#include "font.h"
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>

#define FILE_NAME_SIZE 300

void free_sprite_font(sprite_font* font) {
  free(font->characters);
  SDL_DestroyTexture(font->spritesheet);

  memset(font, 0, sizeof(sprite_font));
}

int get_string_parameter(const char* line, const char* parameter, const char** start) {
  *start = strstr(line, parameter);
  if ((*start) == NULL)
    return -1;

  *start += strlen(parameter);
  if ((*start)[0] != '\"') {
    return -1;
  }

  int length = 0;
  while ((*start)[length+1] != '\0' && (*start)[length+1] != '\"') length++;

  (*start)++;
  return length;
}

char parse_character_tag(const char* character_tag) {
  if (strncmp(character_tag, "space", 5) == 0)
    return ' ';

  return character_tag[0];
}

bool get_int_parameter(const char* line, const char* parameter, int* value) {
  const char* start = strstr(line, parameter);
  if (start == NULL) {
    return false;
  }
  start += strlen(parameter);

  int c = 0;
  bool negative = false;

  if (start[0] == '-') {
    negative = true;
    start++;
  }

  for(int i = 0; start[i] >= '0' && start[i] <= '9'; i++) {
    c *= 10; c += start[i] - '0';
  }

  *value = negative ? -c : c;
  return true;
}

bool load_sprite_font(const char* filename, sprite_font* font) {
  if (font->characters || font->spritesheet) {
    SDL_Log("Trying to reallocate font causing memory leak, exitting!");
    exit(EXIT_FAILURE);
  }

  FILE* f = fopen(filename, "r");
  if (f == NULL) {
    SDL_Log("Failed to open sprite font file %s, error: %s, exitting!",
            filename,
            strerror(errno)
            );
    exit(EXIT_FAILURE);
  }

  char line[PARSER_LINE_SIZE];
  if (fgets(line, sizeof(line), f) == NULL ||
      strncmp(line, "info", 4) != 0) {
    SDL_Log("File %s is not a valid font file, exitting!",
            filename);
    fclose(f);
    exit(EXIT_FAILURE);
  }

  char font_name[FONT_NAME_SIZE];
  const char* font_name_start;
  int font_name_length =
    SDL_min(get_string_parameter(line, "face=", &font_name_start),
            FONT_NAME_SIZE-1
            );

  strncpy(font_name, font_name_start, font_name_length);
  font_name[font_name_length] = '\0';

  int char_size = 0, char_count = 0;
  font_char* characters_unarranged = NULL;

  while (fgets(line, PARSER_LINE_SIZE, f) != NULL) {

    if (strncmp(line, "chars", 5) == 0) {
      int total_char_count;

      if(!get_int_parameter(line, "count=", &total_char_count))
        continue;

      char_size = total_char_count;
      characters_unarranged =
        realloc(characters_unarranged, char_size * sizeof(font_char));

      if (characters_unarranged == NULL) {
        SDL_Log("Failed to allocate space while loading font %s, error %s, exitting!",
                filename,
                strerror(errno));
        exit(EXIT_FAILURE);
      }
    }

    else if (strncmp(line, "char", 4) == 0) {
      font_char new_font_char;

      int val;

      if (!get_int_parameter(line, "x=", &val))
        continue;
      new_font_char.x = val;

      if (!get_int_parameter(line, "y=", &val))
        continue;
      new_font_char.y = val;

      if (!get_int_parameter(line, "width=", &val))
        continue;
      new_font_char.width = val;

      if (!get_int_parameter(line, "height=", &val))
        continue;
      new_font_char.height = val;

      if (!get_int_parameter(line, "xoffset=", &val))
        continue;
      new_font_char.x_offset = val;

      if (!get_int_parameter(line, "yoffset=", &val))
        continue;
      new_font_char.y_offset = val;

      if (!get_int_parameter(line, "xadvance=", &val))
        continue;
      new_font_char.x_advance = val;

      const char* character_tag;
      if (get_string_parameter(line, "letter=", &character_tag) <= 0)
        continue;
      new_font_char.character = parse_character_tag(character_tag);

      if (char_count >= char_size) {
        char_size = char_count+1;
        characters_unarranged =
          realloc(characters_unarranged, char_size * sizeof(font_char));
      }

      if (characters_unarranged == NULL) {
        SDL_Log("Failed to allocate space while loading font %s, error %s, exitting!",
                filename,
                strerror(errno));
        exit(EXIT_FAILURE);
      }

      characters_unarranged[char_count] = new_font_char;
      char_count++;
    }
  }

  fclose(f);
  return true;
}