<?php

namespace App\Services;

use App\Models\Opportunity;
use App\Models\Sector;
use App\Models\User;
use App\Support\CheckedPattern;
use DOMDocument;
use DOMElement;
use DOMNode;
use Illuminate\Database\Query\Builder;
use Illuminate\Support\Collection;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Schema;
use Illuminate\Support\Facades\Validator;
use Illuminate\Support\Str;
use Symfony\Component\HttpFoundation\BinaryFileResponse;
use Symfony\Component\HttpKernel\Exception\HttpException;

/** A reading adapter over the existing library, never a second content/opportunity register. */
final class LegacyContent
{
    public function available(): bool
    {
        // Explicit delivery gate; document publication and access checks remain independent.
        if (config('portal.legacy_content_enabled', false)) {
            return true;
        }

        if (! config('portal.legacy_content_qa_enabled') || ! app()->environment('testing')
            || config('database.connections.pgsql.host') !== '127.0.0.1'
            || config('database.connections.pgsql.url') || (int) config('database.connections.pgsql.port') !== 55441) {
            return false;
        }
        $actual = DB::selectOne('SELECT current_database() AS database, inet_server_port() AS port');

        return $actual && str_ends_with($actual->database, '_test') && (int) $actual->port === 55441
            && $actual->database === config('database.connections.pgsql.database');
    }

    /** @return array<string, mixed> */
    public function article(string $slug = 'agronegocio', bool $includeRelated = true): array
    {
        abort_unless($this->available(), 404);
        $identity = config('legacy_content.articles.'.$slug);
        abort_unless(is_array($identity) && ($identity['publishable'] ?? false), 404);
        $row = $this->identityResources()->get($identity['external_id']);
        abort_unless($row !== null, 404);
        $binary = app(VerifiedDocumentBinary::class)->respond($row);
        $bytes = $binary instanceof BinaryFileResponse ? file_get_contents($binary->getFile()->getPathname()) : $binary->getContent();
        abort_unless(is_string($bytes) && strlen($bytes) <= 10485760 && hash_equals(trim($row->sha256), hash('sha256', $bytes)), 404);
        try {
            $source = json_decode($bytes, true, 64, JSON_THROW_ON_ERROR);
        } catch (\JsonException) {
            abort(404);
        }
        abort_unless(is_array($source) && ($source['format'] ?? '') === 'investmoz-legacy-article-v1'
            && ($source['source_url'] ?? '') === $row->source_url && $row->source_url === $identity['source_url']
            && is_string($source['content_html'] ?? null) && trim(strip_tags($source['content_html'])) !== '', 404);
        foreach (['title', 'author', 'legacy_category', 'published_at', 'modified_at'] as $key) {
            abort_unless(is_string($source[$key] ?? null), 404);
        }
        abort_unless(is_int($source['legacy_id'] ?? null), 404);
        $image = $this->publicResources()->where('d.sha256', $source['image_sha256'] ?? '')->where('d.media_type', 'image/png')->first();
        $sector = $slug === 'energia-mineracao' ? null : Sector::where('slug', $identity['sector_slug'])->where('is_active', true)->first();
        $relatedSectors = $slug === 'energia-mineracao' ? Sector::whereIn('slug', ['energia-especifica', 'mineracao'])->where('is_active', true)->get(['id', 'name', 'slug']) : collect();
        // These are independently published records in the same sector, not claims of article/project linkage.
        $opportunities = $sector ? SectorOrganization::opportunities($sector)->latest('published_at')
            ->limit(12)->get(['title', 'slug', 'province', 'summary']) : [];

