// 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 framework_test

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

	"github.com/pingcap/failpoint"
	"github.com/pingcap/tidb/disttask/framework/dispatcher"
	"github.com/pingcap/tidb/disttask/framework/proto"
	"github.com/pingcap/tidb/disttask/framework/scheduler"
	"github.com/pingcap/tidb/disttask/framework/storage"
	"github.com/pingcap/tidb/domain/infosync"
	"github.com/pingcap/tidb/testkit"
	"github.com/stretchr/testify/require"
)

type testDispatcherExt struct{}

var _ dispatcher.Extension = (*testDispatcherExt)(nil)

func (*testDispatcherExt) OnTick(_ context.Context, _ *proto.Task) {
}

func (*testDispatcherExt) OnNextStage(_ context.Context, _ dispatcher.TaskHandle, gTask *proto.Task) (metas [][]byte, err error) {
	if gTask.State == proto.TaskStatePending {
		gTask.Step = proto.StepOne
		return [][]byte{
			[]byte("task1"),
			[]byte("task2"),
			[]byte("task3"),
		}, nil
	}
	if gTask.Step == proto.StepOne {
		gTask.Step = proto.StepTwo
		return [][]byte{
			[]byte("task4"),
		}, nil
	}
	return nil, nil
}

func (*testDispatcherExt) OnErrStage(_ context.Context, _ dispatcher.TaskHandle, _ *proto.Task, _ []error) (meta []byte, err error) {
	return nil, nil
}

func generateSchedulerNodes4Test() ([]*infosync.ServerInfo, error) {
	serverInfos := infosync.MockGlobalServerInfoManagerEntry.GetAllServerInfo()
	if len(serverInfos) == 0 {
		return nil, errors.New("not found instance")
	}

	serverNodes := make([]*infosync.ServerInfo, 0, len(serverInfos))
	for _, serverInfo := range serverInfos {
		serverNodes = append(serverNodes, serverInfo)
	}
	return serverNodes, nil
}

func (*testDispatcherExt) GetEligibleInstances(_ context.Context, _ *proto.Task) ([]*infosync.ServerInfo, error) {
	return generateSchedulerNodes4Test()
}

func (*testDispatcherExt) IsRetryableErr(error) bool {
	return true
}

type testMiniTask struct{}

func (testMiniTask) IsMinimalTask() {}

func (testMiniTask) String() string {
	return "testMiniTask"
}

type testScheduler struct{}

func (*testScheduler) InitSubtaskExecEnv(_ context.Context) error { return nil }

func (t *testScheduler) CleanupSubtaskExecEnv(_ context.Context) error { return nil }

func (t *testScheduler) Rollback(_ context.Context) error { return nil }

func (t *testScheduler) SplitSubtask(_ context.Context, _ *proto.Subtask) ([]proto.MinimalTask, error) {
	return []proto.MinimalTask{
		testMiniTask{},
		testMiniTask{},
		testMiniTask{},
	}, nil
}

func (t *testScheduler) OnSubtaskFinished(_ context.Context, meta []byte) ([]byte, error) {
	return meta, nil
}

// Note: the subtask must be Reentrant.
type testSubtaskExecutor struct {
	m *sync.Map
}

func (e *testSubtaskExecutor) Run(_ context.Context) error {
	e.m.Store("0", "0")
	return nil
}

type testSubtaskExecutor1 struct {
	m *sync.Map
}

func (e *testSubtaskExecutor1) Run(_ context.Context) error {
	e.m.Store("1", "1")
	return nil
}

