{- |
   Module     : Polysemy.Methodology
   License    : MIT
   Stability  : experimental

Domain modelling algebra for polysemy.
-}
{-# LANGUAGE AllowAmbiguousTypes #-}
{-# LANGUAGE BlockArguments      #-}
{-# LANGUAGE DataKinds           #-}
{-# LANGUAGE FlexibleContexts    #-}
{-# LANGUAGE LambdaCase          #-}
{-# LANGUAGE GADTs               #-}
{-# LANGUAGE PolyKinds           #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE TemplateHaskell     #-}
{-# LANGUAGE TypeApplications    #-}
{-# LANGUAGE TypeOperators       #-}
{-# OPTIONS_GHC -fplugin=Polysemy.Plugin #-}
module Polysemy.Methodology (
-- * Definition
  Methodology(..)
, process

-- * Eliminators
, runMethodologyPure
, runMethodologySem

-- * Decomposition
, cutMethodology
, cutMethodology'
, cutMethodology3
, cutMethodology3'
, divideMethodology
, divideMethodology'
, decideMethodology
, decideMethodology'
, decomposeMethodology
, decomposeMethodology'
, decomposeMethodology3
, separateMethodologyInitial
, endMethodologyInitial
, separateMethodologyTerminal
, endMethodologyTerminal

-- * Simplifcation
, fmapMethodology
, fmapMethodology'
, fmap2Methodology
, fmap2Methodology'
, pureMethodology
, pureMethodology'
, bindMethodology
, bindMethodology'
, traverseMethodology
, traverseMethodology'
, mconcatMethodology
, mconcatMethodology'

-- * Other Effects
, teeMethodologyOutput
, plugMethodologyInput
, runMethodologyAsKVStore
, runMethodologyAsKVStoreWithDefault
, runMethodologyMappendPure
, runMethodologyMappendSem

-- * Tracing
, traceMethodologyStart
, traceMethodologyEnd
, traceMethodologyAround

-- * Logging
, logMethodologyStart
, logMethodologyEnd
, logMethodologyAround
) where

import Control.Applicative
import Control.Arrow
import Control.Monad
import Colog.Polysemy as C
import Polysemy
import Polysemy.KVStore
import Polysemy.Input
import Polysemy.Output
import Polysemy.Several
import Polysemy.Trace

-- | A `Methodology` generalises a semantic process from `b` to `c`.
data Methodology b c m a where
  Process :: b -> Methodology b c m c

makeSem ''Methodology

-- | Run a `Methodology` using a pure function.
--
-- @since 0.1.0.0
runMethodologyPure
            :: forall b c r a.
               (b -> c)
               -- ^ A function from b to c.
            -> Sem (Methodology b c ': r) a
            -> Sem r a
runMethodologyPure f = interpret \case
  Process b -> return $ f b
{-# INLINE runMethodologyPure #-}

-- | Run a `Methodology' using a monadic function with effects in `r`.
--
-- @since 0.1.0.0
runMethodologySem :: forall b c r a.
                     (b -> Sem r c)
                     -- ^ A monadic function from b to c using effects in r.
                  -> Sem (Methodology b c ': r) a
                  -> Sem r a
runMethodologySem f = interpret \case
  Process b -> f b
{-# INLINE runMethodologySem #-}

-- | Cut a `Methodology` into two pieces at a midpoint.
--
-- @since 0.1.0.0
cutMethodology :: forall b c d r a.
                  Members '[ Methodology b c
                           , Methodology c d] r
               => Sem (Methodology b d ': r) a
                  -- ^ Methodology effect to decompose.
               -> Sem r a
cutMethodology = interpret \case
  Process b -> process @b @c b >>= process @c @d
{-# INLINE cutMethodology #-}

-- | Reinterpreting version of `cutMethodology`.
--
-- @since 0.1.6.0
cutMethodology' :: forall b c d r a.
                   Sem (Methodology b d ': r) a
                  -- ^ Methodology effect to decompose.
                -> Sem (Methodology b c ': Methodology c d ': r) a
cutMethodology' = reinterpret2 \case
  Process b -> process @b @c b >>= raise . process @c @d
{-# INLINE cutMethodology' #-}

-- | Cut a `Methodology` into three pieces using two cuts.
--
-- @since 0.1.0.0
cutMethodology3 :: forall b c d e r a.
                   Members '[ Methodology b c
                            , Methodology c d
                            , Methodology d e] r
               => Sem (Methodology b e ': r) a
                  -- ^ Methodology effect to decompose.
               -> Sem r a
cutMethodology3 = interpret \case
  Process b -> process @b @c b >>= process @c @d >>= process @d @e
{-# INLINE cutMethodology3 #-}

