module Simplify.AstHelpers exposing
    ( boolToString
    , declarationListBindings
    , emptyStringAsString
    , getBool
    , getBooleanPattern
    , getCollapsedCons
    , getListLiteral
    , getListSingleton
    , getListSingletonCall
    , getNotFunction
    , getOrder
    , getSpecificFunction
    , getSpecificFunctionCall
    , getSpecificReducedFunction
    , getSpecificReducedFunctionCall
    , getSpecificValueOrFunction
    , getTuple
    , getTypeExposeIncludingVariants
    , getUncomputedNumberValue
    , isBinaryOperation
    , isEmptyList
    , isIdentity
    , isListLiteral
    , isSpecificBool
    , isSpecificCall
    , isSpecificValueOrFunction
    , isTupleFirstAccess
    , isTupleSecondAccess
    , letDeclarationListBindings
    , moduleNameFromString
    , nameOfExpose
    , orderToString
    , patternBindings
    , patternListBindings
    , qualifiedToString
    , removeParens
    , removeParensFromPattern
    )

import Elm.Syntax.Declaration as Declaration exposing (Declaration)
import Elm.Syntax.Exposing as Exposing
import Elm.Syntax.Expression as Expression exposing (Expression)
import Elm.Syntax.ModuleName exposing (ModuleName)
import Elm.Syntax.Node as Node exposing (Node(..))
import Elm.Syntax.Pattern as Pattern exposing (Pattern)
import Elm.Syntax.Range exposing (Range)
import Review.ModuleNameLookupTable as ModuleNameLookupTable exposing (ModuleNameLookupTable)
import Set exposing (Set)
import Simplify.Infer as Infer
import Simplify.Normalize as Normalize


removeParens : Node Expression -> Node Expression
removeParens node =
    case Node.value node of
        Expression.ParenthesizedExpression expr ->
            removeParens expr

        _ ->
            node


removeParensFromPattern : Node Pattern -> Node Pattern
removeParensFromPattern node =
    case Node.value node of
        Pattern.ParenthesizedPattern pattern ->
            removeParensFromPattern pattern

        _ ->
            node


isSpecificValueOrFunction : ModuleName -> String -> ModuleNameLookupTable -> Node Expression -> Bool
isSpecificValueOrFunction moduleName fnName lookupTable node =
    case removeParens node of
        Node noneRange (Expression.FunctionOrValue _ foundFnName) ->
            (foundFnName == fnName)
                && (ModuleNameLookupTable.moduleNameAt lookupTable noneRange == Just moduleName)

        _ ->
            False


getSpecificValueOrFunction : ( ModuleName, String ) -> ModuleNameLookupTable -> Node Expression -> Maybe { fnRange : Range }
getSpecificValueOrFunction ( moduleName, fnName ) lookupTable node =
    case removeParens node of
        Node noneRange (Expression.FunctionOrValue _ foundFnName) ->
            if
                (foundFnName == fnName)
                    && (ModuleNameLookupTable.moduleNameAt lookupTable noneRange == Just moduleName)
            then
                Just { fnRange = noneRange }

            else
                Nothing

        _ ->
            Nothing


isSpecificCall : ModuleName -> String -> ModuleNameLookupTable -> Node Expression -> Bool
isSpecificCall moduleName fnName lookupTable node =
    case Node.value (removeParens node) of
        Expression.Application ((Node noneRange (Expression.FunctionOrValue _ foundFnName)) :: _ :: []) ->
            (foundFnName == fnName)
                && (ModuleNameLookupTable.moduleNameAt lookupTable noneRange == Just moduleName)

        _ ->
            False


getListSingleton : ModuleNameLookupTable -> Node Expression -> Maybe { element : Node Expression }
getListSingleton lookupTable baseNode =
    case Node.value (removeParens baseNode) of
        Expression.ListExpr [ element ] ->
            Just { element = element }

        Expression.ListExpr _ ->
            Nothing

        _ ->
            getListSingletonCall lookupTable baseNode


getListSingletonCall : ModuleNameLookupTable -> Node Expression -> Maybe { element : Node Expression }
getListSingletonCall lookupTable expressionNode =
    case getSpecificFunctionCall ( [ "List" ], "singleton" ) lookupTable expressionNode of
        Just singletonCall ->
            case singletonCall.argsAfterFirst of
                [] ->
                    Just { element = singletonCall.firstArg }

