// Copyright 2023 PingCAP, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package ttlworker

import (
	"context"
	"testing"
	"time"

	"github.com/pingcap/errors"
	"github.com/pingcap/tidb/pkg/kv"
	"github.com/pingcap/tidb/pkg/sessionctx/variable"
	"github.com/pingcap/tidb/pkg/ttl/cache"
	"github.com/pingcap/tidb/pkg/ttl/session"
	"github.com/pingcap/tidb/pkg/util/logutil"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"github.com/tikv/client-go/v2/testutils"
	"github.com/tikv/client-go/v2/tikv"
	"github.com/tikv/client-go/v2/tikvrpc"
)

// NewTaskManager is an exported version of newTaskManager for test
var NewTaskManager = newTaskManager

// Worker is an exported version of worker
type Worker = worker

func (m *taskManager) SetScanWorkers4Test(workers []worker) {
	m.scanWorkers = workers
}

// LockScanTask is an exported version of lockScanTask
func (m *taskManager) LockScanTask(se session.Session, task *cache.TTLTask, now time.Time) (*runningScanTask, error) {
	return m.lockScanTask(se, task, now)
}

// ResizeWorkersWithSysVar is an exported version of resizeWorkersWithSysVar
func (m *taskManager) ResizeWorkersWithSysVar() {
	m.resizeWorkersWithSysVar()
}

// ResizeWorkersToZero resize workers to zero
func (m *taskManager) ResizeWorkersToZero(t *testing.T) {
	require.NoError(t, m.resizeScanWorkers(0))
	require.NoError(t, m.resizeDelWorkers(0))
}

// RescheduleTasks is an exported version of rescheduleTasks
func (m *taskManager) RescheduleTasks(se session.Session, now time.Time) {
	m.rescheduleTasks(se, now)
}

// ResizeScanWorkers is an exported version of resizeScanWorkers
func (m *taskManager) ResizeScanWorkers(count int) error {
	return m.resizeScanWorkers(count)
}

// ResizeDelWorkers is an exported version of resizeDeleteWorkers
func (m *taskManager) ResizeDelWorkers(count int) error {
	return m.resizeDelWorkers(count)
}

// ReportMetrics is an exported version of reportMetrics
func (m *taskManager) ReportMetrics() {
	m.reportMetrics()
}

// CheckFinishedTask is an exported version of checkFinishedTask
func (m *taskManager) CheckFinishedTask(se session.Session, now time.Time) {
	m.checkFinishedTask(se, now)
}

// ReportTaskFinished is an exported version of reportTaskFinished
func (m *taskManager) GetRunningTasks() []*runningScanTask {
	return m.runningTasks
}

// MeetTTLRunningTasks is an exported version of meetTTLRunningTask
func (m *taskManager) MeetTTLRunningTasks(count int, taskStatus cache.TaskStatus) bool {
	return m.meetTTLRunningTask(count, taskStatus)
}

// ReportTaskFinished is an exported version of reportTaskFinished
func (m *taskManager) ReportTaskFinished(se session.Session, now time.Time, task *runningScanTask) error {
	return m.reportTaskFinished(se, now, task)
}

// GetScanWorkers returns the scan workers of the task manager.
func (m *taskManager) GetScanWorkers() []worker {
	return m.scanWorkers
}

// SetResult sets the result of the task
func (t *runningScanTask) SetResult(err error) {
	t.result = t.ttlScanTask.result(err)
}

// UpdateHeartBeat is an exported version of updateHeartBeat
func (m *taskManager) UpdateHeartBeat(ctx context.Context, se session.Session, now time.Time) {
	m.updateHeartBeat(ctx, se, now)
}

// UpdateHeartBeatForTask is an exported version of updateHeartBeatForTask
func (m *taskManager) UpdateHeartBeatForTask(ctx context.Context, se session.Session, now time.Time, task *runningScanTask) error {
	return m.taskHeartbeatOrResignOwner(ctx, se, now, task, false)
}

// SetWaitWorkerStopTimeoutForTest sets the waitWorkerStopTimeout for testing
func SetWaitWorkerStopTimeoutForTest(timeout time.Duration) func() {
	original := waitWorkerStopTimeout
	waitWorkerStopTimeout = timeout
	return func() {
		waitWorkerStopTimeout = original
	}
}

// GetTerminateInfo returns the task terminates info
func (t *runningScanTask) GetTerminateInfo() (bool, TaskTerminateReason, time.Time) {
	if t.result == nil {
		return false, "", time.Time{}
	}
	return true, t.result.reason, t.result.time
}

// GetStatistics returns the ttlStatistics
func (t *runningScanTask) GetStatistics() *ttlStatistics {
	return t.statistics
}

// ResetEndTime resets the end time
func (t *runningScanTask) ResetEndTimeForTest(tb *testing.T, tm time.Time) {
	require.NotNil(tb, t.result)
	t.result.time = tm
}

// SetCancel sets the cancel function of the task
func (t *runningScanTask) SetCancel(cancel func()) {
	t.cancel = cancel
}

// CheckInvalidTask is an exported version of checkInvalidTask
func (m *taskManager) CheckInvalidTask(se session.Session) {
	m.checkInvalidTask(se)
}

func TestResizeWorkers(t *testing.T) {
	tbl := newMockTTLTbl(t, "t1")

