//@version=5
strategy("4-Hour Range Scalper Strategy [Optimized]", overlay=true, initial_capital=10000, default_qty_type=strategy.percent_of_equity, default_qty_value=10)

// --- INPUTS ---
i_rr        = input.float(2.0, title="Risk-to-Reward Ratio", group="Risk Management")
i_ny_tz     = input.string("America/New_York", title="Session Time Zone", group="Session Settings")
i_session   = input.session("0000-0400", title="First 4H Candle Session (NY Time)", group="Session Settings")

// --- SESSION & MULTI-TIMEFRAME LOGIC ---
// Check if current bar is within the designated first 4-hour window of the day (New York time)
in_first_candle = not na(time(timeframe.period, i_session + ":1234567", i_ny_tz))
is_new_session  = ta.change(time("D", i_ny_tz)) != 0

// Variables to store the active day's range
var float r_high = na
var float r_low  = na

// Temporary variables to capture the high/low during the first 4-hour block
var float temp_high = na
var float temp_low  = na

if (is_new_session)
    temp_high := na
    temp_low  := na
    r_high    := na
    r_low     := na

if (in_first_candle)
    temp_high := na(temp_high) ? high : math.max(temp_high, high)
    temp_low  := na(temp_low) ? low : math.min(temp_low, low)
    r_high    := temp_high
    r_low     := temp_low
else
    // Lock values after the first session candle closes
    if (not na(temp_high) and na(r_high))
        r_high := temp_high
        r_low  := temp_low

// Persistent range lines across the day
var float active_high = na
var float active_low  = na

if (is_new_session)
    active_high := na
    active_low  := na

if (not na(r_high))
    active_high := r_high
    active_low  := r_low

// --- PLOTS ---
plot(active_high, title="4H Range High", color=color.red, style=plot.style_linebr, linewidth=2)
plot(active_low,  title="4H Range Low",  color=color.green, style=plot.style_linebr, linewidth=2)

// --- EXECUTION LOGIC ---
bool can_trade = strategy.position_size == 0

var bool broke_above = false
var bool broke_below = false

// Reset breakout flags on a new trading day
if (is_new_session)
    broke_above := false
    broke_below := false

// Track breakouts (candle fully closes outside, or wick breaches)
if (not na(active_high) and high > active_high)
    broke_above := true

if (not na(active_low) and low < active_low)
    broke_below := true

// Short Entry Trigger: Price broke above 4H high, now closing back inside
bool trigger_short = broke_above and not na(active_high) and (close < active_high) and (close[1] >= active_high)

if (can_trade and trigger_short)
    float entry_price = close
    float stop_loss   = ta.highest(high, 5) // Recent swing high fallback
    float risk        = stop_loss - entry_price
    float target      = entry_price - (risk * i_rr)

    if (risk > 0)
        strategy.entry("Short Re-entry", strategy.short)
        strategy.exit("TP/SL Short", "Short Re-entry", stop=stop_loss, limit=target)
        broke_above := false

// Long Entry Trigger: Price broke below 4H low, now closing back inside
bool trigger_long = broke_below and not na(active_low) and (close > active_low) and (close[1] <= active_low)

if (can_trade and trigger_long)
    float entry_price = close
    float stop_loss   = ta.lowest(low, 5) // Recent swing low fallback
    float risk        = entry_price - stop_loss
    float target      = entry_price + (risk * i_rr)

    if (risk > 0)
        strategy.entry("Long Re-entry", strategy.long)
        strategy.exit("TP/SL Long", "Long Re-entry", stop=stop_loss, limit=target)
        broke_below := false