//@version=6
// 功能：短期支撑/压力位（当前周期）
// 原理：
// - 基于枢轴点（Pivot）在当前时间周期内形成的高点/低点，结合 ATR 容差进行“价格聚类”，
//   聚合出更稳定的水平价位；用触碰次数过滤弱水平。
// - 每条水平线从“最新K线”向左以虚线绘制，右侧固定显示标签（类型S/R、价格、触碰次数）。
// 主要参数：
// - Pivot Left/Right：枢轴确认强度；越大越严格、信号越少。
// - Minimum Touches：最少触碰次数；越大越稳定、越少越敏感。
// - ATR Length / Cluster Tolerance：聚类容差（ATR倍数）；越大越易合并为少量更粗水平。
// - Max Visible Levels：图上最多显示的水平数量。
// - Label Size / Label Offset：标签字号与向右偏移的柱数。
// 交易应用（示例，不构成建议）：
// - 震荡区间：靠近“支撑S”观察反弹做多；靠近“压力R”观察回落做空；以水平外的 ATR 容差作为入场缓冲。
// - 趋势回踩：上升趋势中，回踩最近“支撑S”且收盘未跌破→顺势接回；跌破并收回失败→止损或反手。
// - 突破回测：收盘有效突破“压力R”，回测不跌回→看多延续；跌破“支撑S”并回测不过→看空延续。
// - 风险控制：可用“当前价与最近S/R的距离/ATR 倍数”推导止损间距与仓位；（若需要，可在脚本中扩展显示）。
// 说明：本脚本不使用未来函数；水平会随新枢轴与触碰实时更新。

indicator("Support/Resistance (Current TF)", overlay=true, max_lines_count=200, max_labels_count=100)

// Inputs
leftBars           = input.int(3, "Pivot Left", minval=1)
rightBars          = input.int(3, "Pivot Right", minval=1)
lookbackBars       = input.int(500, "Lookback Bars", minval=50, maxval=5000)
atrLength          = input.int(14, "ATR Length", minval=1)
clusterTolATR      = input.float(0.25, "Cluster Tolerance (x ATR)", step=0.05, minval=0.05)
minTouches         = input.int(2, "Minimum Touches to Validate", minval=1)
maxLevelsStored    = input.int(60, "Max Stored Levels", minval=10, maxval=300)
maxVisibleLevels   = input.int(10, "Max Visible Levels", minval=1, maxval=50)
lineWidth          = input.int(2, "Line Width", minval=1, maxval=5)
resistanceColor    = input.color(color.new(color.red, 0), "Resistance Color")
supportColor       = input.color(color.new(color.teal, 0), "Support Color")
showPriceLabels    = input.bool(true, "Show Price Labels", inline="lbl")
showTouchesInLbl   = input.bool(true, "Touches In Label", inline="lbl")
labelSizeOpt       = input.string("Tiny", "Label Size", options=["Tiny", "Small", "Normal", "Large", "Huge"], inline="lbl")
labelOffsetBars    = input.int(1, "Label Offset (bars to right)", minval=1, maxval=500)

// Calculations
atrValue = ta.atr(atrLength)
clusterTolerance = atrValue * clusterTolATR

// Level storage
var float[] levelPrices               = array.new_float()
var int[]   levelTotalTouches         = array.new_int()
var int[]   levelLastTouchBarIndex    = array.new_int()
var int[]   levelSupportTouches       = array.new_int()
var int[]   levelResistanceTouches    = array.new_int()
var line[]  levelLines                = array.new_line()
var label[] levelLabels               = array.new_label()

// helper to map size option to Pine size enum
f_label_size(opt) =>
    opt == "Tiny" ? size.tiny : opt == "Small" ? size.small : opt == "Normal" ? size.normal : opt == "Large" ? size.large : size.huge

