<?php

namespace App\Services;

use App\Exceptions\InviteCodeException;
use App\Models\GameAccountUser;
use App\Models\InviteCode;
use Closure;
use Illuminate\Support\Collection;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Str;

class InviteCodeService
{
    /**
     * @return \Illuminate\Support\Collection<int, \App\Models\InviteCode>
     */
    public function createCodes(int $quantity, GameAccountUser $creator): Collection
    {
        $created = collect();

        for ($index = 0; $index < $quantity; $index++) {
            $created->push(InviteCode::query()->create([
                'code' => $this->generateUniqueCode(),
                'created_by_account_id' => $creator->id,
                'created_by_username' => $creator->username,
            ]));
        }

        return $created;
    }

    /**
     * @template TReturn
     *
     * @param  Closure(): TReturn  $callback
     * @return TReturn
     */
    public function redeemForRegistration(string $code, string $username, Closure $callback): mixed
    {
        $normalizedCode = $this->normalizeCode($code);
        $normalizedUsername = strtoupper(trim($username));

        return DB::transaction(function () use ($callback, $normalizedCode, $normalizedUsername) {
            /** @var InviteCode|null $invite */
            $invite = InviteCode::query()
                ->where('code', $normalizedCode)
                ->lockForUpdate()
                ->first();

            if (! $invite) {
                throw InviteCodeException::invalid();
            }

            if ($invite->redeemed_at !== null) {
                throw InviteCodeException::alreadyUsed();
            }

            $result = $callback();

            $invite->forceFill([
                'redeemed_by_account_id' => $result['id'],
                'redeemed_by_username' => $normalizedUsername,
                'redeemed_at' => now(),
            ])->save();

            return $result;
        });
    }

    /**
     * @return \Illuminate\Support\Collection<int, \App\Models\InviteCode>
     */
    public function latest(int $limit = 100): Collection
    {
        return InviteCode::query()
            ->latest('id')
            ->limit($limit)
            ->get();
    }

    /**
     * @return array{total: int, available: int, redeemed: int}
     */
    public function stats(): array
    {
        $total = InviteCode::query()->count();
        $redeemed = InviteCode::query()->whereNotNull('redeemed_at')->count();

        return [
            'total' => $total,
            'available' => $total - $redeemed,
            'redeemed' => $redeemed,
        ];
    }

    private function generateUniqueCode(): string
    {
        do {
            $code = $this->normalizeCode(
                Str::upper(Str::random(4)).'-'.Str::upper(Str::random(4)).'-'.Str::upper(Str::random(4)),
            );
        } while (InviteCode::query()->where('code', $code)->exists());

        return $code;
    }

    private function normalizeCode(string $code): string
    {
        return Str::upper(trim($code));
    }
}