package main

import (
	"fmt"
	"math/rand"
	"time"
)

func main() {

	ch1 := make(chan string)
	ch2 := make(chan string)

	go func() {
		// Simulate some work by sleeping for a random duration between 1 and 5 seconds before sending a message to ch1.
		time.Sleep(time.Duration(rand.Intn(5)+1) * time.Second)
		ch1 <- "Message from channel 1"
	}()

	go func() {
		// Simulate some work by sleeping for a random duration between 1 and 5 seconds before sending a message to ch2.
		time.Sleep(time.Duration(rand.Intn(5)+1) * time.Second)
		ch2 <- "Message from channel 2"
	}()

	// Create multiple dynamic channels and send messages to them in separate goroutines.
	// This demonstrates how we can use select to wait for messages from a variable number of channels.
	count := 10
	var channels []chan string
	for i := range count {
		ch := make(chan string)
		channels = append(channels, ch)
		go func() {
			time.Sleep(time.Duration(rand.Intn(5)+1) * time.Second)
			ch <- fmt.Sprintf("Message from dynamic channel %d", i)
		}()
	}

	// Fan-in pattern: Create a single channel to receive messages from multiple channels.
	// This allows us to use select to wait for messages from all channels in a single case.
	fanIn := make(chan string)
	for _, ch := range channels {
		go func(c chan string) {
			fanIn <- <-c // Read a message from the dynamic channel and send it to the fanIn channel. A temporary variable is needed to capture the current value of ch.
		}(ch)
	}

	// Use select to wait for messages from multiple channels. The select statement allows us to wait on multiple channel operations
	// and proceed with the one that is ready first.
	select {
	case msg1 := <-ch1:
		println("Received:", msg1)
	case msg2 := <-ch2:
		println("Received:", msg2)
	case msg := <-fanIn:
		println("Received:", msg)
	case <-time.After(3 * time.Second): // The time.After function returns a channel that will send the current time after the specified duration. This case will be selected if no other channels are ready within 3 seconds, allowing us to handle a timeout scenario.
		println("Timeout occurred")
		//default: // The default case is executed if none of the channels are ready. Not to be used in this example, as it would cause the select statement to proceed immediately.
		//	println("Nothing")
	}
}