                _ :: _ ->
                    Nothing

        Nothing ->
            Nothing


getSpecificFunction : ( ModuleName, String ) -> ModuleNameLookupTable -> Node Expression -> Maybe Range
getSpecificFunction ( moduleName, name ) lookupTable baseNode =
    case removeParens baseNode of
        Node fnRange (Expression.FunctionOrValue _ foundName) ->
            if
                (foundName == name)
                    && (ModuleNameLookupTable.moduleNameAt lookupTable fnRange == Just moduleName)
            then
                Just fnRange

            else
                Nothing

        _ ->
            Nothing


getSpecificFunctionCall :
    ( ModuleName, String )
    -> ModuleNameLookupTable
    -> Node Expression
    ->
        Maybe
            { nodeRange : Range
            , fnRange : Range
            , firstArg : Node Expression
            , argsAfterFirst : List (Node Expression)
            }
getSpecificFunctionCall ( moduleName, name ) lookupTable baseNode =
    getFunctionCall baseNode
        |> Maybe.andThen
            (\call ->
                if
                    (call.fnName /= name)
                        || (ModuleNameLookupTable.moduleNameAt lookupTable call.fnRange /= Just moduleName)
                then
                    Nothing

                else
                    Just
                        { nodeRange = call.nodeRange
                        , fnRange = call.fnRange
                        , firstArg = call.firstArg
                        , argsAfterFirst = call.argsAfterFirst
                        }
            )


getFunctionCall :
    Node Expression
    ->
        Maybe
            { nodeRange : Range
            , fnName : String
            , fnRange : Range
            , firstArg : Node Expression
            , argsAfterFirst : List (Node Expression)
            }
getFunctionCall baseNode =
    case Node.value (removeParens baseNode) of
        Expression.Application ((Node fnRange (Expression.FunctionOrValue _ fnName)) :: firstArg :: argsAfterFirst) ->
            Just
                { nodeRange = Node.range baseNode
                , fnRange = fnRange
                , fnName = fnName
                , firstArg = firstArg
                , argsAfterFirst = argsAfterFirst
                }

        Expression.OperatorApplication "|>" _ firstArg fedFunction ->
            case fedFunction of
                Node fnRange (Expression.FunctionOrValue _ fnName) ->
                    Just
                        { nodeRange = Node.range baseNode
                        , fnRange = fnRange
                        , fnName = fnName
                        , firstArg = firstArg
                        , argsAfterFirst = []
                        }

                Node _ (Expression.Application ((Node fnRange (Expression.FunctionOrValue _ fnName)) :: argsAfterFirst)) ->
                    Just
                        { nodeRange = Node.range baseNode
                        , fnRange = fnRange
                        , fnName = fnName
                        , firstArg = firstArg
                        , argsAfterFirst = argsAfterFirst
                        }

                _ ->
                    Nothing

        Expression.OperatorApplication "<|" _ fedFunction firstArg ->
            case fedFunction of
                Node fnRange (Expression.FunctionOrValue _ fnName) ->
                    Just
                        { nodeRange = Node.range baseNode
                        , fnRange = fnRange
                        , fnName = fnName
                        , firstArg = firstArg
                        , argsAfterFirst = []
                        }

                Node _ (Expression.Application ((Node fnRange (Expression.FunctionOrValue _ fnName)) :: argsAfterFirst)) ->
                    Just
                        { nodeRange = Node.range baseNode
                        , fnRange = fnRange
                        , fnName = fnName
                        , firstArg = firstArg
                        , argsAfterFirst = argsAfterFirst
                        }

                _ ->
                    Nothing

        _ ->
            Nothing


getCollapsedValueOrFunction :
    Node Expression
    ->
        Maybe
            { nodeRange : Range
            , fnName : String
            , fnRange : Range
            , args : List (Node Expression)
            }
getCollapsedValueOrFunction baseNode =
    let
        step :
            { firstArg : Node Expression, argsAfterFirst : List (Node Expression), fed : Node Expression }
            -> Maybe { nodeRange : Range, fnRange : Range, fnName : String, args : List (Node Expression) }
        step layer =
            Maybe.map
                (\fed ->
                    { nodeRange = Node.range baseNode
                    , fnRange = fed.fnRange
                    , fnName = fed.fnName
                    , args = fed.args ++ (layer.firstArg :: layer.argsAfterFirst)
                    }
                )
                (getCollapsedValueOrFunction layer.fed)
    in
    case removeParens baseNode of
        Node fnRange (Expression.FunctionOrValue _ fnName) ->
            Just
                { nodeRange = Node.range baseNode
                , fnRange = fnRange
                , fnName = fnName
                , args = []
                }

