{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE DeriveDataTypeable #-}
{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE DeriveFunctor #-}
{-# LANGUAGE DefaultSignatures #-}
{-# LANGUAGE FlexibleContexts #-}

module Language.Fortran.AST where

import Data.Data
import Data.Typeable
import Data.Generics.Uniplate.Data
import Data.Binary
import GHC.Generics (Generic)
import Text.PrettyPrint.GenericPretty
import Language.Fortran.ParserMonad (FortranVersion(..))

import Language.Fortran.Util.Position
import Language.Fortran.Util.FirstParameter
import Language.Fortran.Util.SecondParameter

import Debug.Trace

type A0 = ()

type Name = String

-- AST is polymorphic on some type a as that type is used for arbitrary
-- annotations

-- Many AST nodes such as executable statements, declerations, etc. may
-- appear in lists, hence a dedicated annotated list type is defined
data AList t a = AList a SrcSpan [t a] deriving (Eq, Show, Data, Typeable, Generic)
instance Functor t => Functor (AList t) where
  fmap f (AList a s xs) = AList (f a) s (map (fmap f) xs)

fromList :: Spanned (t a) => a -> [ t a ] -> AList t a
fromList a xs = AList a (getSpan xs) xs

fromReverseList :: Spanned (t ()) => [ t () ] -> AList t ()
fromReverseList = fromList () . reverse

aCons :: t a -> AList t a -> AList t a
aCons x (AList a s xs) = AList a s $ x:xs

infixr 5 `aCons`

aReverse :: AList t a -> AList t a
aReverse (AList a s xs) = AList a s $ reverse xs

aStrip :: AList t a -> [t a]
aStrip (AList _ _ l) = l

aMap :: (t a -> r a) -> AList t a -> AList r a
aMap f (AList a s xs) = AList a s (map f xs)

-- Basic AST nodes
data BaseType =
    TypeInteger
  | TypeReal
  | TypeDoublePrecision
  | TypeComplex
  | TypeDoubleComplex
  | TypeLogical
  | TypeCharacter
  | TypeCustom String
  deriving (Ord, Eq, Show, Data, Typeable, Generic)

instance Binary BaseType

data TypeSpec a = TypeSpec a SrcSpan BaseType (Maybe (Selector a))
  deriving (Eq, Show, Data, Typeable, Generic, Functor)

data Selector a =
--                   Maybe length         | Maybe kind
  Selector a SrcSpan (Maybe (Expression a)) (Maybe (Expression a))
  deriving (Eq, Show, Data, Typeable, Generic, Functor)

data MetaInfo = MetaInfo { miVersion :: FortranVersion, miFilename :: String }
  deriving (Eq, Show, Data, Typeable, Generic)

-- Program structure definition
data ProgramFile a = ProgramFile MetaInfo [ ProgramUnit a ]
  deriving (Eq, Show, Data, Typeable, Generic, Functor)

pfSetFilename fn (ProgramFile mi pus) = ProgramFile (mi { miFilename = fn }) pus
pfGetFilename (ProgramFile mi _) = miFilename mi

data ProgramUnit a =
    PUMain
      a SrcSpan
      (Maybe Name) -- Program name
      [Block a] -- Body
      (Maybe [ProgramUnit a]) -- Subprograms
  | PUModule
      a SrcSpan
      Name -- Program name
      [Block a] -- Body
      (Maybe [ProgramUnit a]) -- Subprograms
  | PUSubroutine
      a SrcSpan
      Bool -- Recursive or not
      Name
      (Maybe (AList Expression a)) -- Arguments
      [Block a] -- Body
      (Maybe [ProgramUnit a]) -- Subprograms
  | PUFunction
      a SrcSpan
      (Maybe (TypeSpec a)) -- Return type
      Bool -- Recursive or not
      Name
      (Maybe (AList Expression a)) -- Arguments
      (Maybe (Expression a)) -- Result
      [Block a] -- Body
      (Maybe [ProgramUnit a]) -- Subprograms
  | PUBlockData
      a SrcSpan
      (Maybe Name)
      [Block a] -- Body
  | PUComment a SrcSpan (Comment a)
  deriving (Eq, Show, Data, Typeable, Generic, Functor)

