module Language.Fiddle.Internal.UnitInterface where

import Data.Aeson
import Data.List.NonEmpty (NonEmpty)
import Data.Text
import Data.Word
import GHC.Generics
import Language.Fiddle.Internal.Scopes (Scope)
import qualified Language.Fiddle.Internal.Scopes as Scopes
import Language.Fiddle.Types (SourceSpan)

data InternalDirectiveExpression
  = InternalDirectiveExpressionNumber String
  | InternalDirectiveExpressionString String
  deriving (Generic, ToJSON, FromJSON, Show, Eq, Ord)

-- | Represents a compiler directive that provides configuration for the compiler
--   or its various backends. Directives can adjust the behavior of the compiler
--   or influence the code generation in the backends.
data InternalDirective = InternalDirective
  { -- | Specifies the backend that this directive is intended for. If 'Nothing',
    --   the directive applies globally across all backends.
    directiveBackend :: Maybe String,
    -- | The key or name of the directive. This identifies the directive's
    --   purpose, such as enabling specific features or setting options.
    directiveKey :: String,
    -- | The optional value associated with this directive. Some directives
    --   may not require a value (e.g., flags), in which case this field is 'Nothing'.
    directiveValue :: Maybe InternalDirectiveExpression
  }
  deriving (Generic, ToJSON, FromJSON, Show, Eq, Ord)

-- | Metadata about an exported value. This includes things like the source
-- location, doc comments and compiler directives associated with the exported
-- symbol.
data Metadata = Metadata
  { -- | Fully-qualified path the the element.
    metadataFullyQualifiedPath :: NonEmpty String,
    -- | Source location for the exported symbol.
    metadataSourceSpan :: SourceSpan,
    -- | Doc comment associated with the symbol.
    metadataDocComment :: Text,
    -- | List of directives associated with this exported symbol.
    metadataDirectives :: [InternalDirective]
  }
  deriving (Generic, ToJSON, FromJSON, Show, Eq, Ord)

-- | Contains a datastructure which represents a FiddleUnit.
--
-- These datastructures contain the exported symobls of a fiddle unit and it's
-- direct dependencies.
data UnitInterface where
  UnitInterface ::
    { rootScope :: Scope String (Metadata, ExportedDecl),
      dependencies :: [FilePath]
    } ->
    UnitInterface
  deriving (Generic, Eq, Ord, Show, FromJSON, ToJSON)

insert :: (ExportableDecl d) => d -> UnitInterface -> UnitInterface
insert decl (UnitInterface sc deps) =
  let metadata = getMetadata decl
      path = metadataFullyQualifiedPath metadata
   in UnitInterface (Scopes.insertScope path (metadata, toExportedDecl decl) sc) deps

singleton :: (ExportableDecl d) => d -> UnitInterface
singleton decl =
  let path = metadataFullyQualifiedPath (getMetadata decl)
      metadata = getMetadata decl
   in UnitInterface (Scopes.singleton path (metadata, toExportedDecl decl)) []

instance Semigroup UnitInterface where
  (<>) (UnitInterface s d) (UnitInterface s1 d1) =
    UnitInterface (s <> s1) (d <> d1)

instance Monoid UnitInterface where
  mempty = UnitInterface mempty mempty

-- | Represents an exported package declaration in the syntax tree.
-- This is a higher-level abstraction with metadata detailing the package.
data ExportedPackageDecl where
  ExportedPackageDecl ::
    { -- | Metadata associated with the package.
      exportedPackageMetadata :: Metadata
    } ->
    ExportedPackageDecl
  deriving (Show, Eq, Ord, Generic, FromJSON, ToJSON)

-- | Represents an exported location declaration in the syntax tree.
-- Contains metadata and the actual integer value of the location.
data ExportedLocationDecl where
  ExportedLocationDecl ::
    { -- | Metadata associated with the location.
      exportedLocationMetadata :: Metadata,
      -- | The value of the location as an integer.
      exportedLocationValue :: Integer
    } ->
    ExportedLocationDecl
  deriving (Show, Eq, Ord, Generic, FromJSON, ToJSON)