        Node _ (Expression.Application (fed :: firstArg :: argsAfterFirst)) ->
            step
                { fed = fed
                , firstArg = firstArg
                , argsAfterFirst = argsAfterFirst
                }

        Node _ (Expression.OperatorApplication "|>" _ firstArg fed) ->
            step
                { fed = fed
                , firstArg = firstArg
                , argsAfterFirst = []
                }

        Node _ (Expression.OperatorApplication "<|" _ fed firstArg) ->
            step
                { fed = fed
                , firstArg = firstArg
                , argsAfterFirst = []
                }

        _ ->
            Nothing


getNotFunction : ModuleNameLookupTable -> Node Expression -> Maybe Range
getNotFunction lookupTable baseNode =
    getSpecificFunction ( [ "Basics" ], "not" ) lookupTable baseNode


isTupleFirstAccess : ModuleNameLookupTable -> Node Expression -> Bool
isTupleFirstAccess lookupTable expressionNode =
    case getSpecificReducedFunction ( [ "Tuple" ], "first" ) lookupTable expressionNode of
        Just _ ->
            True

        Nothing ->
            isTupleFirstPatternLambda expressionNode


isTupleSecondAccess : ModuleNameLookupTable -> Node Expression -> Bool
isTupleSecondAccess lookupTable expressionNode =
    case getSpecificReducedFunction ( [ "Tuple" ], "second" ) lookupTable expressionNode of
        Just _ ->
            True

        Nothing ->
            isTupleSecondPatternLambda expressionNode


isTupleFirstPatternLambda : Node Expression -> Bool
isTupleFirstPatternLambda expressionNode =
    case Node.value (removeParens expressionNode) of
        Expression.LambdaExpression lambda ->
            case lambda.args of
                [ Node _ (Pattern.TuplePattern [ Node _ (Pattern.VarPattern firstVariableName), _ ]) ] ->
                    case Node.value lambda.expression of
                        Expression.FunctionOrValue [] resultName ->
                            resultName == firstVariableName

                        _ ->
                            False

                _ ->
                    False

        _ ->
            False


isTupleSecondPatternLambda : Node Expression -> Bool
isTupleSecondPatternLambda expressionNode =
    case Node.value (removeParens expressionNode) of
        Expression.LambdaExpression lambda ->
            case lambda.args of
                [ Node _ (Pattern.TuplePattern [ _, Node _ (Pattern.VarPattern firstVariableName) ]) ] ->
                    case Node.value lambda.expression of
                        Expression.FunctionOrValue [] resultName ->
                            resultName == firstVariableName

                        _ ->
                            False

                _ ->
                    False

        _ ->
            False


getUncomputedNumberValue : Node Expression -> Maybe Float
getUncomputedNumberValue node =
    case Node.value (removeParens node) of
        Expression.Integer n ->
            Just (toFloat n)

        Expression.Hex n ->
            Just (toFloat n)

        Expression.Floatable n ->
            Just n

        Expression.Negation expr ->
            Maybe.map negate (getUncomputedNumberValue expr)

        _ ->
            Nothing


isIdentity : ModuleNameLookupTable -> Node Expression -> Bool
isIdentity lookupTable baseNode =
    let
        node : Node Expression
        node =
            removeParens baseNode
    in
    case Node.value node of
        Expression.FunctionOrValue _ "identity" ->
            ModuleNameLookupTable.moduleNameFor lookupTable node == Just [ "Basics" ]

        Expression.LambdaExpression { args, expression } ->
            case args of
                arg :: [] ->
                    case getVarPattern arg of
                        Just patternName ->
                            getExpressionName expression
                                == Just patternName

