--
-- Copyright (c) 2026 BEL ESPRIT D ACCORD TRUST HOLDINGS INC
-- All rights reserved.

{-# LANGUAGE BinaryLiterals #-}
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE KindSignatures #-}
{-# LANGUAGE NumericUnderscores #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE TypeApplications #-}
{-# LANGUAGE TypeFamilies #-}

module MarlborgWorm.Hardware.EntropyAdderTree
  ( entropyAdderTree
  , topEntity
  ) where

import Clash.Prelude

-- | Fixed-point parameters (scaling by 10^4)
-- H_BASE = 0.1000 nats -> 1000
-- H_HASH = 0.0400 nats -> 400 (when hash removed)
-- H_MARLBORG = 0.0005 nats/rule -> 5 per rule
-- epsilon = 168/10088352 nats/op -> (1680000 * N) / 10088352 in fixed-point

type HBaseFixed = 1000
type HHashFixed = 400
type HMarlborgPerRule = 5

data AdderState = AdderState
  { hTruncAccum :: Unsigned 32
  , lastOpCount :: Unsigned 32
  } deriving (Show, Eq, Generic, NFDataX)

initialAdderState :: AdderState
initialAdderState = AdderState 0 0

-- | Mealy transition: compute total cognitive entropy in fixed-point
adderStep :: AdderState
          -> (Bit, Unsigned 12, Unsigned 32, Bool, Unsigned 16)
          -> (AdderState, Unsigned 32)
adderStep st (truncValid, _thetaFixed, opCount, hashRemoved, deltaRules) =
  let deltaN = if opCount >= lastOpCount st
               then opCount - lastOpCount st
               else 0
      hTruncAdd = if deltaN == 0
                  then 0
                  else (1680000 * resize deltaN) `div` 10088352
      hTruncNext = hTruncAccum st + hTruncAdd
      hHash = if hashRemoved then HHashFixed else 0
      hMarlborg = resize deltaRules * HMarlborgPerRule
      hCogFixed = HBaseFixed + hTruncNext + hHash + hMarlborg
  in (AdderState hTruncNext opCount, hCogFixed)

-- | Entropy adder tree: sums all entropy components
entropyAdderTree
  :: Clock System
  -> Reset System
  -> Enable System
  -> Signal System Bit
  -> Signal System (Unsigned 12)
  -> Signal System (Unsigned 32)
  -> Signal System Bool
  -> Signal System (Unsigned 16)
  -> Signal System (Unsigned 32)
entropyAdderTree clk rst en truncValid thetaFixed opCount hashRemoved deltaRules =
  mealy clk rst en adderStep initialAdderState
    (bundle (truncValid, thetaFixed, opCount, hashRemoved, deltaRules))

topEntity
  :: Clock System
  -> Reset System
  -> Enable System
  -> Signal System Bit
  -> Signal System (Unsigned 12)
  -> Signal System (Unsigned 32)
  -> Signal System Bool
  -> Signal System (Unsigned 16)
  -> Signal System (Unsigned 32)
topEntity = entropyAdderTree
{-# ANN topEntity
  (Synthesize
    { t_name   = "EntropyAdderTree"
    , t_inputs = [ PortName "clk"
                 , PortName "rst"
                 , PortName "en"
                 , PortName "truncatorValid"
                 , PortName "thetaFixed"
                 , PortName "operationCount"
                 , PortName "hashRemoved"
                 , PortName "deltaRules"
                 ]
    , t_output = PortName "hCogFixed"
    }) #-}