{-# LANGUAGE AllowAmbiguousTypes #-}
{-# LANGUAGE ConstraintKinds #-}
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE DefaultSignatures #-}
{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE DeriveTraversable #-}
{-# LANGUAGE DerivingStrategies #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE GADTs #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE NoStarIsType #-}
{-# LANGUAGE PolyKinds #-}
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE TypeFamilyDependencies #-}
{-# LANGUAGE TypeOperators #-}
{-# LANGUAGE UndecidableInstances #-}
{-# LANGUAGE UndecidableSuperClasses #-}

module Graphula.Dependencies
  ( HasDependencies(..)
  , Only(..)
  , only

  -- * Non-serial keys
  , KeySourceType(..)
  , GenerateKey
  , generateKey
  ) where

import Prelude

import Data.Kind (Constraint)
import Data.Proxy (Proxy(..))
import Database.Persist (Key)
import GHC.Generics (Generic)
import GHC.TypeLits (ErrorMessage(..), TypeError)
import Generics.Eot (Eot, HasEot, fromEot, toEot)
import Graphula.Dependencies.Generic
import Graphula.NoConstraint
import Test.QuickCheck.Arbitrary (Arbitrary(..))
import Test.QuickCheck.Gen (Gen)

class HasDependencies a where
  -- | A data type declaring the model's dependencies
  --
  -- Models with no dependencies can declare an empty instance,
  --
  -- @
  -- instance 'HasDependencies' School
  -- @
  --
  -- Models with one dependency must use the 'Only' 1-tuple constructor,
  --
  -- @
  -- instance 'HasDependencies' Teacher where
  --   type Dependencies Teacher = Only SchoolId
  -- @
  --
  -- Models with multiple dependencies use tuple syntax,
  --
  -- @
  -- instance 'HasDependencies' Course where
  --   type Dependencies Course = (SchoolId, TeacherId)
  -- @
  --
  type Dependencies a
  type instance Dependencies _a = ()

  -- | Specify the method for resolving a node's key
  --
  -- This can be
  --
  -- @
  -- 'SourceDefault   -- automatically generate keys from the database
  -- 'SourceArbitrary -- automatically generate keys using @'Arbitrary'@
  -- 'SourceExternal  -- explicitly pass a key using @'nodeKeyed'@
  -- @
  --
  -- Most types will use 'SourceDefault' or 'SourceArbitrary'. Only use
  -- 'SourceExternal' if the key for a value is always defined externally.
  --
  type KeySource a :: KeySourceType
  type instance KeySource _a = 'SourceDefault

  -- | Assign values from the 'Dependencies' collection to a value
  --
  -- This must be an idempotent operation. Law:
  --
  -- prop> (\x d -> x `dependsOn` d `dependsOn` d) = dependsOn
  --
  -- The default, 'Generic'-based implementation will assign values by the order
  -- of the fields in the model's type.
  --
  dependsOn :: a -> Dependencies a -> a
  default dependsOn
    ::
      ( HasEot a
      , HasEot (Dependencies a)
      , GHasDependencies (Proxy a) (Proxy (Dependencies a)) (Eot a) (Eot (Dependencies a))
      )
    => a -> Dependencies a -> a
  dependsOn a
a Dependencies a
dependencies =
    Eot a -> a
forall a. HasEot a => Eot a -> a
fromEot (Eot a -> a) -> Eot a -> a
forall a b. (a -> b) -> a -> b
$
      Proxy a
-> Proxy (Dependencies a)
-> EotG (Rep a)
-> EotG (Rep (Dependencies a))
-> EotG (Rep a)
forall nodeTyProxy depsTyProxy node deps.
GHasDependencies nodeTyProxy depsTyProxy node deps =>
nodeTyProxy -> depsTyProxy -> node -> deps -> node
genericDependsOn
        (Proxy a
forall k (t :: k). Proxy t
Proxy :: Proxy a)
        (Proxy (Dependencies a)
forall k (t :: k). Proxy t
Proxy :: Proxy (Dependencies a))
        (a -> Eot a
forall a. HasEot a => a -> Eot a
toEot a
a)
        (Dependencies a -> Eot (Dependencies a)
forall a. HasEot a => a -> Eot a
toEot Dependencies a
dependencies)

