#include "tokenizer.h"
#include "error.h"
#include <string>

static bool streq(const char* a, const char* b) {
	while (*a != 0 && *b != 0) {
		if (*a != *b) return false;
		a++; b++;
	}
	return *a == *b;
}

static const char* ptr;
static t_tokentype current_token = TOKEN_ERROR;
static char identifier[255];
static unsigned char array[255];
static float value;
static int line = 0;
static int row = 0;
static int current_tokenline = 0;
static int current_tokenrow = 0;

struct t_token_op {
	const char* str;
	t_tokentype tokentype;
};

t_token_op tkn_tokens[] = {
	{ "struct", TOKEN_STRUCT },
	{ "as", TOKEN_AS },
	{ "end", TOKEN_END },
	{ "function", TOKEN_FUNCTION },
	{ "var", TOKEN_VAR },
	{ "array", TOKEN_ARRAY },
	{ "of", TOKEN_OF },
	{ "const", TOKEN_CONST },
	{ "if", TOKEN_IF },
	{ "then", TOKEN_THEN },
	{ "else", TOKEN_ELSE },
	{ "while", TOKEN_WHILE },
	{ "do", TOKEN_DO },
	{ "repeat", TOKEN_REPEAT },
	{ "until", TOKEN_UNTIL },
	{ "for", TOKEN_FOR },
	{ "to", TOKEN_TO },
	{ "step", TOKEN_STEP },
	{ "return", TOKEN_RETURN },
	{ "rem", TOKEN_REM },
	{ "and", TOKEN_AND },
	{ "or", TOKEN_OR },
	{ "not", TOKEN_NOT },
	{ "mod", TOKEN_MOD }
};

//static char hex_digit(const char digit) { return digit - (digit <= 57 ? 48 : 55); }

