module Ledger.Conway.Foreign.HSLedger.Chain where

open import Ledger.Conway.Foreign.HSLedger.BaseTypes
open import Ledger.Conway.Foreign.HSLedger.NewEpoch
open import Ledger.Conway.Foreign.HSLedger.Transaction

open import Ledger.Conway.Specification.Chain it it using (BHBody; BHeader; Block)
import Ledger.Conway.Specification.Chain it it as ChainSpec using (ChainState)
open import Ledger.Conway.Specification.Chain.Properties.Computational it it
open import Ledger.Conway.Conformance.Epoch it it
open import Ledger.Conway.Conformance.Equivalence.Convert
open import Data.String using () renaming (_++_ to _+ˢ_)

record ChainState : Type where
  field
    newEpochState  : NewEpochState


record HSBlock : Type where
  field
    bheader     : BHeader
    ts          : List Tx
    bBodySize   : ℕ
    bBodyHash   : KeyHash

instance
  HsTy-VKey = autoHsType HSVKey
  Conv-VKey = autoConvert HSVKey

  HsTy-ChainState = autoHsType ChainState
  Conv-ChainState = autoConvert ChainState

  HsTy-BHBody = autoHsType BHBody
  HsTy-BHeader = autoHsType BHeader
  HsTy-HSBlock = autoHsType HSBlock
  Conv-BHBody = autoConvert BHBody
  Conv-BHeader = autoConvert BHeader
  Conv-HSBlock = autoConvert HSBlock

  ChainStateFromConf : ChainState ⭆ ChainSpec.ChainState
  ChainStateFromConf .convⁱ _ chainSt =
    record {newEpochState = conv $ ChainState.newEpochState chainSt}

  ChainStateToConf : ChainSpec.ChainState ⭆ ChainState
  ChainStateToConf .convⁱ deposits chainSt =
    record {newEpochState = conv $ ChainSpec.ChainState.newEpochState chainSt}


open HSBlock

convBlock : HSBlock → Block
convBlock b
  with bBodySize b ≟ BHBody.hBbsize (BHeader.bhbody (bheader b))
... | no _ = error $ "bBodySize check failed: " +ˢ
               show (bBodySize b) +ˢ " ≠ " +ˢ
               show (BHBody.hBbsize (BHeader.bhbody (bheader b)))
... | yes p
  with bBodyHash b ≟ BHBody.bhash (BHeader.bhbody (bheader b))
... | no _ = error $ "BBodyHash check failed: " +ˢ
               show (bBodyHash b) +ˢ " ≠ " +ˢ
               show (BHBody.bhash (BHeader.bhbody (bheader b)))
... | yes q = record
  { bheader = bheader b
  ; ts = ts b
  ; bBodySize = bBodySize b
  ; ≡-bBodySize = p
  ; ≡-bBodyHash = q
  }

chain-step₀ : ⊤ → ChainState → HSBlock → ComputationResult String ChainState
chain-step₀ t record{newEpochState = nes} hsb =
  let b = convBlock hsb
   in conv <$> compute Computational-CHAIN t (ChainSpec.ChainState.constructor (conv nes)) b

chain-step : HsType (⊤ → ChainState → HSBlock → ComputationResult String ChainState)
chain-step = to chain-step₀

{-# COMPILE GHC chain-step as chainStep #-}