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

static struct strbuf git_default_name = STRBUF_INIT;
static struct strbuf git_default_email = STRBUF_INIT;
static struct strbuf git_default_date = STRBUF_INIT;
static int default_email_is_bogus;
static int default_name_is_bogus;

#define IDENT_NAME_GIVEN 01
#define IDENT_MAIL_GIVEN 02
#define IDENT_ALL_GIVEN (IDENT_NAME_GIVEN|IDENT_MAIL_GIVEN)
static int committer_ident_explicitly_given;
static int author_ident_explicitly_given;

#ifdef NO_GECOS_IN_PWENT
#define get_gecos(ignored) "&"
#else
#define get_gecos(struct_passwd) ((struct_passwd)->pw_gecos)
#endif

static struct passwd *xgetpwuid_self(int *is_bogus)
{
        struct passwd *pw;

        errno = 0;
        pw = getpwuid(getuid());
        if (!pw) {
                static struct passwd fallback;
                fallback.pw_name = "unknown";
#ifndef NO_GECOS_IN_PWENT
                fallback.pw_gecos = "Unknown";
#endif
                pw = &fallback;
                if (is_bogus)
                        *is_bogus = 1;
        }
        return pw;
}

static void copy_gecos(const struct passwd *w, struct strbuf *name)
{
        char *src;

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

        for (src = get_gecos(w); *src && *src != ','; src++) {
                int ch = *src;
                if (ch != '&')
                        strbuf_addch(name, ch);
                else {
                        /* Sorry, Mr. McDonald... */
                        strbuf_addch(name, toupper(*w->pw_name));
                        strbuf_addstr(name, w->pw_name + 1);
                }
        }
}

static int add_mailname_host(struct strbuf *buf)
{
        FILE *mailname;
        struct strbuf mailnamebuf = STRBUF_INIT;

        mailname = fopen("/etc/mailname", "r");
        if (!mailname) {
                if (errno != ENOENT)
                        warning("cannot open /etc/mailname: %s",
                                strerror(errno));
                return -1;
        }
        if (strbuf_getline(&mailnamebuf, mailname, '\n') == EOF) {
                if (ferror(mailname))
                        warning("cannot read /etc/mailname: %s",
                                strerror(errno));
                strbuf_release(&mailnamebuf);
                fclose(mailname);
                return -1;
        }
        /* success! */
        strbuf_addbuf(buf, &mailnamebuf);
        strbuf_release(&mailnamebuf);
        fclose(mailname);
        return 0;
}

static int canonical_name(const char *host, struct strbuf *out)
{
        int status = -1;

#ifndef NO_IPV6
        struct addrinfo hints, *ai;
        memset (&hints, '\0', sizeof (hints));
        hints.ai_flags = AI_CANONNAME;
        if (!getaddrinfo(host, NULL, &hints, &ai)) {
                if (ai && strchr(ai->ai_canonname, '.')) {
                        strbuf_addstr(out, ai->ai_canonname);
                        status = 0;
                }
                freeaddrinfo(ai);
        }
#else
        struct hostent *he = gethostbyname(host);
        if (he && strchr(he->h_name, '.')) {
                strbuf_addstr(out, he->h_name);
                status = 0;
        }
#endif /* NO_IPV6 */

        return status;
}

static void add_domainname(struct strbuf *out, int *is_bogus)
{
        char buf[1024];

        if (gethostname(buf, sizeof(buf))) {
                warning("cannot get host name: %s", strerror(errno));
                strbuf_addstr(out, "(none)");
                *is_bogus = 1;
                return;
        }
        if (strchr(buf, '.'))
                strbuf_addstr(out, buf);
        else if (canonical_name(buf, out) < 0) {
                strbuf_addf(out, "%s.(none)", buf);
                *is_bogus = 1;
        }
}

static void copy_email(const struct passwd *pw, struct strbuf *email,
                       int *is_bogus)
{
        /*
         * Make up a fake email address
         * (name + '@' + hostname [+ '.' + domainname])
         */
        strbuf_addstr(email, pw->pw_name);
        strbuf_addch(email, '@');

        if (!add_mailname_host(email))
                return; /* read from "/etc/mailname" (Debian) */
        add_domainname(email, is_bogus);
}

const char *ident_default_name(void)
{
        if (!git_default_name.len) {
                copy_gecos(xgetpwuid_self(&default_name_is_bogus), &git_default_name);
                strbuf_trim(&git_default_name);
        }
        return git_default_name.buf;
}

