaults.default_n); }
    if (o == kArgK)        { args.k        = GetArgument(command_line_args, help, kArgK, defaults.default_k); }
    if (o == kArgChannels)   { args.channels    = GetArgument(command_line_args, help, kArgChannels, defaults.channels); }
    if (o == kArgHeight)     { args.height      = GetArgument(command_line_args, help, kArgHeight, defaults.height); }
    if (o == kArgWidth)      { args.width       = GetArgument(command_line_args, help, kArgWidth, defaults.width); }
    if (o == kArgKernelH)    { args.kernel_h    = GetArgument(command_line_args, help, kArgKernelH, defaults.kernel_h); }
    if (o == kArgKernelW)    { args.kernel_w    = GetArgument(command_line_args, help, kArgKernelW, defaults.kernel_w); }
    if (o == kArgNumKernels) { args.num_kernels = GetArgument(command_line_args, help, kArgNumKernels, defaults.num_kernels); }
    if (o == kArgAlpha)      { args.alpha       = GetArgument(command_line_args, help, kArgAlpha, GetScalar<T>()); }
    if (o == kArgBeta)       { args.beta        = GetArgument(command_line_args, help, kArgBeta, GetScalar<T>()); }
    if (o == kArgBatchCount) { args.batch_count = GetArgument(command_line_args, help, kArgBatchCount, defaults.default_batch_count); }
  }
  args.fraction = GetArgument(command_line_args, help, kArgFraction, defaults.default_fraction);
  args.num_runs = GetArgument(command_line_args, help, kArgNumRuns, defaults.default_num_runs);
  const auto max_l2_norm = GetArgument(command_line_args, help, kArgMaxL2Norm, 1.0e-4);
  printf("%s\n", help.c_str());
  const TunerSettings settings = GetTunerSettings(V, args);

  // Tests validity of the given arguments
  TestValidArguments(V, args);

  // Initializes OpenCL
  const auto platform = Platform(args.platform_id);
  const auto device = Device(platform, args.device_id);
  const auto context = Context(device);
  auto queue = Queue(context, device);

  // Tests for validity of the precision and retrieves properties
  if (!PrecisionSupported<T>(device)) {
    printf("* Unsupported precision, skipping this tuning run\n\n");
    return;
  }
  const auto device_type = GetDeviceType(device);
  const auto device_vendor = GetDeviceVendor(device);
  const auto device_architecture = GetDeviceArchitecture(device);
  const auto device_name = GetDeviceName(device);

  // Creates input buffers with random data. Adds a 'canary' region to detect buffer overflows.
  const auto buffer_sizes = std::vector<size_t>{
      settings.size_x + kCanarySize, settings.size_y + kCanarySize,
      settings.size_a + kCanarySize, settings.size_b + kCanarySize, settings.size_c + kCanarySize,
      settings.size_temp + kCanarySize
  };
  std::mt19937 mt(kSeed);
  std::uniform_real_distribution<double> dist(kTestDataLowerLimit, kTestDataUpperLimit);
  auto source_buffers = std::vector<std::vector<T>>();
  auto reference_buffers = std::vector<std::vector<T>>();
  auto result_buffers = std::vector<std::vector<T>>();
  auto device_buffers = std::vector<Buffer<T>>();
  for (const auto size : buffer_sizes) {
    auto host_buffer = std::vector<T>(size);
    PopulateVector(host_buffer, mt, dist);
    source_buffers.push_back(host_buffer);
    reference_buffers.push_back(std::vector<T>(size));
    result_buffers.push_back(std::vector<T>(size));
    device_buffers.push_back(Buffer<T>(context, size));
  }

  // Sets the tunable parameters and their possible values
  auto configurations = SetConfigurations(device, settings.parameters, settings.local_size,
                                          settings.mul_local, settings.div_local,
                                          SetConstraints(V), ComputeLocalMemSize(V));
  printf("* Found %s%zu configuration(s)%s\n",
         kPrintMessage.c_str(), configurations.size(), kPrintEnd.c_str());