programUnitBody :: ProgramUnit a -> [Block a]
programUnitBody (PUMain _ _ _ bs _)              = bs
programUnitBody (PUModule _ _ _ bs _)            = bs
programUnitBody (PUSubroutine _ _ _ _ _ bs _)    = bs
programUnitBody (PUFunction _ _ _ _ _ _ _ bs _)  = bs
programUnitBody (PUBlockData _ _ _ bs)           = bs
programUnitBody (PUComment {})                   = []

programUnitSubprograms :: ProgramUnit a -> Maybe [ProgramUnit a]
programUnitSubprograms (PUMain _ _ _ _ s)             = s
programUnitSubprograms (PUModule _ _ _ _ s)           = s
programUnitSubprograms (PUSubroutine _ _ _ _ _ _ s)   = s
programUnitSubprograms (PUFunction _ _ _ _ _ _ _ _ s) = s
programUnitSubprograms (PUBlockData {})               = Nothing
programUnitSubprograms (PUComment {})                 = Nothing

newtype Comment a = Comment String
  deriving (Eq, Show, Data, Typeable, Generic, Functor)

data Block a =
    BlStatement a SrcSpan
                (Maybe (Expression a))       -- Label
                (Statement a)                -- Statement

  | BlIf        a SrcSpan
                (Maybe (Expression a))       -- Label
                (Maybe String)               -- Construct name
                [ Maybe (Expression a) ]     -- Conditions
                [ [ Block a ] ]              -- Bodies
                (Maybe (Expression a))       -- Label to END IF

  | BlCase      a SrcSpan
                (Maybe (Expression a))       -- Label
                (Maybe String)               -- Construct name
                (Expression a)               -- Scrutinee
                [ Maybe (AList Index a) ]    -- Case ranges
                [ [ Block a ] ]              -- Bodies
                (Maybe (Expression a))       -- Label to END SELECT

  | BlDo        a SrcSpan
                (Maybe (Expression a))       -- Label
                (Maybe String)               -- Construct name
                (Maybe (Expression a))       -- Target label
                (Maybe (DoSpecification a))  -- Do Specification
                [ Block a ]                  -- Body
                (Maybe (Expression a))       -- Label to END DO

  | BlDoWhile   a SrcSpan
                (Maybe (Expression a))       -- Label
                (Maybe String)               -- Construct name
                (Expression a)               -- Condition
                [ Block a ]                  -- Body
                (Maybe (Expression a))       -- Label to END DO

  | BlInterface a SrcSpan
                (Maybe (Expression a))       -- label
                [ ProgramUnit a ]            -- Routine decls. in the interface
                [ Block a ]                  -- Module procedures

  | BlComment a SrcSpan (Comment a)
  deriving (Eq, Show, Data, Typeable, Generic, Functor)

