ADX and DI

// This source code is subject to the terms of the Mozilla Public License 2.0 at https://mozilla.org/MPL/2.0/
// © claygrace74

//@version=6
indicator("ADX and DI", shorttitle="ADX/DI")

// ==================== ADX Settings ====================
var adx_group = "ADX Settings"
len = input.int(14, "Length", minval=1, group=adx_group)

// ==================== Display Settings ====================
var disp_group = "Display Settings"
i_showDIPlus      = input.bool(true,  "Show DI+", group=disp_group)
i_showDIMinus     = input.bool(true,  "Show DI-", group=disp_group)
i_showDIFill      = input.bool(true,  "Show DI+/DI- Fill", group=disp_group)
i_showCrossSignals = input.bool(true, "Show DI Cross Signals", group=disp_group)
i_showStrength    = input.bool(true,  "Show Trend Strength Label", group=disp_group)
i_bullColor       = input.color(color.green, "Bullish Color (DI+)", group=disp_group)
i_bearColor       = input.color(color.red,   "Bearish Color (DI-)", group=disp_group)

// ==================== Zone Settings ====================
var zone_group = "Zone Settings"
th       = input.int(25, "Weak/Strong Threshold", minval=0, maxval=100, group=zone_group)
strongTh = input.int(50, "Strong Trend Threshold", minval=0, maxval=100, group=zone_group)

// ==================================================================================
// Core Calculations (Wilder Smoothing)
// ==================================================================================
TrueRange = math.max(math.max(high - low, math.abs(high - nz(close[1]))), math.abs(low - nz(close[1])))
DirectionalMovementPlus  = high - nz(high[1]) > nz(low[1]) - low ? math.max(high - nz(high[1]), 0) : 0
DirectionalMovementMinus = nz(low[1]) - low > high - nz(high[1]) ? math.max(nz(low[1]) - low, 0) : 0

float SmoothedTrueRange = 0.0
SmoothedTrueRange := nz(SmoothedTrueRange[1]) - (nz(SmoothedTrueRange[1]) / len) + TrueRange

float SmoothedDMPlus = 0.0
SmoothedDMPlus := nz(SmoothedDMPlus[1]) - (nz(SmoothedDMPlus[1]) / len) + DirectionalMovementPlus

float SmoothedDMMinus = 0.0
SmoothedDMMinus := nz(SmoothedDMMinus[1]) - (nz(SmoothedDMMinus[1]) / len) + DirectionalMovementMinus

DIPlus  = SmoothedDMPlus  / SmoothedTrueRange * 100
DIMinus = SmoothedDMMinus / SmoothedTrueRange * 100
DX  = math.abs(DIPlus - DIMinus) / (DIPlus + DIMinus) * 100
ADX = ta.sma(DX, len)

// Direction and signals
bullish    = DIPlus > DIMinus
diCrossUp  = ta.crossover(DIPlus, DIMinus)
diCrossDown = ta.crossunder(DIPlus, DIMinus)
adxRising  = ta.change(ADX) > 0

// Trend strength category
strengthText  = ADX >= 75 ? "EXTREME" : ADX >= strongTh ? "STRONG" : ADX >= th ? "TRENDING" : "NO TREND"
strengthColor = ADX >= 75 ? color.new(color.orange, 0) : ADX >= strongTh ? color.new(color.yellow, 0) : ADX >= th ? color.new(i_bullColor, 30) : color.new(color.gray, 30)

// ==================================================================================
// Grid Layout
// ==================================================================================
h100    = hline(100, "100", color=color.new(color.gray, 80), linestyle=hline.style_solid)
hStrong = hline(strongTh, "Strong Threshold", color=color.new(color.gray, 50), linestyle=hline.style_dashed)
hWeak   = hline(th,       "Weak/Strong Threshold", color=color.new(color.gray, 50), linestyle=hline.style_solid)
h0      = hline(0,   "0",   color=color.new(color.gray, 80), linestyle=hline.style_solid)

// Zone fills
fill(h0, hWeak,      color=color.new(color.green, 92))   // No trend zone (safe)
fill(hStrong, h100,  color=color.new(color.orange, 92))   // Extreme zone (warning)

// ==================================================================================
// Plots
// ==================================================================================

// DI+ and DI- lines with fill
pPlus  = plot(i_showDIPlus  ? DIPlus  : na, "DI+", color=color.new(i_bullColor, 30), linewidth=1)
pMinus = plot(i_showDIMinus ? DIMinus : na, "DI-", color=color.new(i_bearColor, 30), linewidth=1)
fill(pPlus, pMinus, color=i_showDIFill ? (bullish ? color.new(i_bullColor, 85) : color.new(i_bearColor, 85)) : color(na), title="DI Fill")

// ADX line — gradient colored by value, green/red tint by DI direction
adxColor = bullish ? color.from_gradient(ADX, 0, 75, color.new(i_bullColor, 70), i_bullColor) : color.from_gradient(ADX, 0, 75, color.new(i_bearColor, 70), i_bearColor)
plot(ADX, "ADX", color=adxColor, linewidth=2)

// DI cross signals
plotshape(i_showCrossSignals and diCrossUp,   style=shape.triangleup,   location=location.bottom, color=i_bullColor, text="DI+", textcolor=i_bullColor, size=size.tiny, title="DI+ Cross Up")
plotshape(i_showCrossSignals and diCrossDown, style=shape.triangledown, location=location.top,    color=i_bearColor, text="DI-", textcolor=i_bearColor, size=size.tiny, title="DI- Cross Down")

// ==================================================================================
// Trend Strength Label
// ==================================================================================
var tbl = table.new(position.top_right, 1, 1, bgcolor=color.new(color.black, 50), border_width=1, border_color=color.new(color.gray, 50))

if i_showStrength and barstate.islast
    table.cell(tbl, 0, 0, strengthText + " (" + str.tostring(ADX, "#.0") + ")", bgcolor=strengthColor, text_color=color.white, text_size=size.small)

// ==================================================================================
// Alert Conditions
// ==================================================================================
alertcondition(diCrossUp,                          "DI+ Crosses Above DI-",   "DI+ crossed above DI- — potential bullish signal")
alertcondition(diCrossDown,                        "DI+ Crosses Below DI-",   "DI+ crossed below DI- — potential bearish signal")
alertcondition(ta.crossover(ADX, th),              "ADX Above Threshold",     "ADX crossed above weak/strong threshold — trend strengthening")
alertcondition(ta.crossunder(ADX, th),             "ADX Below Threshold",     "ADX crossed below weak/strong threshold — trend weakening")
alertcondition(ADX > strongTh and adxRising,       "Strong Trend Intensifying","ADX above strong threshold and rising")
alertcondition(diCrossUp and ADX > th,             "Confirmed Bullish Entry", "DI+ crossed DI- with ADX confirming trend strength")