                        _ ->
                            False

                _ ->
                    False

        _ ->
            False


{-| Parses variables and lambdas that are reducible to a variable
-}
getSpecificReducedFunction : ( ModuleName, String ) -> ModuleNameLookupTable -> Node Expression -> Maybe { fnRange : Range }
getSpecificReducedFunction ( moduleName, name ) lookupTable expressionNode =
    Maybe.andThen
        (\reducedFunction ->
            if
                (reducedFunction.fnName /= name)
                    || (ModuleNameLookupTable.moduleNameAt lookupTable reducedFunction.fnRange /= Just moduleName)
            then
                Nothing

            else
                Just { fnRange = reducedFunction.fnRange }
        )
        (getReducedFunction expressionNode)


{-| Parses variables and lambdas that are reducible to a variable
-}
getReducedFunction : Node Expression -> Maybe { fnRange : Range, fnName : String }
getReducedFunction expressionNode =
    case removeParens expressionNode of
        Node fnRange (Expression.FunctionOrValue _ fnName) ->
            Just { fnRange = fnRange, fnName = fnName }

        _ ->
            Maybe.andThen
                (\reducedLambdaToCall ->
                    case ( reducedLambdaToCall.lambdaPatterns, reducedLambdaToCall.callArguments ) of
                        ( [], [] ) ->
                            Just { fnRange = reducedLambdaToCall.fnRange, fnName = reducedLambdaToCall.fnName }

                        ( _ :: _, [] ) ->
                            Nothing

                        ( [], _ :: _ ) ->
                            Nothing

                        ( _ :: _, _ :: _ ) ->
                            Nothing
                )
                (getReducedLambdaToCall expressionNode)


{-| Parses calls and lambdas that are reducible to a call
-}
getSpecificReducedFunctionCall :
    ( ModuleName, String )
    -> ModuleNameLookupTable
    -> Node Expression
    ->
        Maybe
            { nodeRange : Range
            , fnRange : Range
            , firstArg : Node Expression
            , argsAfterFirst : List (Node Expression)
            }
getSpecificReducedFunctionCall ( moduleName, name ) lookupTable expressionNode =
    case getSpecificFunctionCall ( moduleName, name ) lookupTable expressionNode of
        Just call ->
            Just call

        Nothing ->
            Maybe.andThen
                (\reducedLambdaToCall ->
                    case ( reducedLambdaToCall.lambdaPatterns, reducedLambdaToCall.callArguments ) of
                        ( [], [] ) ->
                            Nothing

                        ( _ :: _, [] ) ->
                            Nothing

                        ( _ :: _, _ :: _ ) ->
                            Nothing

                        ( [], firstArg :: argsAfterFirst ) ->
                            Just
                                { nodeRange = reducedLambdaToCall.nodeRange
                                , fnRange = reducedLambdaToCall.fnRange
                                , firstArg = firstArg
                                , argsAfterFirst = argsAfterFirst
                                }
                )
                (getSpecificReducedLambdaToCall ( moduleName, name ) lookupTable expressionNode)


getSpecificReducedLambdaToCall :
    ( ModuleName, String )
    -> ModuleNameLookupTable
    -> Node Expression
    ->
        Maybe
            { nodeRange : Range
            , fnRange : Range
            , callArguments : List (Node Expression)
            , lambdaPatterns : List (Node Pattern)
            }
getSpecificReducedLambdaToCall ( moduleName, name ) lookupTable expressionNode =
    getReducedLambdaToCall expressionNode
        |> Maybe.andThen
            (\reducedLambdaToCall ->
                if
                    (reducedLambdaToCall.fnName /= name)
                        || (ModuleNameLookupTable.moduleNameAt lookupTable reducedLambdaToCall.fnRange /= Just moduleName)
                then
                    Nothing

                else
                    Just
                        { nodeRange = reducedLambdaToCall.nodeRange
                        , fnRange = reducedLambdaToCall.fnRange
                        , callArguments = reducedLambdaToCall.callArguments
                        , lambdaPatterns = reducedLambdaToCall.lambdaPatterns
                        }
            )


getReducedLambdaToCall :
    Node Expression
    ->
        Maybe
            { nodeRange : Range
            , fnName : String
            , fnRange : Range
            , callArguments : List (Node Expression)
            , lambdaPatterns : List (Node Pattern)
            }
getReducedLambdaToCall expressionNode =
    -- maybe a version of this is better located in Normalize?
    case getCollapsedLambda expressionNode of
        Just lambda ->
            case getCollapsedValueOrFunction lambda.expression of
                Just call ->
                    let
                        ( reducedCallArguments, reducedLambdaPatterns ) =
                            drop2EndingsWhile
                                (\( argument, pattern ) ->
                                    case Node.value (removeParens argument) of
                                        Expression.FunctionOrValue [] argument0Name ->
                                            case getVarPattern pattern of
                                                Just pattern0Name ->
                                                    pattern0Name == argument0Name

