<?php

namespace App\Services;

use App\Models\Kamera;
use App\Models\Lensa;
use App\Models\Penyewaan;
use Illuminate\Support\Facades\DB;
use Illuminate\Validation\ValidationException;

class InventoryStockService
{
    public static function reserveKamera(Kamera $kamera, int $qty): void
    {
        $lockedKamera = Kamera::query()->lockForUpdate()->findOrFail($kamera->id);

        self::ensureEnoughStock($lockedKamera->stok, $qty, 'kamera');
        $lockedKamera->decrement('stok', $qty);
    }

    public static function reserveLensa(Lensa $lensa, int $qty): void
    {
        $lockedLensa = Lensa::query()->lockForUpdate()->findOrFail($lensa->id);

        self::ensureEnoughStock($lockedLensa->stok, $qty, 'lensa');
        $lockedLensa->decrement('stok', $qty);
    }

    public static function reservePaket(Kamera $kamera, Lensa $lensa, int $qty): void
    {
        $lockedKamera = Kamera::query()->lockForUpdate()->findOrFail($kamera->id);
        $lockedLensa = Lensa::query()->lockForUpdate()->findOrFail($lensa->id);

        self::ensureEnoughStock($lockedKamera->stok, $qty, 'kamera');
        self::ensureEnoughStock($lockedLensa->stok, $qty, 'lensa');

        $lockedKamera->decrement('stok', $qty);
        $lockedLensa->decrement('stok', $qty);
    }

    public static function syncPenyewaanStock(Penyewaan $penyewaan, int $newQty, string $newStatus): void
    {
        $oldQty = (int) $penyewaan->qty;
        $oldStatus = (string) $penyewaan->status;
        $oldReserved = self::statusUsesStock($oldStatus);
        $newReserved = self::statusUsesStock($newStatus);

        $kamera = $penyewaan->kamera_id ? Kamera::query()->lockForUpdate()->find($penyewaan->kamera_id) : null;
        $lensa = $penyewaan->lensa_id ? Lensa::query()->lockForUpdate()->find($penyewaan->lensa_id) : null;

        if (! $oldReserved && ! $newReserved) {
            return;
        }

        if ($oldReserved && ! $newReserved) {
            self::restoreItems($kamera, $lensa, $oldQty);

            return;
        }

        if (! $oldReserved && $newReserved) {
            self::reserveItems($kamera, $lensa, $newQty);

            return;
        }

        $difference = $newQty - $oldQty;

        if ($difference > 0) {
            self::reserveItems($kamera, $lensa, $difference);

            return;
        }

        if ($difference < 0) {
            self::restoreItems($kamera, $lensa, abs($difference));
        }
    }

    public static function restoreForDeletion(Penyewaan $penyewaan): void
    {
        if (! self::statusUsesStock((string) $penyewaan->status)) {
            return;
        }

        $kamera = $penyewaan->kamera_id ? Kamera::query()->lockForUpdate()->find($penyewaan->kamera_id) : null;
        $lensa = $penyewaan->lensa_id ? Lensa::query()->lockForUpdate()->find($penyewaan->lensa_id) : null;

        self::restoreItems($kamera, $lensa, (int) $penyewaan->qty);
    }

    public static function statusUsesStock(string $status): bool
    {
        return in_array($status, ['menunggu', 'disetujui'], true);
    }

    public static function transaction(callable $callback): mixed
    {
        return DB::transaction($callback);
    }

    private static function reserveItems(?Kamera $kamera, ?Lensa $lensa, int $qty): void
    {
        if ($kamera) {
            self::ensureEnoughStock((int) $kamera->stok, $qty, 'kamera');
        }

        if ($lensa) {
            self::ensureEnoughStock((int) $lensa->stok, $qty, 'lensa');
        }

        if ($kamera) {
            $kamera->decrement('stok', $qty, []);
        }

        if ($lensa) {
            $lensa->decrement('stok', $qty, []);
        }
    }

    private static function restoreItems(?Kamera $kamera, ?Lensa $lensa, int $qty): void
    {
        if ($kamera) {
            $kamera->update([
                'stok' => min((int) $kamera->stok + $qty, Kamera::DEFAULT_STOCK),
            ]);
        }

        if ($lensa) {
            $lensa->update([
                'stok' => min((int) $lensa->stok + $qty, Lensa::DEFAULT_STOCK),
            ]);
        }
    }

    private static function ensureEnoughStock(int $availableStock, int $requestedQty, string $label): void
    {
        if ($requestedQty > $availableStock) {
            throw ValidationException::withMessages([
                'qty' => 'Stok '.$label.' tidak mencukupi. Sisa stok yang tersedia saat ini: '.$availableStock.'.',
            ]);
        }
    }
}