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

static char git_default_date[50];

static void copy_gecos(const struct passwd *w, char *name, size_t sz)
{
        char *src, *dst;
        size_t 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!");

}

static void copy_email(const struct passwd *pw)
{
        /*
         * Make up a fake email address
         * (name + '@' + hostname [+ '.' + domainname])
         */
        size_t len = strlen(pw->pw_name);
        if (len > sizeof(git_default_email)/2)
                die("Your sysadmin must hate you!");
        memcpy(git_default_email, pw->pw_name, len);
        git_default_email[len++] = '@';
        gethostname(git_default_email + len, sizeof(git_default_email) - len);
        if (!strchr(git_default_email+len, '.')) {
                struct hostent *he = gethostbyname(git_default_email + len);
                char *domainname;

                len = strlen(git_default_email);
                git_default_email[len++] = '.';
                if (he && (domainname = strchr(he->h_name, '.')))
                        strlcpy(git_default_email + len, domainname + 1,
                                sizeof(git_default_email) - len);
                else
                        strlcpy(git_default_email + len, "(none)",
                                sizeof(git_default_email) - len);
        }
}

static void setup_ident(void)
{
        struct passwd *pw = NULL;

        /* Get the name ("gecos") */
        if (!git_default_name[0]) {
                pw = getpwuid(getuid());
                if (!pw)
                        die("You don't exist. Go away!");
                copy_gecos(pw, git_default_name, sizeof(git_default_name));
        }

        if (!git_default_email[0]) {
                const char *email = getenv("EMAIL");

                if (email && email[0])
                        strlcpy(git_default_email, email,
                                sizeof(git_default_email));
                else {
                        if (!pw)
                                pw = getpwuid(getuid());
                        if (!pw)
                                die("You don't exist. Go away!");
                        copy_email(pw);
                }
        }

        /* And set the default date */
        if (!git_default_date[0])
                datestamp(git_default_date, sizeof(git_default_date));
}

static int add_raw(char *buf, size_t size, int offset, const char *str)
{
        size_t 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, size_t size, int offset, const char *src)
{
        size_t 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 delimiters 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;
}

static const char au_env[] = "GIT_AUTHOR_NAME";
static const char co_env[] = "GIT_COMMITTER_NAME";
static const char *env_hint =
"\n"
"*** Your name cannot be determined from your system services (gecos).\n"
"\n"
"Run\n"
"\n"
"  git config --global user.email \"you@email.com\"\n"
"  git config --global user.name \"Your Name\"\n"
"\n"
"to set your account\'s default identity.\n"
"Omit --global to set the identity only in this repository.\n"
"\n";

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

        setup_ident();
        if (!name)
                name = git_default_name;
        if (!email)
                email = git_default_email;

        if (!*name) {
                struct passwd *pw;

                if (0 <= error_on_no_name &&
                    name == git_default_name && env_hint) {
                        fprintf(stderr, env_hint, au_env, co_env);
                        env_hint = NULL; /* warn only once, for "git-var -l" */
                }
                if (0 < error_on_no_name)
                        die("empty ident %s <%s> not allowed", name, email);
                pw = getpwuid(getuid());
                if (!pw)
                        die("You don't exist. Go away!");
                strlcpy(git_default_name, pw->pw_name,
                        sizeof(git_default_name));
                name = git_default_name;
        }

        strcpy(date, git_default_date);
        if (date_str) {
                if (*date_str)
                        parse_date(date_str, date, sizeof(date));
                else
                        date[0] = '\0';
        }

        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, date[0] ? "> " : ">");
        i = copy(buffer, sizeof(buffer), i, date);
        if (i >= sizeof(buffer))
                die("Impossibly long personal identifier");
        buffer[i] = 0;
        return buffer;
}

const char *git_author_info(int error_on_no_name)
{
        return fmt_ident(getenv("GIT_AUTHOR_NAME"),
                         getenv("GIT_AUTHOR_EMAIL"),
                         getenv("GIT_AUTHOR_DATE"),
                         error_on_no_name);
}

const char *git_committer_info(int error_on_no_name)
{
        return fmt_ident(getenv("GIT_COMMITTER_NAME"),
                         getenv("GIT_COMMITTER_EMAIL"),
                         getenv("GIT_COMMITTER_DATE"),
                         error_on_no_name);
}