/*
 * GIT - The information manager from hell
 *
 * Copyright (C) Linus Torvalds, 2005
 */
#include "cache.h"

#include <pwd.h>
#include <time.h>
#include <string.h>
#include <ctype.h>
#include <time.h>
#include <curl/curl.h>

#define BLOCKING (1ul << 14)

/*
 * FIXME! Share the code with "write-tree.c"
 */
static void init_buffer(char **bufp, unsigned int *sizep)
{
        char *buf = xmalloc(BLOCKING);
        *sizep = 0;
        *bufp = buf;
}

static void add_buffer(char **bufp, unsigned int *sizep, const char *fmt, ...)
{
        char one_line[2048];
        va_list args;
        int len;
        unsigned long alloc, size, newsize;
        char *buf;

        va_start(args, fmt);
        len = vsnprintf(one_line, sizeof(one_line), fmt, args);
        va_end(args);
        size = *sizep;
        newsize = size + len;
        alloc = (size + 32767) & ~32767;
        buf = *bufp;
        if (newsize > alloc) {
                alloc = (newsize + 32767) & ~32767;
                buf = xrealloc(buf, alloc);
                *bufp = buf;
        }
        *sizep = newsize;
        memcpy(buf + size, one_line, len);
}

static void remove_special(char *p)
{
        char c;
        char *dst = p, *src = p;

        for (;;) {
                c = *src;
                src++;
                switch(c) {
                case '\n': case '<': case '>':
                        continue;
                }
                *dst++ = c;
                if (!c)
                        break;
        }

        /*
         * Go back, and remove crud from the end: some people
         * have commas etc in their gecos field
         */
        dst--;
        while (--dst >= p) {
                unsigned char c = *dst;
                switch (c) {
                case ',': case ';': case '.':
                        *dst = 0;
                        continue;
                }
                break;
        }
}

/* Gr. strptime is crap for this; it doesn't have a way to require RFC2822
   (i.e. English) day/month names, and it doesn't work correctly with %z. */
static void parse_date(char *date, time_t *now, char *result, int maxlen)
{
        char *p;
        time_t then;

        if ((then = curl_getdate(date, now)) == 0)
                return;

        /* find the timezone at the end */
        p = date + strlen(date);
        while (p > date && isdigit(*--p))
                ;
        if ((*p == '+' || *p == '-') && strlen(p) == 5)
                snprintf(result, maxlen, "%lu %5.5s", then, p);
}

static void check_valid(unsigned char *sha1, const char *expect)
{
        void *buf;
        char type[20];
        unsigned long size;

        buf = read_sha1_file(sha1, type, &size);
        if (!buf || strcmp(type, expect))
                die("%s is not a valid '%s' object", sha1_to_hex(sha1), expect);
        free(buf);
}

/*
 * Having more than two parents is not strange at all, and this is
 * how multi-way merges are represented.
 */
#define MAXPARENT (16)

static char *commit_tree_usage = "commit-tree <sha1> [-p <sha1>]* < changelog";

int main(int argc, char **argv)
{
        int i, len;
        int parents = 0;
        unsigned char tree_sha1[20];
        unsigned char parent_sha1[MAXPARENT][20];
        unsigned char commit_sha1[20];
        char *gecos, *realgecos, *commitgecos;
        char *email, *commitemail, realemail[1000];
        char date[20], realdate[20];
        char *audate;
        char comment[1000];
        struct passwd *pw;
        time_t now;
        struct tm *tm;
        char *buffer;
        unsigned int size;

        if (argc < 2 || get_sha1_hex(argv[1], tree_sha1) < 0)
                usage(commit_tree_usage);

        check_valid(tree_sha1, "tree");
        for (i = 2; i < argc; i += 2) {
                char *a, *b;
                a = argv[i]; b = argv[i+1];
                if (!b || strcmp(a, "-p") || get_sha1_hex(b, parent_sha1[parents]))
                        usage(commit_tree_usage);
                check_valid(parent_sha1[parents], "commit");
                parents++;
        }
        if (!parents)
                fprintf(stderr, "Committing initial tree %s\n", argv[1]);
        pw = getpwuid(getuid());
        if (!pw)
                die("You don't exist. Go away!");
        realgecos = pw->pw_gecos;
        len = strlen(pw->pw_name);
        memcpy(realemail, pw->pw_name, len);
        realemail[len] = '@';
        gethostname(realemail+len+1, sizeof(realemail)-len-1);
        if (!strchr(realemail+len+1, '.')) {
                strcat(realemail, ".");
                getdomainname(realemail+strlen(realemail), sizeof(realemail)-strlen(realemail)-1);
        }
        time(&now);
        tm = localtime(&now);

        strftime(realdate, sizeof(realdate), "%s %z", tm);
        strcpy(date, realdate);

        commitgecos = getenv("COMMIT_AUTHOR_NAME") ? : realgecos;
        commitemail = getenv("COMMIT_AUTHOR_EMAIL") ? : realemail;
        gecos = getenv("AUTHOR_NAME") ? : realgecos;
        email = getenv("AUTHOR_EMAIL") ? : realemail;
        audate = getenv("AUTHOR_DATE");
        if (audate)
                parse_date(audate, &now, date, sizeof(date));

        remove_special(gecos); remove_special(realgecos); remove_special(commitgecos);
        remove_special(email); remove_special(realemail); remove_special(commitemail);

        init_buffer(&buffer, &size);
        add_buffer(&buffer, &size, "tree %s\n", sha1_to_hex(tree_sha1));

        /*
         * NOTE! This ordering means that the same exact tree merged with a
         * different order of parents will be a _different_ changeset even
         * if everything else stays the same.
         */
        for (i = 0; i < parents; i++)
                add_buffer(&buffer, &size, "parent %s\n", sha1_to_hex(parent_sha1[i]));

        /* Person/date information */
        add_buffer(&buffer, &size, "author %s <%s> %s\n", gecos, email, date);
        add_buffer(&buffer, &size, "committer %s <%s> %s\n\n", commitgecos, commitemail, realdate);

        /* And add the comment */
        while (fgets(comment, sizeof(comment), stdin) != NULL)
                add_buffer(&buffer, &size, "%s", comment);

        write_sha1_file(buffer, size, "commit", commit_sha1);
        printf("%s\n", sha1_to_hex(commit_sha1));
        return 0;
}