/*
 * Copyright 2022 Frederico de Oliveira Linhares
 *
 * 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 "pgm_image.h"

#include <cstring>
#include <charconv>
#include <fstream>
#include <string>

SDL_bool PGMImage_constructor(PGMImage *self, const char *file_path)
{
  self->data = nullptr;
  int wh_pos;
  std::string line;
  std::ifstream file(file_path);

  if(!file)
  {
    self->error = "Failed to open PGM file";
    return SDL_FALSE;
  }

  // Read file magic.
  std::getline(file, line);
  if(line != "P5")
  {
    self->error = "PGM file contains a invalid magic";
    return SDL_FALSE;
  }

  // Read file comment.
  std::getline(file, line);

  // Read file width and height.
  std::getline(file, line);
  wh_pos = line.find(" ");
  std::from_chars(line.data(), line.data() + wh_pos, self->width);
  std::from_chars(
      line.data() + wh_pos + 1, line.data() + line.size(), self->height);

  // Read file maximum value.
  std::getline(file, line);
  std::from_chars(line.data(), line.data() + line.size(), self->max_value);

  // Read file values.
  self->data_size = self->width * self->height;
  self->data = new char[self->data_size];
  file.read(self->data, self->data_size);

  return SDL_TRUE;
}

void PGMImage_destructor(PGMImage *self)
{
  if(self->data != nullptr) delete[] self->data;
}