        if ($relatedSectors->isNotEmpty()) {
            $opportunities = Opportunity::published()->whereIn('sector_id', $relatedSectors->pluck('id'))->latest('published_at')->limit(12)->get(['id', 'title', 'slug', 'province', 'summary']);
        }
        $localHtml = $this->localLinks($this->sanitize($source['content_html']));
        $editorial = Schema::hasColumn('portal_resources', 'editorial_content')
            ? DB::table('portal_resources')->where('id', $row->resource_id)->value('editorial_content') : null;
        if ($editorial) {
            $adaptation = json_decode($editorial, true, 64, JSON_THROW_ON_ERROR);
            $localHtml = implode('', array_map(fn ($p) => '<p>'.nl2br(e($p)).'</p>', CheckedPattern::split('/\n\s*\n/', $adaptation['body'])));
            $source['title'] = $row->title;
            if (! empty($adaptation['image_resource_id'])) {
                $image = $this->publicResources()->where('r.id', $adaptation['image_resource_id'])->whereIn('d.media_type', ['image/png', 'image/jpeg', 'image/webp'])->first();
            }
        }
        if ($slug === 'agronegocio') {
            $localHtml = app(CorridorAgribusiness::class)->enrich($localHtml, app(CorridorAgribusinessOpportunities::class)->articleLinks());
        }
        preg_match_all('~href="([^"]+)"~i', $localHtml, $existingLinks);
        $alreadyLinked = array_map(fn ($href) => html_entity_decode($href, ENT_QUOTES | ENT_HTML5, 'UTF-8'), $existingLinks[1]);
        $relatedArticles = [];
        if ($includeRelated) {
            foreach ($this->related($identity['group'], $slug) as $item) {
                if (in_array($item['href'], $alreadyLinked, true)) {
                    continue;
                }
                try {
                    $relatedArticles[] = $this->article($item['slug'], false);
                } catch (HttpException $error) {
                    if ($error->getStatusCode() !== 404) {
                        throw $error;
                    }
                }
            }
        }

        return ['id' => (int) $row->resource_id, 'document_id' => $row->id, 'version' => (int) $row->metadata_version,
            'sha256' => trim($row->sha256), 'title' => $source['title'], 'author' => $source['author'],
            'legacy_id' => $source['legacy_id'], 'legacy_category' => $source['legacy_category'],
            'published_at' => $source['published_at'], 'modified_at' => $source['modified_at'], 'source_url' => $source['source_url'],
            'href' => '/'.$slug, 'html' => $localHtml, 'summary' => self::excerpt($localHtml),
            'opportunities_href' => $sector ? '/oportunidades?sector='.rawurlencode($sector->slug) : null,
            'opportunities_label' => $sector ? 'Ver oportunidades de '.$sector->name : null,
            'has_opportunities' => count($opportunities) > 0,
            'landing_href' => '/explorar/'.$identity['group'], 'start_href' => '/investimentos/a-partir-de/'.$slug,
            'group' => config('legacy_content.groups.'.$identity['group']),
            'related_articles' => $relatedArticles,
            'image' => $image ? ['href' => '/documentos/'.$image->resource_id.'/view', 'sha256' => trim($image->sha256),
                'alt' => $slug === 'agronegocio' ? 'Campo agrícola ao pôr do sol; fotografia ilustrativa do artigo Agronegocio'
                    : 'Imagem ilustrativa original do artigo '.$source['title'], 'source_url' => $image->source_url] : null,
            'related_sectors' => $relatedSectors, 'sector' => $sector?->only(['id', 'name', 'slug']), 'opportunities' => $opportunities,
            'territorial_references' => array_values(array_filter($slug === 'agronegocio' ? ['Pemba–Lichinga', 'Nacala', 'Vale do Zambeze', 'Beira', 'Limpopo', 'Maputo'] : [],
                fn ($name) => str_contains(strip_tags($source['content_html']), $name))),
            'territorial_status' => 'Menções territoriais preservadas no artigo. Limites administrativos, parcelas e geometrias não associados automaticamente.',
            'library_href' => '/documentos/'.$row->resource_id,
            'consultation_state' => 'public', 'legal_state' => 'not_applicable', 'calculation_use' => false];
    }

