<?php
/* Portions derived from NoAdCode (https://noadcode.com), GPL v2 or later. */

if (!defined('ABSPATH')) {
    exit;
}

class AdGhost_Safety_Validator {

    const DEFAULT_THRESHOLD = 55;

    const DEFAULT_WIDTH_THRESHOLD = 40;

    const DESKTOP_VIEWPORT = 1200;

    const SEMANTIC_WIDTHS = [
        'article' => 70,
        'main'    => 70,
        'aside'   => 30,
    ];

    const CLASS_WIDTHS = [

        'elementor-col-20' => 20,
        'elementor-col-25' => 25,
        'elementor-col-33' => 33,
        'elementor-col-50' => 50,
        'elementor-col-66' => 66,
        'wp-block-column'  => 30,

        'e-child'          => 50,
        'elementor-inner-column' => 50,
        'widget-area'      => 30,
        'wp-sidebar'       => 30,
        'side-panel'       => 30,
        'sidebar'          => 30,
        'secondary'        => 30,
        'widget_'          => 30,
        'col-sm-3'         => 25,
        'col-md-3'         => 25,
        'col-lg-3'         => 25,
        'col-sm-4'         => 33,
        'col-md-4'         => 33,
        'col-lg-4'         => 33,

        'col-sm-6'         => 50,
        'col-md-6'         => 50,
        'col-lg-6'         => 50,
        'col-xl-6'         => 50,
        'col-6'            => 50,
        'col-sm-7'         => 58,
        'col-md-7'         => 58,
        'col-lg-7'         => 58,
        'col-7'            => 58,

        'col-md-8'         => 66,
        'col-lg-8'         => 66,
        'col-md-9'         => 75,
        'col-lg-9'         => 75,
        'col-md-10'        => 83,
        'entry-content'    => 100,
        'post-content'     => 100,
        'article-content'  => 100,
        'main-content'     => 100,
        'page-content'     => 100,
        'site-content'     => 100,
        'content-area'     => 100,
        'primary-content'  => 100,
    ];

    private $threshold;

    private $width_threshold;

    public function __construct($threshold = null, $width_threshold = null) {
        $this->threshold = (int) ($threshold ?? apply_filters('adghost_safety_threshold', self::DEFAULT_THRESHOLD));
        $this->width_threshold = (int) ($width_threshold ?? apply_filters('adghost_width_threshold', self::DEFAULT_WIDTH_THRESHOLD));
    }

    public function validate(array $point, $content, $sizes = '') {
        $offset = (int) ($point['offset'] ?? 0);
        $before = substr($content, 0, $offset);
        $after  = substr($content, $offset);

        $state = [
            'score'   => 100,
            'checks'  => [],
            'reasons' => [],
        ];

        $this->check_structural($before, $state);
        $width = $this->check_width($before, $sizes, $state);
        $this->check_context($before, $after, $state);
        $this->check_nesting($before, $state);
        $this->check_grid($before, $state);

        $score = max(0, min(100, $state['score']));

        return [
            'passed'        => $score >= $this->threshold && empty($state['reasons']),
            'score'         => $score,
            'checks'        => $state['checks'],
            'reasons'       => $state['reasons'],
            'width_percent' => $width['percent'],
            'width_px'      => $width['px'],
        ];
    }

    private function check_structural($before, array &$state) {

        $penalties = [
            'nav' => 50, 'footer' => 50, 'table' => 40, 'form' => 40,
            'aside' => 40, 'iframe' => 40, 'script' => 50, 'style' => 50,
        ];

        $passed = true;
        foreach (AdGhost_Protected_Elements::TAGS as $tag) {

            if ($tag === 'header' || !$this->is_open($before, $tag)) {
                continue;
            }
            $state['score'] -= ($penalties[$tag] ?? 30);
            $state['reasons'][] = sprintf('Inside a <%s> element', $tag);
            $passed = false;
        }

        if ($this->is_open($before, 'header')
            && !preg_match('/<(main|article|div[^>]*class="[^"]*(?:content|entry|post)[^"]*")[^>]*>/i', $before)) {
            $state['score'] -= 50;
            $state['reasons'][] = 'Inside a <header> element';
            $passed = false;
        }

