package tasksch

import (
	"errors"
	"time"

	"git.rosy.net.cn/baseapi/utils"
	"git.rosy.net.cn/jx-callback/business/jxutils"
	"git.rosy.net.cn/jx-callback/globals"
)

const (
	DefParallelCount = 10
	MaxParallelCount = 10
)

type WorkFunc func(batchItemList []interface{}, params ...interface{}) (retVal interface{}, err error)
type ResultHandlerFunc func(taskName string, result []interface{}, err error)

type ParallelConfig struct {
	ParallelCount       int
	BatchSize           int
	IsContinueWhenError bool
	ResultHandler       ResultHandlerFunc
}

type ParallelTask struct {
	BaseTask

	resultHandler ResultHandlerFunc
	worker        WorkFunc
	jobList       [][]interface{}
	taskChan      chan []interface{}
	subFinishChan chan interface{}
}

var (
	ErrTaskNotFinished = errors.New("任务还未完成")
	ErrTaskIsCanceled  = errors.New("任务被取消了")
)

func NewParallelConfig() *ParallelConfig {
	return &ParallelConfig{
		ParallelCount:       DefParallelCount,
		BatchSize:           1,
		IsContinueWhenError: false,
		ResultHandler:       nil,
	}
}

func (c *ParallelConfig) SetParallelCount(parallelCount int) *ParallelConfig {
	c.ParallelCount = parallelCount
	return c
}

func (c *ParallelConfig) SetBatchSize(batchSize int) *ParallelConfig {
	c.BatchSize = batchSize
	return c
}

func (c *ParallelConfig) SetIsContinueWhenError(isContinueWhenError bool) *ParallelConfig {
	c.IsContinueWhenError = isContinueWhenError
	return c
}

func (c *ParallelConfig) SetResultHandler(resultHandler ResultHandlerFunc) *ParallelConfig {
	c.ResultHandler = resultHandler
	return c
}

func NewParallelTask(taskName string, userName string, config *ParallelConfig, worker WorkFunc, itemList interface{}, params ...interface{}) *ParallelTask {
	if config == nil {
		config = NewParallelConfig()
	}
	if config.ParallelCount == 0 {
		config.ParallelCount = DefParallelCount
	}
	if config.ParallelCount > MaxParallelCount {
		config.ParallelCount = MaxParallelCount
	}
	realItemList := utils.Interface2Slice(itemList)
	jobList := jxutils.SplitSlice(realItemList, config.BatchSize)
	jobListLen := len(jobList)
	if config.ParallelCount > jobListLen {
		config.ParallelCount = jobListLen
	}
	task := &ParallelTask{
		subFinishChan: make(chan interface{}, config.ParallelCount),
		taskChan:      make(chan []interface{}, len(realItemList)+config.ParallelCount), // 确保能装下所有taskitem，加结束标记
		resultHandler: config.ResultHandler,
		worker:        worker,
		jobList:       jobList,
	}
	task.Init(config.ParallelCount, config.BatchSize, config.IsContinueWhenError, params, taskName, userName, len(realItemList), jobListLen)
	return task
}

func RunParallelTask(taskName string, userName string, config *ParallelConfig, worker WorkFunc, itemList interface{}, params ...interface{}) *ParallelTask {
	task := NewParallelTask(taskName, userName, config, worker, itemList, params...)
	task.Run()
	return task
}

func RunTask(taskName string, isContinueWhenError bool, resultHandler ResultHandlerFunc, parallelCount, batchSize int, userName string, worker WorkFunc, itemList interface{}, params ...interface{}) *ParallelTask {
	config := NewParallelConfig()
	config.BatchSize = batchSize
	config.IsContinueWhenError = isContinueWhenError
	config.ParallelCount = parallelCount
	config.ResultHandler = resultHandler
	task := NewParallelTask(taskName, userName, config, worker, itemList, params...)
	task.Run()
	return task
}

func (task *ParallelTask) Run() {
	task.run(func() {
		globals.SugarLogger.Debugf("ParallelTask.Run %s", task.Name)
		for i := 0; i < task.ParallelCount; i++ {
			utils.CallFuncAsync(func() {
				var chanRetVal interface{}
				retVal := make([]interface{}, 0)
				for {
					select {
					case <-task.quitChan: // 取消
						goto end
					case job := <-task.taskChan:
						if job == nil { // 任务完成
							chanRetVal = retVal
							goto end
						} else {
							result, err := task.worker(job, task.params...)
							// globals.SugarLogger.Debugf("ParallelTask.Run %s, after call worker result:%v, err:%v", task.Name, result, err)
							task.finishedOneJob(len(job), err)
							if err == nil {
								if result != nil {
									retVal = append(retVal, utils.Interface2Slice(result)...)
								}
							} else {
								globals.SugarLogger.Infof("ParallelTask.Run %s, subtask(job:%s, params:%s) result:%v, failed with error:%v", task.Name, utils.Format4Output(job, true), utils.Format4Output(task.params, true), result, err)
								if !task.IsContinueWhenError { // 出错
									chanRetVal = err
									goto end
								}
							}
						}
					}
				}
			end:
				// globals.SugarLogger.Debugf("ParallelTask.Run %s, put to chann chanRetVal:%v", task.Name, chanRetVal)
				task.locker.RLock()
				if task.Status < TaskStatusEndBegin {
					task.subFinishChan <- chanRetVal
				}
				task.locker.RUnlock()
			})
		}
		for _, job := range task.jobList {
			task.taskChan <- job
		}
		for i := 0; i < task.ParallelCount; i++ {
			task.taskChan <- nil
		}

		taskResult := make([]interface{}, 0)
		var taskErr error
		for i := 0; i < task.ParallelCount; i++ {
			result := <-task.subFinishChan
			// globals.SugarLogger.Debugf("ParallelTask.Run %s, received from chann result:%v", taskName, result)
			if err, ok := result.(error); ok {
				task.Cancel()
				taskResult = nil
				taskErr = err
				break // 出错情况下是否需要直接跳出？
			} else if result != nil {
				resultList := result.([]interface{})
				taskResult = append(taskResult, resultList...)
			}
		}

		task.locker.Lock()
		if taskErr != nil { // 如果有错误，肯定就是失败了
			task.Status = TaskStatusFailed
		} else {
			if len(task.taskChan) > 0 {
				taskErr = ErrTaskIsCanceled
				task.Status = TaskStatusCanceled
			} else {
				task.Status = TaskStatusFinished
			}
		}
		task.Err = taskErr
		task.Result = taskResult
		task.TerminatedAt = time.Now()
		task.locker.Unlock()

		globals.SugarLogger.Debugf("ParallelTask.Run %s, result:%v, err:%v", task.Name, taskResult, taskErr)

		close(task.finishChan)
		close(task.subFinishChan)
		close(task.quitChan)

		if task.resultHandler != nil {
			task.resultHandler(task.Name, taskResult, task.Err)
		}
	})
}