const char *ident_default_email(void)
{
        if (!git_default_email.len) {
                const char *email = getenv("EMAIL");

                if (email && email[0]) {
                        strbuf_addstr(&git_default_email, email);
                        committer_ident_explicitly_given |= IDENT_MAIL_GIVEN;
                        author_ident_explicitly_given |= IDENT_MAIL_GIVEN;
                } else
                        copy_email(xgetpwuid_self(&default_email_is_bogus),
                                   &git_default_email, &default_email_is_bogus);
                strbuf_trim(&git_default_email);
        }
        return git_default_email.buf;
}

static const char *ident_default_date(void)
{
        if (!git_default_date.len)
                datestamp(&git_default_date);
        return git_default_date.buf;
}

static int crud(unsigned char c)
{
        return  c <= 32  ||
                c == '.' ||
                c == ',' ||
                c == ':' ||
                c == ';' ||
                c == '<' ||
                c == '>' ||
                c == '"' ||
                c == '\\' ||
                c == '\'';
}

/*
 * Copy over a string to the destination, but avoid special
 * characters ('\n', '<' and '>') and remove crud at the end
 */
static void strbuf_addstr_without_crud(struct strbuf *sb, 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
         * an identification line. We can only remove crud, never add it,
         * so 'len' is our maximum.
         */
        strbuf_grow(sb, len);
        for (i = 0; i < len; i++) {
                c = *src++;
                switch (c) {
                case '\n': case '<': case '>':
                        continue;
                }
                sb->buf[sb->len++] = c;
        }
        sb->buf[sb->len] = '\0';
}

/*
 * Reverse of fmt_ident(); given an ident line, split the fields
 * to allow the caller to parse it.
 * Signal a success by returning 0, but date/tz fields of the result
 * can still be NULL if the input line only has the name/email part
 * (e.g. reading from a reflog entry).
 */
int split_ident_line(struct ident_split *split, const char *line, int len)
{
        const char *cp;
        size_t span;
        int status = -1;

        memset(split, 0, sizeof(*split));

        split->name_begin = line;
        for (cp = line; *cp && cp < line + len; cp++)
                if (*cp == '<') {
                        split->mail_begin = cp + 1;
                        break;
                }
        if (!split->mail_begin)
                return status;

        for (cp = split->mail_begin - 2; line <= cp; cp--)
                if (!isspace(*cp)) {
                        split->name_end = cp + 1;
                        break;
                }
        if (!split->name_end) {
                /* no human readable name */
                split->name_end = split->name_begin;
        }

        for (cp = split->mail_begin; cp < line + len; cp++)
                if (*cp == '>') {
                        split->mail_end = cp;
                        break;
                }
        if (!split->mail_end)
                return status;

        /*
         * Look from the end-of-line to find the trailing ">" of the mail
         * address, even though we should already know it as split->mail_end.
         * This can help in cases of broken idents with an extra ">" somewhere
         * in the email address.  Note that we are assuming the timestamp will
         * never have a ">" in it.
         *
         * Note that we will always find some ">" before going off the front of
         * the string, because will always hit the split->mail_end closing
         * bracket.
         */
        for (cp = line + len - 1; *cp != '>'; cp--)
                ;

        for (cp = cp + 1; cp < line + len && isspace(*cp); cp++)
                ;
        if (line + len <= cp)
                goto person_only;
        split->date_begin = cp;
        span = strspn(cp, "0123456789");
        if (!span)
                goto person_only;
        split->date_end = split->date_begin + span;
        for (cp = split->date_end; cp < line + len && isspace(*cp); cp++)
                ;
        if (line + len <= cp || (*cp != '+' && *cp != '-'))
                goto person_only;
        split->tz_begin = cp;
        span = strspn(cp + 1, "0123456789");
        if (!span)
                goto person_only;
        split->tz_end = split->tz_begin + 1 + span;
        return 0;

person_only:
        split->date_begin = NULL;
        split->date_end = NULL;
        split->tz_begin = NULL;
        split->tz_end = NULL;
        return 0;
}

static const char *env_hint =
"\n"
"*** Please tell me who you are.\n"
"\n"
"Run\n"
"\n"
"  git config --global user.email \"you@example.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 flag)
{
        static struct strbuf ident = STRBUF_INIT;
        int strict = (flag & IDENT_STRICT);
        int want_date = !(flag & IDENT_NO_DATE);
        int want_name = !(flag & IDENT_NO_NAME);

        if (want_name && !name)
                name = ident_default_name();
        if (!email)
                email = ident_default_email();

