<?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
        $blur = new cv\Mat();
        cv\GaussianBlur($gray, $blur, new cv\Size(5, 5), 0);
        
        // Detecta bordas
        $edges = new cv\Mat();
        cv\Canny($blur, $edges, 75, 200);
        
        // Encontra contornos
        $contours = [];
        $hierarchy = new cv\Mat();
        cv\findContours($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);
        $this->processedImage = cv\warpPerspective($this->srcImage, $matrix, [$width, $height]);

        return $this;
    }

    private function enhanceImage() {
        if (!isset($this->processedImage)) {
            $this->processedImage = $this->srcImage;
        }

        // Converte para LAB para melhor processamento
        $lab = cv\cvtColor($this->processedImage, cv\COLOR_BGR2LAB);
        $l_channel = cv\split($lab)[0];
        
        // Aplica CLAHE para melhorar contraste
        $clahe = cv\createCLAHE(3.0, [8, 8]);
        $cl = $clahe->apply($l_channel);
        
        // Reconstrói imagem
        $limg = cv\merge([$cl, cv\split($lab)[1], cv\split($lab)[2]]);
        $this->processedImage = cv\cvtColor($limg, cv\COLOR_LAB2BGR);

        return $this;
    }

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

        cv\imwrite($this->outputPath, $this->processedImage);
        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;
    }
}