#define CCHR *ptr
#define NEXT if(*ptr==10){line++;row=0;}else{row++;};ptr++

static void tkn_do_next() {
	identifier[0] = 0;
	value = 0;
	char* id = identifier;
	// Ignore whitespace
	while (CCHR != 0 && CCHR != 10 && CCHR <= 32) { NEXT; }
	// If zero, we are at the end of the file
	current_tokenline = line; current_tokenrow = row;
	if (CCHR == 0) { current_token = TOKEN_ENDFILE; return; }
	// if 13, we are at the end of the line
	if (CCHR == 10) { NEXT; current_token = TOKEN_ENDLINE; return; }
	// if 34, grab the string
	if (CCHR == 34) {
		NEXT;
		while (CCHR != 0 && CCHR != 34) { *id = CCHR; id++; NEXT; }
		if (CCHR == 0) { current_token = TOKEN_ERROR; error_raise("Unexpected end of file."); return; }
		*id = 0; NEXT;
		current_token = TOKEN_STRING; return;
	}
	// If digit, grab the number
	if (CCHR >= 48 && CCHR <= 57) {
		do { value = value * 10 + (CCHR - 48); NEXT; } while (CCHR >= 48 && CCHR <= 57);
		if (CCHR == '.') {
			float d = 0.1f; NEXT;
			do { value = value + (float(CCHR - 48) * d); d *= 0.1f; NEXT; } while (CCHR >= 48 && CCHR <= 57);
		}
		current_token = TOKEN_NUMBER; return;
	}
	// if letter, grab the identifier
	if ((CCHR >= 65 && CCHR <= 90) || (CCHR >= 97 && CCHR <= 122)) {
		do { *id = CCHR; id++; NEXT; } while ((CCHR >= 48 && CCHR <= 57) || (CCHR >= 65 && CCHR <= 90) || (CCHR >= 97 && CCHR <= 122) || CCHR == 95);
		*id = 0;
		int i = 0; while (identifier[i] != 0) { if (identifier[i] < 95) { identifier[i] |= 32; };  i++; } // to lowecase
		// If it matches a keyword, it's a keyword
		for (auto token : tkn_tokens) {
			if (streq(token.str, identifier)) {
				current_token = token.tokentype;
				if (current_token == TOKEN_REM) { while (CCHR != 0 && CCHR != 13) { NEXT; } }
				return;
			}
		}
		// else, it's an identifier
		current_token = TOKEN_IDENTIFIER; return;
	}
	// Check if it's any of the operators
	if (CCHR == '+') { NEXT; current_token = TOKEN_PLUS; return; }
	if (CCHR == '-') { NEXT; current_token = TOKEN_MINUS; return; }
	if (CCHR == '*') { NEXT; current_token = TOKEN_ASTERISC; return; }
	if (CCHR == '/') { NEXT; current_token = TOKEN_SLASH; return; }
	if (CCHR == '.') { NEXT; current_token = TOKEN_DOT; return; }
	if (CCHR == '(') { NEXT; current_token = TOKEN_LPAR; return; }
	if (CCHR == ')') { NEXT; current_token = TOKEN_RPAR; return; }
	if (CCHR == '[') { NEXT; current_token = TOKEN_LBRACKET; return; }
	if (CCHR == ']') { NEXT; current_token = TOKEN_RBRACKET; return; }
	if (CCHR == ',') { NEXT; current_token = TOKEN_COMMA; return; }
	if (CCHR == '<') { NEXT; if (CCHR == '=') { NEXT; current_token = TOKEN_LEQ; } else { if (CCHR == '>') { NEXT; current_token = TOKEN_NEQ; } else { current_token = TOKEN_LT; } } return; }
	if (CCHR == '>') { NEXT; if (CCHR == '=') { NEXT; current_token = TOKEN_GEQ; } else { current_token = TOKEN_GT; } return; }
	if (CCHR == '=') { NEXT; current_token = TOKEN_EQ; return; }
	if (CCHR == '!') { NEXT; if (CCHR == '=') { NEXT; current_token = TOKEN_NEQ; } else { current_token = TOKEN_NOT; } return; }
	if (CCHR == '%') { NEXT; current_token = TOKEN_MOD; return; }
	if (CCHR == 39)  { NEXT; current_token = TOKEN_REM; while (CCHR != 0 && CCHR != 10) { NEXT; };  return; }

	// Per a agafar numeros en hexadecimal o binari, heretat de PaCO, no se si li fa falta a JailBasic
	/*if (CCHR == '&') {
		NEXT;
		if ((CCHR | 32) == 'h') {
			NEXT;
			if ((CCHR >= 48 && CCHR <= 57) || (CCHR >= 65 && CCHR <= 70)) {
				do { value = (value << 4) + hex_digit(CCHR); NEXT; } while ((CCHR >= 48 && CCHR <= 57) || (CCHR >= 65 && CCHR <= 70));
				current_token = TOKEN_NUMBER; return;
			}
		}
		if ((CCHR | 32) == 'b') {
			NEXT;
			if (CCHR == 48 || CCHR == 49) {
				do { value = (value << 1) + (CCHR-48); NEXT; } while (CCHR == 48 || CCHR == 49);
				current_token = TOKEN_NUMBER; return;
			}
		}
		current_token = TOKEN_ERROR;
		error_raise("Syntax error");
		return;
	}*/

	// if no match, it's an error
	current_token = TOKEN_ERROR; return;
}

void tkn_init(const char* buffer) {
	ptr = buffer;
	current_token = TOKEN_ERROR;
	value = line = row = current_tokenline = current_tokenrow = 0;
	identifier[0] = 0; array[0] = 0;
}

void tkn_next() { do { tkn_do_next(); } while (current_token == TOKEN_REM || current_token == TOKEN_ENDLINE); }

t_tokentype tkn_get_token() { return current_token; }
char* tkn_get_string() { return identifier; }
unsigned char* tkn_get_array() { return array; }
float tkn_get_value() { return value; }
int tkn_get_line() { return current_tokenline; }
int tkn_get_row() { return current_tokenrow; }