-- | Reinterpreting version of `cutMethodology`.
--
-- @since 0.1.6.0
cutMethodology3' :: forall b c d e r a.
                    Sem (Methodology b d ': r) a
                   -- ^ Methodology effect to decompose.
                 -> Sem (Methodology b c ': Methodology c d ': Methodology d e ': r) a
cutMethodology3' = reinterpret3 \case
  Process b -> process @b @c b >>= raise . process @c @d
{-# INLINE cutMethodology3' #-}

-- | Divide a `Methodology` into two components using a `Methodology` that accepts a pair.`
--
-- @since 0.1.0.0
divideMethodology :: forall b c c' d r a.
                     Members '[ Methodology b c
                              , Methodology b c'
                              , Methodology (c, c') d] r
                  => Sem (Methodology b d ': r) a
                  -- ^ Methodology effect to decompose.
                  -> Sem r a
divideMethodology = interpret \case
  Process b -> do
    c  <- process @b @c  b
    c' <- process @b @c' b
    process @(c, c') @d (c, c')
{-# INLINE divideMethodology #-}

-- | Reinterpreting version of `divideMethodology`.
--
-- @since 0.1.6.0
divideMethodology' :: forall b c c' d r a.
                      Sem (Methodology b d ': r) a
                   -> Sem (Methodology b c ': Methodology b c' ': Methodology (c, c') d ':   r) a
divideMethodology' = reinterpret3 \case
  Process b -> do
    c  <- process @b @c b
    c' <- raise $ process @b @c' b
    raise $ raise $ process @(c, c') @d (c, c')
{-# INLINE divideMethodology' #-}

-- | Decide between two `Methodology`s using a `Methodology` that computes an `Either`.
--
-- @since 0.1.0.0
decideMethodology :: forall b c c' d r a.
                     Members '[ Methodology b (Either c c')
                              , Methodology c  d
                              , Methodology c' d
                              ] r
                  => Sem (Methodology b d ': r) a
                  -- ^ `Methodology effect to decompose.
                  -> Sem r a
decideMethodology = interpret \case
  Process b -> do
    k <- process @b @(Either c c') b
    case k of
      Left c   -> process @c  @d c
      Right c' -> process @c' @d c'
{-# INLINE decideMethodology #-}

-- | Reinterpreting version of `decideMethodology`.
--
-- @since 0.1.6.0
decideMethodology' :: forall b c c' d r a.
                      Sem (Methodology b d ': r) a
                   -> Sem (Methodology b (Either c c') ': Methodology c d ': Methodology c' d ':   r) a
decideMethodology' = reinterpret3 \case
  Process b -> do
    k <- process @b @(Either c c') b
    case k of
      Left c   -> raise $ process @c  @d c
      Right c' -> raise $ raise $ process @c' @d c'
{-# INLINE decideMethodology' #-}

-- | Tee the output of a `Methodology`, introducing a new `Output` effect to be handled.
--
-- @since 0.1.0.0
teeMethodologyOutput :: forall b c r a.
                        Members '[ Output c
                                 , Methodology b c] r
                     => Sem r a
                     -> Sem r a
teeMethodologyOutput = intercept \case
  Process b -> do
    k <- process @b @c b
    output @c k
    return k
{-# INLINE teeMethodologyOutput #-}

-- | Make a `Methodology` depend on an additional input, introducing a new `Input` effect to be handled.
--
-- @since 0.1.0.0
plugMethodologyInput :: forall b c d r a.
                        Members '[Input b, Methodology (b, c) d] r
                     => Sem (Methodology c d ': r) a
                     -> Sem r a
plugMethodologyInput = interpret \case
  Process b -> do
    k <- input @b
    process @(b, c) @d (k, b)
{-# INLINE plugMethodologyInput #-}

-- | Run a `Methodology` as a `KVStore`, using the input as a key and the output as the value.
--
-- @since 0.1.0.0
runMethodologyAsKVStore :: forall k v r a.
                           Members '[KVStore k v] r
                        => Sem (Methodology k (Maybe v) ': r) a
                        -> Sem r a
runMethodologyAsKVStore = interpret \case
  Process k -> lookupKV k
{-# INLINE runMethodologyAsKVStore #-}