data Statement a  =
    StDeclaration         a SrcSpan (TypeSpec a) (Maybe (AList Attribute a)) (AList Declarator a)
  | StIntent              a SrcSpan Intent (AList Expression a)
  | StOptional            a SrcSpan (AList Expression a)
  | StPublic              a SrcSpan (Maybe (AList Expression a))
  | StPrivate             a SrcSpan (Maybe (AList Expression a))
  | StSave                a SrcSpan (Maybe (AList Expression a))
  | StDimension           a SrcSpan (AList Declarator a)
  | StAllocatable         a SrcSpan (AList Declarator a)
  | StPointer             a SrcSpan (AList Declarator a)
  | StTarget              a SrcSpan (AList Declarator a)
  | StData                a SrcSpan (AList DataGroup a)
  | StNamelist            a SrcSpan (AList Namelist a)
  | StParameter           a SrcSpan (AList Declarator a)
  | StExternal            a SrcSpan (AList Expression a)
  | StIntrinsic           a SrcSpan (AList Expression a)
  | StCommon              a SrcSpan (AList CommonGroup a)
  | StEquivalence         a SrcSpan (AList (AList Expression) a)
  | StFormat              a SrcSpan (AList FormatItem a)
  | StImplicit            a SrcSpan (Maybe (AList ImpList a))
  | StEntry               a SrcSpan (Expression a) (Maybe (AList Expression a)) (Maybe (Expression a))
  | StInclude             a SrcSpan (Expression a)
  | StDo                  a SrcSpan (Maybe String) (Maybe (Expression a)) (Maybe (DoSpecification a))
  | StDoWhile             a SrcSpan (Maybe String) (Maybe (Expression a)) (Expression a)
  | StEnddo               a SrcSpan (Maybe String)
  | StCycle               a SrcSpan (Maybe (Expression a))
  | StExit                a SrcSpan (Maybe (Expression a))
  | StIfLogical           a SrcSpan (Expression a) (Statement a) -- Statement should not further recurse
  | StIfArithmetic        a SrcSpan (Expression a) (Expression a) (Expression a) (Expression a)
  | StIfThen              a SrcSpan (Maybe String) (Expression a)
  | StElse                a SrcSpan (Maybe String)
  | StElsif               a SrcSpan (Maybe String) (Expression a)
  | StEndif               a SrcSpan (Maybe String)
  | StSelectCase          a SrcSpan (Maybe String) (Expression a)
  | StCase                a SrcSpan (Maybe String) (Maybe (AList Index a))
  | StEndcase             a SrcSpan (Maybe String)
  | StFunction            a SrcSpan (Expression a) (AList Expression a) (Expression a)
  | StExpressionAssign    a SrcSpan (Expression a) (Expression a)
  | StPointerAssign       a SrcSpan (Expression a) (Expression a)
  | StLabelAssign         a SrcSpan (Expression a) (Expression a)
  | StGotoUnconditional   a SrcSpan (Expression a)
  | StGotoAssigned        a SrcSpan (Expression a) (AList Expression a)
  | StGotoComputed        a SrcSpan (AList Expression a) (Expression a)
  | StCall                a SrcSpan (Expression a) (Maybe (AList Argument a))
  | StReturn              a SrcSpan (Maybe (Expression a))
  | StContinue            a SrcSpan
  | StStop                a SrcSpan (Maybe (Expression a))
  | StPause               a SrcSpan (Maybe (Expression a))
  | StRead                a SrcSpan (AList ControlPair a) (Maybe (AList Expression a))
  | StRead2               a SrcSpan (Expression a) (Maybe (AList Expression a))
  | StWrite               a SrcSpan (AList ControlPair a) (Maybe (AList Expression a))
  | StPrint               a SrcSpan (Expression a) (Maybe (AList Expression a))
  | StOpen                a SrcSpan (AList ControlPair a)
  | StClose               a SrcSpan (AList ControlPair a)
  | StInquire             a SrcSpan (AList ControlPair a)
  | StRewind              a SrcSpan (AList ControlPair a)
  | StRewind2             a SrcSpan (Expression a)
  | StBackspace           a SrcSpan (AList ControlPair a)
  | StBackspace2          a SrcSpan (Expression a)
  | StEndfile             a SrcSpan (AList ControlPair a)
  | StEndfile2            a SrcSpan (Expression a)
  | StAllocate            a SrcSpan (AList Expression a) (Maybe (ControlPair a))
  | StNullify             a SrcSpan (AList Expression a)
  | StDeallocate          a SrcSpan (AList Expression a) (Maybe (ControlPair a))
  | StWhere               a SrcSpan (Expression a) (Statement a)
  | StWhereConstruct      a SrcSpan (Expression a)
  | StElsewhere           a SrcSpan
  | StEndWhere            a SrcSpan
  | StUse                 a SrcSpan (Expression a) Only (Maybe (AList Use a))
  | StModuleProcedure     a SrcSpan (AList Expression a)
  | StType                a SrcSpan (Maybe (AList Attribute a)) String
  | StEndType             a SrcSpan (Maybe String)
  | StSequence            a SrcSpan
  | StForall              a SrcSpan (ForallHeader a) (Statement a)
  -- Following is a temporary solution to a complicated FORMAT statement
  -- parsing problem.
  | StFormatBogus         a SrcSpan String
  deriving (Eq, Show, Data, Typeable, Generic, Functor)

