#pragma once

#include <stdbool.h> // bool
#include <stdio.h>   // snprintf|stderr
#include <stdlib.h>  // EXIT_FAILURE|EXIT_SUCCESS
#include <string.h>  // strncmp|strlen

/// @brief internal function
static bool iuepo_find_option(const char* option, const char* arg) {
  char buffer[256];
  snprintf(buffer, sizeof(buffer) / sizeof(char), "%s%s", "-", option);
  if (strncmp(buffer, arg, strlen(buffer)) == 0)
    return true;
  snprintf(buffer, sizeof(buffer) / sizeof(char), "%s%s", "--", option);
  if (strncmp(buffer, arg, strlen(buffer)) == 0)
    return true;
  return false;
}

/// @brief internal function
static int iuepo_count_if(const char* option, char** begin, char** end) {
  int res = 0;
  for (char** iter = begin; iter != end; ++iter) {
    if (iuepo_find_option(option, *iter))
      ++res;
  }
  return res;
}

/// @brief internal function
static char** iuepo_find_if(const char* option, char** begin, char** end) {
  int res = 0;
  for (char** iter = begin; iter != end; ++iter) {
    if (iuepo_find_option(option, *iter))
      return iter;
  }
  return end;
}

/// @todo Improve documentation of this enum
enum iuepo_option { IUEPO_REQUIRED = 0, IUEPO_OPTIONAL };

/// @todo Improve documentation of this function
/// @brief Optain a string option from command line arguments
static int iuepo_get_string(int argc, char* argv[], const char* option, char* default_value, int N,
                            enum iuepo_option op) {

  int count = iuepo_count_if(option, argv + 1, argv + argc);

  if (count == 0) {
    if (op == IUEPO_REQUIRED) {
      fprintf(stderr, "required option not provided: -/-- %s\n", option);
      return EXIT_FAILURE;
    }

    return EXIT_SUCCESS;
  }

  if (count > 1) {
    fprintf(stderr, "option not unique: -/-- %s (count = %i )\n", option, count);
    return EXIT_FAILURE;
  }

  char** iter = iuepo_find_if(option, argv + 1, argv + argc);

  ++iter;

  if (iter == argv + argc) {
    fprintf(stderr, "option not followed by value: -/-- %s\n", option);
    return EXIT_FAILURE;
  }

  if (strncmp("-", *iter, 1) == 0) {
    fprintf(stderr, "option -/-- %s not followed by value but another option -/-- %s\n", option, *iter);
    return EXIT_FAILURE;
  }

  if (snprintf(default_value, N, "%s", *iter) >= N) {
    fprintf(stderr, "provided buffer size %i for option -/-- %s not sufficient\n", N, option);
    return EXIT_FAILURE;
  }

  return EXIT_SUCCESS;
}

/// @todo Improve documentation of this function
/// @brief Wrapping iuepo_get_string with a subsequent conversion
static int iuepo_get_int(int argc, char* argv[], const char* option, int* default_value, enum iuepo_option op) {

  char default_value_string[256] = "\0";
  snprintf(default_value_string, sizeof(default_value_string), "%i", *default_value);

  if (iuepo_get_string(argc, argv, option, default_value_string, sizeof(default_value_string), op) == EXIT_FAILURE) {
    return EXIT_FAILURE;
  }

  int res = sscanf(default_value_string, "%i", default_value);

  if (res != 1) {
    fprintf(stderr, "value for option -/-- %s could not be converted\n", option);
    return EXIT_FAILURE;
  }
  return EXIT_SUCCESS;
}