//@version=5
// PipAtlas - Session Range (MIT License) - education only, test on demo.
// Draws Asia / London / New York session high-low boxes, with optional
// 1:RR projection lines when a closed box breaks (risk = box height).
indicator("PipAtlas - Session Range", overlay=true, max_boxes_count=90, max_lines_count=200)

asiaClr   = input.color(color.new(color.gray, 80), "Asia")
londonClr = input.color(color.new(color.teal, 80), "London")
nyClr     = input.color(color.new(color.orange,80), "New York")
showAsia  = input.bool(true, "Show Asia")
showLon   = input.bool(true, "Show London")
showNY    = input.bool(true, "Show New York")
showRR    = input.bool(true, "Project 1:RR on box break")
useHTF    = input.bool(false, "Require 4H trend confluence (EMA50)")
rrMult    = input.float(2.0, "RR multiple", minval=0.5, step=0.5)

tz = "UTC"
inWin(h, a, b) => a <= b ? (h >= a and h < b) : (h >= a or h < b)
hUTC = hour(time, tz)
dOW  = dayofweek(time, tz)
weekend = (dOW == dayofweek.saturday) or (dOW == dayofweek.sunday and hUTC < 22) or (dOW == dayofweek.friday and hUTC >= 22)
active = not weekend

// ---- session boxes: each window draws one high-low box per session ----
f_box(cond, clr) =>
    var float hi = na
    var float lo = na
    var int   st = na
    if cond and not cond[1]
        hi := high
        lo := low
        st := time
    if cond
        hi := math.max(hi, high)
        lo := math.min(lo, low)
    if not cond and cond[1] and not na(st)
        box.new(st, hi, time, lo, bgcolor=clr, border_color=color.new(clr, 40))
        hi := na
        lo := na
        st := na

f_box(showAsia and active and inWin(hUTC, 0, 9),   asiaClr)
f_box(showLon  and active and inWin(hUTC, 8, 17),  londonClr)
f_box(showNY   and active and inWin(hUTC, 13, 21), nyClr)

// ---- RR projection: track the latest session range; project on first break after close ----
anySess = (showAsia and active and inWin(hUTC, 0, 9)) or (showLon and active and inWin(hUTC, 8, 17)) or (showNY and active and inWin(hUTC, 13, 21))
var float sHi   = na
var float sLo   = na
var bool  sDone = false
if anySess and not anySess[1]
    sHi := high
    sLo := low
    sDone := false
if anySess
    sHi := math.max(sHi, high)
    sLo := math.min(sLo, low)
if not anySess and anySess[1]
    sDone := true

htfEma  = request.security(syminfo.tickerid, "240", ta.ema(close, 50), lookahead=barmerge.lookahead_off)
longConf  = not useHTF or close > htfEma
shortConf = not useHTF or close < htfEma

riskH   = sHi - sLo
longBrk  = showRR and sDone and not na(sHi) and ta.crossover(close, sHi)  and longConf
shortBrk = showRR and sDone and not na(sHi) and ta.crossunder(close, sLo) and shortConf

if longBrk
    line.new(bar_index, sHi, bar_index + 20, sHi + riskH * rrMult, color=color.new(color.teal, 0), width=2)   // target
    line.new(bar_index, sHi, bar_index + 20, sHi - riskH,          color=color.new(color.red, 30))           // stop (box low)
    sDone := false
if shortBrk
    line.new(bar_index, sLo, bar_index + 20, sLo - riskH * rrMult, color=color.new(color.red, 0), width=2)    // target
    line.new(bar_index, sLo, bar_index + 20, sLo + riskH,          color=color.new(color.teal, 30))          // stop (box high)
    sDone := false

alertcondition(longBrk,  "Session box broke UP",   "PipAtlas: latest session range broken upward - 1:RR projection drawn")
alertcondition(shortBrk, "Session box broke DOWN", "PipAtlas: latest session range broken downward - 1:RR projection drawn")