	// scale workers
	scanWorker1 := NewMockScanWorker(t)
	scanWorker1.Start()
	scanWorker2 := NewMockScanWorker(t)

	m := newTaskManager(context.Background(), nil, nil, "test-id", nil)
	m.sessPool = newMockSessionPool(t, tbl)
	m.SetScanWorkers4Test([]worker{
		scanWorker1,
	})
	newWorkers, _, err := m.resizeWorkers(m.scanWorkers, 2, func() worker {
		return scanWorker2
	})
	assert.NoError(t, err)
	assert.Len(t, newWorkers, 2)
	scanWorker1.checkWorkerStatus(workerStatusRunning, true, nil)
	scanWorker2.checkWorkerStatus(workerStatusRunning, true, nil)

	// shrink scan workers
	scanWorker1 = NewMockScanWorker(t)
	scanWorker1.Start()
	scanWorker2 = NewMockScanWorker(t)
	scanWorker2.Start()

	m = newTaskManager(context.Background(), nil, nil, "test-id", nil)
	m.sessPool = newMockSessionPool(t, tbl)
	m.SetScanWorkers4Test([]worker{
		scanWorker1,
		scanWorker2,
	})

	assert.NoError(t, m.resizeScanWorkers(1))
	scanWorker2.checkWorkerStatus(workerStatusStopped, false, nil)

	// shrink scan workers after job is run
	scanWorker1 = NewMockScanWorker(t)
	scanWorker1.Start()
	scanWorker2 = NewMockScanWorker(t)
	scanWorker2.Start()

	m = newTaskManager(context.Background(), nil, nil, "test-id", nil)
	m.sessPool = newMockSessionPool(t, tbl)
	m.SetScanWorkers4Test([]worker{
		scanWorker1,
		scanWorker2,
	})
	m.runningTasks = append(m.runningTasks, &runningScanTask{
		ttlScanTask: &ttlScanTask{
			tbl: tbl,
			TTLTask: &cache.TTLTask{
				JobID:  "test-job-id",
				ScanID: 1,
			},
		},
	})

	task := &ttlScanTask{tbl: tbl, TTLTask: &cache.TTLTask{
		JobID:  "test-job-id",
		ScanID: 1,
	}}
	scanWorker2.curTaskResult = task.result(nil)
	assert.NoError(t, m.resizeScanWorkers(1))
	scanWorker2.checkWorkerStatus(workerStatusStopped, false, nil)
	assert.NotNil(t, m.runningTasks[0].result)
}

func TestTaskFinishedCondition(t *testing.T) {
	tbl := newMockTTLTbl(t, "t1")
	task := runningScanTask{
		ttlScanTask: &ttlScanTask{
			tbl: tbl,
			TTLTask: &cache.TTLTask{
				JobID:  "test-job-id",
				ScanID: 1,
			},
			statistics: &ttlStatistics{},
		},
	}
	logger := logutil.BgLogger()

	// result == nil means it is not finished, even if all rows processed
	require.Nil(t, task.result)
	require.False(t, task.finished(logger))
	task.statistics.TotalRows.Store(10)
	task.statistics.SuccessRows.Store(10)
	require.False(t, task.finished(logger))

	for _, resultErr := range []error{nil, errors.New("mockErr")} {
		// result != nil but not all rows processed means it is not finished
		task.statistics.SuccessRows.Store(0)
		task.statistics.ErrorRows.Store(0)
		task.result = task.ttlScanTask.result(resultErr)
		require.InDelta(t, task.result.time.Unix(), time.Now().Unix(), 5)
		require.False(t, task.finished(logger))
		task.statistics.SuccessRows.Store(8)
		task.statistics.ErrorRows.Store(1)
		require.False(t, task.finished(logger))

		// result != nil but time out means it is finished
		task.result = task.ttlScanTask.result(resultErr)
		task.result.time = time.Now().Add(-waitTaskProcessRowsTimeout - time.Second)
		require.True(t, task.finished(logger))

		// result != nil and processed rows are more that total rows means it is finished
		task.statistics.SuccessRows.Store(8)
		task.statistics.ErrorRows.Store(3)
		require.True(t, task.finished(logger))
	}
}

type mockKVStore struct {
	kv.Storage
}

type mockTiKVStore struct {
	mockKVStore
	tikv.Storage
	regionCache *tikv.RegionCache
}

func (s *mockTiKVStore) GetRegionCache() *tikv.RegionCache {
	return s.regionCache
}

func TestGetMaxRunningTasksLimit(t *testing.T) {
	mockClient, _, pdClient, err := testutils.NewMockTiKV("", nil)
	require.NoError(t, err)
	defer func() {
		pdClient.Close()
		err = mockClient.Close()
		require.NoError(t, err)
	}()

	variable.TTLRunningTasks.Store(1)
	require.Equal(t, 1, getMaxRunningTasksLimit(&mockTiKVStore{}))

	variable.TTLRunningTasks.Store(2)
	require.Equal(t, 2, getMaxRunningTasksLimit(&mockTiKVStore{}))

	variable.TTLRunningTasks.Store(-1)
	require.Equal(t, variable.MaxConfigurableConcurrency, getMaxRunningTasksLimit(nil))
	require.Equal(t, variable.MaxConfigurableConcurrency, getMaxRunningTasksLimit(&mockKVStore{}))
	require.Equal(t, variable.MaxConfigurableConcurrency, getMaxRunningTasksLimit(&mockTiKVStore{}))

	s := &mockTiKVStore{regionCache: tikv.NewRegionCache(pdClient)}
	s.GetRegionCache().SetRegionCacheStore(1, "", "", tikvrpc.TiKV, 1, nil)
	s.GetRegionCache().SetRegionCacheStore(2, "", "", tikvrpc.TiKV, 1, nil)
	s.GetRegionCache().SetRegionCacheStore(3, "", "", tikvrpc.TiFlash, 1, nil)
	require.Equal(t, 2, getMaxRunningTasksLimit(s))
}