// @COMPILECMD gcc $@ -o hl
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>

enum { NORMAL,     BOLD,       DARKNESS,   ITALIC,     UNDERLINE,  BLINK,      DUNNO_6,    REVERSE,    INVISIBLE    };
enum { GREY,       RED,        GREEN,      YELLOW,     BLUE,       PINK,       CYAN,       WHITE,      CANCEL       };

static int colour_short_comment = GREY;
static int colour_long_comment  = GREY;
static int colour_short_string  = PINK;
static int colour_long_string   = RED;
static int colour_separator     = BLUE;
static int colour_number        = CYAN;
static int colour_keyword       = YELLOW;
static int colour_preprocessor  = YELLOW;
static int colour_default       = WHITE;

static int effect_short_comment = BOLD;
static int effect_long_comment  = BOLD;
static int effect_short_string  = BOLD;
static int effect_long_string   = BOLD;
static int effect_separator     = BOLD;
static int effect_number        = BOLD;
static int effect_keyword       = BOLD;
static int effect_preprocessor  = BOLD;
static int effect_default       = BOLD;

static char * buffer = NULL;

static unsigned long int buffer_size = 0;

static void render_character (
	char character
) {
	putchar (character);
}

static void render_string (
	char * string
) {
	while (* string) render_character (* string++);
}

static void render_colour (
	int colour,
	int effect
) {
	if (colour == CANCEL) {
		render_string ("\033[0m");
		return;
	}

	render_string    ("\033[");
	render_character ((char) (effect % 9) + '0');
	render_string    (";3");
	render_character ((char) (colour % 8) + '0');
	render_character ('m');
}

static int is_space (
	char character
) {
	if ((character ==  ' ') || (character == '\t') || (character == '\r') || (character == '\n')) {
		return (1);
	} else {
		return (0);
	}
}

static int is_separator (
	char character
) {
	if ((character ==  ' ') || (character == '\t') || (character == '\r') || (character == '\n') ||
	    (character ==  '+') || (character ==  '-') || (character ==  '*') || (character ==  '/') ||
	    (character ==  '(') || (character ==  ')') || (character ==  '[') || (character ==  ']') ||
	    (character ==  '{') || (character ==  '}') || (character ==  '<') || (character ==  '>') ||
	    (character ==  ';') || (character ==  ':') || (character ==  ',') || (character ==  '.') ||
	    (character ==  '!') || (character ==  '&') || (character ==  '|') || (character ==  '?') ||
	    (character ==  '~') || (character ==  '^') || (character ==  '%') || (character ==  '=')) {
		return (1);
	} else {
		return (0);
	}
}

static int compare_multiple_strings (
	      char   * string,
	const char * * strings,
	const int      count
) {
	int i = 0;

	do {
		if (strcmp (string, strings [i]) == 0) {
			return (1);
		}
		++i;
	} while (i != count);

	return (0);
}

static int render_short_comment (
	int data_offset
) {
	render_colour (colour_short_comment, effect_short_comment);

	do {
		render_character (buffer [data_offset]);
		++data_offset;
	} while ((buffer [data_offset] != '\n') && (buffer [data_offset] != '\0'));

	render_character (buffer [data_offset]);
	++data_offset;

	return (data_offset);
}

static int render_long_comment (
	int data_offset
) {
	render_colour (colour_long_comment, effect_long_comment);

	do {
		render_character (buffer [data_offset]);
		++data_offset;
	} while (((buffer [data_offset]     != '/') ||
	         (buffer [data_offset - 1] != '*')) &&
	         (buffer [data_offset]     != '\0'));

	render_character (buffer [data_offset]);
	++data_offset;

	return (data_offset);
}

static int render_short_string (
	int data_offset
) {
	render_colour (colour_short_string, effect_short_string);

	do {
		render_character (buffer [data_offset]);
		++data_offset;
		if (buffer [data_offset - 1] == '\\') {
			render_character (buffer [data_offset]);
			++data_offset;
		}
	} while ((buffer [data_offset] != '\'') && (buffer [data_offset] != '\0'));

