<?php

namespace Modules\Maintenance\Services;

use App\Contact;
use App\PurchaseLine;
use Illuminate\Support\Collection;
use Illuminate\Support\Facades\DB;
use Modules\Maintenance\Models\SparePart;

class MaterialPurchaseSuggestionService
{
    /**
     * Suggest suppliers for a variation based on purchase history.
     *
     * @return Collection<int, array{supplier_id: int, supplier_name: string, last_price: float, last_date: ?string, purchase_count: int}>
     */
    public function suggestSuppliers(int $businessId, int $variationId, int $limit = 5): Collection
    {
        $lines = PurchaseLine::query()
            ->join('transactions as t', 'purchase_lines.transaction_id', '=', 't.id')
            ->join('contacts as c', 't.contact_id', '=', 'c.id')
            ->where('t.business_id', $businessId)
            ->where('t.type', 'purchase')
            ->where('t.status', 'received')
            ->where('purchase_lines.variation_id', $variationId)
            ->whereNotNull('t.contact_id')
            ->select(
                't.contact_id as supplier_id',
                DB::raw("TRIM(CONCAT(COALESCE(c.supplier_business_name, ''), ' ', COALESCE(c.name, ''))) as supplier_name"),
                't.transaction_date',
                'purchase_lines.purchase_price'
            )
            ->orderByDesc('t.transaction_date')
            ->get();

        return $lines->groupBy('supplier_id')->map(function ($group, $supplierId) {
            $latest = $group->first();

            return [
                'supplier_id' => (int) $supplierId,
                'supplier_name' => trim($latest->supplier_name) ?: __('maintenance::lang.unknown_supplier'),
                'last_price' => (float) $latest->purchase_price,
                'last_date' => $latest->transaction_date,
                'purchase_count' => $group->count(),
            ];
        })->sortByDesc('purchase_count')->take($limit)->values();
    }

    public function resolveDefaultSupplierId(int $businessId, ?int $variationId, ?int $sparePartId = null): ?int
    {
        if ($sparePartId) {
            $part = SparePart::where('business_id', $businessId)->find($sparePartId);
            if ($part?->supplier_id) {
                return (int) $part->supplier_id;
            }
        }

        if ($variationId) {
            $suggestions = $this->suggestSuppliers($businessId, $variationId, 1);
            if ($suggestions->isNotEmpty()) {
                return $suggestions->first()['supplier_id'];
            }
        }

        return null;
    }

    public function supplierName(?int $supplierId): string
    {
        if (! $supplierId) {
            return '—';
        }

        $contact = Contact::find($supplierId);

        return $contact
            ? trim($contact->supplier_business_name.' '.$contact->name)
            : '—';
    }
}