package main

import (
	"context"
	"log"
	"os"
	"strings"
	"time"

	amqp "github.com/rabbitmq/amqp091-go"
)

func failOnError(err error, msg string) {
        if err != nil {
                log.Panicf("%s: %s", msg, err)
        }
}

func main() {
        conn, err := amqp.Dial("amqp://guest:guest@localhost:5672/")
        failOnError(err, "Failed to connect to RabbitMQ")
        defer conn.Close()

        ch, err := conn.Channel()
        failOnError(err, "Failed to open a channel")
        defer ch.Close()

        err = ch.ExchangeDeclare(
                "logs_direct", // name
                "direct",      // type
                true,          // durable
                false,         // auto-deleted
                false,         // internal
                false,         // no-wait
                nil,           // arguments
        )
        failOnError(err, "Failed to declare an exchange")

        ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
        defer cancel()

        body := bodyFrom(os.Args)
        err = ch.PublishWithContext(ctx,
                "logs_direct",         // exchange
                severityFrom(os.Args), // routing key
                false, // mandatory
                false, // immediate
                amqp.Publishing{
                        ContentType: "text/plain",
                        Body:        []byte(body),
                })
        failOnError(err, "Failed to publish a message")

        log.Printf(" [x] Sent %s", body)
}

func bodyFrom(args []string) string {
        var s string
        if (len(args) < 3) || os.Args[2] == "" {
                s = "hello"
        } else {
                s = strings.Join(args[2:], " ")
        }
        return s
}

func severityFrom(args []string) string {
        var s string
        if (len(args) < 2) || os.Args[1] == "" {
                s = "info"
        } else {
                s = os.Args[1]
        }
        return s
}
