ast

type Document struct {
	Statements []*Statement
}

type Field struct {
	//Type  int // Fragment, InlineFragment, Field
	Alias sdl.Name_
	Name  sdl.Name_ // must have atleast a name - all else can be empty
	//
	SDLRootAST sdl.GQLTypeProvider // Parent type, populated during checkField. Could be sdl.Object_, sdl.Interface, sdl.Union_(??)
	SDLfld     *sdl.Field_         // matching field in sdl object. populated during checkField
	Path       string              // path to field in statement
	//
	sdl.Arguments_ // promoted from struct: "Arguments []*ArgumentT"   ArgumenT {Name_, value InputValue_}, InputValue_ { InputValueProvider, Loc}
	sdl.Directives_
	SelectionSet []SelectionSetProvider //a Field whose type is an object (within the parent type to which field belongs) will have associated fields. For scalars SS wll be nil
	//
	Resolver func(context.Context, sdl.InputValueProvider, sdl.ObjectVals) <-chan string
}

type FragmentDef interface {
	FragmentNode()
	GetSelectionSet() []SelectionSetProvider
	// parse
	AssignTypeCond(string, *sdl.Loc_, *[]error)
	//	Executable
	AssignTypeCondAST(*[]error, *pse.Cache_)
}

type FragmentSpread struct {
	sdl.Name_ // AST only contains reference to Fragment. At evaluation time it will be expanded to its enclosed fields.
	sdl.Directives_
	FragStmt *FragmentStmt // associated fragment statement

}

type FragmentStmt struct {
	//NodeDef // partially implements Node interface - concrete type must assign its own String method
	//
	Name sdl.Name_
	// on <type>
	TypeCond    sdl.Name_
	TypeCondAST sdl.GQLTypeProvider
	sdl.Directives_
	SelectionSet []SelectionSetProvider // inline fragments, fragment spreads, sdl field from sdl type TypeCond.
}

type GQLStmtProvider interface {
	//Node()
	StatementNode()
	//TypeSystemNode()
	SolicitDependents(unresolved sdl.UnresolvedMap)
	CheckIsInputType(err *[]error)
	CheckInputValueType(err *[]error)
	StmtName() StmtName_
	StmtType() string
	String() string
}

type HasSelectionSetProvider interface {
	AppendSelectionSet(ss SelectionSetProvider) // TODO - this method may not be appropriate for this interface.
}

type InlineFragment struct {
	//
	//Parent      HasSelectionSetProvider
	sdl.Name_                       // dummy name supplied to hold location info
	TypeCond    sdl.Name_           // supplied by typeCondition if specified, otherwise its the type of the parent object's selectionset.
	TypeCondAST sdl.GQLTypeProvider // populated during checkField??
	//
	sdl.Directives_
	SelectionSet []SelectionSetProvider // { only fields and ... fragments. Nil when no TypeCond and adopts selectionSet of enclosing context.
}

type NameI interface {
	AssignName(name string, loc *sdl.Loc_, err *[]error)
	StmtType() string
}

type OperationDef interface {
	OperationNode()
}

type OperationStmt struct {
	//
	Type string // query, mutation, subscription	SelectionSet []SelectionSetProvider // { only fields and ... fragments
	//
	//NodeDef // partially implements Node interface - concrete type must assign its own String method
	//
	Name     sdl.Name_ // validated
	Variable []*VariableDef
	sdl.Directives_
	SelectionSet []SelectionSetProvider // { selection-List: fields,... }
}

type PkRow struct {
	PKey  string
	SortK string
}

type QLInfo struct {
	Dummy string
}

type Scalar_ string

type SelectionSetProvider interface {
	SelectionSetNode()
	SolicitDependents(unresolved sdl.UnresolvedMap) // TODO: don't like this here.
	//	Resolve()
	String() string
}

type Statement struct {
	Type    string // Operational | Fragment
	Name    string
	AST     GQLStmtProvider     // AST of operational stmt (query,mutation,sub) or Fragment stmt
	RootAST sdl.GQLTypeProvider // AST of type which represents the entry point to the graph, from schema(query:<entryType>,... Typically type Query.
}

type StmtName_ string

type TypeRow struct {
	PKey  string
	SortK string
	Stmt  string
	Type  string //TODO: is this necessary?  Reason: is saves having to parse stmt in order to determine its "type"
}

type UnresolvedMap sdl.UnresolvedMap //¬333map[Name_]*sdl.GQLtype

type VariableDef struct {
	sdl.Name_
	Type       *sdl.GQLtype
	DefaultVal *sdl.InputValue_
	Value      *sdl.InputValue_ // assigned by variable statment, defined outside of operationalStmt
}