package io.trygvis.async;

import io.trygvis.queue.QueueExecutor;
import io.trygvis.queue.QueueService;
import io.trygvis.queue.QueueSystem;
import io.trygvis.queue.Task;
import io.trygvis.queue.TaskEffect;

import java.sql.Connection;
import java.sql.SQLException;
import java.util.HashMap;
import java.util.Map;

import static java.lang.System.currentTimeMillis;
import static java.lang.Thread.sleep;

public class JdbcAsyncService {
    private final Map<String, QueueController> queues = new HashMap<>();

    private final QueueSystem queueSystem;

    public JdbcAsyncService(QueueSystem queueSystem) {
        this.queueSystem = queueSystem;
    }

    public synchronized QueueController registerQueue(QueueExecutor queue, QueueService.TaskExecutionRequest req, TaskEffect processor) {
        if (queues.containsKey(queue.queue.name)) {
            throw new IllegalArgumentException("Queue already exist.");
        }

        QueueController queueController = new QueueController(queueSystem, req, processor, queue);

        queues.put(queue.queue.name, queueController);

        return queueController;
    }

    public QueueExecutor getQueue(String name) {
        return getQueueThread(name).queue;
    }

    public Task await(Connection c, Task task, long timeout) throws SQLException {
        final long start = currentTimeMillis();
        final long end = start + timeout;

        while (currentTimeMillis() < end) {
            task = update(c, task);

            if (task == null) {
                throw new RuntimeException("The task went away.");
            }

            try {
                sleep(100);
            } catch (InterruptedException e) {
                // break
            }
        }

        return task;
    }

    public Task update(Connection c, Task ref) throws SQLException {
        return queueSystem.createTaskDao(c).findById(ref.id());
    }

    private synchronized QueueController getQueueThread(String name) {
        QueueController queueController = queues.get(name);

        if (queueController == null) {
            throw new RuntimeException("No such queue: '" + name + "'.");
        }
        return queueController;
    }
}