package indicator

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

// Boll 布林带
type Boll struct {
}

func (c *Boll) Meta() IndicatorMeta {
	return IndicatorMeta{
		Name: "Boll",
		Input: []types.InputArg{
			{Name: "window", Type: types.InputTypeUInt, Desc: "窗口大小"},
			{Name: "pt", Type: types.InputTypeKPriceType, Desc: "k线序列类型"},
		},
		State: []string{"ub", "lb"},
		Plots: []Plot{
			{Name: "中轨", State: "vector", Type: PlotHistogram, Props: PlotProps{"color": ColorOrange}},
			{Name: "上轨", State: "ub", Type: PlotLine, Props: PlotProps{"color": ColorRed2}},
			{Name: "下轨", State: "lb", Type: PlotLine, Props: PlotProps{"color": ColorRed2}},
			{Name: "布林带阴影", State: "ub,lb", Type: PlotShadow, Props: PlotProps{"color": "rgba(247, 169, 167, 0.3)"}},
		},
	}
}

func (c *Boll) CandlePeriods(ctx IIndicatorContext) int16 {
	return ctx.Input().Int16("window")
}

func (c *Boll) Calculate(ctx IIndicatorContext) (vector float64) {
	window := ctx.Input().Int16("window")
	pt := ctx.Input().PriceType()
	priceSeries := ctx.Series(0, int16(window)).Price(pt)
	mb := priceSeries.Avg() // 中轨
	vector = mb

	// 标准差σ_t = sqrt(∑(P-MB)^2 / (n-1))
	sst := float64(0)
	for _, p := range priceSeries {
		sst += math.Pow(p-mb, 2)
	}
	sigma := math.Sqrt(sst / float64(window-1))

	// BollUB 布林带上轨
	ub := mb + 2*sigma
	ctx.State().Set("ub", ub)

	// BollLB 布林带下轨
	lb := mb - 2*sigma
	ctx.State().Set("lb", lb)
	return
}