data ForallHeader a = ForallHeader
    -- List of tuples: index-name, start subscript, end subscript, optional stride
    [(Name, Expression a, Expression a, Maybe (Expression a))]
    -- An optional expression for scaling
    (Maybe (Expression a))
  deriving (Eq, Show, Data, Typeable, Generic, Functor)

data Only = Exclusive | Permissive
  deriving (Eq, Show, Data, Typeable, Generic)

data Use a =
    UseRename a SrcSpan (Expression a) (Expression a)
  | UseID a SrcSpan (Expression a)
  deriving (Eq, Show, Data, Typeable, Generic, Functor)

data Argument a = Argument a SrcSpan (Maybe String) (Expression a)
  deriving (Eq, Show, Data, Typeable, Generic, Functor)

data Attribute a =
    AttrParameter a SrcSpan
  | AttrPublic a SrcSpan
  | AttrPrivate a SrcSpan
  | AttrAllocatable a SrcSpan
  | AttrDimension a SrcSpan (AList DimensionDeclarator a)
  | AttrExternal a SrcSpan
  | AttrIntent a SrcSpan Intent
  | AttrIntrinsic a SrcSpan
  | AttrOptional a SrcSpan
  | AttrPointer a SrcSpan
  | AttrSave a SrcSpan
  | AttrTarget a SrcSpan
  deriving (Eq, Show, Data, Typeable, Generic, Functor)

data Intent = In | Out | InOut
  deriving (Eq, Show, Data, Typeable, Generic)

data ControlPair a = ControlPair a SrcSpan (Maybe String) (Expression a)
  deriving (Eq, Show, Data, Typeable, Generic, Functor)

data ImpList a = ImpList a SrcSpan (TypeSpec a) (AList ImpElement a)
  deriving (Eq, Show, Data, Typeable, Generic, Functor)

data ImpElement a =
    ImpCharacter    a SrcSpan String
  | ImpRange        a SrcSpan String String
  deriving (Eq, Show, Data, Typeable, Generic, Functor)

data CommonGroup a =
  CommonGroup a SrcSpan (Maybe (Expression a)) (AList Expression a)
  deriving (Eq, Show, Data, Typeable, Generic, Functor)

data Namelist a =
  Namelist a SrcSpan (Expression a) (AList Expression a)
  deriving (Eq, Show, Data, Typeable, Generic, Functor)

data DataGroup a =
  DataGroup a SrcSpan (AList Expression a) (AList Expression a)
  deriving (Eq, Show, Data, Typeable, Generic, Functor)

data FormatItem a =
    FIFormatList            a             SrcSpan   (Maybe String) (AList FormatItem a)
  | FIHollerith             a             SrcSpan   (Value a)
  | FIDelimiter             a             SrcSpan
--  descriptor type       | annotation  | span    | repeat          | descriptor  | width   | integer
  | FIFieldDescriptorDEFG   a             SrcSpan   (Maybe Integer)   Char          Integer   Integer
  | FIFieldDescriptorAIL    a             SrcSpan   (Maybe Integer)   Char          Integer
  | FIBlankDescriptor       a             SrcSpan   Integer
  | FIScaleFactor           a             SrcSpan   Integer
  deriving (Eq, Show, Data, Typeable, Generic, Functor)

data DoSpecification a =
  DoSpecification a SrcSpan (Statement a) (Expression a) (Maybe (Expression a))
  deriving (Eq, Show, Data, Typeable, Generic, Functor)

data Expression a =
    ExpValue         a SrcSpan (Value a)
  | ExpBinary        a SrcSpan BinaryOp (Expression a) (Expression a)
  | ExpUnary         a SrcSpan UnaryOp (Expression a)
  | ExpSubscript     a SrcSpan (Expression a) (AList Index a)
  | ExpDataRef       a SrcSpan (Expression a) (Expression a)
  | ExpFunctionCall  a SrcSpan (Expression a) (Maybe (AList Argument a))
  | ExpImpliedDo     a SrcSpan (AList Expression a) (DoSpecification a)
  | ExpInitialisation  a SrcSpan (AList Expression a)
  | ExpReturnSpec    a SrcSpan (Expression a)
  deriving (Eq, Show, Data, Typeable, Generic, Functor)

data Index a =
    IxSingle a SrcSpan (Maybe String) (Expression a)
  | IxRange a SrcSpan
            (Maybe (Expression a)) -- Lower index
            (Maybe (Expression a)) -- Upper index
            (Maybe (Expression a)) -- Stride
  deriving (Eq, Show, Data, Typeable, Generic, Functor)

