/* SPDX-License-Identifier: GPL-2.0 */

/** \file color.c Functions for printing colored messages. */

/*
 * Mostly taken from the git source tree, version 1.6.1.76, January 2009.
 */

#include "para.h"
#include "color.h"

static int parse_color(const char *name, int len)
{
	static const char * const color_names[] = {
		"normal", "black", "red", "green", "yellow",
		"blue", "magenta", "cyan", "white"
	};
	char *end;
	int i;
	for (i = 0; i < ARRAY_SIZE(color_names); i++) {
		const char *str = color_names[i];
		if (!strncasecmp(name, str, len) && !str[len])
			return i - 1;
	}
	i = strtol(name, &end, 10);
	if (end - name == len && i >= -1 && i <= 255)
		return i;
	return -2;
}

static int parse_attr(const char *name, int len)
{
	static const int attr_values[] = { 1, 2, 4, 5, 7 };
	static const char * const attr_names[] = {
		"bold", "dim", "ul", "blink", "reverse"
	};
	int i;
	for (i = 0; i < ARRAY_SIZE(attr_names); i++) {
		const char *str = attr_names[i];
		if (!strncasecmp(name, str, len) && !str[len])
			return attr_values[i];
	}
	return -1;
}

/**
 * Create an escape sequence for colored output.
 *
 * \param value Human-readable color spec.
 * \param dst Result pointer for the escape sequence.
 *
 * Format of \a value: [fg [bg]] [attr].
 */
void color_parse_or_die(const char *value, char *dst)
{
	const char *ptr = value;
	int attr = -1;
	int fg = -2;
	int bg = -2;

	if (!strcasecmp(value, "reset")) {
		strcpy(dst, COLOR_RESET);
		return;
	}

	/* [fg [bg]] [attr] */
	while (*ptr) {
		const char *word = ptr;
		int val, len = 0;

		while (word[len] && !para_isspace(word[len]))
			len++;

		ptr = word + len;
		while (*ptr && para_isspace(*ptr))
			ptr++;

		val = parse_color(word, len);
		if (val >= -1) {
			if (fg == -2) {
				fg = val;
				continue;
			}
			if (bg == -2) {
				bg = val;
				continue;
			}
			goto bad;
		}
		val = parse_attr(word, len);
		if (val < 0 || attr != -1)
			goto bad;
		attr = val;
	}

	if (attr >= 0 || fg >= 0 || bg >= 0) {
		int sep = 0;

		*dst++ = '\033';
		*dst++ = '[';
		if (attr >= 0) {
			*dst++ = '0' + attr;
			sep++;
		}
		if (fg >= 0) {
			if (sep++)
				*dst++ = ';';
			if (fg < 8) {
				*dst++ = '3';
				*dst++ = '0' + fg;
			} else {
				dst += sprintf(dst, "38;5;%d", fg);
			}
		}
		if (bg >= 0) {
			if (sep)
				*dst++ = ';';
			if (bg < 8) {
				*dst++ = '4';
				*dst++ = '0' + bg;
			} else {
				dst += sprintf(dst, "48;5;%d", bg);
			}
		}
		*dst++ = 'm';
	}
	*dst = 0;
	return;
bad:
	PARA_EMERG_LOG("bad color value '%s'\n", value);
	exit(EXIT_FAILURE);
}