#include "parseargs.hh"

#include <boost/program_options.hpp>
#include <iostream>

constexpr int DEFAULT_ITERATIONS = 2000;

using path   = std::filesystem::path;
namespace po = boost::program_options;

/**
 *  \brief Ensures correct output path
 *
 *  Checks if an output file exists, and if yes if it has an extension. In case
 *  it doesn’t exist, `output_` is appended at the beginning of the input
 *  filename. If the output path does not have an extension, the type `.png` is
 *  appended at the end of the path.
 *
 *  \param[in] t_vm Arguments passed to the program
 *  \param[out] t_input Input path
 *  \param[out] t_output Output path
 */
void processFilenames(po::variables_map const &t_vm, path const &t_input,
                      path &t_output)
{
  if (!t_vm.count("output")) {
    t_output.replace_filename("output_"
                              + std::string{t_input.filename().string()});
  } else if (!t_output.has_extension()) {
    t_output.replace_extension(".png");
  }
}

/**
 *  Parses the arguments given to the program, formats them and returns them as
 *  a tuple. If `-h` or `--help` or a malformed argument is passed, then the
 *  list of arguments and their comment will be displayed, and the program will
 *  exit.
 *
 *  \param[in] t_ac Number of arguments passed to the program
 *  \param[in] t_av Arguments passed to the program
 *  \return Tuple of path, path, int, int, int, int, int, bool and bool
 */
[[nodiscard]] auto parse_args(int t_ac, char **t_av) -> ParsedArgs
{
  ParsedArgs ret{};
  po::options_description desc("Allowed options");
  desc.add_options()("help,h", "Display this help message")(
      "input,i", po::value<path>(),
      "Input image")("output,o", po::value<path>(),
                     "Image output path (default: \"output_\" + input path)")(
      "iterations,n", po::value<int>(), "Number of iterations (default: 2000)")(
      "method,m", po::value<int>(), "Method number to be used (default: 1)")(
      "form,f", po::value<int>(), "Select shape (1:square, 2:triangle)")(
      "cols,c", po::value<int>(),
      "For method 5 only, number of columns the reference image should be "
      "divided into. If the value is equal to 0, then it will be assumed "
      "there will be as many rows as there are collumns. (default: 0)")(
      "rows,r", po::value<int>(),
      "For method 5 only, number of rows the reference image should be "
      "divided into. (default: 1)")(
      "submethod,S", po::value<int>(),
      "Sub-method that will be used to generate the individual tiles from "
      "method 5. (default: 1)")("size,s",
                                "Enables controlled size of the random shapes")(
      "verbose,v", "Enables verbosity");
  po::variables_map vm;
  po::store(po::parse_command_line(t_ac, t_av, desc), vm);
  po::notify(vm);
  if (vm.count("help") || !vm.count("input")) {
    std::cout << desc << "\n";
    std::exit(!vm.count("help"));
  }

  auto const input_path = vm["input"].as<path>();
  auto output_path
      = vm.count("output") ? vm["output"].as<path>() : input_path.filename();
  processFilenames(vm, input_path, output_path);

  ret.input_path  = input_path;
  ret.output_path = output_path;
  ret.iterations  = vm.count("iterations") ? vm["iterations"].as<int>()
                                          : DEFAULT_ITERATIONS;
  ret.method = vm.count("method") ? vm["method"].as<int>() : 1;
  switch (vm.count("form") ? vm["form"].as<int>() : 1) {
  case 2: ret.shape = Shape::ShapeType::Triangle; break;
  case 1: ret.shape = Shape::ShapeType::Square; break;
  default: ret.shape = Shape::ShapeType::Square; break;
  }

  ret.cols            = vm.count("cols") ? vm["cols"].as<int>() : 0;
  ret.rows            = vm.count("rows") ? vm["rows"].as<int>() : 1;
  ret.submethod       = vm.count("submethod") ? vm["submethod"].as<int>() : 1;
  ret.controlled_size = vm.count("size");
  ret.verbose         = vm.count("verbose");
  return ret;
}