                                                _ ->
                                                    False

                                        _ ->
                                            False
                                )
                                ( call.args
                                , lambda.patterns
                                )
                    in
                    Just
                        { nodeRange = Node.range expressionNode
                        , fnName = call.fnName
                        , fnRange = call.fnRange
                        , callArguments = reducedCallArguments
                        , lambdaPatterns = reducedLambdaPatterns
                        }

                Nothing ->
                    Nothing

        _ ->
            Nothing


{-| Remove elements at the end of both given lists, then repeat for the previous elements until a given test returns False
-}
drop2EndingsWhile : (( a, b ) -> Bool) -> ( List a, List b ) -> ( List a, List b )
drop2EndingsWhile shouldDrop ( aList, bList ) =
    let
        ( reducedArgumentsReverse, reducedPatternsReverse ) =
            drop2BeginningsWhile
                shouldDrop
                ( List.reverse aList
                , List.reverse bList
                )
    in
    ( List.reverse reducedArgumentsReverse, List.reverse reducedPatternsReverse )


drop2BeginningsWhile : (( a, b ) -> Bool) -> ( List a, List b ) -> ( List a, List b )
drop2BeginningsWhile shouldDrop listPair =
    case listPair of
        ( [], bList ) ->
            ( [], bList )

        ( aList, [] ) ->
            ( aList, [] )

        ( aHead :: aTail, bHead :: bTail ) ->
            if shouldDrop ( aHead, bHead ) then
                drop2BeginningsWhile shouldDrop ( aTail, bTail )

            else
                ( aHead :: aTail, bHead :: bTail )


getCollapsedLambda : Node Expression -> Maybe { patterns : List (Node Pattern), expression : Node Expression }
getCollapsedLambda expressionNode =
    case Node.value (removeParens expressionNode) of
        Expression.LambdaExpression lambda ->
            case getCollapsedLambda lambda.expression of
                Nothing ->
                    Just
                        { patterns = lambda.args
                        , expression = lambda.expression
                        }

                Just innerCollapsedLambda ->
                    Just
                        { patterns = lambda.args ++ innerCollapsedLambda.patterns
                        , expression = innerCollapsedLambda.expression
                        }

        _ ->
            Nothing


getVarPattern : Node Pattern -> Maybe String
getVarPattern node =
    case Node.value node of
        Pattern.VarPattern name ->
            Just name

        Pattern.ParenthesizedPattern pattern ->
            getVarPattern pattern

        _ ->
            Nothing


patternListBindings : List (Node Pattern) -> Set String
patternListBindings patterns =
    List.foldl
        (\(Node _ pattern) soFar -> Set.union soFar (patternBindings pattern))
        Set.empty
        patterns


{-| Recursively find all bindings in a pattern.
-}
patternBindings : Pattern -> Set String
patternBindings pattern =
    case pattern of
        Pattern.ListPattern patterns ->
            patternListBindings patterns

        Pattern.TuplePattern patterns ->
            patternListBindings patterns

        Pattern.RecordPattern patterns ->
            Set.fromList (List.map Node.value patterns)

        Pattern.NamedPattern _ patterns ->
            patternListBindings patterns

        Pattern.UnConsPattern (Node _ headPattern) (Node _ tailPattern) ->
            Set.union (patternBindings tailPattern) (patternBindings headPattern)

        Pattern.VarPattern name ->
            Set.singleton name

        Pattern.AsPattern (Node _ pattern_) (Node _ name) ->
            Set.insert name (patternBindings pattern_)

        Pattern.ParenthesizedPattern (Node _ inParens) ->
            patternBindings inParens

