#include "const.h"
#include "scan.h"
#include "ctype.h"
#include "string.h"
#include "utils.h"
#include "io.h"

void scanner_init( Scanner *s, char *src )
{
	s->src = src;
	scanner_reset( s );
}

void scanner_reset( Scanner *s )
{
	s->peek = ' ';
	s->row = 1;
	s->col = 1;
	s->pos = s->src;
}

void scanner_done( Scanner *s )
{
}

static char get_char( Scanner *s )
{
	char c;

	c = *s->pos;
	s->pos++;
	s->peek = c;
		
	return c;
}

static void skip_whitespace( Scanner *s )
{
	for( ; ; get_char( s ) ) {
		s->col++;
		if( s->peek == ' ' || s->peek == '\t' ) {
			continue;
		} else if( s->peek == '\n' ) {
			s->row++;
			s->col = 1;
			break;
		} else if( s->peek == '\0' ) {
			break;
		} else {
			break;
		}
	}
}

void scanner_skip_line( Scanner *s )
{
	while( s->peek != '\0' && s->peek != '\n' ) {
		s->col++;
		get_char( s );
	}
	
	if( s->peek == '\n' ) {
		s->col++;
	}
}

Symbol get_int( Scanner *s )
{
	Symbol sym;

	sym.sym = S_number;
	sym.data.n = 0;

	do {
		sym.data.n = sym.data.n * 10 + ( s->peek - '0' );
		get_char( s );
	} while( s->peek != '\0' && isdigit( s->peek ) );

	return sym;
}

Symbol get_ident_or_label( Scanner *s )
{
	Symbol newSym;
	char *p;
	
	newSym.sym = S_ident;
	newSym.data.s[0] = '\0';
	p = newSym.data.s;

	do {
		*p++ = s->peek;
		get_char( s );
	} while( ( isalnum( s->peek ) || s->peek == '_' ) && !isspace( s->peek ) && ( s->peek != '\0' ) && ( s->peek != ':' ) && ( p - newSym.data.s < MAX_IDENT_LEN ) );

	if( s->peek == ':' ) {
		newSym.sym = S_label;
		get_char( s );
	}
	
	*p = '\0';

	return newSym;
}

Symbol scanner_scan( Scanner *s )
{
	Symbol sym;

	if( s->peek == '\0' ) {
		sym.sym = S_eof;
		if( s->debug ) {
			print( "SCANNER(EOF)" );
		}
		return sym;
	}

	skip_whitespace( s );

	if( s->peek == '\0' ) {
		sym.sym = S_eof;
		if( s->debug ) {
			print( "SCANNER(EOF)" );
		}
		return sym;
	}

	if( isdigit( s->peek ) ) {
		sym = get_int( s );
		if( s->debug ) {
			char buf[MAX_TMP_LEN];
			char buf2[MAX_TMP_LEN];
			buf[0] = '\0';
			strcat( buf, "SCANNER(NUMBER," );
			inttohex( sym.data.n, buf2 );
			strcat( buf, buf2 );
			strcat( buf, ")" );
			print( buf );
		}
		return sym;
	} else if( isalpha( s->peek ) ) {
		sym = get_ident_or_label( s );
		if( s->debug ) {
			char buf[MAX_TMP_LEN];
			buf[0] = '\0';
			if( sym.sym == S_ident ) {
				strcat( buf, "SCANNER(IDENT," );
			} else if( sym.sym == S_label ) {
				strcat( buf, "SCANNER(LABEL," );
			} else {
				strcat( buf, "SCANNER(<unknown>," );
			}
			strcat( buf, sym.data.s );
			strcat( buf, ")" );
			print( buf );
		}
		return sym;	
	} else if( s->peek == '\n' ) {
		sym.sym = S_newline;	
		if( s->debug ) {
			print( "SCANNER(NEWLINE)" );
		}
		s->peek = ' ';
		return sym;
	} else if( s->peek == ';' ) {
		sym.sym = S_comment;
		if( s->debug ) {
			print( "SCANNER(COMMENT)" );
		}
		s->peek = ' ';
		return sym;		
	} else {
		sym.sym = S_token;
		sym.tag = s->peek;
		s->peek = ' ';
		if( s->debug ) {
			char buf[MAX_TMP_LEN];
			char buf2[MAX_TMP_LEN];
			buf[0] = '\0';
			strcat( buf, "SCANNER(TOKEN," );
			inttohex( sym.tag, buf2 );
			strcat( buf, buf2 );
			strcat( buf, ")" );
			print( buf );
		}
		return sym;
	}
	
	return sym;
}

void scanner_debug( Scanner *s, int enable )
{
	s->debug = enable;
	
	if( s->debug ) {
		print( "SCANNER DEBUGGING ENABLED" );
	}
}