%define api.pure full
%define api.prefix {kalmia}
%locations
%define parse.error verbose
%param { yyscan_t scanner }

%code top {
	#include <stdio.h>
	#include <stdlib.h>
	#include <stdarg.h>
}
%code requires {
	typedef void* yyscan_t;

	struct kalmia_t {
		void *current;
		int index;
	};

	struct ka_float_array_t {
		char *id;
		size_t count;
		double *buf;
	};
}
%parse-param { struct kalmia_t *result }
%code {
	int yylex(YYSTYPE *yylvalp, YYLTYPE *yyllocp, yyscan_t scanner);
	int yyerror(YYLTYPE *yyllocp, yyscan_t unused, struct kalmia_t *unused2, const char *msg);

	#define KAI_ABORT -1
	#define KAI_NOMEM -2
	
	#define KAI_ABORTF(...) \
	do { \
		kai_abortf_(&yylloc, __VA_ARGS__); \
		YYABORT; \
	} while(0)
	void kai_abortf_(YYLTYPE *yyllocp, const char *fmt, ...);

	/* float arrays */
	int kai_set_float_array_attrs(struct ka_float_array_t *a, char *id, char *count);

	#define KAI_WRAP(call) \
	do { \
		int err = call; \
		if (err == KAI_ABORT) { \
			KAI_ABORTF("call returned error: %s", #call); \
		} \
		else if (err == KAI_NOMEM) { \
			KAI_ABORTF("call ran out of memory: %s", #call); \
		} \
	} while(0)
}

%union {
	long lval;
	double dval;
	char *sval;
	char cval;
	struct ka_float_array_t float_array;
}

%token PROLOG
%token S_TAG_OPEN E_TAG_OPEN TAG_CLOSE EMPTY_TAG_CLOSE
%token <sval> NAME
%token <sval> ATTR
%token <sval> TEXT
%token <lval> INTEGER
%token <dval> DOUBLE
%token DATE;

%token <float_array> FLOAT_ARRAY
%type <float_array> float_array
%type <float_array> float_array_start
%type <float_array> float_array_attributes

%token ID_ATTR COUNT_ATTR
%type <sval> attr

%%


document: PROLOG element;

elements:
	element
	| elements element
	;

element:
	empty_tag
	| start_tag end_tag
	| start_tag content end_tag
	| float_array
	;

content:
	elements
	| integers
	| doubles
	| DATE
	;

empty_tag:
	S_TAG_OPEN NAME attributes EMPTY_TAG_CLOSE { printf("empty tag: %s\n", $2); }
	;

start_tag:
	S_TAG_OPEN NAME attributes TAG_CLOSE 
	{
		printf("enter tag: %s\n", $2);
		result->current = NULL;
	}
	;

end_tag:
	E_TAG_OPEN NAME TAG_CLOSE { printf("exit tag: %s\n", $2); }
	;

attributes:
	| attribute
	| attributes attribute
	;

attribute:
	ATTR attr { printf("attribute: %s=%s\n", $1, $2); }
	| ID_ATTR attr
	| COUNT_ATTR attr
	;



float_array:
	float_array_start doubles float_array_close
	{ 
		$$ = $1;
		printf("float_array[id='%s', count=%lu]{ ", $$.id, $$.count);
		for (size_t i=0; i<$$.count; i++) {
			printf("%f, ", $$.buf[i]);
		}
		printf("}\n");
	}
	;

float_array_start:
	S_TAG_OPEN FLOAT_ARRAY float_array_attributes TAG_CLOSE
	{ 
		$$ = $3; 
		result->current = $$.buf;
		result->index = 0;
	}
	;

float_array_close:
	E_TAG_OPEN FLOAT_ARRAY TAG_CLOSE
	;

float_array_attributes:
	COUNT_ATTR attr 
		{ KAI_WRAP(kai_set_float_array_attrs(&$$, NULL, $2)); }
	| COUNT_ATTR attr ID_ATTR attr
		{ KAI_WRAP(kai_set_float_array_attrs(&$$, $4, $2)); }
	| ID_ATTR attr COUNT_ATTR attr
		{ KAI_WRAP(kai_set_float_array_attrs(&$$, $2, $4)); }
	;

attr:
	'=' '"' TEXT '"' { $$ = $3; }
	;


integers:
	INTEGER { printf("%ld\n", $1); }
	| integers INTEGER { printf("%ld\n", $2); }
	;

doubles:
	DOUBLE 
	{ 
		if (result->current != NULL) {
			((double*) result->current)[result->index] = $1;
			result->index += 1; 
		}
	}
	| doubles DOUBLE
	{ 
		if (result->current != NULL) {
			((double*) result->current)[result->index] = $2;
			result->index += 1; 
		}
	}

	;


%%


int yyerror(
	YYLTYPE *yyllocp, 
	yyscan_t unused, 
	struct kalmia_t *unused2, 
	const char *msg)
{
	fprintf(
		stderr, "[%d:%d]: %s\n",
		yyllocp->first_line, yyllocp->first_column, msg
	);
	return 1;
}


void kai_abortf_(YYLTYPE *yyllocp, const char *fmt, ...)
{
	va_list args, args_len;
	va_start(args, fmt);
	va_copy(args_len, args);
	size_t len = vsnprintf(NULL, 0, fmt, args_len) + 1;
	va_end(args_len);

	char *buf = malloc(sizeof(char) * len);
	if (buf == NULL) {
		fprintf(stderr, "failed to allocate buffer for error message!\n");
		return;
	}
	vsnprintf(buf, len, fmt, args);
	va_end(args);

	yyerror(yyllocp, NULL, NULL, buf);
}


/* float arrays */
int kai_set_float_array_attrs(
	struct ka_float_array_t *a, char *id, char *count)
{
	a->id = id;
	char *end = NULL;
	a->count = strtoll(count, &end, 10);
	if (end == count) {
		return -1;
	}

	a->buf = malloc(sizeof(double) * a->count);
	if (a->buf == NULL) {
		return -2;
	}
	return 0;
}