-- All recursive Values
data Value a =
    ValInteger           String
  | ValReal              String
  | ValComplex           (Expression a) (Expression a)
  | ValString            String
  | ValHollerith         String
  | ValVariable          Name
  | ValIntrinsic         Name
  | ValLogical           String
  | ValOperator          String
  | ValAssignment
  | ValType              String
  | ValStar
  deriving (Eq, Show, Data, Typeable, Generic, Functor)

data Declarator a =
    DeclVariable a SrcSpan
                 (Expression a) -- Variable
                 (Maybe (Expression a)) -- Length (character)
                 (Maybe (Expression a)) -- Initial value
  | DeclArray a SrcSpan
              (Expression a) -- Array
              (AList DimensionDeclarator a) -- Dimensions
              (Maybe (Expression a)) -- Length (character)
              (Maybe (Expression a)) -- Initial value
  deriving (Eq, Show, Data, Typeable, Generic, Functor)

setInitialisation :: Declarator a -> Expression a -> Declarator a
setInitialisation (DeclVariable a s v l Nothing) init =
  DeclVariable a (getTransSpan s init) v l (Just init)
setInitialisation (DeclArray a s v ds l Nothing) init =
  DeclArray a (getTransSpan s init) v ds l (Just init)

data DimensionDeclarator a =
  DimensionDeclarator a SrcSpan (Maybe (Expression a)) (Maybe (Expression a))
  deriving (Eq, Show, Data, Typeable, Generic, Functor)

data UnaryOp =
    Plus
  | Minus
  | Not
  | UnCustom String
  deriving (Eq, Show, Data, Typeable, Generic)

data BinaryOp =
    Addition
  | Subtraction
  | Multiplication
  | Division
  | Exponentiation
  | Concatenation
  | GT
  | GTE
  | LT
  | LTE
  | EQ
  | NE
  | Or
  | And
  | Equivalent
  | NotEquivalent
  | BinCustom String
  deriving (Eq, Show, Data, Typeable, Generic)

-- Retrieving SrcSpan and Annotation from nodes
class Annotated f where
  getAnnotation :: f a -> a
  setAnnotation :: a -> f a -> f a
  modifyAnnotation :: (a -> a) -> f a -> f a
  default getAnnotation :: (FirstParameter (f a) a) => f a -> a
  getAnnotation = getFirstParameter

  default setAnnotation :: (FirstParameter (f a) a) => a -> f a -> f a
  setAnnotation = setFirstParameter

  modifyAnnotation f x = setAnnotation (f (getAnnotation x)) x

instance FirstParameter (AList t a) a
instance FirstParameter (ProgramUnit a) a
instance FirstParameter (Block a) a
instance FirstParameter (Statement a) a
instance FirstParameter (Argument a) a
instance FirstParameter (Use a) a
instance FirstParameter (TypeSpec a) a
instance FirstParameter (Selector a) a
instance FirstParameter (Attribute a) a
instance FirstParameter (ImpList a) a
instance FirstParameter (ImpElement a) a
instance FirstParameter (CommonGroup a) a
instance FirstParameter (DataGroup a) a
instance FirstParameter (Namelist a) a
instance FirstParameter (FormatItem a) a
instance FirstParameter (Expression a) a
instance FirstParameter (Index a) a
instance FirstParameter (DoSpecification a) a
instance FirstParameter (Declarator a) a
instance FirstParameter (DimensionDeclarator a) a
instance FirstParameter (ControlPair a) a

