package mqtt

import (
    "fmt"
    "time"

    paho "github.com/eclipse/paho.mqtt.golang"
    "git.piskot.si/SeminarM2/lambdaiot-core/internal/config"
)

type Client struct {
    client paho.Client
}

func Connect(cfg config.MQTTConfig) (*Client, error) {
    opts := paho.NewClientOptions()
    opts.AddBroker(cfg.Broker)
    if cfg.ClientID != "" {
        opts.SetClientID(cfg.ClientID)
    }
    if cfg.Username != "" {
        opts.SetUsername(cfg.Username)
        opts.SetPassword(cfg.Password)
    }
    opts.SetAutoReconnect(true)
    opts.SetConnectRetry(true)
    opts.SetConnectTimeout(5 * time.Second)

    c := paho.NewClient(opts)
    token := c.Connect()
    if ok := token.WaitTimeout(10 * time.Second); !ok {
        return nil, fmt.Errorf("mqtt connect timeout")
    }
    if err := token.Error(); err != nil {
        return nil, err
    }
    return &Client{client: c}, nil
}

func (c *Client) Publish(topic string, payload []byte) error {
    if c == nil || c.client == nil {
        return fmt.Errorf("mqtt client not connected")
    }
    token := c.client.Publish(topic, 0, false, payload)
    if ok := token.WaitTimeout(5 * time.Second); !ok {
        return fmt.Errorf("publish timeout")
    }
    return token.Error()
}

func (c *Client) Close() {
    if c == nil || c.client == nil {
        return
    }
    c.client.Disconnect(250)
}