-- | For entities that only have singular 'Dependencies'
newtype Only a = Only { Only a -> a
fromOnly :: a }
  deriving stock (Only a -> Only a -> Bool
(Only a -> Only a -> Bool)
-> (Only a -> Only a -> Bool) -> Eq (Only a)
forall a. Eq a => Only a -> Only a -> Bool
forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
/= :: Only a -> Only a -> Bool
$c/= :: forall a. Eq a => Only a -> Only a -> Bool
== :: Only a -> Only a -> Bool
$c== :: forall a. Eq a => Only a -> Only a -> Bool
Eq, Int -> Only a -> ShowS
[Only a] -> ShowS
Only a -> String
(Int -> Only a -> ShowS)
-> (Only a -> String) -> ([Only a] -> ShowS) -> Show (Only a)
forall a. Show a => Int -> Only a -> ShowS
forall a. Show a => [Only a] -> ShowS
forall a. Show a => Only a -> String
forall a.
(Int -> a -> ShowS) -> (a -> String) -> ([a] -> ShowS) -> Show a
showList :: [Only a] -> ShowS
$cshowList :: forall a. Show a => [Only a] -> ShowS
show :: Only a -> String
$cshow :: forall a. Show a => Only a -> String
showsPrec :: Int -> Only a -> ShowS
$cshowsPrec :: forall a. Show a => Int -> Only a -> ShowS
Show, Eq (Only a)
Eq (Only a)
-> (Only a -> Only a -> Ordering)
-> (Only a -> Only a -> Bool)
-> (Only a -> Only a -> Bool)
-> (Only a -> Only a -> Bool)
-> (Only a -> Only a -> Bool)
-> (Only a -> Only a -> Only a)
-> (Only a -> Only a -> Only a)
-> Ord (Only a)
Only a -> Only a -> Bool
Only a -> Only a -> Ordering
Only a -> Only a -> Only a
forall a.
Eq a
-> (a -> a -> Ordering)
-> (a -> a -> Bool)
-> (a -> a -> Bool)
-> (a -> a -> Bool)
-> (a -> a -> Bool)
-> (a -> a -> a)
-> (a -> a -> a)
-> Ord a
forall a. Ord a => Eq (Only a)
forall a. Ord a => Only a -> Only a -> Bool
forall a. Ord a => Only a -> Only a -> Ordering
forall a. Ord a => Only a -> Only a -> Only a
min :: Only a -> Only a -> Only a
$cmin :: forall a. Ord a => Only a -> Only a -> Only a
max :: Only a -> Only a -> Only a
$cmax :: forall a. Ord a => Only a -> Only a -> Only a
>= :: Only a -> Only a -> Bool
$c>= :: forall a. Ord a => Only a -> Only a -> Bool
> :: Only a -> Only a -> Bool
$c> :: forall a. Ord a => Only a -> Only a -> Bool
<= :: Only a -> Only a -> Bool
$c<= :: forall a. Ord a => Only a -> Only a -> Bool
< :: Only a -> Only a -> Bool
$c< :: forall a. Ord a => Only a -> Only a -> Bool
compare :: Only a -> Only a -> Ordering
$ccompare :: forall a. Ord a => Only a -> Only a -> Ordering
$cp1Ord :: forall a. Ord a => Eq (Only a)
Ord, (forall x. Only a -> Rep (Only a) x)
-> (forall x. Rep (Only a) x -> Only a) -> Generic (Only a)
forall x. Rep (Only a) x -> Only a
forall x. Only a -> Rep (Only a) x
forall a.
(forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
forall a x. Rep (Only a) x -> Only a
forall a x. Only a -> Rep (Only a) x
$cto :: forall a x. Rep (Only a) x -> Only a
