Williams R EMA Pullback Script

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-- SPDX-License-Identifier: MIT
-- IQOptionWiki QCS Library
-- IQOW Williams R EMA Pullback v1.0.0
--
-- Williams %R(14) shows when price closes near the top or bottom of its recent
-- range. A cross back out of the extreme zone, taken only in the direction of
-- the EMA 50 trend, marks the end of a pullback. The article's plain %R rule
-- (cross over -80 or under -20) is filtered by the EMA.
--
-- HIGHER: close is above EMA 50 and %R closes above -80 after being at or below it.
-- LOWER:  close is below EMA 50 and %R closes below -20 after being at or above it.
--
-- Markers use the previous completed candle: they appear after the next candle
-- opens and are shifted back one bar onto the candle that qualified.
-- Educational chart tool only. It does not place trades, choose an expiry,
-- predict outcomes, or guarantee results. Test on a Practice balance first.

instrument {
    name = "IQOW Williams R EMA Pullback",
    short_name = "IQOW WR EMA",
    overlay = true
}

input_group {
    "1. Williams %R",
    wpr_period = input (14, "Period", input.integer, 2, 100),
    oversold_level = input (-80, "Oversold level", input.double, -99, -55, 1, false),
    overbought_level = input (-20, "Overbought level", input.double, -45, -1, 1, false)
}

input_group {
    "2. Trend filter",
    ema_period = input (50, "EMA period", input.integer, 2, 400)
}

input_group {
    "Display and advice",
    lines_visible = input { default = true, type = input.plot_visibility },
    signals_visible = input { default = true, type = input.plot_visibility },
    advice_enabled = input { default = false, name = "Enable platform advice", type = input.boolean }
}

input_group {
    "Colors",
    ema_color = input { default = "#FFB800", type = input.color },
    line_width = input { default = 2, type = input.line_width },
    higher_color = input { default = "#25E154", type = input.color },
    lower_color = input { default = "#FF6C58", type = input.color },
    signal_text_color = input { default = "#FFFFFF", type = input.color }
}

trend_ema = ema (close, ema_period)

-- Williams %R: 0 at the highest high, -100 at the lowest low of the period.
range_high = highest (high, wpr_period)
range_low = lowest (low, wpr_period)
wpr = 100 * (close - range_high) / max (range_high - range_low, 1e-10)

local close_now = get_value (close, nil)
local ema_now = get_value (trend_ema, nil)
local wpr_now = get_value (wpr, nil)
local wpr_before = get_value (wpr [1], nil)
local range_now = get_value (range_high - range_low, nil)

local levels_are_valid = oversold_level < overbought_level
local data_is_ready =
    levels_are_valid and
    close_now ~= nil and ema_now ~= nil and
    wpr_now ~= nil and wpr_before ~= nil and
    range_now ~= nil and range_now > 1e-10 and
    get_value (trend_ema [ema_period], nil) ~= nil

-- Event: %R crosses back out of the zone on this candle, with the trend.
local wpr_leaves_oversold = data_is_ready and wpr_before <= oversold_level and wpr_now > oversold_level
local wpr_leaves_overbought = data_is_ready and wpr_before >= overbought_level and wpr_now < overbought_level

higher_setup = conditional (wpr_leaves_oversold and close_now > ema_now)
lower_setup = conditional (wpr_leaves_overbought and close_now < ema_now)

-- Confirm only a new setup on the previous completed candle.
confirmed_higher = conditional (
    get_value (higher_setup [1], false) and
    not get_value (higher_setup [2], false)
)

confirmed_lower = conditional (
    get_value (lower_setup [1], false) and
    not get_value (lower_setup [2], false)
)

if lines_visible then
    plot (trend_ema, "EMA", ema_color, line_width)
end

if signals_visible then
    plot_shape (
        confirmed_higher,
        "WR EMA HIGHER",
        shape_style.triangleup,
        shape_size.small,
        higher_color,
        shape_location.belowbar,
        -1,
        "HIGHER",
        signal_text_color
    )

    plot_shape (
        confirmed_lower,
        "WR EMA LOWER",
        shape_style.triangledown,
        shape_size.small,
        lower_color,
        shape_location.abovebar,
        -1,
        "LOWER",
        signal_text_color
    )
end

-- QCS advice is a platform notification state only; it does not place trades.
if advice_enabled and
    get_value (confirmed_higher, false) and
    not get_value (confirmed_lower, false) then
    advise (advice.buy)
elseif advice_enabled and
    get_value (confirmed_lower, false) and
    not get_value (confirmed_higher, false) then
    advise (advice.sell)
else
    advise (advice.neutral)
end