#include <string.h>

#define SYNTAX_LIMIT (64)

enum {
	COLOUR_GREY,
	COLOUR_WHITE,
	COLOUR_BLUE,
	COLOUR_YELLOW,
	COLOUR_CYAN,
	COLOUR_PINK,
	COLOUR_LMAO
};

static int syntax_count = 0;

static int  syntax_enrange [SYNTAX_LIMIT];
static int  syntax_derange [SYNTAX_LIMIT];
static char syntax_begin   [SYNTAX_LIMIT] [96];
static char syntax_end     [SYNTAX_LIMIT] [96];
static char syntax_escape  [SYNTAX_LIMIT];
static int  syntax_colour  [SYNTAX_LIMIT];

static int character_compare_array (char character, char * character_array) {
	int i = 0;

	do {
		if (character == character_array [i]) {
			return (1);
		}
	} while (++i != (int) strlen (character_array));

	return (0);
}

static void syntax_rule (int    enrange,
                         int    derange,
                         char * begin,
                         char * end,
                         char   escape,
                         int    colour) {
	if (syntax_count >= SYNTAX_LIMIT) {
		return;
	}

	strncpy (syntax_begin [syntax_count], begin, 96);
	strncpy (syntax_end   [syntax_count], end,   96);

	syntax_enrange [syntax_count] = enrange;
	syntax_derange [syntax_count] = derange;
	syntax_escape  [syntax_count] = escape;
	syntax_colour  [syntax_count] = colour;

	++syntax_count;
}

static int syntax_loop (char   * string,
                           int * length) {
	int offset, subset, select;

	for (select = offset = 0; select != syntax_count; ++select) {
		if (syntax_enrange [select] == 0) {
			if (syntax_derange [select] == 0) {
				if (strncmp (string, syntax_begin [select], strlen (syntax_begin [select])) == 0) {
					break;
				}
			} else {
				if ((strncmp (string, syntax_begin [select], strlen (syntax_begin [select])) == 0)
				&&  (character_compare_array (string [offset + (int) strlen (syntax_begin [select])], syntax_end [select]) == 1)) {
					break;
				}
			}
		} else {
			for (subset = 0; subset != (int) strlen (syntax_begin [select]); ++subset) {
				if (string [offset] == syntax_begin [select] [subset]) {
					goto selected;
				}
			}
		}
	}

	selected:

	if (select >= syntax_count) {
		* length = 1;
		return (select);
	}

	for (offset = 1; string [offset - 1] != '\0'; ++offset) {
		if (string [offset] == syntax_escape [select]) {
			++offset;
			continue;
		}

		if (syntax_derange [select] == 0) {
			if (strncmp (& string [offset], syntax_end [select], strlen (syntax_end [select])) == 0) {
				* length = offset + (int) strlen (syntax_end [select]);
				goto finished;
			}
		} else {
			subset = 0;
			if (strcmp (syntax_end [select], "") == 0) {
				break;
			} do {
				if (string [offset] == syntax_end [select] [subset]) {
					* length = offset;
					goto finished;
				}
			} while (++subset != (int) strlen (syntax_end [select]));
		}
	}

	finished:

	return (select);
}

static void syntax_c (void) {
	char * separators = ".,:;<=>+-*/%!&~^?|()[]{}'\" \t\r\n";

	char * keywords [] = {
		"register",         "volatile",         "auto",             "const",            "static",           "extern",           "if",               "else",
		"do",               "while",            "for",              "continue",         "switch",           "case",             "default",          "break",
		"enum",             "union",            "struct",           "typedef",          "goto",             "void",             "return",           "sizeof",
		"char",             "short",            "int",              "long",             "signed",           "unsigned",         "float",            "double"
	};

	int word;

	syntax_rule (0, 0, "/*", "*/", '\0', COLOUR_GREY);
	syntax_rule (0, 0, "//", "\n", '\0', COLOUR_GREY);
	syntax_rule (0, 0, "#",  "\n", '\\', COLOUR_LMAO);
	syntax_rule (0, 0, "'",  "'",  '\\', COLOUR_PINK);
	syntax_rule (0, 0, "\"", "\"", '\\', COLOUR_PINK);

	for (word = 0; word != sizeof (keywords) / sizeof (keywords [0]); ++word) {
		syntax_rule (0, 1, keywords [word], separators, '\0', COLOUR_YELLOW);
	}

	syntax_rule (1, 0, "()[]{}",             "", '\0', COLOUR_BLUE);
	syntax_rule (1, 0, ".,:;<=>+*-/%!&~^?|", "", '\0', COLOUR_CYAN);

	syntax_rule (1, 1, "0123456789",                 separators, '\0', COLOUR_PINK);
	syntax_rule (1, 1, "abcdefghijklmnopqrstuvwxyz", separators, '\0', COLOUR_WHITE);
	syntax_rule (1, 1, "ABCDEFGHIJKLMNOPQRSTUVWXYZ", separators, '\0', COLOUR_WHITE);
	syntax_rule (1, 1, "_",                          separators, '\0', COLOUR_WHITE);
}

static void render_c_code (char * string,
                           int    x,
                           int    y) {
	int select, length = 0, offset, reset_x;

	reset_x = x;

	for (offset = 0; offset < (int) strlen (string); offset += length) {
		char substring [1024] = "";

		int i = 0, square = 16;

		Color colour = RED;

		select = syntax_loop (& string [offset], & length);

		strncpy (substring, & string [offset], (unsigned long int) length);

		switch (syntax_colour [select]) {
			case COLOUR_GREY:   colour = GRAY;    break;
			case COLOUR_WHITE:  colour = WHITE;   break;
			case COLOUR_BLUE:   colour = BLUE;    break;
			case COLOUR_YELLOW: colour = YELLOW;  break;
			case COLOUR_CYAN:   colour = PURPLE;  break;
			case COLOUR_PINK:   colour = RED;     break;
			case COLOUR_LMAO:   colour = GREEN;   break;
			default:            colour = GREEN;   break;
		}

		for (i = 0; i < (int) strlen (substring); ++i) {
			if (substring [i] == '\n') {
				y += square;
				x = reset_x;
			} else if (substring [i] == '\t') {
				x += square * 4;
			} else {
				DrawTextCodepoint (GetFontDefault (), substring [i], (Vector2) { x, y }, square, colour);
				x += square;
			}
		}

		if (y > 900) {
			return;
		}
	}
}