/* See LICENSE file for copyright and license details. */
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <libparser.h>


#define LIST_RULES(X, D)\
	X("comment", colourise, "31") D\
	X("intrusive-identifier", colourise, "33") D\
	X("discrete-identifier", colourise, "") D\
	X("escape-payload", ignore, "") D\
	X("ESCAPE", colourise, "2;34") D\
	X("escape", colourise_and_descend, "34") D\
	X("string", colourise_and_descend, "32") D\
	X("character", descend, "") D\
	X("integer", ignore, "") D\
	X("boundary", descend, "") D\
	X("low", descend, "") D\
	X("high", descend, "") D\
	X("NONDETERMINISTIC", colourise, "1;33") D\
	X("COMMITTED", colourise, "1;33") D\
	X("committed", descend, "") D\
	X("REJECTION", colourise, "1;31") D\
	X("rejection", descend, "") D\
	X("EXCEPTION", colourise, "1;31") D\
	X("exception", descend, "") D\
	X("CONCATENATION", colourise, "2") D\
	X("concatenation", descend, "") D\
	X("ALTERNATION", colourise, "") D\
	X("alternation", descend, "") D\
	X("CHAR-RANGE-START", ignore, "") D\
	X("CHAR-RANGE-COMMA", ignore, "") D\
	X("CHAR-RANGE-END", ignore, "") D\
	X("CHAR-RANGE-EDGE", ignore, "") D\
	X("CHAR-RANGE", ignore, "") D\
	X("char-range", colourise_and_descend, "35") D\
	X("OPTIONAL-START", ignore, "") D\
	X("OPTIONAL-END", ignore, "") D\
	X("OPTIONAL", colourise, "1;34") D\
	X("optional", descend, "") D\
	X("REPEATED-START", ignore, "") D\
	X("REPEATED-END", ignore, "") D\
	X("REPEATED", colourise, "1;32") D\
	X("repeated", descend, "") D\
	X("GROUP-START", ignore, "") D\
	X("GROUP-END", ignore, "") D\
	X("GROUP", colourise, "1") D\
	X("group", descend, "") D\
	X("embedded-rule", descend, "") D\
	X("operand", descend, "") D\
	X("DEFINITION", ignore, "") D\
	X("TERMINATION", ignore, "") D\
	X("RULE", colourise, "1;36") D\
	X("rule-name", descend, "") D\
	X("rule", descend, "") D\
	X("grammar", descend, "")


static const char *argv0;

static char *text = NULL;
static size_t size = 0;
static size_t len = 0;
static size_t off = 0;


static void descend(struct libparser_unit *tree, const char *colour);


static void
write_all(const char *s, size_t n)
{
	ssize_t r;
	while (n) {
		r = write(STDOUT_FILENO, s, n);
		if (r < 0) {
			if (errno == EINTR)
				continue;
			fprintf(stderr, "%s: write %s: %s\n", argv0, "<stdout>", strerror(errno));
			exit(1);
		}
		s = &s[r];
		n -= (size_t)r;
	}
}


static void
write_str(const char *s)
{
	write_all(s, strlen(s));
}


static void
output(size_t to)
{
	if (to > off) {
		write_all(&text[off], to - off);
		off = to;
	}
}


static void
ignore(struct libparser_unit *tree, const char *colour)
{
	(void) tree;
	(void) colour;
}


static void
colourise(struct libparser_unit *tree, const char *colour)
{
	output(tree->start);
	write_str("\033[m");
	write_str(colour);
	output(tree->end);
	write_str("\033[m");
}


static void
colourise_and_descend(struct libparser_unit *tree, const char *colour)
{
	struct libparser_unit *node;
	output(tree->start);
	write_str("\033[m");
	write_str(colour);

#define X(RULE, ACTION, COLOUR)\
	if (!strcmp(node->rule, RULE)) ACTION(node, "\033["COLOUR"m");

	for (node = tree->in; node; node = node->next) {
		LIST_RULES(X, else) else descend(node, "");
	}

#undef X

	write_str("\033[m");
	write_str(colour);
	output(tree->end);
	write_str("\033[m");
}


static void
descend(struct libparser_unit *tree, const char *colour)
{
	struct libparser_unit *node;

	(void) colour;

#define X(RULE, ACTION, COLOUR)\
	if (!strcmp(node->rule, RULE)) ACTION(node, "\033["COLOUR"m");

	for (node = tree->in; node; node = node->next) {
		LIST_RULES(X, else) else descend(node, "");
	}

#undef X
}


static void
free_tree(struct libparser_unit *tree)
{
	struct libparser_unit *node;
	struct libparser_unit *next;

	if (!tree)
		return;

	for (node = tree->in; node; node = next) {
		next = node->next;
		free_tree(node);
	}

	free(tree);
}


int
main(int argc, char *argv[])
{
	struct libparser_unit *tree = NULL;
	ssize_t r;
	int fd = STDIN_FILENO;
	const char *path = "<stdin>";

	argv0 = *argv++;
	argc--;

	if (argc && !strcmp(*argv, "--")) {
		argv++;
		argc--;
	} else if (argc && argv[0][0] == '-' && argv[0][1]) {
		goto usage;
	}
	if (argc > 1)
		goto usage;
	if (argc && !strcmp(*argv, "-"))
		argc--;

	if (argc) {
		path = *argv;
		fd = open(path, O_RDONLY);
		if (fd < 0) {
			fprintf(stderr, "%s: open %s O_RDONLY: %s\n", argv[0], path, strerror(errno));
			exit(1);
		}
	}

	for (;;) {
		if (len == size) {
			size += 8096u;
			text = realloc(text, size);
			if (!text) {
				fprintf(stderr, "%s: realloc %zu: %s\n", argv[0], size, strerror(errno));
				exit(1);
			}
		}
		r = read(fd, &text[len], size - len);
		if (!r)
			break;
		if (r < 0) {
			if (errno == EINTR)
				continue;
			fprintf(stderr, "%s: read %s: %s\n", argv[0], path, strerror(errno));
			exit(1);
		}
		len += (size_t)r;
	}

	if (argc)
		close(fd);

	r = libparser_parse_file(libparser_rule_table, text, len, &tree);
	if (r < 0) {
		fprintf(stderr, "%s: libparser_parse_file: %s\n", argv0, strerror(errno));
		exit(1);
	} else if (!tree || tree->end != (size_t)len || !r) {
		fprintf(stderr, "%s: failed to parse input\n", argv0);
		exit(1);
	}

	descend(tree, "");
	output(len);

	free(text);
	free_tree(tree);
	return 0;

usage:
	fprintf(stderr, "usage: %s [file]\n", argv0);
	exit(1);
}