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

                if (strict) {
                        if (name == git_default_name.buf)
                                fputs(env_hint, stderr);
                        die("empty ident name (for <%s>) not allowed", email);
                }
                pw = xgetpwuid_self(NULL);
                name = pw->pw_name;
        }

        if (want_name && strict &&
            name == git_default_name.buf && default_name_is_bogus) {
                fputs(env_hint, stderr);
                die("unable to auto-detect name (got '%s')", name);
        }

        if (strict && email == git_default_email.buf && default_email_is_bogus) {
                fputs(env_hint, stderr);
                die("unable to auto-detect email address (got '%s')", email);
        }

        strbuf_reset(&ident);
        if (want_name) {
                strbuf_addstr_without_crud(&ident, name);
                strbuf_addstr(&ident, " <");
        }
        strbuf_addstr_without_crud(&ident, email);
        if (want_name)
                        strbuf_addch(&ident, '>');
        if (want_date) {
                strbuf_addch(&ident, ' ');
                if (date_str && date_str[0]) {
                        if (parse_date(date_str, &ident) < 0)
                                die("invalid date format: %s", date_str);
                }
                else
                        strbuf_addstr(&ident, ident_default_date());
        }

        return ident.buf;
}

const char *fmt_name(const char *name, const char *email)
{
        return fmt_ident(name, email, NULL, IDENT_STRICT | IDENT_NO_DATE);
}

const char *git_author_info(int flag)
{
        if (getenv("GIT_AUTHOR_NAME"))
                author_ident_explicitly_given |= IDENT_NAME_GIVEN;
        if (getenv("GIT_AUTHOR_EMAIL"))
                author_ident_explicitly_given |= IDENT_MAIL_GIVEN;
        return fmt_ident(getenv("GIT_AUTHOR_NAME"),
                         getenv("GIT_AUTHOR_EMAIL"),
                         getenv("GIT_AUTHOR_DATE"),
                         flag);
}

const char *git_committer_info(int flag)
{
        if (getenv("GIT_COMMITTER_NAME"))
                committer_ident_explicitly_given |= IDENT_NAME_GIVEN;
        if (getenv("GIT_COMMITTER_EMAIL"))
                committer_ident_explicitly_given |= IDENT_MAIL_GIVEN;
        return fmt_ident(getenv("GIT_COMMITTER_NAME"),
                         getenv("GIT_COMMITTER_EMAIL"),
                         getenv("GIT_COMMITTER_DATE"),
                         flag);
}

static int ident_is_sufficient(int user_ident_explicitly_given)
{
#ifndef WINDOWS
        return (user_ident_explicitly_given & IDENT_MAIL_GIVEN);
#else
        return (user_ident_explicitly_given == IDENT_ALL_GIVEN);
#endif
}

int committer_ident_sufficiently_given(void)
{
        return ident_is_sufficient(committer_ident_explicitly_given);
}

int author_ident_sufficiently_given(void)
{
        return ident_is_sufficient(author_ident_explicitly_given);
}

int git_ident_config(const char *var, const char *value, void *data)
{
        if (!strcmp(var, "user.name")) {
                if (!value)
                        return config_error_nonbool(var);
                strbuf_reset(&git_default_name);
                strbuf_addstr(&git_default_name, value);
                committer_ident_explicitly_given |= IDENT_NAME_GIVEN;
                author_ident_explicitly_given |= IDENT_NAME_GIVEN;
                return 0;
        }

        if (!strcmp(var, "user.email")) {
                if (!value)
                        return config_error_nonbool(var);
                strbuf_reset(&git_default_email);
                strbuf_addstr(&git_default_email, value);
                committer_ident_explicitly_given |= IDENT_MAIL_GIVEN;
                author_ident_explicitly_given |= IDENT_MAIL_GIVEN;
                return 0;
        }

        return 0;
}

static int buf_cmp(const char *a_begin, const char *a_end,
                   const char *b_begin, const char *b_end)
{
        int a_len = a_end - a_begin;
        int b_len = b_end - b_begin;
        int min = a_len < b_len ? a_len : b_len;
        int cmp;

        cmp = memcmp(a_begin, b_begin, min);
        if (cmp)
                return cmp;

        return a_len - b_len;
}

int ident_cmp(const struct ident_split *a,
              const struct ident_split *b)
{
        int cmp;

        cmp = buf_cmp(a->mail_begin, a->mail_end,
                      b->mail_begin, b->mail_end);
        if (cmp)
                return cmp;

        return buf_cmp(a->name_begin, a->name_end,
                       b->name_begin, b->name_end);
}