<?php

declare(strict_types=1);

namespace app\miniapi\protection;

use support\Redis;

/** All-or-nothing counters with server-side expiry and one denial notice per window. */
final class RedisQuota
{
    private const SCRIPT = <<<'LUA'
local values = {}
local blocked = 0
local retry = 0
for i, key in ipairs(KEYS) do
    local offset = (i - 1) * 3
    local limit = tonumber(ARGV[offset + 1])
    local seconds = tonumber(ARGV[offset + 2])
    local cost = tonumber(ARGV[offset + 3])
    local count = tonumber(redis.call('GET', key) or '0')
    local ttl = redis.call('TTL', key)
    if ttl < 0 then count = 0 end
    values[i] = count
    if count + cost > limit and math.max(1, ttl) > retry then
        blocked = i
        retry = math.max(1, ttl)
    end
end
if blocked > 0 then
    local notice = redis.call('SET', KEYS[blocked] .. ':notice', '1', 'EX', retry, 'NX')
    return {blocked, retry, notice and 1 or 0}
end
for i, key in ipairs(KEYS) do
    local offset = (i - 1) * 3
    if values[i] == 0 then
        redis.call('SET', key, ARGV[offset + 3], 'EX', ARGV[offset + 2])
    else
        redis.call('INCRBY', key, ARGV[offset + 3])
    end
end
return {0, 0, 0}
LUA;

    /** @param array<array{key:string,limit:int,seconds:int,cost:int,rule:string}> $buckets */
    public function consume(array $buckets): array
    {
        $keys = array_column($buckets, 'key');
        $arguments = [];
        foreach ($buckets as $bucket) {
            if ($bucket['limit'] < 1 || $bucket['seconds'] < 1 || $bucket['cost'] < 1 || $bucket['cost'] > $bucket['limit']) {
                throw new \LogicException('Invalid protection quota configuration');
            }
            array_push($arguments, $bucket['limit'], $bucket['seconds'], $bucket['cost']);
        }

        return Redis::connection(config('mini_protection.connection', 'default'))
            ->eval(self::SCRIPT, count($keys), ...array_merge($keys, $arguments));
    }
}