<?php

declare(strict_types=1);

namespace Website\Docs\Controllers;

use Illuminate\Http\Request;
use Illuminate\Routing\Controller;
use Illuminate\Support\Facades\Cache;
use Illuminate\Support\Str;

/**
 * docs.lthn.io — render markdown documentation.
 *
 *   GET /                    — docs homepage
 *   GET /search?q=query      — search docs
 *   GET /{section}/{page?}   — render a doc page
 */
class DocsController extends Controller
{
    private string $contentPath;

    /** Sidebar navigation structure */
    private array $navigation = [
        'getting-started' => [
            'label' => 'Getting Started',
            'pages' => [
                'introduction' => 'Introduction',
                'quick-start' => 'Quick Start',
                'registration' => 'Register a Name',
                'dns-management' => 'Manage DNS',
            ],
        ],
        'chain' => [
            'label' => 'Blockchain',
            'pages' => [
                'overview' => 'Overview',
                'daemon-rpc' => 'Daemon RPC',
                'wallet-rpc' => 'Wallet RPC',
                'mining' => 'Mining',
                'aliases' => 'Chain Aliases',
                'hardforks' => 'Hardfork History',
            ],
        ],
        'names' => [
            'label' => 'Name System',
            'pages' => [
                'overview' => 'Overview',
                'registration' => 'Registration',
                'dns-records' => 'DNS Records',
                'sunrise' => 'Sunrise Period',
                'sidechain' => 'ITNS Sidechain',
            ],
        ],
        'services' => [
            'label' => 'Services',
            'pages' => [
                'dns-hosting' => 'DNS Hosting',
                'ssl-certificates' => 'SSL Certificates',
                'proxy-network' => 'Proxy Network',
                'gateway-operators' => 'Gateway Operators',
            ],
        ],
        'api' => [
            'label' => 'API Reference',
            'pages' => [
                'overview' => 'Overview',
                'names' => 'Names API',
                'explorer' => 'Explorer API',
                'proxy' => 'Proxy API',
                'gateway' => 'Gateway API',
                'authentication' => 'Authentication',
            ],
        ],
        'governance' => [
            'label' => 'Governance',
            'pages' => [
                'cic' => 'Community Interest Company',
                'wallet-holders' => 'Wallet Holders',
                'economics' => 'Token Economics',
            ],
        ],
    ];

    public function __construct()
    {
        $this->contentPath = base_path('app/Website/Docs/Content');
    }

    public function index(): \Illuminate\View\View
    {
        return view('docs::index', [
            'navigation' => $this->navigation,
        ]);
    }

    public function show(string $section, ?string $page = null): \Illuminate\View\View
    {
        $page = $page ?? 'overview';
        $filePath = "{$this->contentPath}/{$section}/{$page}.md";

        if (! file_exists($filePath)) {
            abort(404);
        }

        $markdown = file_get_contents($filePath);
        $html = $this->renderMarkdown($markdown);
        $title = $this->extractTitle($markdown);

        // Find current position in nav for prev/next
        $prevNext = $this->findPrevNext($section, $page);

        return view('docs::show', [
            'navigation' => $this->navigation,
            'currentSection' => $section,
            'currentPage' => $page,
            'content' => $html,
            'title' => $title,
            'prev' => $prevNext['prev'],
            'next' => $prevNext['next'],
        ]);
    }

    public function search(Request $request): \Illuminate\View\View
    {
        $query = trim((string) $request->get('q', ''));
        $results = [];

        if (strlen($query) >= 2) {
            $results = $this->searchContent($query);
        }

        return view('docs::search', [
            'navigation' => $this->navigation,
            'query' => $query,
            'results' => $results,
        ]);
    }

    private function renderMarkdown(string $markdown): string
    {
        // Strip YAML frontmatter
        $markdown = preg_replace('/^---\n.*?\n---\n/s', '', $markdown);

        // Basic markdown to HTML (no external dependency)
        $html = e($markdown);

