[RS]Session Pivot V0

//@version=2
study(title='[RS]Session Pivot V0', shorttitle='SP', overlay=true)
session_time = input(title='Session time:', type=string, defval='0300-1500')
isinsession = not na(time('1', session_time))
isnewsession = change(isinsession)>0

session_open = isnewsession ? open : session_open[1]
session_high = na(session_high[1]) ? high :isnewsession ? high : high >= session_high[1] ? high : session_high[1]
session_low = na(session_low[1]) ? low :isnewsession ? low : low <= session_low[1] ? low : session_low[1]

//plot(session_open, color=gray)
//plot(session_high, color=gray)
//plot(session_low, color=gray)

P = isnewsession ? (session_high[1] + session_low[1] + session_open) / 3 : P[1]
S1 = isnewsession ? (P * 2) - session_high[1] : S1[1]
S2 = isnewsession ? P - (session_high[1]-session_low[1]) : S2[1]
R1 = isnewsession ? (P * 2) - session_low[1] : R1[1]
R2 = isnewsession ? P + (session_high[1]-session_low[1]) : R2[1]

plot(title='P', series=P, color=isnewsession?na:black)
plot(title='S1', series=S1, color=isnewsession?na:black)
plot(title='S2', series=S2, color=isnewsession?na:black)
plot(title='R1', series=R1, color=isnewsession?na:black)
plot(title='R2', series=R2, color=isnewsession?na:black)