instance SecondParameter (AList t a) SrcSpan
instance SecondParameter (ProgramUnit a) SrcSpan
instance SecondParameter (Block a) SrcSpan
instance SecondParameter (Statement a) SrcSpan
instance SecondParameter (Argument a) SrcSpan
instance SecondParameter (Use a) SrcSpan
instance SecondParameter (TypeSpec a) SrcSpan
instance SecondParameter (Selector a) SrcSpan
instance SecondParameter (Attribute a) SrcSpan
instance SecondParameter (ImpList a) SrcSpan
instance SecondParameter (ImpElement a) SrcSpan
instance SecondParameter (CommonGroup a) SrcSpan
instance SecondParameter (DataGroup a) SrcSpan
instance SecondParameter (Namelist a) SrcSpan
instance SecondParameter (FormatItem a) SrcSpan
instance SecondParameter (Expression a) SrcSpan
instance SecondParameter (Index a) SrcSpan
instance SecondParameter (DoSpecification a) SrcSpan
instance SecondParameter (Declarator a) SrcSpan
instance SecondParameter (DimensionDeclarator a) SrcSpan
instance SecondParameter (ControlPair a) SrcSpan

instance Annotated (AList t)
instance Annotated ProgramUnit
instance Annotated Block
instance Annotated Statement
instance Annotated Argument
instance Annotated Use
instance Annotated TypeSpec
instance Annotated Selector
instance Annotated Attribute
instance Annotated ImpList
instance Annotated ImpElement
instance Annotated CommonGroup
instance Annotated DataGroup
instance Annotated Namelist
instance Annotated FormatItem
instance Annotated Expression
instance Annotated Index
instance Annotated DoSpecification
instance Annotated Declarator
instance Annotated DimensionDeclarator
instance Annotated ControlPair

instance Spanned (AList t a)
instance Spanned (ProgramUnit a)
instance Spanned (Statement a)
instance Spanned (Argument a)
instance Spanned (Use a)
instance Spanned (Attribute a)
instance Spanned (TypeSpec a)
instance Spanned (Selector a)
instance Spanned (ImpList a)
instance Spanned (ImpElement a)
instance Spanned (Block a)
instance Spanned (CommonGroup a)
instance Spanned (DataGroup a)
instance Spanned (Namelist a)
instance Spanned (FormatItem a)
instance Spanned (Expression a)
instance Spanned (Index a)
instance Spanned (DoSpecification a)
instance Spanned (Declarator a)
instance Spanned (DimensionDeclarator a)
instance Spanned (ControlPair a)

instance (Spanned a) => Spanned [a] where
  getSpan [] = error "Trying to find how long an empty list spans for."
  getSpan [x]   = getSpan x
  getSpan (x:xs) = getTransSpan x (last xs)
  setSpan _ _ = error "Cannot set span to an array"

instance (Spanned a, Spanned b) => Spanned (a, Maybe b) where
  getSpan (x, Just y) = getTransSpan x y
  getSpan (x,_) = getSpan x
  setSpan _ = undefined

instance (Spanned a, Spanned b) => Spanned (Maybe a, b) where
  getSpan (Just x,y) = getTransSpan x y
  getSpan (_,y) = getSpan y
  setSpan _ = undefined

instance {-# OVERLAPPABLE #-} (Spanned a, Spanned b) => Spanned (a, b) where
  getSpan (x,y) = getTransSpan x y
  setSpan _ = undefined

instance {-# OVERLAPPING #-}(Spanned a, Spanned b, Spanned c) => Spanned (Maybe a, Maybe b, Maybe c) where
  getSpan (Just x,_,Just z) = getTransSpan x z
  getSpan (Just x,Just y,Nothing) = getTransSpan x y
  getSpan (Nothing,Just y,Just z) = getTransSpan y z
  getSpan (Just x,Nothing,Nothing) = getSpan x
  getSpan (Nothing,Just y,Nothing) = getSpan y
  getSpan (Nothing,Nothing,Just z) = getSpan z
  getSpan (Nothing,Nothing,Nothing) = undefined
  setSpan _ = undefined

instance {-# OVERLAPPING #-}(Spanned a, Spanned b, Spanned c) => Spanned (a, Maybe b, Maybe c) where
  getSpan (x,_,Just z) = getTransSpan x z
  getSpan (x,Just y,Nothing) = getTransSpan x y
  getSpan (x,Nothing,Nothing) = getSpan x
  setSpan _ = undefined