  // Select the search method (full search or a random fraction)
  if (args.fraction != 0.0 && args.fraction != 1.0) {
    const auto new_size = static_cast<size_t>(configurations.size() / args.fraction);
    auto rng = std::default_random_engine{};
    std::shuffle(std::begin(configurations), std::end(configurations), rng);
    configurations.resize(new_size);
    printf("* Exploring a random subset of %s%zu configuration(s)%s\n",
           kPrintMessage.c_str(), configurations.size(), kPrintEnd.c_str());
  }

  // Prints information about the parameters
  printf("* Parameters explored: ");
  for (const auto& parameter : settings.parameters) { printf("%s ", parameter.first.c_str()); }
  printf("\n");

  // Prints the header of the table
  printf("\n");
  printf("|   ID | total |");
  for (auto i = size_t{0}; i < settings.parameters.size() - 1; ++i) { printf("     "); }
  printf("param |      local      |      global     |       compiles |         time | %6s |            status |\n", settings.performance_unit.c_str());
  print_separator(settings.parameters.size());

  // First runs a reference example to compare against
  try {
    printf("|  ref |     - |");
    for (auto i = size_t{0}; i < settings.parameters.size() - 1; ++i) { printf("     "); }
    printf("    - |");


    // Sets the input
    for (const auto id : settings.inputs) {
      device_buffers[id].Write(queue, buffer_sizes[id], source_buffers[id]);
    }

    // Sets the thread configuration
    auto global = settings.global_size_ref;
    auto local = settings.local_size_ref;

    // Make sure that the global worksize is a multiple of the local
    for (auto i=size_t{0}; i<global.size(); ++i) {
      while ((global[i] / local[i]) * local[i] != global[i]) { global[i]++; }
    }
    printf("%8zu%8zu |%8zu%8zu |", local[0], local[1], global[0], global[1]);

    // Compiles the kernel
    auto compiler_options = std::vector<std::string>();
    const auto program = CompileFromSource(settings.sources, args.precision, settings.kernel_name,
                                           device, context, compiler_options, 0);
    auto kernel = Kernel(program, settings.kernel_name);
    SetArguments(V, kernel, args, device_buffers);
    printf("             %sOK%s |", kPrintSuccess.c_str(), kPrintEnd.c_str());

    // Runs the kernel
    const auto time_ms = TimeKernel(args.num_runs, kernel, queue, device,
                                    global, local);
    printf("      - |");
    if (time_ms == -1.0) { throw std::runtime_error("Error in reference implementation"); }

    // Saves the result
    for (const auto id : settings.outputs) {
      device_buffers[id].Read(queue, buffer_sizes[id], reference_buffers[id]);
    }
    printf("      %sreference OK%s |\n", kPrintSuccess.c_str(), kPrintEnd.c_str());
  }
  catch (...) {
    const auto status_code = DispatchExceptionCatchAll(true);
    printf("* Exception caught with status %d while running the reference, aborting\n",
           static_cast<int>(status_code));
    return;
  }
  print_separator(settings.parameters.size());

  // Starts the tuning process
  auto results = std::vector<TuningResult>();
  for (auto config_id = size_t{0}; config_id < configurations.size(); ++config_id) {
    try {
      auto configuration = configurations[config_id];
      printf("| %4zu | %5zu |", config_id + 1, configurations.size());
      for (const auto& parameter : settings.parameters) {
        printf("%5zu", configuration.at(parameter.first));
      }
      printf(" |");

      // Sets the input
      for (const auto id : settings.inputs) {
        device_buffers[id].Write(queue, buffer_sizes[id], source_buffers[id]);
      }

      // Sets the thread configuration
      auto global = SetThreadConfiguration(configuration, settings.global_size,
                                           settings.mul_global, settings.div_global);
      auto local = SetThreadConfiguration(configuration, settings.local_size,
                                          settings.mul_local, settings.div_local);

      // Make sure that the global worksize is a multiple of the local
      for (auto i=size_t{0}; i<global.size(); ++i) {
        while ((global[i] / local[i]) * local[i] != global[i]) { global[i]++; }
      }
      printf("%8zu%8zu |%8zu%8zu |", local[0], local[1], global[0], global[1]);

      // Sets the parameters for this configuration
      auto kernel_source = std::string{""};
      for (const auto &parameter : configuration) {
        kernel_source += "#define " + parameter.first + " " + ToString(parameter.second) + "\n";
      }
      kernel_source += settings.sources;

