grammar InkBlotAntlrGrammar;

import InkBlotAntlrLexer;

/*
 * STORY
 */

story: topLevelStatements ;

/*
 * STATEMENTS FOR THE VARIOUS LEVELS
 */

topLevelStatements:
    topLevelStatement (NL+ topLevelStatement)* NL*
    ;

topLevelStatement:
    multiDivert
    ;

//topLevelStatement:
//    multiDivert
//    | contentText
//    ;
//
// knotLevelStatements:
//    (contentText
//    | multiDivert
//    )+
//    ;
//
// stitchLevelStatements:
//    (contentText
//    | multiDivert
//    )+
//    ;
//
// innerBlockLevelStatements:
//    (contentText
//    | multiDivert
//    )+
//    ;
//
///*
// * STATEMENTS
// */
//
//contentText: (CONTENT_TEXT_NO_ESCAPE_NO_IDENT_SIMPLE | IDENTIFIER | WS | SEQUENCE_TYPE_SYMBOL_ANNOTATION | '&' | '$' | '!')+ ;
//
//mixedTextAndLogic:
//    // TODO: ~ is not allowed as first symbol of this (see InkParser_Content => MixedTextAndLog), let's implement it in the C# side?
//    // like in innerInlineSequenceObjects, a bit of a chaos to avoid having completely empty entries
//    contentText? (inlineLogicOrGlueOrTagStart? contentText | inlineLogicOrGlueOrTagStart contentText?)+
//    // TODO: this is valid only when not parsing a choice, see above for the code where this logic is implemented
//    multiDivert
//    // TODO: management of tag ftw O_O
//    ;
//
//inlineLogicOrGlueOrTagStart:
//    inlineLogic
//    // TODO: glue, tag start
//    ;
//
//inlineLogic:
//    INLINE_LOGIC_START
//    WS?
//    innerLogic
//    // TODO: += and -= are disabled here (don't know why, maybe because they're statements?)
//    WS?
//    INLINE_LOGIC_END
//    // TODO: tags ftw
//    ;
//    
//innerLogic:
//    WS?
//    sequenceTypeAnnotation innerSequenceObjects
//    // TODO: the rest of InkParser_Logic => InnerLogic
//    ;
//
multiDivert:
    WS?
    multiDivert_withoutWS
    ;

multiDivert_withoutWS:
	THREAD_ARROW divertIdentifierWithArguments 	# MultiDivertThread
	// here be dragons: trying to express the various "Possible patterns" of InkParser_Divert => MultiDivert
	// syntax in the original ink parser is overly concessive: https://discord.com/channels/329929050866843648/329929390358265857/1342130940981284945
	| (DIVERT_ARROW divertIdentifierWithArguments)* multiDivertArrows_tail # MultiDivertArrows
	// TODO: a single DIVERT_ARROW above is only valid in default choices ( https://github.com/inkle/ink/blob/master/Documentation/WritingWithInk.md#fallback-choices )
	// TODO: tags ftw
    ;

multiDivertArrows_tail:
	DIVERT_ARROW # MultiDivertArrows_tailDefaultChoice
	| DIVERT_ARROW divertIdentifierWithArguments # MultiDivertArrows_tailDivert
	| TUNNEL_ARROW divertIdentifierWithArguments # MultiDivertArrows_tailTunnelWithReplacement
	| TUNNEL_ARROW # MultiDivertArrows_tailTunnel
	;

divertIdentifierWithArguments:
    divertIdentifierWithArguments_name
    WS?
    divertIdentifierWithArguments_arguments?
    WS?
    ;

divertIdentifierWithArguments_name:
	WS? identifier WS? ('.' WS? identifier WS? )*
	;

divertIdentifierWithArguments_arguments:
    '('
    expression (',' WS? expression)*
    ')'
    ;

identifier:
    // TODO: reject numbers-only identifier - see InkParser_Logic => Identifier
    IDENTIFIER
    ;

expression:
    // TODO: temporary stuff here
    IDENTIFIER
    ;

//// all possible symbols or word(s) for sequencing
//sequenceTypeAnnotation:
//    op=SEQUENCE_TYPE_SYMBOL_ANNOTATION
//    | 'once' WS? ':'
//    | 'cycle' WS? ':'
//    | 'shuffle' WS? ':'
//    | 'stopping' WS? ':'
//    | 'shuffle' WS 'once' WS? ':'
//    | 'shuffle' WS 'stopping' WS? ':'
//    ;
//
///* a list of sequence objects, either compressed in a single line (e.g.: {a|b|c}) or expanded in multiple lines (e.g.:
//{\n- a\n- b\n- c}
//*/
//innerSequenceObjects:
//    NL innerMultilineSequenceObjects
//    | innerInlineSequenceObjects
//    ;
//
//innerMultilineSequenceObjects:
//    singleMultilineSequenceElement+
//    ;
//
//singleMultilineSequenceElement:
//    WS?
//    /* TODO: how to express this? and why is it here? InkParser_Sequences => SingleMultilineSequenceElement
//            if (ParseString ("->") != null)
//                return null;
//    */
//    '-'
//    WS?
//    (
//        innerBlockLevelStatements
//        | MULTILINE_WS
//    )
//    ;
//
//innerInlineSequenceObjects:
//    // it's a bit chaotic, in order to allow for empty mixedTextAndLogic, but always require at least one entry
//    (mixedTextAndLogic ('|' mixedTextAndLogic?)*)
//    | ('|' mixedTextAndLogic?)+
//    ;