#include "lexer.h"

struct TMPL_token*           TMPL_alloc_token(void);
void                         TMPL_free_token(struct TMPL_token* token);
enum TMPL_tagtype            starts_with_token(const char* str, size_t strlen);
size_t                       tagtype_len(enum TMPL_tagtype t);
struct TMPL_token*           scan_text(
                                       const char* start,
                                       size_t strlen,
                                       size_t* consumed
                                      );
struct TMPL_token*           scan_tag(
                                      const char* start,
                                      size_t strlen,
                                      size_t* consumed
                                     );
void                         print_tokens(struct TMPL_token* head);


/*Allocates a token*/
struct TMPL_token*
TMPL_alloc_token(){
	struct TMPL_token* ret = (struct TMPL_token*)malloc(sizeof(struct TMPL_token));
	ret->next = NULL;
	return ret;
}

/*Frees an allocated token*/
void
TMPL_free_token(struct TMPL_token* token){
	struct TMPL_token* cursor = token;
	while(cursor != NULL){
		struct TMPL_token* this = cursor;
		cursor = cursor->next;
		free(this);
	}
}

/*Check if it starts with the names of any of our tokens*/
enum TMPL_tagtype
starts_with_token(const char* str, size_t strlen){
	/*Make sure we get TMPL_ first*/
	if(strlen < 5){
		return tag_null;
	}
	if(*str != 'T'
	|| *(str + 1) != 'M'
	|| *(str + 2) != 'P'
	|| *(str + 3) != 'L'
	|| *(str + 4) != '_'){
		return tag_null;
	}
	if(strlen > TAG_VAR_LENGTH
	&& *(str + 5) == 'V'
	&& *(str + 6) == 'A'
	&& *(str + 7) == 'R'
	&& *(str + 8) == ' '){
		return tag_var;
	}else if(strlen > TAG_IF_LENGTH
	&& *(str + 5) == 'I'
	&& *(str + 6) == 'F'
	&& *(str + 7) == ' '){
		return tag_if;
	}else if(strlen > TAG_END_LENGTH
	&& *(str + 5) == 'E'
	&& *(str + 6) == 'N'
	&& *(str + 7) == 'D'){
		return tag_end;
	}else if(strlen > TAG_ELSE_LENGTH
	&& *(str + 5) == 'E'/*Check for both else and elseif*/
	&& *(str + 6) == 'L'
	&& *(str + 7) == 'S'
	&& *(str + 8) == 'E'){
		if(*(str + 9) != 'I'){
			return tag_else;
		}else if(strlen > TAG_ELSEIF_LENGTH
		&& *(str + 9) == 'I'
		&& *(str + 10) == 'F'
		&& *(str + 11) == ' '){
			return tag_elseif;
		}else{
			return tag_null;
		}
	}else if(strlen > TAG_LOOP_LENGTH
	&& *(str + 5) == 'L'
	&& *(str + 6) == 'O'
	&& *(str + 7) == 'O'
	&& *(str + 8) == 'P'
	&& *(str + 9) == ' '){
		return tag_loop;
	}else if(strlen > TAG_BREAK_LENGTH
	&& *(str + 5) == 'B'
	&& *(str + 6) == 'R'
	&& *(str + 7) == 'E'
	&& *(str + 8) == 'A'
	&& *(str + 9) == 'K'){
		return tag_break;
	}else if(strlen > TAG_CONTINUE_LENGTH
	&& *(str + 5) == 'C'
	&& *(str + 6) == 'O'
	&& *(str + 7) == 'N'
	&& *(str + 8) == 'T'
	&& *(str + 9) == 'I'
	&& *(str + 10) == 'N'
	&& *(str + 11) == 'U'
	&& *(str + 12) == 'E'){
		return tag_continue;
	}else{
		return tag_null;
	}
}

/*Find the lenth of a tag*/
size_t
tagtype_len(enum TMPL_tagtype t){
	switch(t){
		case tag_null:
			return TAG_NULL_LENGTH;
		case tag_text:
			return TAG_TEXT_LENGTH;
		case tag_var:
			return TAG_VAR_LENGTH;
		case tag_if:
			return TAG_IF_LENGTH;
		case tag_end:
			return TAG_END_LENGTH;
		case tag_elseif:
			return TAG_ELSEIF_LENGTH;
		case tag_else:
			return TAG_ELSE_LENGTH;
		case tag_loop:
			return TAG_LOOP_LENGTH;
		case tag_break:
			return TAG_BREAK_LENGTH;
		case tag_continue:
			return TAG_CONTINUE_LENGTH;
	}
	return 0;
}

/*Quickly find the token*/
struct TMPL_token*
scan_text(const char* start, size_t strlen, size_t* consumed){
	struct TMPL_token* t = TMPL_alloc_token();
	t->start = start;
	enum TMPL_tagtype type = tag_null;
	const char* cursor = start;
	while(type == tag_null){
		int left = strlen - (cursor - start);
		cursor = (const char*)memchr(cursor,'<',left);
		if(cursor == NULL){
			cursor = start + (strlen > 0 ? strlen : 1);
			break;
		}
		type = starts_with_token(cursor+1,strlen);
		if(type == tag_null){
			cursor++;
		}
	}
	t->end = cursor;
	t->length = t->end - t->start;
	*consumed = t->length;
	return t;
}

struct TMPL_token*
scan_tag(const char* start, size_t strlen, size_t* consumed){
	struct TMPL_token* t = TMPL_alloc_token();
	t->start = start;
	char* cursor = (char*)memchr(start,'>',strlen);
	t->end = cursor+1;/*Include the '>'*/
	t->length = t->end - t->start;
	*consumed = t->length;
	return t;
}

void
print_tokens(struct TMPL_token* head){
	struct TMPL_token* cursor = head;
	while(cursor != NULL){
		printf("char start is %p char end is %p cursor is %p type is %d\n",cursor->start, cursor->end,(void*)cursor,(int)cursor->type);
		const char* i;
		for(i = cursor->start; i != cursor->end; i++){
			printf("%c",*i);
		}
		printf("\n----\n");
		cursor = cursor->next;
	}
	printf("Finished printing tokens\n");
}