{-# OPTIONS --safe #-}
 
module Leios.FFD where
 
open import Leios.Prelude
 
record FFDAbstract : Type₁ where
  field Header Body ID : Type
        ⦃ DecEq-Header ⦄ : DecEq Header
        ⦃ DecEq-Body ⦄ : DecEq Body
        match : Header → Body → Type
        msgID : Header → ID
 
  data Input : Type where
    Send  : Header → Maybe Body → Input
    Fetch : Input
 
  data Output : Type where
    SendRes  : Output
    FetchRes : List (Header ⊎ Body) → Output
 
  record Functionality : Type₁ where
    field State : Type
          initFFDState : State
          _-⟦_/_⟧⇀_ : State → Input → Output → State → Type
          Send-total : ∀ {ffds h b} → ∃[ ffds' ] ffds -⟦ Send h b / SendRes ⟧⇀ ffds'
          Fetch-total : ∀ {ffds} → ∃[ r ] (∃[ ffds' ] (ffds -⟦ Fetch / FetchRes r ⟧⇀ ffds'))
 
    open Input public
    open Output public