#include <ncurses.h>
#include <string.h>
#include <stdlib.h>
#include <ctype.h>
#include <stdio.h>


typedef struct {
    const char* name;
    int enabled;
} option_t;

typedef struct {
    const char* title;
    option_t* options;
    size_t num_options;
} menu_t;

void show_menu(menu_t* menu);
void load_config(menu_t* menus, size_t menu_count);
void save_config(menu_t* menus, size_t menu_count);

#define SIZE(x) (sizeof(x) / sizeof(option_t))
#define NUM_MENUS (sizeof(all_menus) / sizeof(menu_t))
#define KEY_ESCAPE 27

option_t general_opts[] = {
  { "Enable Debugging Messages", 1 },
  { "Enable Filesystems", 0 },
};

option_t drivers_opts[] = {
  { "Enable IDE", 1 },
  { "Enable USB", 0 },
  { "Enable Network", 0 },
};

menu_t all_menus[] = {
  { "General Settings", general_opts, SIZE(general_opts) },
  { "Device Drivers", drivers_opts, SIZE(drivers_opts) },
};

bool current_config_saved = false;

void strfix(char *str)
{
  for (size_t i = 0; str[i] != '\0'; ++i)
  {
    if (isspace((unsigned char)str[i]))
    {
      str[i] = '_';
    }
    else
    {
      str[i] = toupper((unsigned char)str[i]);
    }
  }
}

void load_config(menu_t* menus, size_t menu_count)
{
  FILE* f = fopen(".config", "r");
  if (!f)
  {
    return;
  }

  char line[128];
  while (fgets(line, sizeof(line), f))
  {
    char* newline = strchr(line, '\n');
    if (newline)
    {
      *newline = 0;
    }

    for (size_t m = 0; m < menu_count; m++)
    {
      for (size_t i = 0; i < menus[m].num_options; i++)
      {
        if (strncmp(line, menus[m].options[i].name, strlen(menus[m].options[i].name)) == 0)
        {
          if (strstr(line, "=y"))
          {
            menus[m].options[i].enabled = 1;
          }
          else
          {
            menus[m].options[i].enabled = 0;
          }
        }
      }
    }
  }

  fclose(f);
}

const char* cc = "\n\nstatic inline kconf_t get_kconfig(void)\n"
                 "{\n"
                 "\tkconf_t kc = { false, false, false, false, false };\n\n"
                 "#ifdef ENABLE_DEBUGGING_MESSAGES\n"
                 "\tkc.enable_debug = true;\n"
                 "#endif\n"
                 "#ifdef ENABLE_FILESYSTEMS\n"
                 "\tkc.enable_fs = true;\n"
                 "#endif\n"
                 "#ifdef ENABLE_IDE\n"
                 "\tkc.enable_ide = true;\n"
                 "#endif\n"
                 "#ifdef ENABLE_USB\n"
                 "\tkc.enable_usb = true;\n"
                 "#endif\n"
                 "#ifdef ENABLE_NETWORK\n"
                 "\tkc.enable_networking = true;\n"
                 "#endif\n\n"
                 "\treturn kc;\n"
                 "}\n\n"
                 "#ifdef __cplusplus\n"
                 "}\n"
                 "#endif\n";

/* Save current configuration options to Makefile and/or kconfig.h */
void save_config(menu_t* menus, size_t menu_count)
{
  FILE* kconff = fopen("../include/kernel/kconfig.h", "w");
  
  if (!kconff)
  {
    return;
  }
  
  const char* hg = "#ifndef _KCONFIG_H\n#define _KCONFIG_H\n\n#include <types.h>\n\n#ifdef __cplusplus\nextern \"C\" {\n#endif\n\n";
  
  
  fprintf(kconff, hg);
  
  for (size_t m = 0; m < menu_count; m++)
  {
    for (size_t i = 0; i < menus[m].num_options; i++)
    {
      
      char buffer[128];
      strncpy(buffer, menus[m].options[i].name, sizeof(buffer));
      buffer[sizeof(buffer)-1] = '\0';
      strfix(buffer);
      
      if (menus[m].options[i].enabled == 0)
      {
        fprintf(kconff, "//");
      }
      
      fprintf(kconff, "#define %s\n", buffer, menus[m].options[i].enabled);
    }
  }

  fprintf(kconff, cc);

  fprintf(kconff, "\n#endif\n");

  fclose(kconff);
  
  current_config_saved = true;
}

menu_t* create_menu(const char* title)
{
  menu_t* menu = malloc(sizeof(menu_t));
  menu->title = strdup(title);
  menu->options = NULL;
  menu->num_options = 0;
  return menu;
}

void add_option(menu_t* menu, const char* name, int default_value)
{
  menu->options = realloc(menu->options, sizeof(option_t) * (menu->num_options + 1));
  menu->options[menu->num_options].name = strdup(name);
  menu->options[menu->num_options].enabled = default_value;
  menu->num_options++;
}


/* Display a single submenu */
void show_menu(menu_t* menu)
{
  int selected = 0;

  while (1)
  {
    clear();
    mvprintw(0, 0, "%s (SPACE=toggle, (left arrow key or esc)=back, S=save)", menu->title);

    for (size_t i = 0; i < menu->num_options; i++)
    {
      if ((int)i == selected)
      {
        attron(A_REVERSE);
      }
      mvprintw(i + 2, 2, "[%c] %s", menu->options[i].enabled ? 'X' : ' ', menu->options[i].name);
      if ((int)i == selected)
      {
        attroff(A_REVERSE);
      }
    }

    int ch = getch();
    
    if (ch == KEY_UP && selected > 0)
    {
      selected--;
    }
    else if (ch == KEY_DOWN && selected < (int)menu->num_options - 1)
    {
      selected++;
    }
    else if (ch == ' ')
    {
      menu->options[selected].enabled = !menu->options[selected].enabled;
      current_config_saved = false;
    }
    else if (ch == 's' || ch == 'S')
    {
      save_config(all_menus, NUM_MENUS);
      mvprintw(menu->num_options + 3, 2, "Saved.");
      refresh();
      getch();
    }
    else if (ch == KEY_LEFT || ch == KEY_ESCAPE || ch == 'q' || ch == 'Q')
    {
      break;
    }
  }
}

/* Main menu with submenu navigation */
int main(void)
{
  initscr();
  noecho();
  cbreak();
  keypad(stdscr, TRUE);
  set_escdelay(25); /* wait only 25ms for escape sequences */

  /*load_config(all_menus, NUM_MENUS);*/

  int selected = 0;
  while (1)
  {
    clear();
    mvprintw(0, 0, "Kernel Configuration (ENTER=submenu, S=save, Q=quit)");

    for (size_t i = 0; i < NUM_MENUS; i++)
    {
      if ((int)i == selected)
      {
        attron(A_REVERSE);
      }
      mvprintw(i + 2, 2, "> %s", all_menus[i].title);
      if ((int)i == selected)
      {
        attroff(A_REVERSE);
      }
    }

    int ch = getch();
    
    if (ch == KEY_UP && selected > 0)
    {
      selected--;
    }
    else if (ch == KEY_DOWN && selected < (int)NUM_MENUS - 1)
    {
      selected++;
    }
    else if (ch == '\n')
    {
      show_menu(&all_menus[selected]);
    }
    else if (ch == 's' || ch == 'S')
    {
      save_config(all_menus, NUM_MENUS);
      mvprintw(NUM_MENUS + 3, 2, "Saved.");
      refresh();
      getch();
    }
    else if (ch == 'q' || ch == 'Q')
    {
      break;
    }
  }

  endwin();
  return 0;
}