type State {
  source: Json
  update: Bool
  checksum: Int
}

run(source: Json, update: Bool, ticks: Text) (sample: Sample) {
  input = dever.bytes.fromText(ticks)
  initial = State {
    source = source
    update = update
    checksum = 0
  }
  output = transform(source, update)
  begin = dever.time.monotonicNanos()
  final = reduce(step, input, initial)
  end = dever.time.monotonicNanos()
  sample = Sample {
    elapsed_ns = end - begin
    checksum = final.checksum
    output = output
  }
}

type Sample {
  elapsed_ns: Int
  checksum: Int
  output: Text
}

step(unused: Int, state: State) (next: State) {
  output = transform(state.source, state.update)
  next = State {
    source = state.source
    update = state.update
    checksum = state.checksum + length(dever.bytes.fromText(output))
  }
}

transform(source: Json, update: false) (output: Text) {
  output = selected(dever.json.propertyValue(source, "data"))
}

transform(source: Json, update: true) (output: Text) {
  output = dever.json.toText(
    dever.json.setProperty(source, "active", dever.json.boolean(true))
  )
}

selected(value: Json) (output: Text) {
  output = dever.json.toText(value)
}

selected(value: null) (output: Text) {
  output = "null"
}