        Pattern.AllPattern ->
            Set.empty

        Pattern.UnitPattern ->
            Set.empty

        Pattern.CharPattern _ ->
            Set.empty

        Pattern.StringPattern _ ->
            Set.empty

        Pattern.IntPattern _ ->
            Set.empty

        Pattern.HexPattern _ ->
            Set.empty

        Pattern.FloatPattern _ ->
            Set.empty


declarationListBindings : List (Node Declaration) -> Set String
declarationListBindings declarationList =
    declarationList
        |> List.map (\(Node _ declaration) -> declarationBindings declaration)
        |> List.foldl (\bindings soFar -> Set.union soFar bindings) Set.empty


declarationBindings : Declaration -> Set String
declarationBindings declaration =
    case declaration of
        Declaration.CustomTypeDeclaration variantType ->
            variantType.constructors
                |> List.map (\(Node _ variant) -> Node.value variant.name)
                |> Set.fromList

        Declaration.FunctionDeclaration functionDeclaration ->
            Set.singleton
                (Node.value (Node.value functionDeclaration.declaration).name)

        _ ->
            Set.empty


letDeclarationBindings : Expression.LetDeclaration -> Set String
letDeclarationBindings letDeclaration =
    case letDeclaration of
        Expression.LetFunction fun ->
            Set.singleton
                (fun.declaration |> Node.value |> .name |> Node.value)

        Expression.LetDestructuring (Node _ pattern) _ ->
            patternBindings pattern


letDeclarationListBindings : List (Node Expression.LetDeclaration) -> Set String
letDeclarationListBindings letDeclarationList =
    letDeclarationList
        |> List.map
            (\(Node _ declaration) -> letDeclarationBindings declaration)
        |> List.foldl (\bindings soFar -> Set.union soFar bindings) Set.empty


getExpressionName : Node Expression -> Maybe String
getExpressionName node =
    case Node.value (removeParens node) of
        Expression.FunctionOrValue [] name ->
            Just name

        _ ->
            Nothing


isListLiteral : Node Expression -> Bool
isListLiteral node =
    case Node.value node of
        Expression.ListExpr _ ->
            True

        _ ->
            False


getListLiteral : Node Expression -> Maybe (List (Node Expression))
getListLiteral expressionNode =
    case Node.value expressionNode of
        Expression.ListExpr list ->
            Just list

        _ ->
            Nothing


getCollapsedCons : Node Expression -> Maybe { consed : List (Node Expression), tail : Node Expression }
getCollapsedCons expressionNode =
    case Node.value (removeParens expressionNode) of
        Expression.OperatorApplication "::" _ head tail ->
            let
                tailCollapsed : Maybe { consed : List (Node Expression), tail : Node Expression }
                tailCollapsed =
                    getCollapsedCons tail
            in
            case tailCollapsed of
                Nothing ->
                    Just { consed = [ head ], tail = tail }

                Just tailCollapsedList ->
                    Just { consed = head :: tailCollapsedList.consed, tail = tailCollapsedList.tail }

        _ ->
            Nothing


getBool : ModuleNameLookupTable -> Node Expression -> Maybe Bool
getBool lookupTable expressionNode =
    if isSpecificBool True lookupTable expressionNode then
        Just True

    else if isSpecificBool False lookupTable expressionNode then
        Just False

    else
        Nothing


isSpecificBool : Bool -> ModuleNameLookupTable -> Node Expression -> Bool
isSpecificBool specificBool lookupTable expressionNode =
    isSpecificValueOrFunction [ "Basics" ] (boolToString specificBool) lookupTable expressionNode


getTuple : Node Expression -> Maybe { range : Range, first : Node Expression, second : Node Expression }
getTuple expressionNode =
    case Node.value expressionNode of
        Expression.TupledExpression (first :: second :: []) ->
            Just { range = Node.range expressionNode, first = first, second = second }

        _ ->
            Nothing


getBooleanPattern : ModuleNameLookupTable -> Node Pattern -> Maybe Bool
getBooleanPattern lookupTable node =
    case Node.value node of
        Pattern.NamedPattern { name } _ ->
            case name of
                "True" ->
                    if ModuleNameLookupTable.moduleNameFor lookupTable node == Just [ "Basics" ] then
                        Just True

                    else
                        Nothing

                "False" ->
                    if ModuleNameLookupTable.moduleNameFor lookupTable node == Just [ "Basics" ] then
                        Just False

                    else
                        Nothing

                _ ->
                    Nothing

        Pattern.ParenthesizedPattern pattern ->
            getBooleanPattern lookupTable pattern

