package strategy

import (
	"github.com/shopspring/decimal"
	"testing"
)

func TestBoll_WarmupAndSliding(t *testing.T) {
	n := 5
	k := d(2.0)
	b := NewBollW(n)

	// 前 n-1 根：not ready
	for i, px := range []float64{10, 11, 12, 13} {
		out := b.Push(d(int64(px)), k)
		if out.Ready {
			t.Fatalf("i=%d: should not be ready yet", i)
		}
	}

	// 第 n 根開始：ready
	out := b.Push(d(14), k)
	if !out.Ready {
		t.Fatalf("should be ready at %d-th push", n)
	}
	// 中線應為 (10+11+12+13+14)/5 = 12
	if out.Mid.StringFixed(6) != d(12).StringFixed(6) {
		t.Fatalf("mid expect 12, got %s", out.Mid)
	}
	// 標準差 > 0；上軌 > 中線 > 下軌
	if !out.Std.GreaterThan(decimal.Zero) ||
		!out.Upper.GreaterThan(out.Mid) ||
		!out.Mid.GreaterThan(out.Lower) {
		t.Fatalf("band ordering violated: U=%s M=%s L=%s Std=%s", out.Upper, out.Mid, out.Lower, out.Std)
	}

	// 再推兩根 -> 視窗滑到 [12,13,14,15,16]，中線=14
	for _, px := range []float64{15, 16} {
		out = b.Push(d(int64(px)), k)
	}
	if out.Mid.StringFixed(6) != d(14).StringFixed(6) {
		t.Fatalf("sliding mid expect 14, got %s", out.Mid)
	}
	if !out.Std.GreaterThan(decimal.Zero) {
		t.Fatalf("std should remain > 0 after slide, got %s", out.Std)
	}
}

func TestBoll_FlatSeries(t *testing.T) {
	n := 4
	k := d(2.0)
	b := NewBollW(n)

	// 全部相同價格 -> 標準差=0、三條線重合
	for i := 0; i < n; i++ {
		_ = b.Push(d(10), k)
	}
	out := b.Push(d(10), k) // 視窗仍為相同值
	if !out.Std.Equal(decimal.Zero) {
		t.Fatalf("std should be 0 on flat series, got %s", out.Std)
	}
	if !(out.Upper.Equal(out.Mid) && out.Mid.Equal(out.Lower) && out.Mid.Equal(d(10))) {
		t.Fatalf("bands should coincide at 10: U=%s M=%s L=%s", out.Upper, out.Mid, out.Lower)
	}
}