/*
 * ident.c
 *
 * create git identifier lines of the form "name <email> date"
 *
 * Copyright (C) 2005 Linus Torvalds
 */
#include "cache.h"

#include <pwd.h>
#include <time.h>
#include <ctype.h>

static char real_email[1000];
static char real_name[1000];
static char real_date[50];

static void copy_gecos(struct passwd *w, char *name, int sz)
{
	char *src, *dst;
	int len, nlen;

	nlen = strlen(w->pw_name);

	/* Traditionally GECOS field had office phone numbers etc, separated
	 * with commas.  Also & stands for capitalized form of the login name.
	 */

	for (len = 0, dst = name, src = w->pw_gecos; len < sz; src++) {
		int ch = *src;
		if (ch != '&') {
			*dst++ = ch;
			if (ch == 0 || ch == ',')
				break;
			len++;
			continue;
		}
		if (len + nlen < sz) {
			/* Sorry, Mr. McDonald... */
			*dst++ = toupper(*w->pw_name);
			memcpy(dst, w->pw_name + 1, nlen - 1);
			dst += nlen - 1;
		}
	}
	if (len < sz)
		name[len] = 0;
	else
		die("Your parents must have hated you!");

}

int setup_ident(void)
{
	int len;
	struct passwd *pw = getpwuid(getuid());

	if (!pw)
		die("You don't exist. Go away!");

	/* Get the name ("gecos") */
	copy_gecos(pw, real_name, sizeof(real_name));

	/* Make up a fake email address (name + '@' + hostname [+ '.' + domainname]) */
	len = strlen(pw->pw_name);
	if (len > sizeof(real_email)/2)
		die("Your sysadmin must hate you!");
	memcpy(real_email, pw->pw_name, len);
	real_email[len++] = '@';
	gethostname(real_email + len, sizeof(real_email) - len);
	if (!strchr(real_email+len, '.')) {
		len = strlen(real_email);
		real_email[len++] = '.';
		getdomainname(real_email+len, sizeof(real_email)-len);
	}
	/* And set the default date */
	datestamp(real_date, sizeof(real_date));
	return 0;
}

static int add_raw(char *buf, int size, int offset, const char *str)
{
	int len = strlen(str);
	if (offset + len > size)
		return size;
	memcpy(buf + offset, str, len);
	return offset + len;
}

static int crud(unsigned char c)
{
	static char crud_array[256];
	static int crud_array_initialized = 0;

	if (!crud_array_initialized) {
		int k;

		for (k = 0; k <= 31; ++k) crud_array[k] = 1;
		crud_array[' '] = 1;
		crud_array['.'] = 1;
		crud_array[','] = 1;
		crud_array[':'] = 1;
		crud_array[';'] = 1;
		crud_array['<'] = 1;
		crud_array['>'] = 1;
		crud_array['"'] = 1;
		crud_array['\''] = 1;
		crud_array_initialized = 1;
	}
	return crud_array[c];
}

/*
 * Copy over a string to the destination, but avoid special
 * characters ('\n', '<' and '>') and remove crud at the end
 */
static int copy(char *buf, int size, int offset, const char *src)
{
	int i, len;
	unsigned char c;

	/* Remove crud from the beginning.. */
	while ((c = *src) != 0) {
		if (!crud(c))
			break;
		src++;
	}

	/* Remove crud from the end.. */
	len = strlen(src);
	while (len > 0) {
		c = src[len-1];
		if (!crud(c))
			break;
		--len;
	}

	/*
	 * Copy the rest to the buffer, but avoid the special
	 * characters '\n' '<' and '>' that act as delimeters on
	 * a identification line
	 */
	for (i = 0; i < len; i++) {
		c = *src++;
		switch (c) {
		case '\n': case '<': case '>':
			continue;
		}
		if (offset >= size)
			return size;
		buf[offset++] = c;
	}
	return offset;
}

char *get_ident(const char *name, const char *email, const char *date_str)
{
	static char buffer[1000];
	char date[50];
	int i;

	if (!name)
		name = real_name;
	if (!email)
		email = real_email;
	strcpy(date, real_date);
	if (date_str)
		parse_date(date_str, date, sizeof(date));

	i = copy(buffer, sizeof(buffer), 0, name);
	i = add_raw(buffer, sizeof(buffer), i, " <");
	i = copy(buffer, sizeof(buffer), i, email);
	i = add_raw(buffer, sizeof(buffer), i, "> ");
	i = copy(buffer, sizeof(buffer), i, date);
	if (i >= sizeof(buffer))
		die("Impossibly long personal identifier");
	buffer[i] = 0;
	return buffer;
}

char *git_author_info(void)
{
	return get_ident(getenv("GIT_AUTHOR_NAME"), getenv("GIT_AUTHOR_EMAIL"), getenv("GIT_AUTHOR_DATE"));
}

char *git_committer_info(void)
{
	return get_ident(getenv("GIT_COMMITTER_NAME"), getenv("GIT_COMMITTER_EMAIL"), getenv("GIT_COMMITTER_DATE"));
}