-- | Run a `Methodology` as a `KVStore`, with a default value for lookup failure.
--
-- @since 0.1.0.0
runMethodologyAsKVStoreWithDefault :: forall k v r a.
                                      Members '[KVStore k v] r
                                   => v
                                      -- ^ A default value v.
                                   -> Sem (Methodology k v ': r) a
                                   -> Sem r a
runMethodologyAsKVStoreWithDefault d = interpret \case
  Process k -> do
    z <- lookupKV k
    case z of
      Just a -> return a
      Nothing -> return d
{-# INLINE runMethodologyAsKVStoreWithDefault #-}

-- | Run a `Methodology` targetting a `Monoid` without consuming it, pure version. This should probably be considered an
-- anti-pattern, and it's probably better to decompose the inputs fully, but is otherwise sound.
--
-- @since 0.1.8.0
runMethodologyMappendPure :: forall b c r a.
                             (Monoid c,
                             Members '[Methodology b c] r)
                          => (b -> c)
                          -> Sem r a -> Sem r a
runMethodologyMappendPure f = intercept \case
  Process b -> (f b <>) <$> process @b @c b
{-# INLINE runMethodologyMappendPure #-}

-- | Run a `Methodology` targetting a `Monoid` without consuming it, `Sem` version. This should probably be considered an
-- anti-pattern, and it's probably better to decompose the inputs fully, but is otherwise sound.
--
-- @since 0.1.8.0
runMethodologyMappendSem :: forall b c r a.
                            (Monoid c,
                            Members '[Methodology b c] r)
                          => (b -> Sem r c)
                          -> Sem r a -> Sem r a
runMethodologyMappendSem f = intercept \case
  Process b -> liftA2 (<>) (f b) (process @b @c b)
{-# INLINE runMethodologyMappendSem #-}

-- | Decompose a `Methodology` into several components to be recombined. This is `cutMethodology` specialised to `HList`.
--
-- @since 0.1.0.0
decomposeMethodology :: forall b f c r a.
                        Members ' [Methodology b (HList f)
                                 , Methodology (HList f) c] r
                     => Sem (Methodology b c ': r) a
                     -> Sem r a
decomposeMethodology = cutMethodology @b @(HList f) @c
{-# INLINE decomposeMethodology #-}

-- | Reinterpreting version of `decomposeMethodology`.
--
-- @since 0.1.6.0
decomposeMethodology' :: forall b f c r a.
                         Sem (Methodology b c ': r) a
                      -> Sem (Methodology b (HList f) ': Methodology (HList f) c ': r) a
decomposeMethodology' = cutMethodology' @b @(HList f) @c
{-# INLINE decomposeMethodology' #-}

-- | Decompose a `Methodology` into several components over three sections with two cuts.
--
-- @since 0.1.0.0
decomposeMethodology3 :: forall b f g c r a.
                         Members '[ Methodology b (HList f)
                                  , Methodology (HList f) (HList g)
                                  , Methodology (HList g) c] r
                      => Sem (Methodology b c ': r) a
                      -> Sem r a
decomposeMethodology3 = cutMethodology3 @b @(HList f) @(HList g) @c
{-# INLINE decomposeMethodology3 #-}

-- | Factor a `Methodology` decomposed over an `HList` in the result by a `Methodology` to the first variable.
--
-- @since 0.1.0.0
separateMethodologyInitial :: forall b x xs r a.
                              Members '[ Methodology b (HList xs)
                                       , Methodology b x] r
                           => Sem (Methodology b (HList (x ': xs)) ': r) a
                           -> Sem r a
separateMethodologyInitial = interpret \case
  Process b -> do
    k   <- process @b @x b
    k'  <- process @b @(HList xs) b
    return $ k ::: k'
{-# INLINE separateMethodologyInitial #-}

-- | Finish an `HList` separated `Methodology` by consuming it for no effect.
--
-- @since 0.1.0.0
endMethodologyInitial :: Sem (Methodology b (HList '[]) ': r) a
                      -> Sem r a
endMethodologyInitial = interpret \case
  Process _ -> return HNil
{-# INLINE endMethodologyInitial #-}

-- | Factor a `Methodology` decomposed over an `HList` in the source by a
-- `Methodology` from the first variable. Assumes the result is a `Monoid`.
--
-- @since 0.1.0.0
separateMethodologyTerminal :: forall x c xs r a.
                               (Monoid c,
                               Members '[ Methodology (HList xs) c
                                        , Methodology x c] r)
                            => Sem (Methodology (HList (x ': xs)) c ': r) a
                            -> Sem r a
separateMethodologyTerminal = interpret \case
  Process (b ::: bs) -> do
    k   <- process @x @c b
    k'  <- process @(HList xs) @c bs
    return $ k <> k'
{-# INLINE separateMethodologyTerminal #-}

