package indicator

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

// MACD 拆分成: MACD线, MacdDEA(信号线), MacdHist(柱状图)
// 计算 MACD 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 {
}

// indicator interface
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"},
		},
	}
}

func (c *MACD) 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 *MACD) 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 max(
		ctx.Input().Int16("singal")+1,
		ctx.Indicator("macd", ctx.Input()).CandlePeriods(),
	)
}

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

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

	vector = dea
	return
}

// MacdSingal macd柱状图计算
type MacdHist struct {
}

func (c *MacdHist) Meta() IndicatorMeta {
	return IndicatorMeta{
		Name: "macd_hist",
		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 *MacdHist) CandlePeriods(ctx IIndicatorContext) int16 {
	return max(
		ctx.Indicator("macd", ctx.Input()).CandlePeriods(),
		ctx.Indicator("macd_dea", ctx.Input()).CandlePeriods(),
	)
}

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