package crontab

import (
	"errors"
	"fmt"
	"log"
	"regexp"
	"strconv"
	"strings"
	"time"

	clinked "474420502.top/eson/structure/circular_linked"
	"github.com/Pallinder/go-randomdata"

	"github.com/davecgh/go-spew/spew"
)

type randLR struct {
	left, right int
}

type hInterval struct {
	PlanFail   []randLR
	PlanNormal []randLR

	Count      int
	ConstCount int
}

func (interval *hInterval) reset() {
	interval.Count = interval.ConstCount
}

type timePointer struct {
	left, right           int
	leftlimit, rightlimit int
	per                   int
	isAll                 bool
}

func (tp *timePointer) String() string {
	return fmt.Sprintf("left: %d, right: %d, leftlimit: %d, rightlimit: %d, per: %d", tp.left, tp.right, tp.leftlimit, tp.rightlimit, tp.per)
}

// Crontab 的string解析
type Crontab struct {
	min   []timePointer
	hour  []timePointer
	day   []timePointer
	month []timePointer
	week  []timePointer

	WillPlans []time.Time
	SkipPlans []time.Time

	YearPlan *trieYear

	interval   *clinked.CircularLinked
	lastStatus bool
	nextTime   time.Time
}

// NewCrontab create 一个crontab
func NewCrontab(crontab string) *Crontab {
	cron := &Crontab{}
	cron.FromString(crontab)
	return cron
}

// UnmarshalYAML 添加序列化接口 Marshal没实现, 需要的时候可以自己添加
func (cron *Crontab) UnmarshalYAML(unmarshal func(interface{}) error) error {
	var buf string
	err := unmarshal(&buf)
	if err != nil {
		return nil
	}

	if err := cron.FromString(buf); err != nil {
		return err
	}

	return nil
}

// SetStatus 设置状态 接口定义
func (cron *Crontab) SetStatus(status interface{}) {

	if cron.interval != nil {
		cron.lastStatus = status.(bool)
	}
}

// GetStatus 设置状态 接口定义
func (cron *Crontab) GetStatus() (status interface{}) {
	if cron.interval != nil {
		return cron.lastStatus
	}
	return nil
}

// TimeUp 是否时间快到
func (cron *Crontab) TimeUp() bool {

	if cron.interval != nil {
		return cron.intervalTimeUp()
	}

	return cron.linuxTimeUp()
}

// NextTime 返回下次任务的时间
func (cron *Crontab) NextTime() time.Time {
	if cron.interval != nil {
		return cron.nextTime
	}

	if len(cron.WillPlans) > 0 {
		return cron.WillPlans[0]
	}

	return time.Now().Add(time.Second * 2)
}

func (cron *Crontab) String() string {
	return fmt.Sprintf("min:%s\nhour:%s\nday:%s\nmonth:%s\nweek:%s\n", spew.Sdump(cron.min), spew.Sdump(cron.hour), spew.Sdump(cron.day), spew.Sdump(cron.month), spew.Sdump(cron.week))
}

// FromString 解析crontab 的 表达式
func (cron *Crontab) FromString(crontab string) error {
	crontab = strings.TrimSpace(crontab)

	matches := regexp.MustCompile("[^ ]+").FindAllString(crontab, -1)
	mlen := len(matches)
	switch mlen {
	case 1:
		// "f1-2|5-10x5,f1|10m,10-15,f1"

		cron.lastStatus = true
		cron.interval = clinked.NewCircularLinked()
		var intervalList []interface{}
		intervalList = parseIntervalString(matches[0])
		cron.interval.Append(intervalList...)
		cron.TimeUp()
	case 5:
		cron.min = createTimePointer(matches[0], 0, 59, true)
		cron.hour = createTimePointer(matches[1], 0, 23, true)
		cron.day = createTimePointer(matches[2], 1, 31, false)
		cron.month = createTimePointer(matches[3], 1, 12, true)
		cron.week = createTimePointer(matches[4], 0, 6, true)

		cron.createYearPlan()
		cron.TimeUp()
	default:
		return errors.New("mathches len != want, check crontab string")
	}

	return nil
}

// createYearPlan 创建年度计划
func (cron *Crontab) createYearPlan() {
	cron.YearPlan = newTrieYear()
	cron.YearPlan.FromCrontab(cron)
}

func (cron *Crontab) linuxTimeUp() bool {
	now := time.Now()
	maxlen := 1000
	createlen := 500

	plen := len(cron.WillPlans)
	if plen <= createlen {
		var lastplan time.Time
		if plen == 0 {
			lastplan = now
		} else {
			lastplan = cron.WillPlans[plen-1].Add(time.Minute)
		}
		if !cron.YearPlan.CheckYear() {
			cron.createYearPlan()
		}

		timeplans := cron.YearPlan.GetPlanTime(cron, lastplan, uint(maxlen-plen))
		cron.WillPlans = append(cron.WillPlans, timeplans...)
	}

	if len(cron.WillPlans) > 0 {
		istimeup := false
		for i := 0; i < maxlen; i++ {
			if now.Unix() >= cron.WillPlans[i].Unix() {
				istimeup = true
			} else {
				if istimeup {
					if i-1 > 0 {
						cron.SkipPlans = append(cron.SkipPlans, cron.WillPlans[0:i-1]...)
						if len(cron.SkipPlans) >= maxlen+200 {
							cron.SkipPlans = cron.SkipPlans[200:]
						}
					}
					cron.WillPlans = cron.WillPlans[i:]
					return istimeup
				}

