# emit_time.ludic — the Time.* namespace. frame/elapsed/delta are deterministic
# (driven by @L_frame, the per-frame counter the game loop increments); now() is
# the wall clock and is explicitly non-deterministic. The frame clock ticks at a
# fixed 60 per second, so delta is the constant 1/60 s = 1092 in Q16.16.

function is_time_ns(meth: pointer) -> bool {
  if (meth == "frame") or (meth == "delta") or (meth == "elapsed") or (meth == "now") { return true }
  if (meth == "since") { return true }
  return false
}

function emit_time_ns(meth: pointer, e: Node) -> Val {
  if (meth == "frame") {                            # completed frames since start
    return val(emit_bind("load i32, ptr @L_frame"), "int")
  }
  if (meth == "delta") {                            # seconds per frame, 1/60 (fixed)
    return val("1092", "fixed")
  }
  if (meth == "elapsed") {                          # seconds since start = frame / 60 (fixed)
    let f = emit_bind("load i32, ptr @L_frame")
    return val(emit_bind(`mul i32 {f}, 1092`), "fixed")
  }
  if (meth == "since") {                            # seconds elapsed from a past instant to now
    let past = emit_expr(e.kids[0])                 # NON-DETERMINISTIC (reads the wall clock)
    let nw = emit_bind("call i64 @time(ptr null)")
    let n32 = emit_bind(`trunc i64 {nw} to i32`)
    return val(emit_bind(`sub i32 {n32}, {past.code}`), "int")
  }
  # now: wall-clock seconds since the epoch — NON-DETERMINISTIC, for seeding /
  # telemetry only, never the lockstep simulation.
  let t = emit_bind("call i64 @time(ptr null)")
  return val(emit_bind(`trunc i64 {t} to i32`), "int")
}