func RegisterTaskMeta(m *sync.Map, dispatcherHandle dispatcher.Extension) {
	dispatcher.ClearDispatcherFactory()
	dispatcher.RegisterDispatcherFactory(proto.TaskTypeExample,
		func(ctx context.Context, taskMgr *storage.TaskManager, serverID string, task *proto.Task) dispatcher.Dispatcher {
			baseDispatcher := dispatcher.NewBaseDispatcher(ctx, taskMgr, serverID, task)
			baseDispatcher.Extension = dispatcherHandle
			return baseDispatcher
		})
	scheduler.ClearSchedulers()
	scheduler.RegisterTaskType(proto.TaskTypeExample)
	scheduler.RegisterSchedulerConstructor(proto.TaskTypeExample, proto.StepOne, func(_ context.Context, _ *proto.Task, _ *scheduler.Summary) (scheduler.Scheduler, error) {
		return &testScheduler{}, nil
	})
	scheduler.RegisterSchedulerConstructor(proto.TaskTypeExample, proto.StepTwo, func(_ context.Context, _ *proto.Task, _ *scheduler.Summary) (scheduler.Scheduler, error) {
		return &testScheduler{}, nil
	})
	scheduler.RegisterSubtaskExectorConstructor(proto.TaskTypeExample, proto.StepOne, func(_ proto.MinimalTask, _ int64) (scheduler.SubtaskExecutor, error) {
		return &testSubtaskExecutor{m: m}, nil
	})
	scheduler.RegisterSubtaskExectorConstructor(proto.TaskTypeExample, proto.StepTwo, func(_ proto.MinimalTask, _ int64) (scheduler.SubtaskExecutor, error) {
		return &testSubtaskExecutor1{m: m}, nil
	})
}

func DispatchTask(taskKey string, t *testing.T) *proto.Task {
	mgr, err := storage.GetTaskManager()
	require.NoError(t, err)
	taskID, err := mgr.AddNewGlobalTask(taskKey, proto.TaskTypeExample, 8, nil)
	require.NoError(t, err)
	start := time.Now()

	var task *proto.Task
	for {
		if time.Since(start) > 10*time.Minute {
			require.FailNow(t, "timeout")
		}

		time.Sleep(time.Second)
		task, err = mgr.GetGlobalTaskByID(taskID)

		require.NoError(t, err)
		require.NotNil(t, task)
		if task.State != proto.TaskStatePending && task.State != proto.TaskStateRunning && task.State != proto.TaskStateCancelling && task.State != proto.TaskStateReverting {
			break
		}
	}
	return task
}

func DispatchTaskAndCheckSuccess(taskKey string, t *testing.T, m *sync.Map) {
	task := DispatchTask(taskKey, t)
	require.Equal(t, proto.TaskStateSucceed, task.State)
	v, ok := m.Load("1")
	require.Equal(t, true, ok)
	require.Equal(t, "1", v)
	v, ok = m.Load("0")
	require.Equal(t, true, ok)
	require.Equal(t, "0", v)
	m = &sync.Map{}
}

func DispatchAndCancelTask(taskKey string, t *testing.T, m *sync.Map) {
	require.NoError(t, failpoint.Enable("github.com/pingcap/tidb/disttask/framework/scheduler/MockExecutorRunCancel", "1*return(1)"))
	defer func() {
		require.NoError(t, failpoint.Disable("github.com/pingcap/tidb/disttask/framework/scheduler/MockExecutorRunCancel"))
	}()
	task := DispatchTask(taskKey, t)
	require.Equal(t, proto.TaskStateReverted, task.State)
	m.Range(func(key, value interface{}) bool {
		m.Delete(key)
		return true
	})
}

func DispatchTaskAndCheckState(taskKey string, t *testing.T, m *sync.Map, state string) {
	task := DispatchTask(taskKey, t)
	require.Equal(t, state, task.State)
	m.Range(func(key, value interface{}) bool {
		m.Delete(key)
		return true
	})
}

func TestFrameworkBasic(t *testing.T) {
	defer dispatcher.ClearDispatcherFactory()
	defer scheduler.ClearSchedulers()
	var m sync.Map
	RegisterTaskMeta(&m, &testDispatcherExt{})
	distContext := testkit.NewDistExecutionContext(t, 2)
	DispatchTaskAndCheckSuccess("key1", t, &m)
	DispatchTaskAndCheckSuccess("key2", t, &m)
	distContext.SetOwner(0)
	time.Sleep(2 * time.Second) // make sure owner changed
	DispatchTaskAndCheckSuccess("key3", t, &m)
	DispatchTaskAndCheckSuccess("key4", t, &m)
	distContext.SetOwner(1)
	time.Sleep(2 * time.Second) // make sure owner changed
	DispatchTaskAndCheckSuccess("key5", t, &m)
	distContext.Close()
}

func TestFramework3Server(t *testing.T) {
	defer dispatcher.ClearDispatcherFactory()
	defer scheduler.ClearSchedulers()
	var m sync.Map
	RegisterTaskMeta(&m, &testDispatcherExt{})
	distContext := testkit.NewDistExecutionContext(t, 3)
	DispatchTaskAndCheckSuccess("key1", t, &m)
	DispatchTaskAndCheckSuccess("key2", t, &m)
	distContext.SetOwner(0)
	time.Sleep(2 * time.Second) // make sure owner changed
	DispatchTaskAndCheckSuccess("key3", t, &m)
	DispatchTaskAndCheckSuccess("key4", t, &m)
	distContext.Close()
}