$cfrom :: forall a x. Only a -> Rep (Only a) x
Generic, a -> Only b -> Only a
(a -> b) -> Only a -> Only b
(forall a b. (a -> b) -> Only a -> Only b)
-> (forall a b. a -> Only b -> Only a) -> Functor Only
forall a b. a -> Only b -> Only a
forall a b. (a -> b) -> Only a -> Only b
forall (f :: Type -> Type).
(forall a b. (a -> b) -> f a -> f b)
-> (forall a b. a -> f b -> f a) -> Functor f
<$ :: a -> Only b -> Only a
$c<$ :: forall a b. a -> Only b -> Only a
fmap :: (a -> b) -> Only a -> Only b
$cfmap :: forall a b. (a -> b) -> Only a -> Only b
Functor, Only a -> Bool
(a -> m) -> Only a -> m
(a -> b -> b) -> b -> Only a -> b
(forall m. Monoid m => Only m -> m)
-> (forall m a. Monoid m => (a -> m) -> Only a -> m)
-> (forall m a. Monoid m => (a -> m) -> Only a -> m)
-> (forall a b. (a -> b -> b) -> b -> Only a -> b)
-> (forall a b. (a -> b -> b) -> b -> Only a -> b)
-> (forall b a. (b -> a -> b) -> b -> Only a -> b)
-> (forall b a. (b -> a -> b) -> b -> Only a -> b)
-> (forall a. (a -> a -> a) -> Only a -> a)
-> (forall a. (a -> a -> a) -> Only a -> a)
-> (forall a. Only a -> [a])
-> (forall a. Only a -> Bool)
-> (forall a. Only a -> Int)
-> (forall a. Eq a => a -> Only a -> Bool)
-> (forall a. Ord a => Only a -> a)
-> (forall a. Ord a => Only a -> a)
-> (forall a. Num a => Only a -> a)
-> (forall a. Num a => Only a -> a)
-> Foldable Only
forall a. Eq a => a -> Only a -> Bool
forall a. Num a => Only a -> a
forall a. Ord a => Only a -> a
forall m. Monoid m => Only m -> m
forall a. Only a -> Bool
forall a. Only a -> Int
forall a. Only a -> [a]
forall a. (a -> a -> a) -> Only a -> a
forall m a. Monoid m => (a -> m) -> Only a -> m
forall b a. (b -> a -> b) -> b -> Only a -> b
forall a b. (a -> b -> b) -> b -> Only a -> b
forall (t :: Type -> Type).
(forall m. Monoid m => t m -> m)
-> (forall m a. Monoid m => (a -> m) -> t a -> m)
-> (forall m a. Monoid m => (a -> m) -> t a -> m)
-> (forall a b. (a -> b -> b) -> b -> t a -> b)
-> (forall a b. (a -> b -> b) -> b -> t a -> b)
-> (forall b a. (b -> a -> b) -> b -> t a -> b)
-> (forall b a. (b -> a -> b) -> b -> t a -> b)
-> (forall a. (a -> a -> a) -> t a -> a)
-> (forall a. (a -> a -> a) -> t a -> a)
-> (forall a. t a -> [a])
-> (forall a. t a -> Bool)
-> (forall a. t a -> Int)
-> (forall a. Eq a => a -> t a -> Bool)
-> (forall a. Ord a => t a -> a)
-> (forall a. Ord a => t a -> a)
-> (forall a. Num a => t a -> a)
-> (forall a. Num a => t a -> a)
-> Foldable t
product :: Only a -> a
$cproduct :: forall a. Num a => Only a -> a
sum :: Only a -> a
$csum :: forall a. Num a => Only a -> a
minimum :: Only a -> a
$cminimum :: forall a. Ord a => Only a -> a
maximum :: Only a -> a
$cmaximum :: forall a. Ord a => Only a -> a
elem :: a -> Only a -> Bool
$celem :: forall a. Eq a => a -> Only a -> Bool