instance {-# OVERLAPPING #-} (Spanned a, Spanned b, Spanned c) => Spanned (Maybe a, b, c) where
  getSpan (Just x,_,z) = getTransSpan x z
  getSpan (_,y,z) = getSpan (y,z)
  setSpan _ = undefined

instance {-# OVERLAPPABLE #-} (Spanned a, Spanned b, Spanned c) => Spanned (a, b, c) where
  getSpan (x,y,z) = getTransSpan x z
  setSpan _ = undefined

class (Spanned a, Spanned b) => SpannedPair a b where
  getTransSpan :: a -> b -> SrcSpan

instance {-# OVERLAPPABLE #-} (Spanned a, Spanned b) => SpannedPair a b where
  getTransSpan x y = SrcSpan l1 l2'
    where SrcSpan l1 _ = getSpan x
          SrcSpan _ l2' = getSpan y

instance {-# OVERLAPS #-} (Spanned a, Spanned b) => SpannedPair a [b] where
  getTransSpan x [] = getSpan x
  getTransSpan x y = SrcSpan l1 l2'
    where SrcSpan l1 _ = getSpan x
          SrcSpan _ l2' = getSpan y

instance {-# OVERLAPS #-} (Spanned a, Spanned b) => SpannedPair a [[b]] where
  getTransSpan x [] = getSpan x
  getTransSpan x y | all null y = getSpan x
  getTransSpan x y | any null y = getTransSpan x (filter (not . null) y)
  getTransSpan x y = SrcSpan l1 l2'
    where SrcSpan l1 _ = getSpan x
          SrcSpan _ l2' = getSpan y

class Labeled f where
  getLabel :: f a -> Maybe (Expression a)
  getLastLabel :: f a -> Maybe (Expression a)
  setLabel :: f a -> Expression a -> f a

instance Labeled Block where
  getLabel (BlStatement _ _ l _) = l
  getLabel (BlIf _ _ l _ _ _ _) = l
  getLabel (BlCase _ _ l _ _ _ _ _) = l
  getLabel (BlDo _ _ l _ _ _ _ _) = l
  getLabel (BlDoWhile _ _ l _ _ _ _) = l
  getLabel _ = Nothing

  getLastLabel b@BlStatement{} = getLabel b
  getLastLabel (BlIf _ _ _ _ _ _ l) = l
  getLastLabel (BlCase _ _ _ _ _ _ _ l) = l
  getLastLabel (BlDo _ _ _ _ _ _ _ l) = l
  getLastLabel (BlDoWhile _ _ _ _ _ _ l) = l
  getLastLabel _ = Nothing

  setLabel (BlStatement a s _ st) l = BlStatement a s (Just l) st
  setLabel (BlIf a s _ mn conds bs el) l = BlIf a s (Just l) mn conds bs el
  setLabel (BlDo a s _ mn tl spec bs el) l = BlDo a s (Just l) mn tl spec bs el
  setLabel (BlDoWhile a s _ n spec bs el) l = BlDoWhile a s (Just l) n spec bs el
  setLabel b l = b

class Conditioned f where
  getCondition :: f a -> Maybe (Expression a)

instance Conditioned Block where
  getCondition (BlStatement _ _ _ s) = getCondition s
  getCondition _ = Nothing

instance Conditioned Statement where
  getCondition (StIfThen _ _ _ c) = Just c
  getCondition (StElsif _ _ _ c) = Just c
  getCondition _ = Nothing

data ProgramUnitName =
    Named String
  | NamelessBlockData
  | NamelessComment
  | NamelessMain
  deriving (Ord, Eq, Show, Data, Typeable, Generic)

instance Binary ProgramUnitName

class Named a where
  getName :: a -> ProgramUnitName
  setName :: ProgramUnitName -> a -> a