// Utilities
f_find_level_index(price, tolerance) =>
    int foundIndex = -1
    sz = array.size(levelPrices)
    if sz > 0
        for i = 0 to sz - 1
            existing = array.get(levelPrices, i)
            if math.abs(existing - price) <= tolerance
                foundIndex := i
                break
    foundIndex

f_remove_level(idx) =>
    ln = array.get(levelLines, idx)
    if not na(ln)
        line.delete(ln)
    lb = array.get(levelLabels, idx)
    if not na(lb)
        label.delete(lb)
    array.remove(levelPrices, idx)
    array.remove(levelTotalTouches, idx)
    array.remove(levelLastTouchBarIndex, idx)
    array.remove(levelSupportTouches, idx)
    array.remove(levelResistanceTouches, idx)
    array.remove(levelLines, idx)
    array.remove(levelLabels, idx)

f_remove_old_levels() =>
    sz = array.size(levelPrices)
    if sz > 0
        // iterate safely in reverse using computed index
        for k = 0 to sz - 1
            i = sz - 1 - k
            lastBar = array.get(levelLastTouchBarIndex, i)
            if bar_index - lastBar > lookbackBars
                f_remove_level(i)

f_ensure_capacity() =>
    if array.size(levelPrices) >= maxLevelsStored
        // Remove the oldest by last touch
        oldestIdx = 0
        oldestBar = array.get(levelLastTouchBarIndex, 0)
        for i = 1 to array.size(levelPrices) - 1
            b = array.get(levelLastTouchBarIndex, i)
            if b < oldestBar
                oldestBar := b
                oldestIdx := i
        f_remove_level(oldestIdx)

f_add_or_update_level(price, isResistance) =>
    idx = f_find_level_index(price, clusterTolerance)
    if idx == -1
        f_ensure_capacity()
        array.push(levelPrices, price)
        array.push(levelTotalTouches, 1)
        array.push(levelLastTouchBarIndex, bar_index)
        array.push(levelSupportTouches, isResistance ? 0 : 1)
        array.push(levelResistanceTouches, isResistance ? 1 : 0)
        array.push(levelLines, na)
        array.push(levelLabels, na)
    else
        prevPrice   = array.get(levelPrices, idx)
        touches     = array.get(levelTotalTouches, idx)
        newTouches  = touches + 1
        // Re-anchor price by averaging to stabilize the level
        newPrice    = (prevPrice * touches + price) / newTouches
        array.set(levelPrices, idx, newPrice)
        array.set(levelTotalTouches, idx, newTouches)
        array.set(levelLastTouchBarIndex, idx, bar_index)
        if isResistance
            r = array.get(levelResistanceTouches, idx) + 1
            array.set(levelResistanceTouches, idx, r)
        else
            s = array.get(levelSupportTouches, idx) + 1
            array.set(levelSupportTouches, idx, s)

f_draw_levels() =>
    // Collect candidate indices
    var int[] candidates = array.new_int()
    array.clear(candidates)
    sz = array.size(levelPrices)
    if sz > 0
        for i = 0 to sz - 1
            touches = array.get(levelTotalTouches, i)
            lastBar = array.get(levelLastTouchBarIndex, i)
            if touches >= minTouches and bar_index - lastBar <= lookbackBars
                array.push(candidates, i)

    // Select up to maxVisibleLevels by distance to close
    var int[] chosen = array.new_int()
    array.clear(chosen)
    candSz = array.size(candidates)
    if candSz > 0
        chooseCount = math.min(maxVisibleLevels, candSz)
        for _ = 0 to chooseCount - 1
            if array.size(candidates) == 0
                break
            bestPos = -1
            bestDist = 10e10
            curSz = array.size(candidates)
            if curSz > 0
                for pos = 0 to curSz - 1
                    idx = array.get(candidates, pos)
                    price = array.get(levelPrices, idx)
                    d = math.abs(close - price)
                    if d < bestDist
                        bestDist := d
                        bestPos  := pos
            if bestPos != -1
                pickedIdx = array.get(candidates, bestPos)
                array.push(chosen, pickedIdx)
                array.remove(candidates, bestPos)

