/*
 * Copyright 2019 The Android Open Source Project
 *
 * 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 <unistd.h>

#include <cerrno>
#include <cstdio>
#include <cstring>
#include <filesystem>
#include <fstream>
#include <iomanip>
#include <iostream>
#include <queue>
#include <regex>
#include <sstream>
#include <vector>

#include "declarations.h"
#include "language_y.h"
#include "struct_parser_generator.h"

int yylex_init(void**);
int yylex_destroy(void*);
void yyset_debug(int, void*);
void yyset_in(FILE*, void*);

bool generate_cpp_headers_one_file(const Declarations& decls, bool generate_fuzzing,
                                   bool generate_tests, const std::filesystem::path& input_file,
                                   const std::filesystem::path& include_dir,
                                   const std::filesystem::path& out_dir,
                                   const std::string& root_namespace);

bool parse_declarations_one_file(const std::filesystem::path& input_file,
                                 Declarations* declarations) {
  void* scanner;
  yylex_init(&scanner);

  FILE* in_file = fopen(input_file.string().c_str(), "r");
  if (in_file == nullptr) {
    std::cerr << "can't open " << input_file << ": " << strerror(errno) << std::endl;
    return false;
  }

  yyset_in(in_file, scanner);

  int ret = yy::parser(scanner, declarations).parse();
  if (ret != 0) {
    std::cerr << "yylex parsing failed: returned " << ret << std::endl;
    return false;
  }

  yylex_destroy(scanner);

  fclose(in_file);

  // Set endianess before returning
  for (auto& s : declarations->type_defs_queue_) {
    if (s.second->GetDefinitionType() == TypeDef::Type::STRUCT) {
      auto* struct_def = static_cast<StructDef*>(s.second);
      struct_def->SetEndianness(declarations->is_little_endian);
    }
  }

  for (auto& packet_def : declarations->packet_defs_queue_) {
    packet_def.second->SetEndianness(declarations->is_little_endian);
    if (packet_def.second->parent_ != nullptr) {
      packet_def.second->parent_->children_.push_back(packet_def.second);
    }
  }

  return true;
}

// TODO(b/141583809): stop leaks
extern "C" const char* __asan_default_options() { return "detect_leaks=0"; }

void usage(const char* prog) {
  auto& ofs = std::cerr;

  ofs << "Usage: " << prog << " [OPTIONS] file1 file2..." << std::endl;

  ofs << std::setw(24) << "--out= ";
  ofs << "Root directory for generated output (relative to cwd)." << std::endl;

  ofs << std::setw(24) << "--include= ";
  ofs << "Generate namespaces relative to this path per file." << std::endl;

  ofs << std::setw(24) << "--root_namespace= ";
  ofs << "Change root namespace (default = bluetooth)." << std::endl;

  ofs << std::setw(24) << "--source_root= ";
  ofs << "Root path to the source directory. Find input files relative to this." << std::endl;
}

int main(int argc, const char** argv) {
  std::filesystem::path out_dir;
  std::filesystem::path include_dir;
  std::filesystem::path cwd = std::filesystem::current_path();
  std::filesystem::path source_root = cwd;
  std::string root_namespace = "bluetooth";
  bool generate_fuzzing = false;
  bool generate_tests = false;
  std::queue<std::filesystem::path> input_files;

  const std::string arg_out = "--out=";
  const std::string arg_include = "--include=";
  const std::string arg_namespace = "--root_namespace=";
  const std::string arg_fuzzing = "--fuzzing";
  const std::string arg_testing = "--testing";
  const std::string arg_source_root = "--source_root=";

  // Parse the source root first (if it exists) since it will be used for other
  // paths.
  for (int i = 1; i < argc; i++) {
    std::string arg = argv[i];
    if (arg.find(arg_source_root) == 0) {
      source_root = std::filesystem::path(arg.substr(arg_source_root.size()));
    }
  }

  for (int i = 1; i < argc; i++) {
    std::string arg = argv[i];
    if (arg.find(arg_out) == 0) {
      out_dir = cwd / std::filesystem::path(arg.substr(arg_out.size()));
    } else if (arg.find(arg_include) == 0) {
      include_dir = source_root / std::filesystem::path(arg.substr(arg_include.size()));
    } else if (arg.find(arg_namespace) == 0) {
      root_namespace = arg.substr(arg_namespace.size());
    } else if (arg.find(arg_fuzzing) == 0) {
      generate_fuzzing = true;
    } else if (arg.find(arg_testing) == 0) {
      generate_tests = true;
    } else if (arg.find(arg_source_root) == 0) {
      // Do nothing (just don't treat it as input_files)
    } else {
      input_files.emplace(source_root / std::filesystem::path(arg));
    }
  }
  if (out_dir == std::filesystem::path() || include_dir == std::filesystem::path()) {
    usage(argv[0]);
    return 1;
  }

  std::cout << "out dir: " << out_dir << std::endl;

  while (!input_files.empty()) {
    Declarations declarations;
    std::cout << "parsing: " << input_files.front() << std::endl;
    if (!parse_declarations_one_file(input_files.front(), &declarations)) {
      std::cerr << "Cannot parse " << input_files.front() << " correctly" << std::endl;
      return 2;
    }
    std::cout << "generating c++" << std::endl;
    if (!generate_cpp_headers_one_file(declarations, generate_fuzzing, generate_tests,
                                       input_files.front(), include_dir, out_dir, root_namespace)) {
      std::cerr << "Didn't generate cpp headers for " << input_files.front() << std::endl;
      return 3;
    }
    input_files.pop();
  }

  return 0;
}