/* Trigo Game Notation Parser
 * Similar as PGN (Portable Game Notation) format
 */

/* ========== Lexical Grammar ========== */
%lex

%%

\s+						/* skip whitespace */
\n						/* skip newlines */
";"[^\n]*				/* skip line comments */
"{"[^}]*"}"				/* skip block comments */

/* Brackets */
"["						return '['
"]"						return ']'

/* String literals */
\"([^\\\"]|\\.)*\"		return 'STRING'

/* Tag names - Common PGN tags */
"Event"					return 'TAG_EVENT'
"Site"					return 'TAG_SITE'
"Date"					return 'TAG_DATE'
"Round"					return 'TAG_ROUND'
"Black"					return 'TAG_BLACK'
"White"					return 'TAG_WHITE'
"Result"				return 'TAG_RESULT'

/* Trigo-specific tags */
"Board"					return 'TAG_BOARD'
"Handicap"				return 'TAG_HANDICAP'
"Rules"					return 'TAG_RULES'
"TimeControl"			return 'TAG_TIMECONTROL'
"Annotator"				return 'TAG_ANNOTATOR'
"Application"			return 'TAG_APPLICATION'

/* Game result symbols */
"B+"					return 'RESULT_BLACK'
"W+"					return 'RESULT_WHITE'
"="						return '='	/* draw */
"*"						return '*'	/* unknown */

/* Move notation placeholders - will be expanded later */
[1-9][0-9]*				return 'NUMBER'
"."						return 'DOT'
"Pass"					return 'PASS'
"Resign"				return 'RESIGN'
"points"				return 'POINTS'
"stones"				return 'STONES'

[x](?=[1-9])			return 'TIMES'

/* Coordinates for moves - will be refined */
[a-z0]+					return 'COORDINATE'

/* Generic tag name for extensibility */
[A-Z][A-Za-z0-9_]*		return 'TAG_NAME'

/* End of file */
<<EOF>>					return 'EOF'

/* Catch-all for unexpected characters */
.						return 'INVALID'

/lex

/* ========== Grammar Rules ========== */

%%

game
	: tag_section move_section EOF
		{
			return {
				tags: $1,
				moves: $2,
				success: true
			};
		}
	| tag_section EOF
		{
			return {
				tags: $1,
				moves: null,
				success: true
			};
		}
	| move_section EOF
		{
			return {
				tags: {},
				moves: $1,
				success: true
			};
		}
	| EOF
		{
			return {
				tags: {},
				moves: null,
				success: true
			};
		}
	;

/* ========== Tag Section (Metadata) ========== */

tag_section
	: tag_pair								-> $1
	| tag_section tag_pair					-> Object.assign({}, $1, $2)
	;

tag_pair
	: "[" tag_name STRING "]"
		{
			const tagName = $2;
			const tagValue = $3.slice(1, -1); // Remove quotes
			$$ = { [tagName]: tagValue };
		}
	| "[" TAG_RESULT game_result "]"		-> $3
	| "[" TAG_BOARD board_shape "]"			-> ({[$2]: $3})
	;

tag_name
	: TAG_EVENT
	| TAG_SITE
	| TAG_DATE
	| TAG_ROUND
	| TAG_BLACK
	| TAG_WHITE
	| TAG_HANDICAP
	| TAG_RULES
	| TAG_TIMECONTROL
	| TAG_ANNOTATOR
	| TAG_APPLICATION
	| TAG_NAME									{ $$ = yytext; }
	;

/* ========== Movetext Section (Game Body) ========== */
/* PLACEHOLDER: Will be implemented in future iterations */

move_section
	: move_sequence
	//| move_sequence game_termination
	;

move_sequence
	: move_sequence_intact						-> $1
	| move_sequence_truncated					-> $1
	;

move_sequence_intact
	: /* empty */								-> []
	| move_sequence_intact move_round			-> $1.concat([$2])
	;

move_sequence_truncated
	: move_sequence_intact move_round_half		-> $1.concat([$2])
	;

move_round
	: number DOT move_action move_action		-> ({ round: $1, action_black: $3, action_white: $4 })
	;

move_round_half
	: number DOT move_action					-> ({ round: $1, action_black: $3 })
	;

move_action
	: PASS										-> ({ type: 'pass' })
	| RESIGN									-> ({ type: 'resign' })
	| COORDINATE
		{
			// Placeholder: Parse coordinate notation
			$$ = {
				type: 'move',
				position: yytext
			};
		}
	;

game_result
	: win										-> ({Result: $1})
	| win conquer								-> ({Result: $1, Conquer: $2})
	| "="										-> ({Result: "draw"})
	| "*"										-> ({Result: "unknown"})
	;

win
	: RESULT_BLACK								-> "black win"
	| RESULT_WHITE								-> "white win"
	;

conquer
	: number conquer_unit						-> ({n: $1, unit: $2})
	;

conquer_unit
	: POINTS
	| STONES
	;

board_shape
	: number									-> [$1]
	| board_shape TIMES number					-> $1.concat($3)
	;

number
	: NUMBER									-> parseInt($1)
	;

%%

/* ========== Additional JavaScript Code ========== */

// Parser configuration
parser.yy = {
	// Helper functions can be added here
	parseError: function(str, hash) {
		throw new Error('Parse error: ' + str);
	}
};