pub(open) trait FetchPort {
  async fn fetch_processes(self : Self) -> Array[ProcessRow] raise ViewError
  async fn fetch_ets(self : Self) -> Array[EtsRow] raise ViewError
  async fn fetch_sup_tree(self : Self, sup : String) -> SupNode raise ViewError
  async fn fetch_memory(self : Self) -> MemorySummary raise ViewError
  async fn fetch_ports(self : Self) -> Int raise ViewError
}

pub(open) trait RenderPort {
  fn render_processes(self : Self, rows : Array[ProcessRow]) -> Unit
  fn render_ets(self : Self, rows : Array[EtsRow]) -> Unit
  fn render_sup_tree(self : Self, tree : SupNode) -> Unit
  fn render_memory(self : Self, mem : MemorySummary) -> Unit
  fn render_ports(self : Self, count : Int) -> Unit
}

pub(all) suberror ViewError {
  ShapeMismatch(String)
}

pub(all) struct EtsRow {
  name : String
  kind : String
  size : Int
}

pub(all) struct MemorySummary {
  total : Int
  processes : Int
  ets : Int
  atom : Int
}

pub struct Observer {
  fetch : &FetchPort
}

pub(all) struct ProcessRow {
  pid : String
  name : String
  initial_call : String
  memory_words : Int
  message_queue_len : Int
}

pub(all) struct SupChild {
  child_id : String
  kind : String
}

pub(all) struct SupNode {
  name : String
  children : Array[SupChild]
}