<?php
require_once 'vendor/autoload.php';

class DocumentProcessor {
    private $srcImage;
    private $processedImage;
    private $outputPath;
    
    public function __construct() {
        if (!extension_loaded('opencv')) {
            throw new Exception('OpenCV PHP extension is required');
        }
    }

    public function processDocument($imagePath, $outputPath) {
        $this->outputPath = $outputPath;
        
        // Carrega a imagem
        $this->srcImage = cv\imread($imagePath);
        if ($this->srcImage === null) {
            throw new Exception('Failed to load image');
        }

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

        return $this->outputPath;
    }

    private function detectDocument() {
        // Converte para escala de cinza
        $gray = cv\cvtColor($this->srcImage, cv\COLOR_BGR2GRAY);
        
        // Aplica blur para reduzir ruído
        $blur = cv\GaussianBlur($gray, new cv\Size(5, 5), 0);
        
        // Detecta bordas
        $edges = cv\Canny($blur, 75, 200);
        
        // Encontra contornos
        $contours = new cv\Mat();
        $hierarchy = new cv\Mat();
        cv\findContours($edges, $contours, $hierarchy, cv\RETR_LIST, cv\CHAIN_APPROX_SIMPLE);
        
        // Ordena contornos por área
        usort($contours, function($a, $b) {
            return cv\contourArea($b) - cv\contourArea($a);
        });

        // Procura o contorno mais próximo de um documento
        foreach ($contours as $contour) {
            $peri = cv\arcLength($contour, true);
            $approx = cv\approxPolyDP($contour, 0.02 * $peri, true);
            
            if (count($approx) == 4) {
                $this->documentContour = $approx;
                break;
            }
        }

        return $this;
    }

    private function correctPerspective() {
        if (!isset($this->documentContour)) {
            return $this;
        }

        // Ordena os pontos para perspectiva
        $points = $this->orderPoints($this->documentContour);
        
        // Calcula dimensões do documento
        $width = max(
            sqrt(pow($points[1][0] - $points[0][0], 2) + pow($points[1][1] - $points[0][1], 2)),
            sqrt(pow($points[3][0] - $points[2][0], 2) + pow($points[3][1] - $points[2][1], 2))
        );
        
        $height = max(
            sqrt(pow($points[2][0] - $points[1][0], 2) + pow($points[2][1] - $points[1][1], 2)),
            sqrt(pow($points[3][0] - $points[0][0], 2) + pow($points[3][1] - $points[0][1], 2))
        );

        // Define pontos de destino
        $dst = cv\Mat::zeros([4, 2], CV_32F);
        $dst[0] = [0, 0];
        $dst[1] = [$width - 1, 0];
        $dst[2] = [$width - 1, $height - 1];
        $dst[3] = [0, $height - 1];

        // Aplica transformação de perspectiva
        $matrix = cv\getPerspectiveTransform($points, $dst);
        for ($x = 0; $x < $width; $x++) {
            for ($y = 0; $y < $height; $y++) {
                $rgb = imagecolorat($image, $x, $y);
                $colors = imagecolorsforindex($image, $rgb);
                $value = ($colors['red'] + $colors['green'] + $colors['blue']) / 3;
                $total += $value;
                $count++;
            }
        }

        return $total / $count;
    }

    private function findDocumentBounds($binary) {
        $width = imagesx($binary);
        $height = imagesy($binary);
        $left = $width;
        $right = 0;
        $top = $height;
        $bottom = 0;

        for ($x = 0; $x < $width; $x++) {
            for ($y = 0; $y < $height; $y++) {
                $rgb = imagecolorat($binary, $x, $y);
                if ($rgb == 0x000000) { // Pixel preto
                    if ($x < $left) $left = $x;
                    if ($x > $right) $right = $x;
                    if ($y < $top) $top = $y;
                    if ($y > $bottom) $bottom = $y;
                }
            }
        }

        if ($left < $right && $top < $bottom) {
            return ['left' => $left, 'right' => $right, 'top' => $top, 'bottom' => $bottom];
        }

        return null;
    }

    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, $this->outputPath, 90);
                break;
            case 'png':
                imagepng($this->processedImage, $this->outputPath, 9);
                break;
            default:
                throw new Exception('Unsupported output image type');
        }

        if (is_resource($this->srcImage)) {
            imagedestroy($this->srcImage);
        }
        if (is_resource($this->processedImage)) {
            imagedestroy($this->processedImage);
        }

        return $this;
    }
}