    // Build a quick lookup for chosen to manage create/update/delete of lines
    var bool[] isChosen = array.new_bool()
    array.clear(isChosen)
    if sz > 0
        for _ = 0 to sz - 1
            array.push(isChosen, false)
    chosenSz = array.size(chosen)
    if chosenSz > 0 and sz > 0
        for j = 0 to chosenSz - 1
            chIdx = array.get(chosen, j)
            if chIdx >= 0 and chIdx < sz
                array.set(isChosen, chIdx, true)

    // Create/Update lines for chosen, delete lines for non-chosen
    if sz > 0
        for i = 0 to sz - 1
            ln = array.get(levelLines, i)
            price = array.get(levelPrices, i)
            supTouches = array.get(levelSupportTouches, i)
            resTouches = array.get(levelResistanceTouches, i)
            isRes = resTouches >= supTouches
            col = isRes ? resistanceColor : supportColor
            if array.get(isChosen, i)
                xRight = bar_index
                xLeft  = math.max(0, bar_index - lookbackBars)
                if na(ln)
                    ln := line.new(x1=xLeft, y1=price, x2=xRight, y2=price, extend=extend.none, color=col, width=lineWidth)
                    line.set_style(ln, line.style_dotted)
                    array.set(levelLines, i, ln)
                else
                    line.set_xy1(ln, xLeft, price)
                    line.set_xy2(ln, xRight, price)
                    line.set_extend(ln, extend.none)
                    line.set_color(ln, col)
                    line.set_width(ln, lineWidth)
                    line.set_style(ln, line.style_dotted)
                // labels
                lb = array.get(levelLabels, i)
                if showPriceLabels
                    touches = array.get(levelTotalTouches, i)
                    lblTxt = (isRes ? "R " : "S ") + str.tostring(price, format.price) + (showTouchesInLbl ? " x" + str.tostring(touches) : "")
                    // Always recreate to honor size/offset changes reliably
                    if not na(lb)
                        label.delete(lb)
                        lb := na
                    desiredSize = f_label_size(labelSizeOpt)
                    lblX = bar_index + labelOffsetBars
                    lb := label.new(x=lblX, y=price, text=lblTxt, style=label.style_label_left, color=color.new(col, 85), textcolor=color.white, size=desiredSize)
                    array.set(levelLabels, i, lb)
                else
                    if not na(lb)
                        label.delete(lb)
                        array.set(levelLabels, i, na)
            else
                if not na(ln)
                    line.delete(ln)
                    array.set(levelLines, i, na)
                lb = array.get(levelLabels, i)
                if not na(lb)
                    label.delete(lb)
                    array.set(levelLabels, i, na)

// Detect pivots on current timeframe
ph = ta.pivothigh(high, leftBars, rightBars)
pl = ta.pivotlow(low, leftBars, rightBars)

if not na(ph)
    f_add_or_update_level(ph, true)
if not na(pl)
    f_add_or_update_level(pl, false)

// Maintenance and drawing
f_remove_old_levels()
f_draw_levels()

// Optional: show nearest support/resistance prices
var float nearestSupport = na
var float nearestResistance = na
// Scan chosen candidates quickly by direction
float bestBelow = na
float bestAbove = na
szAll = array.size(levelPrices)
if szAll > 0
    for i = 0 to szAll - 1
        touches = array.get(levelTotalTouches, i)
        lastBar = array.get(levelLastTouchBarIndex, i)
        if touches >= minTouches and bar_index - lastBar <= lookbackBars
            p = array.get(levelPrices, i)
            if p <= close
                bestBelow := na(bestBelow) ? p : math.max(bestBelow, p)
            if p >= close
                bestAbove := na(bestAbove) ? p : math.min(bestAbove, p)

nearestSupport := bestBelow
nearestResistance := bestAbove

plot(nearestSupport, title="Nearest Support", color=color.new(supportColor, 60), linewidth=1, style=plot.style_linebr)
plot(nearestResistance, title="Nearest Resistance", color=color.new(resistanceColor, 60), linewidth=1, style=plot.style_linebr)