package indicator

import (
	"sig-pub/pkg/types"
)

// Macd macd柱状图计算

// Macd 拆分成: Macd(柱状图), MacdDIF线, MacdDEA(信号线)
// 计算 MacdDIF 线 (DIF): 反映短期趋势与长期趋势的“收敛/散度”
// Macd: https://www.investopedia.com/terms/m/macd.asp
type Macd struct {
}

func (c *Macd) Meta() IndicatorMeta {
	return IndicatorMeta{
		Name: "macd",
		Input: []types.InputArg{
			{Name: "fast", Type: types.InputTypeUInt, Desc: "快线周期"},
			{Name: "slow", Type: types.InputTypeUInt, Desc: "慢线周期"},
			{Name: "singal", Type: types.InputTypeUInt, Desc: "信号线周期"},
		},
	}
}

func (c *Macd) CandlePeriods(ctx IIndicatorContext) int16 {
	return max(
		ctx.Indicator("macd_dif", ctx.Input()).CandlePeriods(),
		ctx.Indicator("macd_dea", ctx.Input()).CandlePeriods(),
	)
}

func (c *Macd) Calculate(ctx IIndicatorContext) (vector float64) {
	macd_dea := ctx.Indicator("macd_dea", ctx.Input()).Get(0)
	macd_dif := ctx.Indicator("macd_dif", ctx.Input()).Get(0)
	vector = (macd_dif - macd_dea) * 2
	return
}

type MacdDIF struct {
}

// indicator interface
func (c *MacdDIF) Meta() IndicatorMeta {
	return IndicatorMeta{
		Name: "macd_dif",
		Input: []types.InputArg{
			{Name: "fast", Type: types.InputTypeUInt, Desc: "快线周期"},
			{Name: "slow", Type: types.InputTypeUInt, Desc: "慢线周期"},
		},
	}
}

func (c *MacdDIF) CandlePeriods(ctx IIndicatorContext) int16 {
	return max(
		ctx.Indicator("ema", ctx.Input().Int16("fast")).CandlePeriods(),
		ctx.Indicator("ema", ctx.Input().Int16("slow")).CandlePeriods(),
	)
}

// Calculate 计算单根k线sma指标
func (c *MacdDIF) Calculate(ctx IIndicatorContext) (vector float64) {
	fast := ctx.Input().Int16("fast") // 12
	slow := ctx.Input().Int16("slow") // 26

	// macd计算从第max(fast, slow)期开始稳定
	fastEma := ctx.Indicator("ema", fast).Get(0)
	slowEma := ctx.Indicator("ema", slow).Get(0)
	macd := fastEma - slowEma
	vector = macd
	return
}

// MacdDEA macd信号线计算
type MacdDEA struct {
}

func (c *MacdDEA) Meta() IndicatorMeta {
	return IndicatorMeta{
		Name: "macd_dea",
		Input: []types.InputArg{
			{Name: "fast", Type: types.InputTypeUInt, Desc: "快线周期"},
			{Name: "slow", Type: types.InputTypeUInt, Desc: "慢线周期"},
			{Name: "singal", Type: types.InputTypeUInt, Desc: "信号线周期"},
		},
	}
}

func (c *MacdDEA) CandlePeriods(ctx IIndicatorContext) int16 {
	return ctx.Indicator("macd_dif", ctx.Input()).CandlePeriods() + ctx.Input().Int16("singal") + 1
}

func (c *MacdDEA) Calculate(ctx IIndicatorContext) (vector float64) {
	singal := ctx.Input().Int16("singal") // 9

	deaPrev, ok := ctx.State().Get("vector", 1)
	if !ok {
		// 初始值前9期的 MACD_DIF SMA
		macdDifs := ctx.Indicator("macd_dif", ctx.Input()).Series(1, singal)
		deaPrev = macdDifs.Avg()
	}
	macd_dif := ctx.Indicator("macd_dif", ctx.Input()).Get(0)
	// 计算DEA
	beta := 2 / float64(singal+1)
	dea := beta*macd_dif + (1-beta)*deaPrev
	ctx.State().Set("vector", dea)

	vector = dea
	return
}