      // Compiles the kernel
      const auto start_time = std::chrono::steady_clock::now();
      auto compiler_options = std::vector<std::string>();
      const auto program = CompileFromSource(kernel_source, args.precision, settings.kernel_name,
                                             device, context, compiler_options, 0, true);
      auto kernel = Kernel(program, settings.kernel_name);
      const auto elapsed_time = std::chrono::steady_clock::now() - start_time;
      const auto timing = std::chrono::duration<double,std::milli>(elapsed_time).count();
      printf("   %sOK%s  %5.0lf ms |", kPrintSuccess.c_str(), kPrintEnd.c_str(), timing);

      // Runs the kernel
      SetArguments(V, kernel, args, device_buffers);
      const auto time_ms = TimeKernel(args.num_runs, kernel, queue, device, global, local);

      // Kernel run was not successful
      if (time_ms == -1.0) {
        printf("      - |");
        printf("   %sinvalid config.%s |", kPrintError.c_str(), kPrintEnd.c_str());
        printf(" <-- skipping\n");
        continue;
      }

      // Compares the results
      auto l2_error = 0.0;
      for (const auto id : settings.outputs) {
        device_buffers[id].Read(queue, buffer_sizes[id], result_buffers[id]);
        for (auto index = size_t{0}; index<buffer_sizes[id]; ++index) {
          const auto diff = SquaredDifference(result_buffers[id][index], reference_buffers[id][index]);
          l2_error += diff;
        }
        l2_error /= static_cast<double>(buffer_sizes[id]);
        if (std::isnan(l2_error) || l2_error > max_l2_norm) {
          printf("      - |");
          printf(" %sL2 error %8.2e%s |", kPrintError.c_str(), l2_error, kPrintEnd.c_str());
          throw std::runtime_error("L2 error too large");
        }
      }

      // All was OK
      configuration["PRECISION"] = static_cast<size_t>(args.precision);
      results.push_back(TuningResult{settings.kernel_name, time_ms, configuration});
      printf(" %6.1lf |", settings.metric_amount / (time_ms * 1.0e6));
      printf("     %sresults match%s |\n", kPrintSuccess.c_str(), kPrintEnd.c_str());
    }
    catch (CLCudaAPIBuildError&) {
      const auto status_code = DispatchExceptionCatchAll(true);
      printf("  %scompilation error: %5d%s     |",
             kPrintError.c_str(), static_cast<int>(status_code), kPrintEnd.c_str());
      printf("      - |                 - | <-- skipping\n");
    }
    catch (...) {
      const auto status_code = DispatchExceptionCatchAll(true);
      if (status_code != StatusCode::kUnknownError) {
        printf("   %serror code %d%s |",
               kPrintError.c_str(), static_cast<int>(status_code), kPrintEnd.c_str());
      }
      printf(" <-- skipping\n");
    }
  }

  // Completed the tuning process
  print_separator(settings.parameters.size());
  printf("\n");
  if (results.size() == 0) { return; }

  // Computes the best results
  auto comparison = [](const TuningResult& lhs, const TuningResult& rhs) { return lhs.score < rhs.score; };
  const auto best_configuration = std::min_element(results.begin(), results.end(), comparison);
  const auto best_time_ms = best_configuration->score;
  if (best_time_ms == 0.0) { return; }

  // Computes and prints some other statistics
  auto average_ms = 0.0;
  for (const auto& result : results) { average_ms += result.score; }
  average_ms /= results.size();
  printf("\n");
  printf("* Got average result of %.2lf ms", average_ms);
  printf(": %.1lf %s\n", settings.metric_amount / (average_ms * 1.0e6),
         settings.performance_unit.c_str());


  // Also prints the performance of the best-case in terms of GB/s or GFLOPS
  printf("* Found best result %.2lf ms", best_time_ms);
  printf(": %.1lf %s\n", settings.metric_amount / (best_time_ms * 1.0e6),
         settings.performance_unit.c_str());
  printf("* Best parameters: ");
  auto best_string = std::string{""};
  auto i = size_t{0};
  for (const auto& config : best_configuration->config) {
    best_string += "" + config.first + "=" + ToString(config.second);
    if (i < best_configuration->config.size() - 1) { best_string += " "; }
    ++i;
  }
  printf("%s\n\n", best_string.c_str());