    /** An excerpt of the displayed edition, never a claim about returns or availability. */
    public static function excerpt(string $html): string
    {
        $plain = html_entity_decode(strip_tags($html), ENT_QUOTES | ENT_HTML5, 'UTF-8');
        if (str_contains($plain, 'Hotelaria e resorts') && str_contains($plain, 'Ecoturismo')
            && str_contains($plain, 'Infraestruturas turísticas') && str_contains($plain, 'Oportunidades Regionais')) {
            return 'Conheça os temas de turismo e hospitalidade abordados no guia: hotelaria, ecoturismo, infraestruturas de apoio e referências regionais. Use este enquadramento para preparar a sua ideia de investimento.';
        }
        if (preg_match_all('~<p\b[^>]*>(.*?)</p>~isu', $html, $paragraphs) === false) {
            throw new \RuntimeException('Invalid paragraph encoding; original preserved.');
        }
        foreach ([...$paragraphs[1], $html] as $paragraph) {
            $text = trim(preg_replace('/\s+/u', ' ', html_entity_decode(strip_tags($paragraph), ENT_QUOTES | ENT_HTML5, 'UTF-8')));
            if (mb_strlen($text) >= 60) {
                return Str::limit($text, 320);
            }
        }

        return trim(html_entity_decode(strip_tags($html), ENT_QUOTES | ENT_HTML5, 'UTF-8'));
    }

    /** Resolve a library identity, preserving the already stored source URLs and versions.
     * @return array<string, mixed> */
    public function articleForResource(int $resourceId): array
    {
        abort_unless($this->available(), 404);
        $externalId = $this->identityResources()->firstWhere('resource_id', $resourceId)?->legacy_identity;
        foreach (config('legacy_content.articles', []) as $slug => $identity) {
            if ($identity['external_id'] === $externalId && $identity['publishable']) {
                return $this->article($slug);
            }
        }
        abort(422, 'Escolha um artigo disponível para consulta; a referência não foi guardada.');
    }

    /** @return list<array<string,mixed>> */
    public function articlesForGroup(string $group): array
    {
        abort_unless($this->available() && is_array(config('legacy_content.groups.'.$group)), 404);
        $articles = [];
        foreach ($this->related($group) as $item) {
            $articles[] = $this->article($item['slug']);
        }
        abort_unless($articles !== [], 404);

        return $articles;
    }

    /** @return list<array<string,mixed>> */
    private function related(string $group, ?string $except = null): array
    {
        $identities = array_filter(config('legacy_content.articles', []), fn ($identity, $slug) => $identity['group'] === $group && $identity['publishable'] && $slug !== $except, ARRAY_FILTER_USE_BOTH);
        $resources = $this->identityResources();
        $result = [];
        foreach ($identities as $slug => $identity) {
            $row = $resources->get($identity['external_id']);
            if ($row && $row->source_url === $identity['source_url']) {
                $result[] = ['slug' => $slug, 'id' => (int) $row->resource_id, 'title' => $row->title, 'href' => '/'.$slug];
            }
        }

        return $result;
    }

    private function localLinks(string $html): string
    {
        $public = $this->identityResources();
        $links = [];
        foreach (config('legacy_content.articles', []) as $slug => $identity) {
            if ($identity['publishable'] && $public->get($identity['external_id'])?->source_url === $identity['source_url']) {
                $links[rtrim($identity['source_url'], '/')] = '/'.$slug;
            }
        }
        $doc = new DOMDocument;
        $old = libxml_use_internal_errors(true);
        try {
            $doc->loadHTML('<?xml encoding="UTF-8"><html><body>'.$html.'</body></html>', LIBXML_NONET);
            foreach ($doc->getElementsByTagName('a') as $anchor) {
                $href = $anchor->getAttribute('href');
                if (isset($links[rtrim($href, '/')])) {
                    $anchor->setAttribute('href', $links[rtrim($href, '/')]);
                }
            }
            $body = $doc->getElementsByTagName('body')->item(0);

            return $body ? implode('', array_map(fn ($child) => $doc->saveHTML($child), iterator_to_array($body->childNodes))) : '';
        } finally {
            libxml_clear_errors();
            libxml_use_internal_errors($old);
        }
    }

