<?php

namespace App\Http\Controllers\Api;

use App\Exceptions\OllamaUnavailableException;
use App\Http\Controllers\Controller;
use App\Repositories\Contracts\ArticleRepositoryInterface;
use App\Services\EmbeddingService;
use Illuminate\Http\JsonResponse;
use Illuminate\Http\Request;

class NearestArticleController extends Controller
{
    public function __invoke(
        Request $request,
        EmbeddingService $embeddingService,
        ArticleRepositoryInterface $articleRepository
    ): JsonResponse {
        $validated = $request->validate([
            'query' => ['required', 'string', 'min:2', 'max:1000'],
            'limit' => ['sometimes', 'integer', 'min:1', 'max:20'],
            'min_similarity' => ['sometimes', 'numeric', 'min:0', 'max:1'],
            'include_content' => ['sometimes', 'boolean'],
        ]);

        $query = trim($validated['query']);
        $limit = (int) ($validated['limit'] ?? 5);
        $minSimilarity = (float) ($validated['min_similarity'] ?? 0);
        $includeContent = $request->boolean('include_content', false);

        try {
            $embedding = $embeddingService->embed($query);
        } catch (OllamaUnavailableException $exception) {
            return response()->json([
                'message' => 'Embedding provider is unavailable.',
                'error' => $exception->getMessage(),
            ], 503);
        }

        $embeddingContext = $embeddingService->context();
        $candidates = $articleRepository->findSimilarByEmbedding(
            embedding: $embedding,
            limit: $limit,
            embeddingContext: $embeddingContext,
            filters: ['published_only' => true]
        );

        $results = collect($candidates)
            ->map(function ($candidate) use ($includeContent) {
                $similarity = max(0, min(1, 1 - $candidate->distance));
                $content = trim($candidate->content);

                return [
                    'article_id' => $candidate->articleId,
                    'title' => $candidate->title,
                    'similarity' => round($similarity, 4),
                    'distance' => round($candidate->distance, 4),
                    'snippet' => str($content)->limit(220)->toString(),
                    'content' => $includeContent ? $content : null,
                    'source_url' => $candidate->sourceUrl,
                    'source_article_id' => $candidate->sourceArticleId,
                    'note' => $candidate->note,
                    'allowed_actions' => $candidate->allowedActions,
                ];
            })
            ->filter(fn (array $result) => $result['similarity'] >= $minSimilarity)
            ->values();

        return response()->json([
            'data' => $results,
            'meta' => [
                'query' => $query,
                'limit' => $limit,
                'min_similarity' => $minSimilarity,
                'published_only' => true,
                'embedding_provider_instance_id' => $embeddingContext['provider_instance_id'] ?? null,
                'embedding_model' => $embeddingContext['embedding_model'] ?? null,
            ],
        ]);
    }
}