<?php

namespace App\Services;

use App\Models\ClassPackageUnit;
use App\Models\ClassPackageUnitProduct;
use Illuminate\Database\Eloquent\Collection;

class ClassPackageUnitService
{
    public function getByUnit(int $unitId): Collection
    {
        return ClassPackageUnit::with('products.product')
            ->where('unit_id', $unitId)
            ->where('visible', true)
            ->orderBy('name')
            ->get();
    }

    public function getAllByUnit(int $unitId): Collection
    {
        return ClassPackageUnit::with('products.product')
            ->where('unit_id', $unitId)
            ->orderBy('name')
            ->get();
    }

    public function findById(int $id): ?ClassPackageUnit
    {
        return ClassPackageUnit::with('products.product')->find($id);
    }

    public function create(array $data): ClassPackageUnit
    {
        $materials = $data['materials'] ?? [];
        unset($data['materials']);

        $data['contract_material_value'] = $this->calcMaterialValue($materials);

        $packageUnit = ClassPackageUnit::create($data);

        $this->syncProducts($packageUnit, $materials);

        return $packageUnit->load('products.product');
    }

    public function update(int $id, array $data): ?ClassPackageUnit
    {
        $packageUnit = $this->findById($id);
        if (!$packageUnit) return null;

        $materials = $data['materials'] ?? null;
        unset($data['materials']);

        if ($materials !== null) {
            $data['contract_material_value'] = $this->calcMaterialValue($materials);
        }

        $packageUnit->update($data);

        if ($materials !== null) {
            $this->syncProducts($packageUnit, $materials);
        }

        return $packageUnit->fresh('products.product');
    }

    public function toggleVisibility(int $id): ?ClassPackageUnit
    {
        $packageUnit = ClassPackageUnit::find($id);
        if (!$packageUnit) return null;

        $packageUnit->update(['visible' => !$packageUnit->visible]);

        return $packageUnit->fresh();
    }

    public function delete(int $id): bool
    {
        $packageUnit = ClassPackageUnit::find($id);
        if (!$packageUnit) return false;

        return $packageUnit->delete();
    }

    /**
     * Sync products on an existing ClassPackageUnit from the base package.
     */
    public function syncProductsFromBasePackage(ClassPackageUnit $packageUnit, \App\Models\ClassPackage $basePackage): void
    {
        $packageUnit->products()->delete();

        $basePackage->products->each(function ($product) use ($packageUnit) {
            ClassPackageUnitProduct::create([
                'class_package_unit_id' => $packageUnit->id,
                'product_id'            => $product->id,
                'quantity'              => $product->pivot->quantity,
                'price'                 => $product->pivot->price,
            ]);
        });
    }

    public function replicateFromBasePackage(int $unitId, \App\Models\ClassPackage $basePackage): ClassPackageUnit
    {
        $packageUnit = ClassPackageUnit::create([
            'unit_id'                 => $unitId,
            'class_package_id'        => $basePackage->id,
            'name'                    => $basePackage->name,
            'quantity_classes'        => $basePackage->quantity_classes,
            'contract_value'          => $basePackage->contract_value,
            'contract_material_value' => $basePackage->contract_material_value,
            'contract_register_value' => $basePackage->contract_register_value,
            'contrat_discount_value'  => $basePackage->contrat_discount_value,
            'visible'                 => true,
        ]);

        $basePackage->products->each(function ($product) use ($packageUnit) {
            ClassPackageUnitProduct::create([
                'class_package_unit_id' => $packageUnit->id,
                'product_id'            => $product->id,
                'quantity'              => $product->pivot->quantity,
                'price'                 => $product->pivot->price,
            ]);
        });

        return $packageUnit;
    }

    private function syncProducts(ClassPackageUnit $packageUnit, array $materials): void
    {
        $packageUnit->products()->delete();

        foreach ($materials as $m) {
            ClassPackageUnitProduct::create([
                'class_package_unit_id' => $packageUnit->id,
                'product_id'            => $m['product_id'],
                'quantity'              => $m['quantity'],
                'price'                 => $m['price'],
            ]);
        }
    }

    private function calcMaterialValue(array $materials): float
    {
        return array_reduce($materials, fn($carry, $m) => $carry + ($m['quantity'] * $m['price']), 0.0);
    }
}