instance Named (ProgramUnit a) where
  getName (PUMain _ _ Nothing _ _) = NamelessMain
  getName (PUMain _ _ (Just n) _ _) = Named n
  getName (PUModule _ _ n _ _) = Named n
  getName (PUSubroutine _ _ _ n _ _ _) = Named n
  getName (PUFunction _ _ _ _ n _ _ _ _) = Named n
  getName (PUBlockData _ _ Nothing _)  = NamelessBlockData
  getName (PUBlockData _ _ (Just n) _) = Named n
  getName (PUComment {}) = NamelessComment
  setName (Named n) (PUMain a s _ b pus) = PUMain a s (Just n) b pus
  setName _         (PUMain a s _ b pus) = PUMain a s Nothing b pus
  setName (Named n) (PUModule a s _ b pus) = PUModule a s n b pus
  setName (Named n) (PUSubroutine a s r _ p b subs) =
    PUSubroutine a s r n p b subs
  setName (Named n) (PUFunction   a s r rec _ p res b subs) =
    PUFunction a s r rec n p res b subs
  setName (Named n) (PUBlockData  a s _ b) = PUBlockData  a s (Just n) b
  setName _         (PUBlockData  a s _ b) = PUBlockData  a s Nothing b

instance Out FortranVersion
instance Out MetaInfo
instance Out a => Out (ProgramFile a)
instance Out a => Out (ProgramUnit a)
instance (Out a, Out (t a)) => Out (AList t a)
instance Out a => Out (Statement a)
instance Out Only
instance Out a => Out (Argument a)
instance Out a => Out (Use a)
instance Out a => Out (Attribute a)
instance Out Intent
instance Out a => Out (ImpList a)
instance Out a => Out (ImpElement a)
instance Out a => Out (Comment a)
instance Out a => Out (Block a)
instance Out a => Out (CommonGroup a)
instance Out a => Out (DataGroup a)
instance Out a => Out (Namelist a)
instance Out a => Out (FormatItem a)
instance Out a => Out (Expression a)
instance Out a => Out (Index a)
instance Out a => Out (DoSpecification a)
instance Out a => Out (Value a)
instance Out a => Out (TypeSpec a)
instance Out a => Out (Selector a)
instance Out BaseType
instance Out a => Out (Declarator a)
instance Out a => Out (DimensionDeclarator a)
instance Out a => Out (ControlPair a)
instance Out UnaryOp
instance Out BinaryOp
instance Out a => Out (ForallHeader a)

-- Classifiers on statement and blocks ASTs

nonExecutableStatement :: FortranVersion -> Statement a -> Bool
nonExecutableStatement v s = case s of
    StIntent {}      -> True
    StOptional {}    -> True
    StPublic {}      -> True
    StPrivate {}     -> True
    StSave {}        -> True
    StDimension {}   -> True
    StAllocatable {} -> True
    StPointer {}     -> True
    StTarget {}      -> True
    StData {}        -> True
    StParameter {}   -> True
    StImplicit {}    -> True
    StNamelist {}    -> True
    StEquivalence {} -> True
    StCommon {}      -> True
    StExternal {}    -> True
    StIntrinsic {}   -> True
    StUse {}         -> True
    StEntry {}       -> True
    StSequence {}    -> True
    StType {}        -> True
    StEndType {}     -> True
    StFormat {}      -> True
    StFormatBogus {} -> True
    StInclude {}     -> True
    StDeclaration {} -> True
    _                -> False

executableStatement :: FortranVersion -> Statement a -> Bool
-- Some statements are both executable and non-executable in Fortran 90 upwards
executableStatement v StFormat{} | v >= Fortran90 = True
executableStatement v StEntry{}  | v >= Fortran90 = True
executableStatement v StData{}   | v >= Fortran90 = True
executableStatement v s = not $ nonExecutableStatement v s

executableStatementBlock :: FortranVersion -> Block a -> Bool
executableStatementBlock v (BlStatement _ _ _ s) = executableStatement v s
executableStatementBlock v _ = False

nonExecutableStatementBlock :: FortranVersion -> Block a -> Bool
nonExecutableStatementBlock v (BlStatement _ _ _ s) = nonExecutableStatement v s
nonExecutableStatementBlock v BlInterface{} = True
nonExecutableStatementBlock v _ = False