	render_character (buffer [data_offset]);
	++data_offset;

	return (data_offset);
}

static int render_long_string (
	int data_offset
) {
	render_colour (colour_long_string, effect_long_string);

	do {
		render_character (buffer [data_offset]);
		++data_offset;
		if (buffer [data_offset - 1] == '\\') {
			render_character (buffer [data_offset]);
			++data_offset;
		}
	} while ((buffer [data_offset] != '"') && (buffer [data_offset] != '\0'));

	render_character (buffer [data_offset]);
	++data_offset;

	return (data_offset);
}

static int render_separator (
	int data_offset
) {
	if (is_space (buffer [data_offset]) != 0) {
		render_colour (WHITE, NORMAL);
	} else {
		render_colour (colour_separator, effect_separator);
	}

	render_character (buffer [data_offset]);
	++data_offset;

	return (data_offset);
}

static int render_number (
	int data_offset
) {
	render_colour (colour_number, effect_number);

	do {
		render_character (buffer [data_offset]);
		++data_offset;
	} while ((is_separator (buffer [data_offset]) == 0) && (buffer [data_offset] != '\0'));

	return (data_offset);
}

static int render_word (
	int data_offset
) {
	const char * c_keywords [32] = {
		"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"
	};

	const char * preprocessor_keywords [16] = {
		"#include",     "#pragma",      "#define",      "#undef",       "#ifdef",       "#ifndef",      "#elifdef",     "#elifndef",
		"#if",          "#elif",        "#else",        "#endif",       "#embed",       "#line",        "#error",       "#warning"
	};

	char * word = NULL;

	int i = 0;

	do {
		word = realloc (word, sizeof (* word) * (unsigned long int) (i + 1));
		word [i] = buffer [data_offset + i];
		++i;
	} while ((is_separator (buffer [data_offset + i]) == 0) && (buffer [data_offset + i] != '\0'));

	word = realloc (word, sizeof (* word) * (unsigned long int) (i + 1));
	word [i] = '\0';

	if (compare_multiple_strings (word, c_keywords, 32) != 0) {
		render_colour (colour_keyword, effect_keyword);
	} else if (compare_multiple_strings (word, preprocessor_keywords, 16) != 0) {
		render_colour (colour_preprocessor, effect_preprocessor);
	} else {
		render_colour (colour_default, effect_default);
	}

	do {
		render_character (buffer [data_offset]);
		++data_offset;
	} while ((is_separator (buffer [data_offset]) == 0) && (buffer [data_offset] != '\0'));

	return (data_offset);
}

int main (
	int      argc,
	char * * argv
) {
	int offset = 0;

	if (argc != 1) {
		(void) argv;
		puts ("ARGUMENTS \"Heyo world!\"");
		return (-1);
	}

	do {
		++buffer_size;
		buffer = realloc (buffer, buffer_size);
		read (STDIN_FILENO, & buffer [buffer_size - 1], sizeof (* buffer));
	} while ((buffer [buffer_size] != '\0') || (buffer_size != 10000));

	++buffer_size;
	buffer = realloc (buffer, buffer_size);
	buffer [buffer_size] = '\0';

	/* Checking if long comments work... */
	// Checking if long comments work...

	while (buffer [offset] != '\0') {
		if ((buffer [offset] == '/') && (buffer [offset + 1] == '/')) {
			offset = render_short_comment (offset);
		} else if ((buffer [offset] == '/') && (buffer [offset + 1] == '*')) {
			offset = render_long_comment (offset);
		} else if (buffer [offset] == '\'') {
			offset = render_short_string (offset);
		} else if (buffer [offset] == '"') {
			offset = render_long_string (offset);
		} else if (is_separator (buffer [offset]) != 0) {
			offset = render_separator (offset);
		} else if ((buffer [offset] >= '0') && (buffer [offset] <= '9')) {
			offset = render_number (offset);
		} else {
			offset = render_word (offset);
		}
		render_colour (CANCEL, NORMAL);
	}

	free (buffer);

	return (0);
}