length :: Only a -> Int
$clength :: forall a. Only a -> Int
null :: Only a -> Bool
$cnull :: forall a. Only a -> Bool
toList :: Only a -> [a]
$ctoList :: forall a. Only a -> [a]
foldl1 :: (a -> a -> a) -> Only a -> a
$cfoldl1 :: forall a. (a -> a -> a) -> Only a -> a
foldr1 :: (a -> a -> a) -> Only a -> a
$cfoldr1 :: forall a. (a -> a -> a) -> Only a -> a
foldl' :: (b -> a -> b) -> b -> Only a -> b
$cfoldl' :: forall b a. (b -> a -> b) -> b -> Only a -> b
foldl :: (b -> a -> b) -> b -> Only a -> b
$cfoldl :: forall b a. (b -> a -> b) -> b -> Only a -> b
foldr' :: (a -> b -> b) -> b -> Only a -> b
$cfoldr' :: forall a b. (a -> b -> b) -> b -> Only a -> b
foldr :: (a -> b -> b) -> b -> Only a -> b
$cfoldr :: forall a b. (a -> b -> b) -> b -> Only a -> b
foldMap' :: (a -> m) -> Only a -> m
$cfoldMap' :: forall m a. Monoid m => (a -> m) -> Only a -> m
foldMap :: (a -> m) -> Only a -> m
$cfoldMap :: forall m a. Monoid m => (a -> m) -> Only a -> m
fold :: Only m -> m
$cfold :: forall m. Monoid m => Only m -> m
Foldable, Functor Only
Foldable Only
Functor Only
-> Foldable Only
-> (forall (f :: Type -> Type) a b.
    Applicative f =>
    (a -> f b) -> Only a -> f (Only b))
-> (forall (f :: Type -> Type) a.
    Applicative f =>
    Only (f a) -> f (Only a))
-> (forall (m :: Type -> Type) a b.
    Monad m =>
    (a -> m b) -> Only a -> m (Only b))
-> (forall (m :: Type -> Type) a.
    Monad m =>
    Only (m a) -> m (Only a))
-> Traversable Only
(a -> f b) -> Only a -> f (Only b)
forall (t :: Type -> Type).
Functor t
-> Foldable t
-> (forall (f :: Type -> Type) a b.
    Applicative f =>
    (a -> f b) -> t a -> f (t b))
-> (forall (f :: Type -> Type) a.
    Applicative f =>
    t (f a) -> f (t a))
-> (forall (m :: Type -> Type) a b.
    Monad m =>
    (a -> m b) -> t a -> m (t b))
-> (forall (m :: Type -> Type) a. Monad m => t (m a) -> m (t a))
-> Traversable t
forall (m :: Type -> Type) a. Monad m => Only (m a) -> m (Only a)
forall (f :: Type -> Type) a.
Applicative f =>
Only (f a) -> f (Only a)
forall (m :: Type -> Type) a b.
Monad m =>
(a -> m b) -> Only a -> m (Only b)
forall (f :: Type -> Type) a b.
Applicative f =>
(a -> f b) -> Only a -> f (Only b)
sequence :: Only (m a) -> m (Only a)
$csequence :: forall (m :: Type -> Type) a. Monad m => Only (m a) -> m (Only a)
mapM :: (a -> m b) -> Only a -> m (Only b)
$cmapM :: forall (m :: Type -> Type) a b.
Monad m =>
(a -> m b) -> Only a -> m (Only b)
sequenceA :: Only (f a) -> f (Only a)
$csequenceA :: forall (f :: Type -> Type) a.
Applicative f =>
Only (f a) -> f (Only a)
traverse :: (a -> f b) -> Only a -> f (Only b)
$ctraverse :: forall (f :: Type -> Type) a b.
Applicative f =>
(a -> f b) -> Only a -> f (Only b)
$cp2Traversable :: Foldable Only
$cp1Traversable :: Functor Only
Traversable)

