<?php
/*************************************************************
# 076 License

Copyright (c) テクニカル諏訪子

Permission is hereby granted to any person obtaining a copy of the software
Little Beast (the "Software") to use, modify, merge, copy, publish, distribute,
sublicense, and/or sell copies of the Software, subject to the following conditions:

    1. **Origin Attribution**:
       - You must not misrepresent the origin of the Software; you must not claim
         you created the original Software.
       - If the Software is used in a product, you must either:
         a. Provide clear attribution in the product's documentation, user interface,
            or other visible areas, **OR**
         b. Pay the original developers a fee they specify in writing.
    2. **Usage Restriction**:
       - The Software, or any derivative works, dependencies, or libraries
         incorporating it, must not be used for censorship or to suppress freedom of
         speech, expression, or creativity. Prohibited uses include, but are not
         limited to:
         - Censorship of so-called "hate speech", visuals, non-mainstream opinions,
           ideas, or objective reality.
         - Tools or systems designed to restrict access to information or
           artistic works.
    3. **Notice Preservation**:
       - This license and the above copyright notice must remain intact in all copies
         of the source code.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE
OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
namespace Std\Lib;

use Std\Lib\Image\ImageInterface;
use Std\Lib\Image\Bitmap;
use Std\Lib\Image\Bmp;
use Std\Lib\Image\Gif;
use Std\Lib\Image\Jpeg;
use Std\Lib\Image\Png;
use Std\Lib\Image\Targa;
use Std\Lib\Image\Webp;

class RGB {
  public int $r;
  public int $g;
  public int $b;
  public array $rgb;

  public function __construct(int $r, int $g, int $b) {
    $this->r = $r;
    $this->g = $g;
    $this->b = $b;
    $this->rgb = ['r' => $r, 'g' => $g, 'b' => $b];
  }
}

class Image {
  public string $filename = 'UNKNOWN';
  public string $extension = 'UNKNOWN';
  public string $type = 'UNSUPPORTED';
  public string $size = '0 B';
  public int $bytes = 0;
  public \stdClass $fullInfo;

  private const SUPPORTED = [
    'image/bmp'   => Bmp::class,
    'image/gif'   => Gif::class,
    'image/jpeg'  => Jpeg::class,
    'image/png'   => Png::class,
    'image/webp'  => Webp::class,
    'image/x-tga' => Targa::class,
  ];

  public function __construct(string $file) {
    // ファイルが無くてもfullInfoを読める様に（以前は未初期化のままで、記事のサムネイルが無いとページが落ちた）
    $this->fullInfo = (object)['type' => $this->type, 'size' => $this->size, 'bytes' => 0, 'width' => 0, 'height' => 0];
    $file = ROOT.$file;
    // $file = ROOT.'/public/static/article/mock-screenshot.tga';
    if (!file_exists($file)) return;
    $fp = fopen($file, 'rb');
    if (!$fp) return;
    $extBytes = (string)fread($fp, 32);
    fclose($fp);

    $this->bytes = filesize($file);
    $this->size = $this->formatBytes($this->bytes);
    $this->extension = pathinfo($file, PATHINFO_EXTENSION);
    $this->filename = str_replace('.'.$this->extension, '', array_last(explode('/', $file)));

    $this->type = self::detect($extBytes, $file) ?? 'UNSUPPORTED';

    $this->fullInfo = self::handler($this->type)->parse($file);
    $this->fullInfo->type = $this->type;
    $this->fullInfo->size = $this->size;
    $this->fullInfo->bytes = $this->bytes;
    if (!isset($this->fullInfo->width) && isset($this->fullInfo->header->width)) {
      $this->fullInfo->width = $this->fullInfo->header->width;
      $this->fullInfo->height = $this->fullInfo->header->height;
    }
  }

  /**
   * ファイルの先頭から形式を判断する（TGAは印が無いので、ファイル名が「.tga」の場合だけ）
   *
   * @param string $head  ファイルの先頭（32バイト以上）
   * @param string $name  ファイル名（TGA用、任意）
   * @return string|null  MIME、分からなければnull
   */
  public static function detect(string $head, string $name = ''): ?string {
    if (str_starts_with($head, "\xff\xd8\xff")) return 'image/jpeg';
    if (str_starts_with($head, "\x89PNG\r\n\x1a\n")) return 'image/png';
    if (str_starts_with($head, 'GIF87a') || str_starts_with($head, 'GIF89a')) return 'image/gif';
    if (str_starts_with($head, 'RIFF') && substr($head, 8, 4) === 'WEBP') return 'image/webp';
    // BMP：「BM」と、知っているヘッダーの大きさ
    if (str_starts_with($head, 'BM') && strlen($head) >= 18 && in_array(unpack('V', substr($head, 14, 4))[1], [12, 16, 40, 52, 56, 64, 108, 124], true)) return 'image/bmp';
    if (str_ends_with(strtolower($name), '.tga')) return 'image/x-tga';
    return null;
  }

  /**
   * ファイルの中身を画素にする
   *
   * @param string $data  ファイルの中身
   * @param string $name  ファイル名（TGA用、任意）
   * @return Bitmap
   * @throws \RuntimeException  未対応の形式又は壊れたファイル
   */
  public static function decode(string $data, string $name = ''): Bitmap {
    return self::handler(self::detect($data, $name) ?? '')->decode($data);
  }

  /**
   * 画素をファイルの中身にする
   *
   * @param string $type  MIME（image/png等）
   * @param array $opt  形式毎の設定（PNG：level、JPEG：quality等）
   */
  public static function encode(Bitmap $img, string $type, array $opt = []): string {
    return self::handler($type)->encode($img, $opt);
  }

  ///////////////

  private static function handler(string $type): ImageInterface {
    $class = self::SUPPORTED[$type] ?? null;
    if (!$class) throw new \RuntimeException("形式のハンドルが存在しない： {$type}");
    return new $class();
  }

  private function formatBytes(int $size, int $precision = 2): string {
    $units = ['B', 'KiB', 'MiB', 'GiB', 'TiB'];
    for ($i = 0; $size > 1024 && $i < count($units) - 1; ++$i) $size /= 1024;
    return round($size, $precision).' '.$units[$i];
  }
}