    /** @param array<string, mixed> $input */
    public function attach(User $actor, string $caseId, array $input): void
    {
        $data = Validator::make($input, ['version' => 'required|integer|min:1', 'resource_id' => 'required|integer|min:1'])->validate();
        $article = $this->articleForResource((int) $data['resource_id']);
        abort_unless(app(InvestorPath::class)->available(), 404);
        DB::transaction(function () use ($actor, $caseId, $data, $article): void {
            $desk = app(VirtualDesk::class);
            $case = $desk->case($actor, $caseId, true, true);
            abort_if($case->closed_at, 409);
            abort_unless(DB::table('investor_journeys')->where('id', $case->journey_id)->whereNotNull('path_definition_id')->whereNull('deleted_at')->exists(),
                409, 'Este dossier conserva outro roteiro; não foi convertido automaticamente.');
            $payload = $desk->decode($case->payload);
            foreach ($payload['investor_path']['content_sources'] ?? [] as $existing) {
                if ($existing['resource_id'] === $article['id'] && $existing['sha256'] === $article['sha256']) {
                    if ($article['sector']) {
                        app(SectorInvestment::class)->attach($actor, $caseId, ['version' => $data['version'], 'sector_slug' => $article['sector']['slug']]);
                    }

                    return; // Same source/version replay: neither another reference nor another event.
                }
            }
            abort_unless((int) $case->version === $data['version'], 409, 'O dossier foi alterado; recupere a versão atual.');
            $payload['investor_path']['content_sources'][] = ['resource_id' => $article['id'], 'document_id' => $article['document_id'],
                'sha256' => $article['sha256'], 'metadata_version' => $article['version'], 'title' => $article['title'],
                'source_url' => $article['source_url'], 'return_href' => $article['href'], 'actor_id' => $actor->id,
                'saved_at' => now()->toIso8601String()];
            DB::table('desk_cases')->where('id', $caseId)->update(['payload' => $desk->encode($payload), 'version' => $case->version + 1, 'updated_at' => now()]);
            $desk->event($desk->case($actor, $caseId), $actor, 'legacy_content_referenced', ['resource_id' => $article['id'], 'sha256' => $article['sha256']]);
            if ($article['sector']) {
                app(SectorInvestment::class)->attach($actor, $caseId, ['version' => $case->version + 1, 'sector_slug' => $article['sector']['slug']]);
            }
        });
    }

    /** Resolve explicit transport aliases without changing original IDs, versions or relations.
     * @return Collection<int, \stdClass>
     */
    private function identityResources(): Collection
    {
        $identities = array_column(config('legacy_content.articles', []), 'external_id');
        $aliases = config('legacy_content_aliases', []);
        $rows = $this->publicResources()->where(function ($query) use ($identities, $aliases) {
            $query->whereIn('d.external_id', $identities);
            if ($aliases !== []) {
                $query->orWhereIn('r.id', array_column($aliases, 'resource_id'));
            }
        })->get();
        $resolved = collect();
        foreach ($rows as $row) {
            $identity = in_array($row->external_id, $identities, true) ? $row->external_id : null;
            foreach ($aliases as $original => $alias) {
                if ((int) $row->resource_id === (int) $alias['resource_id']
                    && $row->external_id === $alias['external_id']
                    && hash_equals($alias['sha256'], trim($row->sha256))
                    && $row->source_url === $alias['source_url']) {
                    abort_if($identity !== null && $identity !== $original, 409, 'Correspondência de artigo em reconciliação.');
                    $identity = $original;
                }
            }
            if ($identity === null) {
                continue;
            }
            abort_if($resolved->has($identity), 409, 'Correspondência de artigo em reconciliação.');
            $row->legacy_identity = $identity;
            $resolved->put($identity, $row);
        }