-- | Represents an exported bits declaration in the syntax tree.
-- Contains metadata and the size of the bits in a Word32 format.
data ExportedBitsDecl where
  ExportedBitsDecl ::
    { -- | Metadata associated with the bits declaration.
      exportedBitsDeclMetadata :: Metadata,
      -- | The size of the bits in this declaration.
      exportedBitsDeclSizeBits :: Word32
    } ->
    ExportedBitsDecl
  deriving (Show, Eq, Ord, Generic, FromJSON, ToJSON)

-- | Represents an exported type declaration in the syntax tree.
-- Contains metadata and the size of the type in bytes.
data ExportedTypeDecl where
  ExportedTypeDecl ::
    { -- | Metadata associated with the type declaration.
      exportedTypeDeclMetadata :: Metadata,
      -- | The size of the type in bytes.
      exportedTypeDeclSizeBytes :: Word32
    } ->
    ExportedTypeDecl
  deriving (Show, Eq, Ord, Generic, FromJSON, ToJSON)

data ReferencedObjectType where
  ReferencedObjectType ::
    {objectTypeReference :: String} -> ReferencedObjectType
  ArrayObjectType ::
    { arrayObjectTypeType :: ReferencedObjectType,
      arryObjecttTypeNumber :: Word32
    } ->
    ReferencedObjectType
  deriving (Show, Eq, Ord, Generic, FromJSON, ToJSON)

-- | Represents an exported object declaration in the syntax tree.
-- This includes metadata, location, and the type of the object.
data ExportedObjectDecl where
  ExportedObjectDecl ::
    { -- | Metadata associated with the object declaration.
      exportedObjectDeclMetadata :: Metadata,
      -- | The memory location of the object.
      exportedObjectDeclLocation :: Integer,
      -- | The type of the object as a string.
      exportedObjectDeclType :: ReferencedObjectType
    } ->
    ExportedObjectDecl
  deriving (Show, Eq, Ord, Generic, FromJSON, ToJSON)

-- | A typeclass for converting various exported declarations into the
-- generalized 'ExportedDecl' type. This allows treating different exported
-- declarations uniformly in the compilation process.
class ExportableDecl a where
  toExportedDecl :: a -> ExportedDecl
  fromExportedDecl :: ExportedDecl -> Maybe a
  getMetadata :: a -> Metadata

-- Instances of 'ExportableDecl' to convert specific exported declaration types
-- into the generalized 'ExportedDecl' type.
instance ExportableDecl ExportedPackageDecl where
  toExportedDecl = ExportedPackage
  fromExportedDecl = \case
    ExportedPackage x -> Just x
    _ -> Nothing
  getMetadata = exportedPackageMetadata

instance ExportableDecl ExportedLocationDecl where
  toExportedDecl = ExportedLocation
  fromExportedDecl = \case
    ExportedLocation x -> Just x
    _ -> Nothing
  getMetadata = exportedLocationMetadata

instance ExportableDecl ExportedBitsDecl where
  toExportedDecl = ExportedBits
  fromExportedDecl = \case
    ExportedBits x -> Just x
    _ -> Nothing
  getMetadata = exportedBitsDeclMetadata

instance ExportableDecl ExportedTypeDecl where
  toExportedDecl = ExportedType
  fromExportedDecl = \case
    ExportedType x -> Just x
    _ -> Nothing
  getMetadata = exportedTypeDeclMetadata

instance ExportableDecl ExportedObjectDecl where
  toExportedDecl = ExportedObject
  fromExportedDecl = \case
    ExportedObject x -> Just x
    _ -> Nothing
  getMetadata = exportedObjectDeclMetadata

-- | A generalized representation of different exported declarations.
-- This data type allows for a uniform way to handle various exportable
-- syntax tree elements (e.g., packages, locations, bits, types, objects).
data ExportedDecl where
  ExportedPackage :: ExportedPackageDecl -> ExportedDecl
  ExportedLocation :: ExportedLocationDecl -> ExportedDecl
  ExportedBits :: ExportedBitsDecl -> ExportedDecl
  ExportedType :: ExportedTypeDecl -> ExportedDecl
  ExportedObject :: ExportedObjectDecl -> ExportedDecl
  deriving (Show, Eq, Ord, Generic, FromJSON, ToJSON)