//@version=6
indicator("背了又背：最后一笔顶/底背离（单周期简化版）", shorttitle="LastDiv_Simple", overlay=true, max_labels_count=500)

// 参数
pivot_left  = input.int(3, "左侧枢轴K数", minval=1)
pivot_right = input.int(3, "右侧枢轴K数", minval=1)
fastlen  = input.int(12, "MACD快线")
slowlen  = input.int(26, "MACD慢线")
siglen   = input.int(9,  "MACD信号线")
min_div_strength = input.float(0.6, "背离强度系数阈值", minval=0.1, maxval=1.0, step=0.05)
need_double_div  = input.bool(true, "必须『背了又背』（同向至少两次背离）")

// MACD
[dif, dea, hist] = ta.macd(close, fastlen, slowlen, siglen)

// 枢轴
ph_val = ta.pivothigh(high, pivot_left, pivot_right)
pl_val = ta.pivotlow(low,  pivot_left, pivot_right)

is_pivoth = not na(ph_val)
is_pivotl = not na(pl_val)

ph_price = is_pivoth ? ph_val : na
pl_price = is_pivotl ? pl_val : na
ph_osc   = is_pivoth ? hist[pivot_right] : na
pl_osc   = is_pivotl ? hist[pivot_right] : na
ph_bar   = is_pivoth ? bar_index[pivot_right] : na
pl_bar   = is_pivotl ? bar_index[pivot_right] : na

// 工具函数
// 隐形背离定义：
// - 顶：价格创新高，但对应枢轴处没有正的能量柱（hist <= 0）
// - 底：价格创新低，但对应枢轴处没有负的能量柱（hist >= 0）
f_top_div(price1, price2, osc1, osc2) =>
    price2 > price1 and osc2 <= 0

f_bottom_div(price1, price2, osc1, osc2) =>
    price2 < price1 and osc2 >= 0

// 状态变量：记录连续同向背离
var float last_ph_price = na
var float last_ph_osc   = na
var int   last_ph_bar   = na

var float last_pl_price = na
var float last_pl_osc   = na
var int   last_pl_bar   = na

var float prev_div_top_price = na
var float prev_div_top_osc   = na
var int   prev_div_top_bar   = na

var float last_div_top_price = na
var float last_div_top_osc   = na
var int   last_div_top_bar   = na

var float prev_div_bot_price = na
var float prev_div_bot_osc   = na
var int   prev_div_bot_bar   = na

var float last_div_bot_price = na
var float last_div_bot_osc   = na
var int   last_div_bot_bar   = na

var int top_div_count_seq = 0
var int bot_div_count_seq = 0

new_top_div = false
new_bot_div = false

// 顶背离（隐形）
if is_pivoth and not na(last_ph_price)
    if f_top_div(last_ph_price, ph_price, last_ph_osc, ph_osc)
        new_top_div := true
        // 更新链
        prev_div_top_price := last_div_top_price
        prev_div_top_osc   := last_div_top_osc
        prev_div_top_bar   := last_div_top_bar

        last_div_top_price := ph_price
        last_div_top_osc   := ph_osc
        last_div_top_bar   := ph_bar

        top_div_count_seq += 1
    else
        if ph_price > last_ph_price and ph_osc >= last_ph_osc
            top_div_count_seq := 0

if is_pivoth
    last_ph_price := ph_price
    last_ph_osc   := ph_osc
    last_ph_bar   := ph_bar

// 底背离（隐形）
if is_pivotl and not na(last_pl_price)
    if f_bottom_div(last_pl_price, pl_price, last_pl_osc, pl_osc)
        new_bot_div := true
        // 更新链
        prev_div_bot_price := last_div_bot_price
        prev_div_bot_osc   := last_div_bot_osc
        prev_div_bot_bar   := last_div_bot_bar

        last_div_bot_price := pl_price
        last_div_bot_osc   := pl_osc
        last_div_bot_bar   := pl_bar

        bot_div_count_seq += 1
    else
        if pl_price < last_pl_price and pl_osc <= last_pl_osc
            bot_div_count_seq := 0

if is_pivotl
    last_pl_price := pl_price
    last_pl_osc   := pl_osc
    last_pl_bar   := pl_bar

// 只在『最后一笔』背了又背时画信号
need_count_top = need_double_div ? top_div_count_seq >= 2 : top_div_count_seq >= 1
need_count_bot = need_double_div ? bot_div_count_seq >= 2 : bot_div_count_seq >= 1

final_top_div = new_top_div and need_count_top
final_bot_div = new_bot_div and need_count_bot

plotshape(
     final_bot_div
    ,title="最后一笔底背离"
    ,location=location.belowbar
    ,style=shape.labelup
    ,color=color.new(color.green, 0)
    ,text="背了又背\n底终点"
    ,textcolor=color.white
    ,size=size.normal
)

plotshape(
     final_top_div
    ,title="最后一笔顶背离"
    ,location=location.abovebar
    ,style=shape.labeldown
    ,color=color.new(color.red, 0)
    ,text="背了又背\n顶终点"
    ,textcolor=color.white
    ,size=size.normal
)