package testing

import (
	"context"
	"sync"
	"testing"
	"time"

	"forge.cadoles.com/arcad/edge/pkg/bus"
	"github.com/pkg/errors"
)

const (
	testTypeReqRes bus.MessageNamespace = "testNamspaceReqRes"
)

type testReqResMessage struct {
	i int
}

func (m *testReqResMessage) MessageNamespace() bus.MessageNamespace {
	return testNamespace
}

func TestRequestReply(t *testing.T, b bus.Bus) {
	expectedRoundTrips := 256
	timeout := time.Now().Add(time.Duration(expectedRoundTrips) * time.Second)

	var (
		initWaitGroup sync.WaitGroup
		resWaitGroup  sync.WaitGroup
	)

	initWaitGroup.Add(1)

	go func() {
		repondCtx, cancelRespond := context.WithDeadline(context.Background(), timeout)
		defer cancelRespond()

		initWaitGroup.Done()

		err := b.Reply(repondCtx, testNamespace, func(msg bus.Message) (bus.Message, error) {
			defer resWaitGroup.Done()

			req, ok := msg.(*testReqResMessage)
			if !ok {
				return nil, errors.WithStack(bus.ErrUnexpectedMessage)
			}

			result := &testReqResMessage{req.i}

			// Simulate random work
			time.Sleep(time.Millisecond * 100)

			t.Logf("[RES] sending res #%d", req.i)

			return result, nil
		})
		if err != nil {
			t.Error(err)
		}
	}()

	initWaitGroup.Wait()

	var reqWaitGroup sync.WaitGroup

	for i := 0; i < expectedRoundTrips; i++ {
		resWaitGroup.Add(1)
		reqWaitGroup.Add(1)

		go func(i int) {
			defer reqWaitGroup.Done()

			requestCtx, cancelRequest := context.WithDeadline(context.Background(), timeout)
			defer cancelRequest()

			req := &testReqResMessage{i}

			t.Logf("[REQ] sending req #%d", i)

			result, err := b.Request(requestCtx, req)
			if err != nil {
				t.Error(err)
			}

			t.Logf("[REQ] received req #%d reply", i)

			if result == nil {
				t.Error("result should not be nil")

				return
			}

			res, ok := result.(*testReqResMessage)
			if !ok {
				t.Error(errors.WithStack(bus.ErrUnexpectedMessage))

				return
			}

			if e, g := req.i, res.i; e != g {
				t.Errorf("res.i: expected '%v', got '%v'", e, g)
			}
		}(i)
	}

	reqWaitGroup.Wait()
	resWaitGroup.Wait()
}