// Example pipeline demonstrates a three-stage pipeline with an actor for each
// stage.
package main

import "log"
import "time"
import "context"
import "math/rand"
import "git.tebibyte.media/sashakoshka/camfish"

func main() {
	camfish.Run("pipeline",
		"Example pipeline demonstrates a three-stage pipeline with " +
		"an actor for each stage",
		new(generator),
		new(reverser),
		new(printer))
}

// generator produces strings randomly.
type generator struct { }
var _ camfish.Runnable = new(generator)
func (this *generator) Type() string { return "generator" }

func (this *generator) Run(ctx context.Context) error {
	reverser := camfish.Find("reverser").(*reverser)
	timer := time.NewTimer(0)
	for {
		select {
		case <- timer.C:
			timer.Reset(time.Duration(float64(time.Second) * (rand.Float64() + 0.2)))
			reverser.Send([]string {
				"red", "yellow", "green", "blue",
			}[rand.Int() % 4])
		case <- ctx.Done(): return ctx.Err()
		}
	}
}

// reverser reverses strings.
type reverser struct { input chan string }
var _ camfish.Runnable = new(reverser)
var _ camfish.Initializable = new(reverser)
func (this *reverser) Type() string { return "reverser" }

func (this *reverser) Init(ctx context.Context) error {
	this.input = make(chan string)
	return ctx.Err()
}

func (this *reverser) Run(ctx context.Context) error {
	printer := camfish.Find("printer").(*printer)
	for {
		select {
		case str := <- this.input:
			runes := []rune(str)
			for i, j := 0, len(runes) - 1; i < j; i, j = i + 1, j - 1 {
				runes[i], runes[j] = runes[j], runes[i]
			}
			printer.Print(string(runes))
		case <- ctx.Done(): return ctx.Err()
		}
	}
}

func (this *reverser) Send(str string) {
	this.input <- str
}

// printer prints strings.
type printer struct { input chan string }
var _ camfish.Runnable = new(printer)
var _ camfish.Initializable = new(printer)
func (this *printer) Type() string { return "printer" }

func (this *printer) Init(ctx context.Context) error {
	this.input = make(chan string)
	return ctx.Err()
}

func (this *printer) Run(ctx context.Context) error {
	for {
		select {
		case str := <- this.input:
			log.Println("(i) [printer]", str)
		case <- ctx.Done(): return ctx.Err()
		}
	}
}

func (this *printer) Print(str string) {
	this.input <- str
}