func TestFrameworkAddDomain(t *testing.T) {
	defer dispatcher.ClearDispatcherFactory()
	defer scheduler.ClearSchedulers()
	var m sync.Map
	RegisterTaskMeta(&m, &testDispatcherExt{})
	distContext := testkit.NewDistExecutionContext(t, 2)
	DispatchTaskAndCheckSuccess("key1", t, &m)
	distContext.AddDomain()
	DispatchTaskAndCheckSuccess("key2", t, &m)
	distContext.SetOwner(1)
	time.Sleep(2 * time.Second) // make sure owner changed
	DispatchTaskAndCheckSuccess("key3", t, &m)
	distContext.Close()
	distContext.AddDomain()
	DispatchTaskAndCheckSuccess("key4", t, &m)
}

func TestFrameworkDeleteDomain(t *testing.T) {
	defer dispatcher.ClearDispatcherFactory()
	defer scheduler.ClearSchedulers()
	var m sync.Map
	RegisterTaskMeta(&m, &testDispatcherExt{})
	distContext := testkit.NewDistExecutionContext(t, 2)
	DispatchTaskAndCheckSuccess("key1", t, &m)
	distContext.DeleteDomain(1)
	time.Sleep(2 * time.Second) // make sure the owner changed
	DispatchTaskAndCheckSuccess("key2", t, &m)
	distContext.Close()
}

func TestFrameworkWithQuery(t *testing.T) {
	defer dispatcher.ClearDispatcherFactory()
	defer scheduler.ClearSchedulers()
	var m sync.Map
	RegisterTaskMeta(&m, &testDispatcherExt{})
	distContext := testkit.NewDistExecutionContext(t, 2)
	DispatchTaskAndCheckSuccess("key1", t, &m)

	tk := testkit.NewTestKit(t, distContext.Store)

	tk.MustExec("use test")
	tk.MustExec("drop table if exists t")
	tk.MustExec("create table t(a int not null, b int not null)")
	rs, err := tk.Exec("select ifnull(a,b) from t")
	require.NoError(t, err)
	fields := rs.Fields()
	require.Greater(t, len(fields), 0)
	require.Equal(t, "ifnull(a,b)", rs.Fields()[0].Column.Name.L)
	require.NoError(t, rs.Close())
	distContext.Close()
}

func TestFrameworkCancelGTask(t *testing.T) {
	defer dispatcher.ClearDispatcherFactory()
	defer scheduler.ClearSchedulers()
	var m sync.Map
	RegisterTaskMeta(&m, &testDispatcherExt{})
	distContext := testkit.NewDistExecutionContext(t, 2)
	DispatchAndCancelTask("key1", t, &m)
	distContext.Close()
}

func TestFrameworkSubTaskFailed(t *testing.T) {
	defer dispatcher.ClearDispatcherFactory()
	defer scheduler.ClearSchedulers()

	var m sync.Map
	RegisterTaskMeta(&m, &testDispatcherExt{})
	distContext := testkit.NewDistExecutionContext(t, 1)
	require.NoError(t, failpoint.Enable("github.com/pingcap/tidb/disttask/framework/scheduler/MockExecutorRunErr", "1*return(true)"))
	defer func() {
		require.NoError(t, failpoint.Disable("github.com/pingcap/tidb/disttask/framework/scheduler/MockExecutorRunErr"))
	}()
	DispatchTaskAndCheckState("key1", t, &m, proto.TaskStateReverted)
	distContext.Close()
}

func TestFrameworkSubTaskInitEnvFailed(t *testing.T) {
	defer dispatcher.ClearDispatcherFactory()
	defer scheduler.ClearSchedulers()

	var m sync.Map
	RegisterTaskMeta(&m, &testDispatcherExt{})
	distContext := testkit.NewDistExecutionContext(t, 1)
	require.NoError(t, failpoint.Enable("github.com/pingcap/tidb/disttask/framework/scheduler/mockExecSubtaskInitEnvErr", "return()"))
	defer func() {
		require.NoError(t, failpoint.Disable("github.com/pingcap/tidb/disttask/framework/scheduler/mockExecSubtaskInitEnvErr"))
	}()
	DispatchTaskAndCheckState("key1", t, &m, proto.TaskStateReverted)
	distContext.Close()
}