        // Headers
        $html = preg_replace('/^######\s+(.+)$/m', '<h6>$1</h6>', $html);
        $html = preg_replace('/^#####\s+(.+)$/m', '<h5>$1</h5>', $html);
        $html = preg_replace('/^####\s+(.+)$/m', '<h4 id="' . '${1}' . '">$1</h4>', $html);
        $html = preg_replace('/^###\s+(.+)$/m', '<h3>$1</h3>', $html);
        $html = preg_replace('/^##\s+(.+)$/m', '<h2>$1</h2>', $html);
        $html = preg_replace('/^#\s+(.+)$/m', '<h1>$1</h1>', $html);

        // Code blocks
        $html = preg_replace('/```(\w*)\n(.*?)\n```/s', '<pre><code class="language-$1">$2</code></pre>', $html);

        // Inline code
        $html = preg_replace('/`([^`]+)`/', '<code>$1</code>', $html);

        // Bold and italic
        $html = preg_replace('/\*\*(.+?)\*\*/', '<strong>$1</strong>', $html);
        $html = preg_replace('/\*(.+?)\*/', '<em>$1</em>', $html);

        // Links
        $html = preg_replace('/\[([^\]]+)\]\(([^)]+)\)/', '<a href="$2">$1</a>', $html);

        // Lists
        $html = preg_replace('/^- (.+)$/m', '<li>$1</li>', $html);
        $html = preg_replace('/(<li>.*<\/li>\n?)+/', '<ul>$0</ul>', $html);

        // Paragraphs
        $html = preg_replace('/\n\n([^<])/', '</p><p>$1', $html);
        $html = '<p>' . $html . '</p>';

        // Clean up
        $html = str_replace('<p><h', '<h', $html);
        $html = preg_replace('/<\/h(\d)><\/p>/', '</h$1>', $html);
        $html = str_replace('<p><pre>', '<pre>', $html);
        $html = str_replace('</pre></p>', '</pre>', $html);
        $html = str_replace('<p><ul>', '<ul>', $html);
        $html = str_replace('</ul></p>', '</ul>', $html);
        $html = str_replace('<p></p>', '', $html);

        return $html;
    }

    private function extractTitle(string $markdown): string
    {
        if (preg_match('/^#\s+(.+)$/m', $markdown, $matches)) {
            return $matches[1];
        }

        return 'Documentation';
    }

    private function findPrevNext(string $section, string $page): array
    {
        $flat = [];
        foreach ($this->navigation as $sec => $data) {
            foreach ($data['pages'] as $pg => $label) {
                $flat[] = ['section' => $sec, 'page' => $pg, 'label' => $label];
            }
        }

        $current = null;
        foreach ($flat as $i => $item) {
            if ($item['section'] === $section && $item['page'] === $page) {
                $current = $i;
                break;
            }
        }

        return [
            'prev' => $current !== null && $current > 0 ? $flat[$current - 1] : null,
            'next' => $current !== null && $current < count($flat) - 1 ? $flat[$current + 1] : null,
        ];
    }

    private function searchContent(string $query): array
    {
        $results = [];
        $query = strtolower($query);

        foreach ($this->navigation as $section => $data) {
            foreach ($data['pages'] as $page => $label) {
                $filePath = "{$this->contentPath}/{$section}/{$page}.md";
                if (! file_exists($filePath)) {
                    continue;
                }

                $content = strtolower(file_get_contents($filePath));
                if (str_contains($content, $query)) {
                    // Extract snippet around match
                    $pos = strpos($content, $query);
                    $start = max(0, $pos - 80);
                    $snippet = substr(file_get_contents($filePath), $start, 200);
                    $snippet = trim(preg_replace('/\s+/', ' ', $snippet));

                    $results[] = [
                        'section' => $section,
                        'page' => $page,
                        'label' => $label,
                        'sectionLabel' => $data['label'],
                        'snippet' => $snippet,
                    ];
                }
            }
        }

        return $results;
    }
}