  // Outputs the results as JSON to disk, including some meta-data
  auto precision_string = std::to_string(static_cast<size_t>(args.precision));
  auto metadata = std::vector<std::pair<std::string,std::string>>{
    {"kernel_family", settings.kernel_family},
    {"precision", precision_string},
    {"best_kernel", best_configuration->name},
    {"best_time", ToString(best_configuration->score)},
    {"best_parameters", best_string}
  };
  for (auto &o: defaults.options) {
    if (o == kArgM)     { metadata.push_back({"arg_m", ToString(args.m)}); }
    if (o == kArgN)     { metadata.push_back({"arg_n", ToString(args.n)}); }
    if (o == kArgK)     { metadata.push_back({"arg_k", ToString(args.k)}); }
    if (o == kArgAlpha) { metadata.push_back({"arg_alpha", ToString(args.alpha)}); }
    if (o == kArgBeta)  { metadata.push_back({"arg_beta", ToString(args.beta)}); }
    if (o == kArgBatchCount) { metadata.push_back({"arg_batch_count", ToString(args.batch_count)}); }
    if (o == kArgHeight)     { metadata.push_back({"arg_height", ToString(args.height)}); }
    if (o == kArgWidth)      { metadata.push_back({"arg_width", ToString(args.width)}); }
    if (o == kArgKernelH)    { metadata.push_back({"arg_kernel_h", ToString(args.kernel_h)}); }
    if (o == kArgKernelW)    { metadata.push_back({"arg_kernel_w", ToString(args.kernel_w)}); }
    if (o == kArgChannels)   { metadata.push_back({"arg_channels", ToString(args.channels)}); }
    if (o == kArgNumKernels) { metadata.push_back({"arg_num_kernels", ToString(args.num_kernels)}); }
  }
  PrintTimingsToFileAsJSON("clblast_" + settings.kernel_family + "_" + precision_string + ".json",
                           device, platform, metadata, results);

  printf("* Completed tuning process\n");
  printf("\n");
}

// Compiles the above function
template void Tuner<half>(int argc, char* argv[], const int V, GetTunerDefaultsFunc GetTunerDefaults, GetTunerSettingsFunc<half> GetTunerSettings, TestValidArgumentsFunc<half> TestValidArguments, SetConstraintsFunc SetConstraints, ComputeLocalMemSizeFunc<half> ComputeLocalMemSize, SetArgumentsFunc<half> SetArguments);
template void Tuner<float>(int argc, char* argv[], const int V, GetTunerDefaultsFunc GetTunerDefaults, GetTunerSettingsFunc<float> GetTunerSettings, TestValidArgumentsFunc<float> TestValidArguments, SetConstraintsFunc SetConstraints, ComputeLocalMemSizeFunc<float> ComputeLocalMemSize, SetArgumentsFunc<float> SetArguments);
template void Tuner<double>(int argc, char* argv[], const int V, GetTunerDefaultsFunc GetTunerDefaults, GetTunerSettingsFunc<double> GetTunerSettings, TestValidArgumentsFunc<double> TestValidArguments, SetConstraintsFunc SetConstraints, ComputeLocalMemSizeFunc<double> ComputeLocalMemSize, SetArgumentsFunc<double> SetArguments);
template void Tuner<float2>(int argc, char* argv[], const int V, GetTunerDefaultsFunc GetTunerDefaults, GetTunerSettingsFunc<float2> GetTunerSettings, TestValidArgumentsFunc<float2> TestValidArguments, SetConstraintsFunc SetConstraints, ComputeLocalMemSizeFunc<float2> ComputeLocalMemSize, SetArgumentsFunc<float2> SetArguments);
template void Tuner<double2>(int argc, char* argv[], const int V, GetTunerDefaultsFunc GetTunerDefaults, GetTunerSettingsFunc<double2> GetTunerSettings, TestValidArgumentsFunc<double2> TestValidArguments, SetConstraintsFunc SetConstraints, ComputeLocalMemSizeFunc<double2> ComputeLocalMemSize, SetArgumentsFunc<double2> SetArguments);

// =================================================================================================
} // namespace clblast