        $state['checks']['structural'] = $passed;
    }

    private function check_width($before, $sizes, array &$state) {
        $container = $this->detect_container_width($before);
        $percent   = $container['percent'];
        $px        = (int) round((self::DESKTOP_VIEWPORT * $percent) / 100);

        $passed = $percent >= $this->width_threshold;
        if (!$passed) {
            $state['score'] -= 40;
            $state['reasons'][] = sprintf(
                'Container is only %d%% wide (%s)',
                $percent,
                $container['source']
            );
        }

        if ($sizes !== '') {
            $widest = $this->widest_size($sizes);
            if ($widest > 0 && $widest > $px) {
                $state['score'] -= 40;
                $state['reasons'][] = sprintf(
                    'Creative is %dpx wide but the container is about %dpx (%d%%, %s)',
                    $widest,
                    $px,
                    $percent,
                    $container['source']
                );
                $passed = false;
            }
        }

        $state['checks']['width'] = $passed;

        return ['percent' => $percent, 'px' => $px];
    }

    /* Portions derived from NoAdCode (https://noadcode.com), GPL v2 or later. */
    public function detect_container_width($before) {
        $stack = $this->parse_parent_containers($before);
        if (empty($stack)) {
            return ['percent' => 100, 'source' => 'no container detected'];
        }
        $immediate = end($stack);
        return ['percent' => $immediate['width'], 'source' => $immediate['source']];
    }

    private function parse_parent_containers($before) {

        $containers = [];
        foreach ($this->open_elements($before) as $el) {
            $el['width'] = $this->width_of($el['tag'], $el['attributes']);
            if ($el['width'] !== null) {
                $containers[] = [
                    'tag'    => $el['tag'],
                    'width'  => $el['width']['percent'],
                    'source' => $el['width']['source'],
                ];
            }
        }
        return $containers;
    }

    private function open_elements($before) {

        $before = preg_replace_callback('/<!--.*?-->/s', function ($c) {
            return str_repeat(' ', strlen($c[0]));
        }, $before);
        if (!preg_match_all('/<(\/?)([a-z][a-z0-9]*)\b([^>]*)>/i', $before, $m)) {
            return [];
        }

        $open = [];
        $void = ['img', 'br', 'hr', 'input', 'meta', 'link', 'source', 'area', 'col', 'embed', 'track', 'wbr'];

        foreach ($m[0] as $i => $unused) {
            $tag        = strtolower($m[2][$i]);
            $attributes = $m[3][$i];

            if (in_array($tag, $void, true) || substr(rtrim($attributes), -1) === '/') {
                continue;
            }

            if ($m[1][$i] === '/') {
                for ($s = count($open) - 1; $s >= 0; $s--) {
                    if ($open[$s]['tag'] === $tag) {
                        array_splice($open, $s);
                        break;
                    }
                }
                continue;
            }

            $open[] = ['tag' => $tag, 'attributes' => $attributes];
        }
        return $open;
    }

    private function width_of($tag, $attributes) {

        if (preg_match('/style=["\']([^"\']*)["\']/i', $attributes, $style_match)) {
            $style = $style_match[1];
            if (preg_match('/flex:\s*\d+\s+\d+\s+(\d+)%/i', $style, $m)) {
                return ['percent' => (int) $m[1], 'source' => 'inline flex-basis'];
            }
            if (preg_match('/max-width:\s*(\d+)%/i', $style, $m)) {
                return ['percent' => (int) $m[1], 'source' => 'inline max-width'];
            }

            if (preg_match('/(?<![\w-])width:\s*(\d+)%/i', $style, $m)) {
                return ['percent' => (int) $m[1], 'source' => 'inline width'];
            }
            if (preg_match('/(?<![\w-])width:\s*(\d+)px/i', $style, $m)) {
                $percent = (int) round(((int) $m[1] / self::DESKTOP_VIEWPORT) * 100);
                return ['percent' => min(100, $percent), 'source' => 'inline width ' . $m[1] . 'px'];
            }
        }

        if (isset(self::SEMANTIC_WIDTHS[$tag])) {
            return ['percent' => self::SEMANTIC_WIDTHS[$tag], 'source' => '<' . $tag . '>'];
        }

