<?php
// Cargar configuración
require_once __DIR__ . '/../../config/config.php';

class HtmlToDiscordMarkdownConverter
{
    private const DISCORD_MESSAGE_LIMIT = 2000;

    public function convert(string $html): string
    {
        $dom = new DOMDocument();
        libxml_use_internal_errors(true); // Suppress warnings for malformed HTML
        // Use LIBXML_HTML_NOIMPLIED | LIBXML_HTML_NODEFDTD to prevent adding html/body tags
        $dom->loadHTML('<?xml encoding="utf-8" ?>' . $html, LIBXML_HTML_NOIMPLIED | LIBXML_HTML_NODEFDTD);
        libxml_clear_errors();

        $markdown = '';

        foreach ($dom->childNodes as $node) {
            $markdown .= $this->processNode($node);
        }

        // Clean up extra newlines
        $markdown = preg_replace('/\n{3,}/', "\n\n", $markdown);
        $markdown = trim($markdown);

        return $markdown;
    }

    private function processNode(DOMNode $node): string
    {
        $output = '';

        switch ($node->nodeType) {
            case XML_TEXT_NODE:
                $output .= $this->decodeHtmlEntities($node->nodeValue);
                break;
            case XML_ELEMENT_NODE:
                switch (strtolower($node->nodeName)) {
                    case 'b':
                    case 'strong':
                        $output .= '**' . $this->processChildren($node) . '**';
                        break;
                    case 'i':
                    case 'em':
                        $output .= '*' . $this->processChildren($node) . '*';
                        break;
                    case 'u':
                        $output .= '__' . $this->processChildren($node) . '__';
                        break;
                    case 'a':
                        $href = $node->getAttribute('href');
                        
                        // Ignorar nodos de texto con solo espacios en blanco para un análisis más preciso.
                        $realChildNodes = [];
                        foreach ($node->childNodes as $child) {
                            if ($child->nodeType === XML_TEXT_NODE && trim($child->nodeValue) === '') {
                                continue;
                            }
                            $realChildNodes[] = $child;
                        }

                        // Si el único hijo real es una imagen, procesarla directamente.
                        if (count($realChildNodes) === 1 && strtolower($realChildNodes[0]->nodeName) === 'img') {
                            $output .= $this->processChildren($node);
                        } else {
                            // Si no, trátalo como un enlace de texto normal.
                            $text = $this->processChildren($node);
                            $output .= "[{$text}]({$href})";
                        }
                        break;
                    case 'p':
                        $output .= $this->processChildren($node) . "\n\n";
                        break;
                    case 'br':
                        $output .= "\n";
                        break;
                    case 'ul':
                    case 'ol':
                        $listContent = $this->processChildren($node);
                        $listItems = explode("\n", trim($listContent));
                        $formattedList = [];
                        $counter = 1;
                        foreach($listItems as $item) {
                            if(empty(trim($item))) continue;
                            if (strtolower($node->nodeName) === 'ul') {
                                $formattedList[] = '- ' . trim($item);
                            } else {
                                $formattedList[] = ($counter++) . '. ' . trim($item);
                            }
                        }
                        $output .= implode("\n", $formattedList) . "\n\n";
                        break;
                    case 'li':
                        $output .= $this->processChildren($node);
                        break;
                    case 'img':
                        $src = $node->getAttribute('src');
                        if (!empty($src)) {
                            $absoluteImageUrl = $src;
                            // Convertir URL relativa a absoluta si es necesario
                            if (strpos($src, 'http') !== 0 && strpos($src, '//') !== 0) {
                                $base = rtrim(BOT_BASE_URL, '/');
                                $path = ltrim($src, '/');
                                $absoluteImageUrl = "{$base}/{$path}";
                            }
                            // Dejar solo la URL para que Discord la renderice
                            $output .= "\n" . $absoluteImageUrl . "\n";
                        }
                        break;
                    case 'div':
                        $output .= $this->processChildren($node);
                        break;
                    default:
                        // For unknown tags, just process their children
                        $output .= $this->processChildren($node);
                        break;
                }
                break;
        }
        return $output;
    }

    private function processChildren(DOMNode $node): string
    {
        $childrenOutput = '';
        foreach ($node->childNodes as $child) {
            $childrenOutput .= $this->processNode($child);
        }
        return $childrenOutput;
    }

    private function decodeHtmlEntities(string $encodedString): string
    {
        return html_entity_decode($encodedString, ENT_QUOTES | ENT_HTML5, 'UTF-8');
    }

    public function convertToArray(string $html): array
    {
        $parts = [];
        $dom = new DOMDocument();
        libxml_use_internal_errors(true);
        $dom->loadHTML('<?xml encoding="utf-8" ?>' . $html, LIBXML_HTML_NOIMPLIED | LIBXML_HTML_NODEFDTD);
        libxml_clear_errors();

        foreach ($dom->childNodes as $node) {
            $this->processNodeForArray($node, $parts);
        }

        return $parts;
    }

    private function processNodeForArray(DOMNode $node, array &$parts)
    {
        if ($node->nodeType === XML_TEXT_NODE) {
            $this->addTextPart($parts, $this->decodeHtmlEntities($node->nodeValue));
            return;
        }

        if ($node->nodeType !== XML_ELEMENT_NODE) {
            return;
        }

        switch (strtolower($node->nodeName)) {
            case 'img':
                $src = $node->getAttribute('src');
                if (!empty($src)) {
                    $absoluteImageUrl = $src;
                    if (strpos($src, 'http') !== 0 && strpos($src, '//') !== 0) {
                        $base = rtrim(BOT_BASE_URL, '/');
                        $path = ltrim($src, '/');
                        $absoluteImageUrl = "{$base}/{$path}";
                    }
                    $parts[] = ['type' => 'image', 'url' => $absoluteImageUrl];
                }
                break;
            
            case 'p':
            case 'div':
                if ($node->hasChildNodes()) {
                    foreach ($node->childNodes as $child) {
                        $this->processNodeForArray($child, $parts);
                    }
                }
                $this->addTextPart($parts, "\n\n");
                break;

            default:
                if ($node->hasChildNodes()) {
                    foreach ($node->childNodes as $child) {
                        $this->processNodeForArray($child, $parts);
                    }
                }
                break;
        }
    }

    private function addTextPart(array &$parts, string $text)
    {
        if (empty($text)) return;

        // Si la última parte fue texto, la unimos a ella.
        if (!empty($parts) && end($parts)['type'] === 'text') {
            $parts[key($parts)]['content'] .= $text;
        } else {
            $parts[] = ['type' => 'text', 'content' => $text];
        }
    }
}