-- | Finalise an `HList` separated `Methodology` in the source by returning the `Monoid` unit.
--
-- @since 0.1.0.0
endMethodologyTerminal :: Monoid c
                       => Sem (Methodology (HList '[]) c ': r) a
                       -> Sem r a
endMethodologyTerminal = interpret \case
  Process _ -> return mempty
{-# INLINE endMethodologyTerminal #-}

-- | Run a `Methodology` (f b) (f c) by way of a `Methodology` b c. Note that
-- `f` must be `Traversable`.
--
-- @since 0.1.2.0
fmapMethodology :: forall f b c r a.
                 ( Members '[Methodology b c] r
                 , Traversable f)
                => Sem (Methodology (f b) (f c) ': r) a
                -> Sem r a
fmapMethodology = interpret \case
  Process b -> traverse (process @b @c) b
{-# INLINE fmapMethodology #-}

-- | Reinterpreting version of `fmapMethodology`.
--
-- @since 0.1.6.0
fmapMethodology' :: forall f b c r a.
                    Traversable f
                 => Sem (Methodology (f b) (f c) ': r) a
                 -> Sem (Methodology b c ': r) a
fmapMethodology' = raiseUnder >>> fmapMethodology
{-# INLINE fmapMethodology' #-}

-- | Run a `Methodology` (f (g b)) (f (g c))) by way of a `Methodology` b c. Note that
-- `f` and `g` must be `Traversable`.
--
-- @since 0.1.2.0
fmap2Methodology :: forall f g b c r a.
                  ( Members '[Methodology b c] r
                  , Traversable f, Traversable g)
                 => Sem (Methodology (f (g b)) (f (g c)) ': r) a
                 -> Sem r a
fmap2Methodology = fmapMethodology' @f @(g b) @(g c) >>> fmapMethodology @g @b @c
{-# INLINE fmap2Methodology #-}

-- | Reinterpreting version of `fmapMethodology`.
--
-- @since 0.1.6.0
fmap2Methodology' :: forall f g b c r a.
                     (Traversable f, Traversable g)
                  => Sem (Methodology (f (g b)) (f (g c)) ': r) a
                  -> Sem (Methodology b c ': r) a
fmap2Methodology' = raiseUnder >>> fmap2Methodology
{-# INLINE fmap2Methodology' #-}

-- | Run a `Methodology` b (f c) in terms of a `Methodology` b c.
--
-- @since 0.1.7.0
pureMethodology :: forall f b c r a.
                   (Members '[Methodology b c] r, Applicative f)
                => Sem (Methodology b (f c) ': r) a
                -> Sem r a
pureMethodology = interpret \case
  Process b -> pure <$> process @b @c b
{-# INLINE pureMethodology #-}

-- | Reinterpreting version of `pureMethodology`.
--
-- @since 0.1.7.0
pureMethodology' :: forall f b c r a. Applicative f
                 => Sem (Methodology b (f c) ': r) a
                 -> Sem (Methodology b c ': r) a
pureMethodology' = raiseUnder >>> pureMethodology
{-# INLINE pureMethodology' #-}

-- | Run a `Methodology` (f b) (f c) by way of a `Methodology` b (f c). Note that
-- `f` must be both `Traversable` and `Monad`.
--
-- @since 0.1.2.0
bindMethodology :: forall f b c r a.
                 ( Members '[Methodology b (f c)] r
                 , Traversable f, Monad f)
                => Sem (Methodology (f b) (f c) ': r) a
                -> Sem r a
bindMethodology = interpret \case
  Process b -> join <$> traverse (process @b @(f c)) b
{-# INLINE bindMethodology #-}

-- | Reinterpreting version of `bindMethodology`.
--
-- @since 0.1.6.0
bindMethodology' :: forall f b c r a.
                  ( Traversable f, Monad f)
                 => Sem (Methodology (f b) (f c) ': r) a
                 -> Sem (Methodology b (f c) ': r) a
bindMethodology' = raiseUnder >>> bindMethodology
{-# INLINE bindMethodology' #-}

-- | Run a `Methodology` (t b) (f (t b)) by way of a `Methodology` b (f c). Note that
-- `t` must be `Traversable` and `f` must be `Applicative`.
--
-- @since 0.1.2.0
traverseMethodology :: forall t f b c r a.
                     ( Members '[Methodology b (f c)] r
                     , Traversable t, Applicative f)
                    => Sem (Methodology (t b) (f (t c)) ': r) a
                    -> Sem r a
traverseMethodology = interpret \case
  Process b -> sequenceA <$> traverse (process @b @(f c)) b
{-# INLINE traverseMethodology #-}

