<?php

namespace App\Services;

use Illuminate\Support\Facades\DB;
use RuntimeException;
use Throwable;

class ProjectSearchService
{
    public function __construct(
        private readonly OllamaService $ollama
    ) {
    }

    public function isAvailable(): bool
    {
        try {
            return DB::connection('project_search')->getSchemaBuilder()->hasTable('project_index');
        } catch (Throwable) {
            return false;
        }
    }

    /**
     * @return array<int, string>
     */
    public function configuredSources(): array
    {
        return array_keys(config('project_search.sources', []));
    }

    /**
     * @return array<int, array<string, mixed>>
     */
    public function listSources(): array
    {
        $sources = config('project_search.sources', []);

        return collect($sources)
            ->map(fn (array $meta, string $id) => [
                'id' => $id,
                'label' => $meta['label'] ?? $id,
                'smb' => $meta['smb'] ?? null,
            ])
            ->values()
            ->all();
    }

    /**
     * @param  array<int, string>  $sources
     * @param  array<int, array{role: string, content: string}>  $history
     * @return array{answer: string, results: array<int, array<string, mixed>>, meta: array<string, mixed>}
     */
    public function ask(string $query, array $sources, int $limit, array $history = []): array
    {
        if (! $this->isAvailable()) {
            throw new RuntimeException('Indeks project_search belum tersedia di PostgreSQL.');
        }

        $sources = $this->normalizeSources($sources);
        $limit = max(1, min($limit, (int) config('project_search.max_limit', 50)));
        $terms = $this->extractTerms($query);

        $results = $this->searchIndex($sources, $terms, $limit);
        $answer = $this->formatAnswer($query, $results, $history);

        return [
            'answer' => $answer,
            'results' => $results,
            'meta' => [
                'query' => $query,
                'sources' => $sources,
                'result_count' => count($results),
                'terms' => $terms,
            ],
        ];
    }

    /**
     * @return array<int, array<string, mixed>>
     */
    public function indexStatus(): array
    {
        if (! $this->isAvailable()) {
            return [];
        }

        return DB::connection('project_search')
            ->table('project_index_runs')
            ->orderByDesc('id')
            ->limit(20)
            ->get()
            ->map(fn ($row) => [
                'id' => (int) $row->id,
                'source_id' => $row->source_id,
                'status' => $row->status,
                'started_at' => $row->started_at,
                'finished_at' => $row->finished_at,
                'rows_upserted' => (int) $row->rows_upserted,
                'error_message' => $row->error_message,
            ])
            ->all();
    }

    /**
     * @param  array<int, string>  $sources
     * @return array<int, string>
     */
    private function normalizeSources(array $sources): array
    {
        $allowed = $this->configuredSources();
        $sources = array_values(array_filter(array_map('trim', $sources)));

        if ($sources === []) {
            return config('project_search.default_sources', ['project']);
        }

        foreach ($sources as $source) {
            if (! in_array($source, $allowed, true)) {
                throw new RuntimeException("Source tidak dikenal: {$source}");
            }
        }

        return $sources;
    }

    /**
     * @return array<int, string>
     */
    private function extractTerms(string $query): array
    {
        $normalized = mb_strtolower($query);
        $normalized = preg_replace('/[^\p{L}\p{N}\s]+/u', ' ', $normalized) ?? $normalized;
        $parts = preg_split('/\s+/', trim($normalized)) ?: [];

        $stopwords = ['carikan', 'cari', 'projek', 'project', 'folder', 'lokasi', 'dan', 'atau', 'the', 'a'];
        $terms = array_values(array_filter($parts, fn (string $part) => strlen($part) >= 3 && ! in_array($part, $stopwords, true)));

        return array_slice(array_unique($terms), 0, 5);
    }

    /**
     * @param  array<int, string>  $sources
     * @param  array<int, string>  $terms
     * @return array<int, array<string, mixed>>
     */
    private function searchIndex(array $sources, array $terms, int $limit): array
    {
        $builder = DB::connection('project_search')
            ->table('project_index')
            ->whereIn('source_id', $sources)
            ->where('is_directory', true);

        if ($terms !== []) {
            $builder->where(function ($query) use ($terms) {
                foreach ($terms as $term) {
                    $like = '%'.$term.'%';
                    $query->orWhere('client_name', 'ilike', $like)
                        ->orWhere('relative_path', 'ilike', $like);
                }
            });
        }

        return $builder
            ->orderByDesc('year_folder')
            ->orderByDesc('mtime')
            ->limit($limit)
            ->get()
            ->map(fn ($row) => [
                'source_id' => $row->source_id,
                'path' => $row->full_smb_path,
                'relative_path' => $row->relative_path,
                'client_name' => $row->client_name,
                'year_folder' => $row->year_folder,
                'mtime' => $row->mtime,
            ])
            ->all();
    }

    /**
     * @param  array<int, array<string, mixed>>  $results
     * @param  array<int, array{role: string, content: string}>  $history
     */
    private function formatAnswer(string $query, array $results, array $history = []): string
    {
        if ($results === []) {
            return 'Tidak ditemukan folder proyek yang cocok di indeks metadata. Pastikan indexer sudah dijalankan.';
        }

        if (! $this->ollama->isConfigured()) {
            return $this->fallbackAnswer($results);
        }

        $context = collect($results)
            ->map(function (array $row, int $index) {
                $year = $row['year_folder'] ?? '-';
                $mtime = $row['mtime'] ?? '-';

                return ($index + 1).'. '.$row['path'].' | tahun='.$year.' | mtime='.$mtime;
            })
            ->implode("\n");

        $system = 'Anda asisten pencarian folder proyek Geonet. Jawab dalam Bahasa Indonesia. '
            .'Gunakan HANYA daftar hasil berikut. Jangan mengarang path. '
            .'Sebutkan lokasi UNC path dan tahun folder bila ada.';

        $user = "Pertanyaan: {$query}\n\nHasil indeks:\n{$context}";

        $messages = [['role' => 'system', 'content' => $system]];

        foreach ($history as $item) {
            $role = $item['role'] ?? '';
            $content = $item['content'] ?? '';
            if (! in_array($role, ['user', 'assistant'], true) || $content === '') {
                continue;
            }
            $messages[] = ['role' => $role, 'content' => $content];
        }

        $messages[] = ['role' => 'user', 'content' => $user];

        try {
            return $this->ollama->chat($messages);
        } catch (Throwable) {
            return $this->fallbackAnswer($results);
        }
    }

    /**
     * @param  array<int, array<string, mixed>>  $results
     */
    private function fallbackAnswer(array $results): string
    {
        $count = count($results);
        $lines = collect($results)
            ->take(5)
            ->map(fn (array $row) => '- '.$row['path'])
            ->implode("\n");

        return "Ditemukan {$count} folder proyek:\n{$lines}";
    }
}