        return $resolved;
    }

    private function publicResources(): Builder
    {
        return DB::table('portal_resources as r')->join('documents as d', 'd.id', '=', 'r.document_id')
            ->where('r.published', true)->where('r.rights_status', 'authorized')->where('d.rights_status', 'authorized')
            ->where('d.status', 'active')->where('d.data_classification', 'public')->whereNull('d.deleted_at')
            ->where('d.malware_scan_status', 'clean')->whereColumn('d.malware_scanned_sha256', 'd.sha256')
            ->select(['d.*', 'r.id as resource_id', 'r.metadata_version', 'r.source_url', 'r.title']);
    }

    /** Allow presentation markup only. No scripts, styles, events, embeds or remote image execution. */
    public function sanitize(string $html, bool $preserveStructure = false): string
    {
        $doc = new DOMDocument;
        $old = libxml_use_internal_errors(true);
        try {
            $doc->loadHTML('<?xml encoding="UTF-8"><html><body>'.$html.'</body></html>', LIBXML_NONET);
            $body = $doc->getElementsByTagName('body')->item(0);
            // Preserve the source text and relative sections, but start the displayed
            // article below the page h1. Originals and their hashes remain untouched.
            $sourceLevels = [];
            foreach (['h1', 'h2', 'h3', 'h4'] as $heading) {
                if ($doc->getElementsByTagName($heading)->length > 0) {
                    $sourceLevels[] = (int) substr($heading, 1);
                }
            }
            $headingOffset = 2 - (empty($sourceLevels) ? 2 : min($sourceLevels));
            $previousHeading = 1;
            $clean = function (DOMNode $node) use (&$clean, $doc, $headingOffset, &$previousHeading, $preserveStructure): void {
                foreach (iterator_to_array($node->childNodes) as $child) {
                    if (! $child instanceof DOMElement) {
                        continue;
                    }
                    if (preg_match('/^h([1-4])$/i', $child->tagName, $level)) {
                        $displayLevel = max(2, min(6, (int) $level[1] + $headingOffset, $previousHeading + 1));
                        $previousHeading = $displayLevel;
                        $section = $doc->createElement('h'.$displayLevel);
                        while ($child->firstChild !== null) {
                            $section->appendChild($child->firstChild);
                        }
                        $node->replaceChild($section, $child);
                        $child = $section;
                    }
                    if (! in_array(strtolower($child->tagName), array_merge(['p', 'strong', 'b', 'em', 'i', 'ul', 'ol', 'li', 'br', 'h2', 'h3', 'h4', 'h5', 'h6', 'blockquote', 'a'], $preserveStructure ? ['div', 'span', 'small', 'section', 'table', 'caption', 'thead', 'tbody', 'tfoot', 'tr', 'th', 'td', 'figure', 'figcaption'] : []), true)) {
                        $node->removeChild($child);

                        continue;
                    }
                    $href = $child->tagName === 'a' ? $child->getAttribute('href') : '';
                    foreach (iterator_to_array($child->attributes) as $attribute) {
                        $child->removeAttribute($attribute->nodeName);
                    }
                    if ($href !== '') {
                        if (str_starts_with($href, '/') && ! str_starts_with($href, '//')) {
                            $href = 'https://investemoz.tempo.co.mz'.$href;
                        }
                        if (filter_var($href, FILTER_VALIDATE_URL) && strtolower((string) parse_url($href, PHP_URL_SCHEME)) === 'https') {
                            $child->setAttribute('href', $href);
                            $child->setAttribute('rel', 'noopener noreferrer');
                        }
                    }
                    $clean($child);
                }
            };
            if (! $body) {
                return '';
            }
            $clean($body);

            return implode('', array_map(fn ($child) => $doc->saveHTML($child), iterator_to_array($body->childNodes)));
        } finally {
            libxml_clear_errors();
            libxml_use_internal_errors($old);
        }
    }
}