<?php
class DocumentProcessor {
    private $srcImage;
    private $processedImage;
    private $outputPath;
    
    public function __construct() {
        if (!extension_loaded('gd')) {
            throw new Exception('GD extension is required');
        }
    }

    public function processDocument($imagePath, $outputPath) {
        $this->outputPath = $outputPath;
        
        // Detecta o tipo da imagem e carrega
        $imageInfo = getimagesize($imagePath);
        if ($imageInfo === false) {
            throw new Exception('Failed to load image');
        }

        switch ($imageInfo[2]) {
            case IMAGETYPE_JPEG:
                $this->srcImage = imagecreatefromjpeg($imagePath);
                break;
            case IMAGETYPE_PNG:
                $this->srcImage = imagecreatefrompng($imagePath);
                break;
            default:
                throw new Exception('Unsupported image type');
        }

        if ($this->srcImage === false) {
            throw new Exception('Failed to create image resource');
        }

        // Pipeline de processamento
        $this->enhanceImage()
             ->saveResult();

        return $this->outputPath;
    }

    private function enhanceImage() {
        // Obtém dimensões originais
        $width = imagesx($this->srcImage);
        $height = imagesy($this->srcImage);
        
        // Cria nova imagem
        $this->processedImage = imagecreatetruecolor($width, $height);
        
        // Preserva transparência para PNGs
        imagealphablending($this->processedImage, false);
        imagesavealpha($this->processedImage, true);
        
        // Copia imagem original
        imagecopy($this->processedImage, $this->srcImage, 0, 0, 0, 0, $width, $height);
        
        // Ajusta contraste
        imagefilter($this->processedImage, IMG_FILTER_CONTRAST, -10);
        
        // Ajusta brilho
        imagefilter($this->processedImage, IMG_FILTER_BRIGHTNESS, 10);
        
        // Ajusta nitidez
        imagefilter($this->processedImage, IMG_FILTER_SMOOTH, -7);
        
        // Ajusta saturação
        imagefilter($this->processedImage, IMG_FILTER_COLORIZE, 0, 0, 0, 10);

        return $this;
    }

    private function saveResult() {
        if (!isset($this->processedImage)) {
            throw new Exception('No processed image to save');
        }

        $extension = strtolower(pathinfo($this->outputPath, PATHINFO_EXTENSION));
        
        switch ($extension) {
            case 'jpg':
            case 'jpeg':
                imagejpeg($this->processedImage, $this->outputPath);
                break;
            case 'png':
                imagepng($this->processedImage, $this->outputPath);
                break;
            default:
                throw new Exception('Unsupported output image type');
        }

        return $this;
    }

    private function orderPoints($pts) {
        // Ordena pontos para transformação de perspectiva
        $rect = array_fill(0, 4, [0, 0]);
        $s = array_map(function($p) { return $p[0] + $p[1]; }, $pts);
        $d = array_map(function($p) { return $p[0] - $p[1]; }, $pts);
        
        $rect[0] = $pts[array_search(min($s), $s)]; // top-left
        $rect[2] = $pts[array_search(max($s), $s)]; // bottom-right
        $rect[1] = $pts[array_search(min($d), $d)]; // top-right
        $rect[3] = $pts[array_search(max($d), $d)]; // bottom-left
        
        return $rect;
    }
}