// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.

// +build integration_api

package api

import (
	"context"
	"io"
	"io/ioutil"
	"time"

	"github.com/talos-systems/talos/api/common"
	"github.com/talos-systems/talos/internal/integration/base"
	"github.com/talos-systems/talos/pkg/client"
)

// DmesgSuite verifies Dmesg API
type DmesgSuite struct {
	base.APISuite

	ctx       context.Context
	ctxCancel context.CancelFunc
}

// SuiteName ...
func (suite *DmesgSuite) SuiteName() string {
	return "api.DmesgSuite"
}

// SetupTest ...
func (suite *DmesgSuite) SetupTest() {
	// make sure API calls have timeout
	suite.ctx, suite.ctxCancel = context.WithTimeout(context.Background(), 2*time.Minute)
}

// TearDownTest ...
func (suite *DmesgSuite) TearDownTest() {
	suite.ctxCancel()
}

// TestNodeHasDmesg verifies that default node has dmesg
func (suite *DmesgSuite) TestNodeHasDmesg() {
	dmesgStream, err := suite.Client.Dmesg(
		suite.ctx,
		false,
		false,
	)
	suite.Require().NoError(err)

	logReader, errCh, err := client.ReadStream(dmesgStream)
	suite.Require().NoError(err)

	n, err := io.Copy(ioutil.Discard, logReader)
	suite.Require().NoError(err)

	suite.Require().NoError(<-errCh)

	// dmesg shouldn't be empty
	suite.Require().Greater(n, int64(1024))
}

// TestStreaming verifies that logs are streamed in real-time
func (suite *DmesgSuite) TestStreaming() {
	dmesgStream, err := suite.Client.Dmesg(
		suite.ctx,
		true,
		false,
	)
	suite.Require().NoError(err)

	suite.Require().NoError(dmesgStream.CloseSend())

	respCh := make(chan *common.Data)
	errCh := make(chan error, 1)

	go func() {
		defer close(respCh)

		for {
			msg, err := dmesgStream.Recv()
			if err != nil {
				errCh <- err
				return
			}

			respCh <- msg
		}
	}()

	defer func() {
		suite.ctxCancel()
		// drain respCh
		for range respCh {
		}
	}()

	// drain the stream until flow stops
	logCount := 0

DrainLoop:
	for {
		select {
		case msg, ok := <-respCh:
			logCount++
			suite.Require().True(ok)
			suite.Assert().NotEmpty(msg.Bytes)
		case <-time.After(200 * time.Millisecond):
			break DrainLoop
		}
	}

	suite.Assert().Greater(logCount, 10)
}

// TestClusterHasDmesg verifies that all the cluster nodes have dmesg
func (suite *DmesgSuite) TestClusterHasDmesg() {
	nodes := suite.DiscoverNodes()
	suite.Require().NotEmpty(nodes)

	ctx := client.WithNodes(suite.ctx, nodes...)

	dmesgStream, err := suite.Client.Dmesg(
		ctx,
		false,
		false,
	)
	suite.Require().NoError(err)

	sizeByNode := map[string]int{}

	for {
		msg, err := dmesgStream.Recv()
		if err != nil {
			if err == io.EOF {
				break
			}
			suite.Require().NoError(err)
		}

		suite.Require().NotNil(msg.Metadata)
		suite.Assert().Empty(msg.Metadata.Error)

		sizeByNode[msg.Metadata.Hostname] += len(msg.Bytes)
	}

	for _, node := range nodes {
		suite.Assert().Greater(sizeByNode[node], 1024)
	}

	for node := range sizeByNode {
		suite.Assert().Contains(nodes, node)
	}
}

func init() {
	allSuites = append(allSuites, new(DmesgSuite))
}