<?php

namespace app\service\Task;

use support\Redis;

class ProofDbTaskQueue
{
    public function push(array $task): void
    {
        Redis::lPush($this->pendingKey(), json_encode($task, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES));
    }

    public function pop(int $timeout = 5): ?array
    {
        $result = Redis::brPop([$this->pendingKey()], $timeout);
        if (!is_array($result) || count($result) < 2) {
            return null;
        }

        $task = json_decode((string) $result[1], true);
        return is_array($task) ? $task : null;
    }

    public function retryLater(array $task, string $error): void
    {
        $taskId = $this->taskId($task);
        $retryKey = $this->retryKey($taskId);
        $retryCount = (int) Redis::incr($retryKey);
        Redis::setEx($this->errorKey($taskId), 86400, $error);

        $task['attempt'] = $retryCount + 1;
        if ($retryCount > $this->maxRetries()) {
            Redis::lPush($this->failedKey(), json_encode($task, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES));
            return;
        }

        $delay = $this->baseDelaySeconds() * (2 ** max(0, $retryCount - 1));
        Redis::zAdd($this->delayedKey(), time() + $delay, json_encode($task, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES));
    }

    public function releaseDueDelayed(): int
    {
        $items = Redis::zRangeByScore($this->delayedKey(), '-inf', (string) time(), ['limit' => [0, 100]]);
        if (!is_array($items) || $items === []) {
            return 0;
        }

        foreach ($items as $task) {
            Redis::zRem($this->delayedKey(), $task);
            Redis::lPush($this->pendingKey(), $task);
        }

        return count($items);
    }

    public function clearRetry(array $task): void
    {
        $taskId = $this->taskId($task);
        Redis::del($this->retryKey($taskId), $this->errorKey($taskId));
    }

    public function blockTimeout(): int
    {
        return (int) config('queue.tasks.block_timeout', 5);
    }

    public function idleSleepSeconds(): int
    {
        return max(1, (int) config('queue.tasks.idle_sleep_seconds', 1));
    }

    public function dispatcherIntervalSeconds(): int
    {
        return max(1, (int) config('queue.tasks.dispatcher_interval_seconds', 15));
    }

    public function dispatcherBatchSize(): int
    {
        return max(1, (int) config('queue.tasks.dispatcher_batch_size', 20));
    }

    private function taskId(array $task): string
    {
        return implode(':', [
            (string) ($task['task_type'] ?? 'unknown'),
            (string) ($task['target_type'] ?? 'unknown'),
            (string) ($task['target_uid'] ?? 'unknown'),
        ]);
    }

    private function pendingKey(): string
    {
        return config('queue.tasks.pending', 'proofdb:tasks:pending');
    }

    private function delayedKey(): string
    {
        return config('queue.tasks.delayed', 'proofdb:tasks:delayed');
    }

    private function failedKey(): string
    {
        return config('queue.tasks.failed', 'proofdb:tasks:failed');
    }

    private function retryKey(string $taskId): string
    {
        return config('queue.tasks.retry_prefix', 'proofdb:tasks:retry:') . $taskId;
    }

    private function errorKey(string $taskId): string
    {
        return config('queue.tasks.error_prefix', 'proofdb:tasks:error:') . $taskId;
    }

    private function maxRetries(): int
    {
        return (int) config('queue.tasks.max_retries', 5);
    }

    private function baseDelaySeconds(): int
    {
        return (int) config('queue.tasks.base_delay_seconds', 60);
    }
}