        if (preg_match('/class=["\']([^"\']+)["\']/i', $attributes, $class_match)) {
            $classes = $class_match[1];
            foreach (self::CLASS_WIDTHS as $pattern => $width) {
                if (stripos($classes, $pattern) !== false) {
                    return ['percent' => $width, 'source' => 'class "' . $pattern . '"'];
                }
            }
        }

        return null;
    }

    public function creative_fit($width_px, $sizes_str) {
        if ($width_px <= 0 || trim((string) $sizes_str) === '') {
            return null;
        }
        $widest = $this->widest_size($sizes_str);
        if ($widest > 0 && $widest > $width_px) {
            return sprintf(
                'Creative is %dpx wide but this container is about %dpx',
                $widest,
                $width_px
            );
        }
        return null;
    }

    private function widest_size($sizes_str) {
        $widest = 0;
        foreach (preg_split('/[;,]/', $sizes_str) as $size) {
            if (preg_match('/(\d+)\s*x\s*\d+/i', trim($size), $m)) {
                $widest = max($widest, (int) $m[1]);
            }
        }
        return $widest;
    }

    private function check_context($before, $after, array &$state) {
        $chars_before = strlen(trim(wp_strip_all_tags($before)));
        $chars_after  = strlen(trim(wp_strip_all_tags($after)));

        $min   = 50;
        $ideal = 150;
        $passed = true;

        if ($chars_before < 10) {
            $state['score'] -= 2;
        }

        if ($chars_after < $min) {
            $state['score'] -= ($chars_after < 20) ? 15 : 10;
            $state['reasons'][] = sprintf('Only %d characters of content follow this point', $chars_after);
            $passed = false;
        }

        if ($chars_before >= $ideal && $chars_after >= $ideal) {
            $state['score'] += 15;
        } elseif ($chars_before >= $min && $chars_after >= $min) {
            $state['score'] += 10;
        }

        $state['checks']['context'] = $passed;
    }

    private function check_nesting($before, array &$state) {
        $depth = preg_match_all('/<div\b/i', $before) - preg_match_all('/<\/div>/i', $before);

        $passed = true;
        if ($depth > 10) {
            $state['score'] -= 20;
            $state['reasons'][] = sprintf('Nested %d levels deep (likely a widget)', $depth);
            $passed = false;
        } elseif ($depth < 5) {
            $state['score'] += 10;
        }

        $state['checks']['nesting'] = $passed;
        $state['nesting_depth'] = $depth;
    }

    private function check_grid($before, array &$state) {
        $passed = true;
        $type   = null;

        foreach (array_reverse($this->open_elements($before)) as $el) {
            $attributes = $el['attributes'];
            $style = preg_match('/style\s*=\s*("([^"]*)"|\'([^\']*)\')/i', $attributes, $sm) ? ($sm[2] !== '' ? $sm[2] : ($sm[3] ?? '')) : '';
            $class = preg_match('/class\s*=\s*("([^"]*)"|\'([^\']*)\')/i', $attributes, $cm) ? ($cm[2] !== '' ? $cm[2] : ($cm[3] ?? '')) : '';
            if (preg_match('/(?<![\w-])display:\s*(?:inline-)?grid/i', $style)) {
                $type = 'a CSS grid';
            } elseif (preg_match('/(?<![\w-])display:\s*(?:inline-)?flex/i', $style)) {
                $type = 'a flex row';
            } else {
                foreach (['wp-block-columns', 'wp-block-media-text', 'e-grid', 'elementor-grid', 'grid-cols', 'd-flex', 'row'] as $cls) {
                    if (preg_match('/(?<![\w-])' . preg_quote($cls, '/') . '(?![\w-])/i', $class)) {
                        $type = 'a "' . $cls . '" layout';
                        break;
                    }
                }
            }
            if ($type !== null) {
                break;
            }
        }

        if ($type !== null) {
            $state['score'] -= 40;
            $state['reasons'][] = 'Inside ' . $type . ' — an ad here breaks the row';
            $passed = false;
        }

        $state['checks']['grid'] = $passed;
    }

    private function is_open($before, $tag) {
        $opened = preg_match_all('/<' . $tag . '(?:\s[^>]*)?>/i', $before);
        $closed = preg_match_all('/<\/' . $tag . '>/i', $before);
        return $opened > $closed;
    }
}