package iowrappers

import (
	"context"
	"github.com/stretchr/testify/suite"
	"log"
	"sync"
	"testing"
	"time"
)

type ChannelReadWriterTestSuite struct {
	suite.Suite

	ctx         context.Context
	cancelFunc  context.CancelFunc
	toChannel   chan<- []byte
	fromChannel <-chan []byte
	conn        *ChannelReadWriter
}

func TestChannelReadWriterSuite(t *testing.T) {
	suite.Run(t, &ChannelReadWriterTestSuite{})
}

func (suite *ChannelReadWriterTestSuite) createChannel() {
	toChannel := make(chan []byte)
	fromChannel := make(chan []byte)
	suite.toChannel = toChannel
	suite.fromChannel = fromChannel
	ctx, cancelFunc := context.WithCancel(context.Background())
	ctx, timeoutCancelFunc := context.WithTimeout(ctx, 10*time.Second)
	suite.ctx = ctx
	suite.cancelFunc = func() {
		timeoutCancelFunc()
		cancelFunc()
	}
	suite.cancelFunc = cancelFunc
	suite.conn = NewChannelReadWriter(ctx, toChannel, fromChannel)
}

func (suite *ChannelReadWriterTestSuite) SetupTest() {
	suite.createChannel()
}

func (suite *ChannelReadWriterTestSuite) TearDownTest() {
	suite.cancelFunc()
}

type TestFunc func() any

func runAndWait(functions ...TestFunc) []any {
	wg := sync.WaitGroup{}
	wg.Add(len(functions))
	res := make([]any, len(functions))
	for i, function := range functions {
		go func() {
			res[i] = function()
			wg.Done()
		}()
	}
	wg.Wait()
	return res
}

func (suite *ChannelReadWriterTestSuite) Test_SlicesLargeEnough() {
	requires := suite.Require()
	data := []byte("hello")

	runAndWait(
		func() any {
			suite.toChannel <- data
			log.Println("data sent")
			return nil
		},
		func() any {
			buf := make([]byte, len(data)*2)
			n, err := suite.conn.Read(buf)
			requires.Nil(err)
			requires.Equal(n, len(data))
			requires.Equal(data, buf[:n])
			return nil
		},
	)
}

func (suite *ChannelReadWriterTestSuite) Test_SliceTooSmallFullReadInTwoParts() {
	suite.FailNow("todo")
}

func (suite *ChannelReadWriterTestSuite) Test_SliceTooSmallFullREadInManyParts() {
	suite.FailNow("todo")
}

func (suite *ChannelReadWriterTestSuite) Test_Close() {
	suite.FailNow("todo")
}

func (suite *ChannelReadWriterTestSuite) Test_CloseTwice() {
	suite.FailNow("todo")
}

func (suite *ChannelReadWriterTestSuite) Test_ContextCanceled() {
	suite.FailNow("todo")
}