func TestOwnerChange(t *testing.T) {
	defer dispatcher.ClearDispatcherFactory()
	defer scheduler.ClearSchedulers()
	var m sync.Map
	RegisterTaskMeta(&m, &testDispatcherExt{})

	distContext := testkit.NewDistExecutionContext(t, 3)
	dispatcher.MockOwnerChange = func() {
		distContext.SetOwner(0)
	}
	require.NoError(t, failpoint.Enable("github.com/pingcap/tidb/disttask/framework/dispatcher/mockOwnerChange", "1*return(true)"))
	DispatchTaskAndCheckSuccess("😊", t, &m)
	require.NoError(t, failpoint.Disable("github.com/pingcap/tidb/disttask/framework/dispatcher/mockOwnerChange"))
	distContext.Close()
}

func TestFrameworkCancelThenSubmitSubTask(t *testing.T) {
	defer dispatcher.ClearDispatcherFactory()
	defer scheduler.ClearSchedulers()
	var m sync.Map
	RegisterTaskMeta(&m, &testDispatcherExt{})
	distContext := testkit.NewDistExecutionContext(t, 3)
	require.NoError(t, failpoint.Enable("github.com/pingcap/tidb/disttask/framework/dispatcher/cancelBeforeUpdate", "return()"))
	DispatchTaskAndCheckState("😊", t, &m, proto.TaskStateReverted)
	require.NoError(t, failpoint.Disable("github.com/pingcap/tidb/disttask/framework/dispatcher/cancelBeforeUpdate"))
	distContext.Close()
}

func TestSchedulerDownBasic(t *testing.T) {
	defer dispatcher.ClearDispatcherFactory()
	defer scheduler.ClearSchedulers()
	var m sync.Map
	RegisterTaskMeta(&m, &testDispatcherExt{})

	distContext := testkit.NewDistExecutionContext(t, 4)
	require.NoError(t, failpoint.Enable("github.com/pingcap/tidb/disttask/framework/scheduler/mockCleanScheduler", "return()"))
	require.NoError(t, failpoint.Enable("github.com/pingcap/tidb/disttask/framework/scheduler/mockStopManager", "4*return(\":4000\")"))
	require.NoError(t, failpoint.Enable("github.com/pingcap/tidb/disttask/framework/scheduler/mockTiDBDown", "return(\":4000\")"))
	DispatchTaskAndCheckSuccess("😊", t, &m)
	require.NoError(t, failpoint.Disable("github.com/pingcap/tidb/disttask/framework/scheduler/mockCleanScheduler"))
	require.NoError(t, failpoint.Disable("github.com/pingcap/tidb/disttask/framework/scheduler/mockTiDBDown"))
	require.NoError(t, failpoint.Disable("github.com/pingcap/tidb/disttask/framework/scheduler/mockStopManager"))

	distContext.Close()
}

func TestSchedulerDownManyNodes(t *testing.T) {
	defer dispatcher.ClearDispatcherFactory()
	defer scheduler.ClearSchedulers()
	var m sync.Map
	RegisterTaskMeta(&m, &testDispatcherExt{})

	distContext := testkit.NewDistExecutionContext(t, 30)
	require.NoError(t, failpoint.Enable("github.com/pingcap/tidb/disttask/framework/scheduler/mockCleanScheduler", "return()"))
	require.NoError(t, failpoint.Enable("github.com/pingcap/tidb/disttask/framework/scheduler/mockStopManager", "30*return(\":4000\")"))
	require.NoError(t, failpoint.Enable("github.com/pingcap/tidb/disttask/framework/scheduler/mockTiDBDown", "return(\":4000\")"))
	DispatchTaskAndCheckSuccess("😊", t, &m)
	require.NoError(t, failpoint.Disable("github.com/pingcap/tidb/disttask/framework/scheduler/mockCleanScheduler"))
	require.NoError(t, failpoint.Disable("github.com/pingcap/tidb/disttask/framework/scheduler/mockTiDBDown"))
	require.NoError(t, failpoint.Disable("github.com/pingcap/tidb/disttask/framework/scheduler/mockStopManager"))

	distContext.Close()
}