//@version=6
indicator("Previous Day Levels", overlay = true)

// 1. Settings: the colours of the two lines
highColor = input.color(color.green, "High colour")
lowColor  = input.color(color.red, "Low colour")

// 2. The safe way to read yesterday (no repainting)
noRepaint = barmerge.lookahead_on

// 3. Yesterday's high and low, taken from the daily chart
prevHigh = request.security(syminfo.tickerid, "D", high[1], lookahead = noRepaint)
prevLow  = request.security(syminfo.tickerid, "D", low[1], lookahead = noRepaint)

// 4. Draw them as step lines that jump to the new level each day
pHigh = plot(prevHigh, "Prev day high", highColor, 2, plot.style_stepline)
pLow  = plot(prevLow, "Prev day low", lowColor, 2, plot.style_stepline)

// 5. Shade yesterday's range
fill(pHigh, pLow, color.new(color.gray, 90))

// 6. Did price break out of yesterday's range?
breakUp   = ta.crossover(close, prevHigh)
breakDown = ta.crossunder(close, prevLow)
plotshape(breakUp, "Break up", shape.triangleup, location.belowbar, highColor)
plotshape(breakDown, "Break down", shape.triangledown, location.abovebar, lowColor)

// 7. Alerts
alertcondition(breakUp, "Broke yesterday's high", "{{ticker}} broke the high")
alertcondition(breakDown, "Broke yesterday's low", "{{ticker}} broke the low")