				return istimeup
			}
		}

		cron.SkipPlans = append(cron.SkipPlans, cron.WillPlans...)
		cron.WillPlans = nil
		return istimeup
	}

	log.Panicln("error willplans range")
	return false
}

func (cron *Crontab) intervalTimeUp() bool {

	now := time.Now()
	if now.Unix() >= cron.nextTime.Unix() {

		iv := cron.interval.Cursor().GetValue().(hInterval)
		isecond := 0
		if cron.lastStatus == false && len(iv.PlanFail) > 0 {
			idx := randomdata.Number(len(iv.PlanFail))
			lr := iv.PlanFail[idx]
			isecond = randomdata.Number(lr.left, lr.right+1)
		} else {
			idx := randomdata.Number(len(iv.PlanNormal))
			lr := iv.PlanNormal[idx]
			isecond = randomdata.Number(lr.left, lr.right+1)
		}

		iv.Count--
		if iv.Count <= 0 {
			iv.reset()
			cron.interval.MoveNext()
		}

		cron.nextTime = now.Add(time.Duration(isecond) * time.Second)
		return true
	}

	return false
}

func createTimePointer(min string, llimit, rlimit int, fixedLeftRight bool) []timePointer {

	var result []timePointer

	exelist := strings.Split(min, ",")
	for _, exe := range exelist {
		tp := timePointer{}

		takeper := strings.Split(exe, "/") // per
		var rangevalue, per string
		if len(takeper) == 1 {
			rangevalue = exe
			per = "1"
		} else {
			rangevalue = takeper[0]
			per = takeper[1]
		}
		// takeRange
		be := strings.Split(rangevalue, "-")
		var left, rigth string
		switch len(be) {
		case 1:
			left = be[0]
			rigth = be[0]
		case 2:
			left = be[0]
			rigth = be[1]
		default:
			panic(errors.New("range value is > 2"))
		}

		if left == "*" {
			tp.left = llimit
		} else {
			ileft, err := strconv.Atoi(strings.Replace(left, "^", "-", -1))
			if err != nil {
				panic(err)
			}
			tp.left = ileft
		}

		if rigth == "*" {
			tp.right = rlimit
		} else {
			iright, err := strconv.Atoi(strings.Replace(rigth, "^", "-", -1))
			if err != nil {
				panic(err)
			}
			tp.right = iright
		}

		iper, err := strconv.Atoi(per)
		if err != nil {
			panic(err)
		}

		tp.per = iper
		tp.leftlimit = llimit
		tp.rightlimit = rlimit

		// 修正左值
		leftfixed := tp.left
		if leftfixed < 0 {
			leftfixed += tp.rightlimit + 1
			if fixedLeftRight {
				tp.left = leftfixed
			}
		}

		rightfixed := tp.right
		if rightfixed < 0 {
			rightfixed += tp.rightlimit + 1
			if fixedLeftRight {
				tp.right = rightfixed
			}
		}

		// 全部符合 当左等于左 且 右等于右最大 并且 per == 1 TODO: 如果加入时间间隔 就需要 加多一个 附加值
		if leftfixed == tp.leftlimit && rightfixed == tp.rightlimit && tp.per == 1 {
			tp.isAll = true
		}

		result = append(result, tp)
	}

	return result
}

func parseIntervalString(crontab string) []interface{} {
	var result []interface{}

	values := strings.Split(crontab, ",")
	for _, value := range values {
		interval := hInterval{}
		// 次数
		valuesCounts := strings.Split(value, "x")
		switch len(valuesCounts) {
		case 1:
			interval.ConstCount = 1

		case 2:
			count, err := strconv.Atoi(valuesCounts[1])
			if err != nil {
				panic(err)
			}
			interval.ConstCount = count
		default:
			panic("valuesCounts error, the len is not in range")
		}

		// 统计失败与普通间隔值的数组
		failAndNormal := valuesCounts[0]

		valuesFN := strings.Split(failAndNormal, "|")

		for _, FN := range valuesFN {
			if FN == "" {
				continue
			}

			switch FN[0] {
			case 'f', 'F':
				fvalue := FN[1:]
				interval.PlanFail = append(interval.PlanFail, parseRandLR(fvalue))
			case 'n':
				value := FN[1:]
				interval.PlanNormal = append(interval.PlanNormal, parseRandLR(value))
			default:
				interval.PlanNormal = append(interval.PlanNormal, parseRandLR(FN))
			}
		}

		interval.reset()
		result = append(result, interval)
	}

	return result
}

func parseRandLR(value string) randLR {
	vlen := len(value)
	lastchar := value[vlen-1]

	lr := strings.Split(value, "-")
	switch len(lr) {
	case 1:
		lr := randLR{parseTimeValue(lr[0], lastchar), parseTimeValue(lr[0], lastchar)}
		return lr
	case 2:

		lr := randLR{parseTimeValue(lr[0], lastchar), parseTimeValue(lr[1], lastchar)}
		return lr
	default:
		panic("lr is error")
	}
}

func getInt(v string) int {
	vint, err := strconv.Atoi(v)
	if err != nil {
		panic(err)
	}
	return vint
}

func parseTimeValue(v string, lastchar byte) int {

	vlen := len(v)

	switch lastchar {
	case 's':
		return getInt(v[:vlen-1])
	case 'm':
		return getInt(v[:vlen-1]) * 60
	case 'h':
		return getInt(v[:vlen-1]) * 3600
	case 'd':
		return getInt(v[:vlen-1]) * 3600 * 24
	default:
		return getInt(v)
	}
}