-- | Reinterpreting version of `traverseMethodology`.
--
-- @since 0.1.6.0
traverseMethodology' :: forall t f b c r a.
                      ( Traversable t, Applicative f)
                    => Sem (Methodology (t b) (f (t c)) ': r) a
                    -> Sem (Methodology b (f c) ': r) a
traverseMethodology' = raiseUnder >>> traverseMethodology
{-# INLINE traverseMethodology' #-}

-- | Run a `Methodology` concatenating the results as a monoid.
--
-- @since 0.1.5.0
mconcatMethodology :: forall f b c r a.
                      ( Members '[Methodology b c] r
                      , Monoid c, Traversable f)
                   => Sem (Methodology (f b) c ': r) a
                   -> Sem r a
mconcatMethodology = interpret \case
  Process b -> traverse (process @b @c) b >>= return . foldr (<>) mempty
{-# INLINE mconcatMethodology #-}

-- | Reinterpreting version of `mconcatMethodology`.
--
-- @since 0.1.6.0
mconcatMethodology' :: forall f b c r a.
                      ( Monoid c, Traversable f)
                   => Sem (Methodology (f b) c ': r) a
                   -> Sem (Methodology b c ': r) a
mconcatMethodology' = raiseUnder >>> mconcatMethodology
{-# INLINE mconcatMethodology' #-}

-- | `Trace` a `String` based on the input to a `Methodology`.
--
-- @since 0.1.3.0
traceMethodologyStart :: forall b c r a.
                         Members '[Methodology b c,
                                   Trace] r
                       => (b -> String)
                          -- ^ A function from the input type b to a `String`.
                       -> Sem r a
                       -> Sem r a
traceMethodologyStart f = intercept \case
  Process b -> trace (f b) >> process @b @c b
{-# INLINE traceMethodologyStart #-}

-- | `Trace` a `String` based on the output to a `Methodology`.
--
-- @since 0.1.3.0
traceMethodologyEnd :: forall b c r a.
                       Members '[Methodology b c,
                                Trace] r
                       => (c -> String)
                          -- ^ A function from the output type c to a `String`.
                       -> Sem r a
                       -> Sem r a
traceMethodologyEnd f = intercept \case
  Process b -> do
    c <- process @b @c b
    trace $ f c
    return c
{-# INLINE traceMethodologyEnd #-}

-- | `Trace` both the start and the end of a `Methodology`.
--
-- @since 0.1.3.0
traceMethodologyAround :: forall b c r a.
                           Members '[Methodology b c,
                                     Trace] r
                       => (b -> String)
                          -- ^ A function from the input type b to a `String`.
                       -> (c -> String)
                          -- ^ A function from the output type c to a `String`.
                       -> Sem r a
                       -> Sem r a
traceMethodologyAround f g = intercept \case
  Process b -> do
    trace $ f b
    c <- process @b @c b
    trace $ g c
    return c
{-# INLINE traceMethodologyAround #-}

-- | `Log` a type based on the input to a `Methodology`.
--
-- @since 0.1.4.0
logMethodologyStart :: forall b c p r a.
                       Members '[Methodology b c,
                                 Log p] r
                       => (b -> p)
                          -- ^ A function from the input type b to an event type p.
                       -> Sem r a
                       -> Sem r a
logMethodologyStart f = intercept \case
  Process b -> C.log (f b) >> process @b @c b
{-# INLINE logMethodologyStart #-}

-- | `Log` a type based on the output to a `Methodology`.
--
-- @since 0.1.4.0
logMethodologyEnd :: forall b c q r a.
                       Members '[Methodology b c,
                                Log q] r
                       => (c -> q)
                          -- ^ A function from the input type c to an event type q.
                       -> Sem r a
                       -> Sem r a
logMethodologyEnd f = intercept \case
  Process b -> do
    c <- process @b @c b
    C.log $ f c
    return c
{-# INLINE logMethodologyEnd #-}

-- | `Log` both the start and the end of a `Methodology`.
--
-- @since 0.1.4.0
logMethodologyAround :: forall b c p q r a.
                           Members '[ Methodology b c
                                    , Log p
                                    , Log q] r
                       => (b -> p)
                          -- ^ A function from the input type b to an event type p.
                       -> (c -> q)
                          -- ^ A function from the output type b to an event type q,
                       -> Sem r a
                       -> Sem r a
logMethodologyAround f g = intercept \case
  Process b -> do
    C.log $ f b
    c <- process @b @c b
    C.log $ g c
    return c
{-# INLINE logMethodologyAround #-}