        _ ->
            Nothing


getOrder : ModuleNameLookupTable -> Node Expression -> Maybe Order
getOrder lookupTable expression =
    if isSpecificValueOrFunction [ "Basics" ] "LT" lookupTable expression then
        Just LT

    else if isSpecificValueOrFunction [ "Basics" ] "EQ" lookupTable expression then
        Just EQ

    else if isSpecificValueOrFunction [ "Basics" ] "GT" lookupTable expression then
        Just GT

    else
        Nothing


isEmptyList : Node Expression -> Bool
isEmptyList node =
    case Node.value (removeParens node) of
        Expression.ListExpr [] ->
            True

        _ ->
            False


isBinaryOperation : String -> Infer.Resources a -> Node Expression -> Bool
isBinaryOperation symbol checkInfo expression =
    case expression |> Normalize.normalize checkInfo |> Node.value of
        Expression.PrefixOperator operatorSymbol ->
            operatorSymbol == symbol

        Expression.LambdaExpression lambda ->
            case lambda.args of
                -- invalid syntax
                [] ->
                    False

                [ Node _ (Pattern.VarPattern element) ] ->
                    case Node.value lambda.expression of
                        Expression.Application [ Node _ (Expression.PrefixOperator operatorSymbol), Node _ (Expression.FunctionOrValue [] argument) ] ->
                            (operatorSymbol == symbol)
                                && (argument == element)

                        -- no simple application
                        _ ->
                            False

                [ Node _ (Pattern.VarPattern element), Node _ (Pattern.VarPattern soFar) ] ->
                    case Node.value lambda.expression of
                        Expression.Application [ Node _ (Expression.PrefixOperator operatorSymbol), Node _ (Expression.FunctionOrValue [] left), Node _ (Expression.FunctionOrValue [] right) ] ->
                            (operatorSymbol == symbol)
                                && ((left == element && right == soFar)
                                        || (left == soFar && right == element)
                                   )

                        Expression.OperatorApplication operatorSymbol _ (Node _ (Expression.FunctionOrValue [] left)) (Node _ (Expression.FunctionOrValue [] right)) ->
                            (operatorSymbol == symbol)
                                && ((left == element && right == soFar)
                                        || (left == soFar && right == element)
                                   )

                        _ ->
                            False

                -- too many/unsimplified patterns
                _ ->
                    False

        -- not a known simple operator function
        _ ->
            False


getTypeExposeIncludingVariants : Exposing.TopLevelExpose -> Maybe String
getTypeExposeIncludingVariants expose =
    case expose of
        Exposing.InfixExpose _ ->
            Nothing

        Exposing.FunctionExpose _ ->
            Nothing

        Exposing.TypeOrAliasExpose _ ->
            Nothing

        Exposing.TypeExpose variantType ->
            case variantType.open of
                Nothing ->
                    Nothing

                Just _ ->
                    Just variantType.name


nameOfExpose : Exposing.TopLevelExpose -> String
nameOfExpose topLevelExpose =
    case topLevelExpose of
        Exposing.FunctionExpose name ->
            name

        Exposing.TypeOrAliasExpose name ->
            name

        Exposing.InfixExpose name ->
            name

        Exposing.TypeExpose { name } ->
            name



-- STRING


emptyStringAsString : String
emptyStringAsString =
    "\"\""


boolToString : Bool -> String
boolToString bool =
    if bool then
        "True"

    else
        "False"


orderToString : Order -> String
orderToString order =
    case order of
        LT ->
            "LT"

        EQ ->
            "EQ"

        GT ->
            "GT"


{-| Put a `ModuleName` and thing name together as a string.
If desired, call in combination with `qualify`
-}
qualifiedToString : ( ModuleName, String ) -> String
qualifiedToString ( moduleName, name ) =
    if List.isEmpty moduleName then
        name

    else
        moduleNameToString moduleName ++ "." ++ name


moduleNameToString : ModuleName -> String
moduleNameToString moduleName =
    String.join "." moduleName


moduleNameFromString : String -> ModuleName
moduleNameFromString string =
    String.split "." string