// This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0.
// If a copy of the MPL was not distributed with this file, You can obtain one at https://mozilla.org/MPL/2.0/
// © Venture Lab – https://venturelab-bots.pages.dev/pine/
//
// EMA cross with alerts.
// What it does: plots a fast and a slow EMA, marks the bars where the fast EMA crosses above or below the
// slow EMA and offers alerts for both directions.
// What it does NOT do: it does not filter false signals in sideways markets, it does not size positions,
// it is not a trading system and it is not financial advice. Crosses can appear and disappear while a bar is
// still open; with "Confirm on bar close" enabled, marks and alerts only use closed bars.

//@version=6
indicator("EMA Cross with Alerts [Venture Lab]", shorttitle = "EMA Cross", overlay = true)

// ---- Inputs
int   fastLen   = input.int(9, "Fast EMA length", minval = 1)
int   slowLen   = input.int(21, "Slow EMA length", minval = 2)
float src       = input.source(close, "Source")
bool  confirmed = input.bool(true, "Confirm on bar close")

// ---- Calculation
float fastEma   = ta.ema(src, fastLen)
float slowEma   = ta.ema(src, slowLen)
bool  rawUp     = ta.crossover(fastEma, slowEma)
bool  rawDown   = ta.crossunder(fastEma, slowEma)
bool  barOk     = not confirmed or barstate.isconfirmed
bool  crossUp   = rawUp and barOk
bool  crossDown = rawDown and barOk

// ---- Plots
p1 = plot(fastEma, "Fast EMA", color = color.teal, linewidth = 2)
p2 = plot(slowEma, "Slow EMA", color = color.orange, linewidth = 2)
fill(p1, p2, color = fastEma > slowEma ? color.new(color.teal, 85) : color.new(color.red, 85), title = "EMA zone")
plotshape(crossUp, "Cross up", shape.triangleup, location.belowbar, color.teal, size = size.small)
plotshape(crossDown, "Cross down", shape.triangledown, location.abovebar, color.red, size = size.small)

// ---- Alerts
// Option 1: in the alert dialog choose "EMA cross up" or "EMA cross down".
alertcondition(crossUp, "EMA cross up", "Fast EMA crossed above slow EMA on {{ticker}} ({{interval}}), close {{close}}")
alertcondition(crossDown, "EMA cross down", "Fast EMA crossed below slow EMA on {{ticker}} ({{interval}}), close {{close}}")
// Option 2: choose "Any alert() function call" to get one alert with the direction in the message.
if rawUp
    alert("Fast EMA (" + str.tostring(fastLen) + ") crossed above slow EMA (" + str.tostring(slowLen) + ") on " + syminfo.ticker + ", close " + str.tostring(close), alert.freq_once_per_bar_close)
if rawDown
    alert("Fast EMA (" + str.tostring(fastLen) + ") crossed below slow EMA (" + str.tostring(slowLen) + ") on " + syminfo.ticker + ", close " + str.tostring(close), alert.freq_once_per_bar_close)