<?php

namespace App\Services;

use App\Models\Category;
use Illuminate\Support\Collection;
use Illuminate\Support\Facades\Http;
use Throwable;

class CarRecommendationService
{
    private const PRICE_TOLERANCE_PERCENT = 10;

    public function recommendForBudget(float $budget, int $limit = 50, array $criteria = []): array
    {
        $year = $this->positiveInt($criteria['year'] ?? null);
        $mesinCc = $this->positiveInt($criteria['mesin_cc'] ?? null);

        try {
            $filters = [
                'toleransi_harga_percent' => self::PRICE_TOLERANCE_PERCENT,
                'jumlah_cluster' => 4,
            ];

            if ($year) {
                $filters['tahun_min'] = $year;
            }

            $preferences = [];
            if ($mesinCc) {
                $preferences['mesin_cc'] = $mesinCc;
            }

            $response = Http::timeout(config('services.car_recommendation.timeout', 3))
                ->post(rtrim(config('services.car_recommendation.base_url'), '/') . '/recommend', [
                    'budget' => $budget,
                    'limit' => $limit,
                    'strategi' => 'harga_pas',
                    'preferences' => $preferences,
                    'filter' => $filters,
                ]);

            if ($response->failed()) {
                return $this->fallback($budget, $criteria);
            }

            $payload = $response->json();
            $cars = $this->mapRecommendationsToCategories($payload['recommendations'] ?? []);

            if ($cars->isEmpty()) {
                return $this->fallback($budget, $criteria);
            }

            return [
                'cars' => $cars,
                'source' => 'python_kmeans',
                'meta' => $payload['model'] ?? null,
                'has_exact_budget_match' => (bool) data_get($payload, 'model.exact_budget_match', false),
            ];
        } catch (Throwable $exception) {
            return $this->fallback($budget, $criteria);
        }
    }

    public function fallback(float $budget, array $criteria = []): array
    {
        $year = $this->positiveInt($criteria['year'] ?? null);
        $mesinCc = $this->positiveInt($criteria['mesin_cc'] ?? null);

        $baseQuery = Category::where('status', 'available');

        if ($year) {
            $baseQuery->where('year', '>=', $year);
        }

        if ($mesinCc) {
            $engineTolerance = 250;
            $baseQuery->whereBetween('mesin_cc', [$mesinCc - $engineTolerance, $mesinCc + $engineTolerance]);
        }

        $exactMatches = (clone $baseQuery)
            ->where('price', $budget)
            ->orderBy('year', 'desc')
            ->get();

        if ($exactMatches->isNotEmpty()) {
            return [
                'cars' => $exactMatches,
                'source' => 'laravel_fallback',
                'meta' => null,
                'has_exact_budget_match' => true,
            ];
        }

        $minimumPrice = $budget * (1 - (self::PRICE_TOLERANCE_PERCENT / 100));

        return [
            'cars' => (clone $baseQuery)
                ->where('price', '>', 0)
                ->where('price', '>=', $minimumPrice)
                ->where('price', '<=', $budget)
                ->orderByRaw('ABS(price - ?) ASC', [$budget])
                ->when($mesinCc, fn ($query) => $query->orderByRaw('ABS(mesin_cc - ?) ASC', [$mesinCc]))
                ->orderBy('year', 'desc')
                ->get(),
            'source' => 'laravel_fallback',
            'meta' => null,
            'has_exact_budget_match' => false,
        ];
    }

    private function mapRecommendationsToCategories(array $recommendations): Collection
    {
        $categories = Category::where('status', 'available')->get();
        $matched = collect();

        foreach ($recommendations as $recommendation) {
            $category = $this->findMatchingCategory($categories, $recommendation, $matched->pluck('id')->all());

            if ($category) {
                $matched->push($category);
            }
        }

        return $matched;
    }

    private function findMatchingCategory(Collection $categories, array $recommendation, array $usedIds): ?Category
    {
        $name = $this->normalize($recommendation['nama'] ?? '');
        $year = (int) ($recommendation['tahun'] ?? 0);
        $price = (float) ($recommendation['harga'] ?? 0);

        return $categories->first(function (Category $category) use ($name, $year, $price, $usedIds) {
            return ! in_array($category->id, $usedIds, true)
                && $this->normalize($category->name) === $name
                && (int) $category->year === $year
                && (float) $category->price === $price;
        }) ?? $categories->first(function (Category $category) use ($name, $year, $usedIds) {
            return ! in_array($category->id, $usedIds, true)
                && $this->normalize($category->name) === $name
                && (int) $category->year === $year;
        });
    }

    private function normalize(string $value): string
    {
        return preg_replace('/\s+/', ' ', strtolower(trim($value))) ?? '';
    }

    private function positiveInt(mixed $value): ?int
    {
        if (! is_numeric($value)) {
            return null;
        }

        $value = (int) $value;

        return $value > 0 ? $value : null;
    }
}