only :: a -> Only a
only :: a -> Only a
only = a -> Only a
forall a. a -> Only a
Only

data KeySourceType
  = SourceDefault
  -- ^ Generate keys using the database's @DEFAULT@ strategy
  | SourceArbitrary
  -- ^ Generate keys using the 'Arbitrary' instance for the 'Key'
  | SourceExternal
  -- ^ Always explicitly pass an external key
  --
  -- See 'nodeKeyed'.
  --

-- | Abstract constraint that some @a@ can generate a key
--
-- This is part of ensuring better error messages.
--
class (GenerateKeyInternal (KeySource a) a, KeyConstraint (KeySource a) a) => GenerateKey a
instance (GenerateKeyInternal (KeySource a) a, KeyConstraint (KeySource a) a) => GenerateKey a

class GenerateKeyInternal (s :: KeySourceType) a where
  type KeyConstraint s a :: Constraint
  generateKey :: KeyConstraint s a => Gen (Maybe (Key a))

instance GenerateKeyInternal 'SourceDefault a where
  type KeyConstraint 'SourceDefault a = NoConstraint a
  generateKey :: Gen (Maybe (Key a))
generateKey = Maybe (Key a) -> Gen (Maybe (Key a))
forall (f :: Type -> Type) a. Applicative f => a -> f a
pure Maybe (Key a)
forall a. Maybe a
Nothing

instance GenerateKeyInternal 'SourceArbitrary a where
  type KeyConstraint 'SourceArbitrary a = Arbitrary (Key a)
  generateKey :: Gen (Maybe (Key a))
generateKey = Key a -> Maybe (Key a)
forall a. a -> Maybe a
Just (Key a -> Maybe (Key a)) -> Gen (Key a) -> Gen (Maybe (Key a))
forall (f :: Type -> Type) a b. Functor f => (a -> b) -> f a -> f b
<$> Gen (Key a)
forall a. Arbitrary a => Gen a
arbitrary

-- Rendered:
--
-- @
-- Cannot generate a value of type ‘X’ using ‘node’ since
--
--   instance HasDependencies X where
--     type KeySource X = 'SourceExternal
--
-- Possible fixes include:
-- • Use ‘nodeKeyed’ instead of ‘node’
-- • Change ‘KeySource X’ to 'SourceDefault or 'SourceArbitrary
-- @
--
instance TypeError
  ( 'Text "Cannot generate a value of type "
    ':<>: Quote ('ShowType a)
    ':<>: 'Text " using "
    ':<>: Quote ('Text "node")
    ':<>: 'Text " since"
    ':$$: 'Text ""
    ':$$: 'Text "  instance HasDependencies "
    ':<>: 'ShowType a
    ':<>: 'Text " where"
    ':$$: 'Text "    "
    ':<>: 'Text "type KeySource "
    ':<>: 'ShowType a
    ':<>: 'Text  " = "
    ':<>: 'ShowType 'SourceExternal
    ':$$: 'Text ""
    ':$$: 'Text "Possible fixes include:"
    ':$$: 'Text "• Use "
    ':<>: Quote ('Text "nodeKeyed")
    ':<>: 'Text " instead of "
    ':<>: Quote ('Text "node")
    ':$$: 'Text "• Change "
    ':<>: Quote ('Text "KeySource " ':<>: 'ShowType a)
    ':<>: 'Text " to "
    ':<>: 'Text "'SourceDefault"
    ':<>: 'Text " or "
    ':<>: 'Text "'SourceArbitrary"
  ) => GenerateKeyInternal 'SourceExternal a where
  type KeyConstraint 'SourceExternal a = NoConstraint a
  generateKey :: Gen (Maybe (Key a))
generateKey = String -> Gen (Maybe (Key a))
forall a. HasCallStack => String -> a
error String
"unreachable"

type family Quote t where
  Quote t = 'Text "‘" ':<>: t ':<>: 'Text "’"