# A stopwatch. Time is an input: a timer ticks while a surface runs the app,
# and each tick sees the time it happened (now); the views only show states.
use vega

record Lap {
  at = 0
}

state running = 0
state started = 0
state elapsed = 0
state laps: list of Lap
state at: index of laps

input toggle = key Space
input lap = key KeyL
input reset = key KeyR
input tick = every 100 ms

fn two(n) = if n < 10 { "0{n}" } else { "{n}" }
fn tenths(ms) = "{floor(ms / 60000)}:{two(floor(ms / 1000) % 60)}.{floor(ms / 100) % 10}"

on toggle.down {
  if running { elapsed = now - started }
  running = !running
  if running { started = now - elapsed }
}
on tick { if running { elapsed = now - started } }
on lap.down {
  laps.append(Lap { at: elapsed })
  at = laps.last
}
on reset.down { if !running { elapsed = 0 } }

view title = "Stopwatch"
view time = tenths(elapsed)
view status = if running { "running" } else { "stopped" }

view laps_list = each l in laps {
  label = tenths(l.at)
  tone = vega.when(l.position == laps.count - 1, vega.accent)
}
view laps_list_focus = at.position