#include "cache.h"
#include "exec_cmd.h"
#include "pkt-line.h"
#include "sideband.h"
#include <sys/wait.h>
#include <sys/time.h>

static int finish_pack(const char *pack_tmp_name, const char *me)
{
        int pipe_fd[2];
        pid_t pid;
        char idx[PATH_MAX];
        char final[PATH_MAX];
        char hash[41];
        unsigned char sha1[20];
        char *cp;
        int err = 0;

        if (pipe(pipe_fd) < 0)
                die("%s: unable to set up pipe", me);

        strcpy(idx, pack_tmp_name); /* ".git/objects/pack-XXXXXX" */
        cp = strrchr(idx, '/');
        memcpy(cp, "/pidx", 5);

        pid = fork();
        if (pid < 0)
                die("%s: unable to fork off git-index-pack", me);
        if (!pid) {
                close(0);
                dup2(pipe_fd[1], 1);
                close(pipe_fd[0]);
                close(pipe_fd[1]);
                execl_git_cmd("index-pack", "-o", idx, pack_tmp_name, NULL);
                error("cannot exec git-index-pack <%s> <%s>",
                      idx, pack_tmp_name);
                exit(1);
        }
        close(pipe_fd[1]);
        if (read(pipe_fd[0], hash, 40) != 40) {
                error("%s: unable to read from git-index-pack", me);
                err = 1;
        }
        close(pipe_fd[0]);

        for (;;) {
                int status, code;

                if (waitpid(pid, &status, 0) < 0) {
                        if (errno == EINTR)
                                continue;
                        error("waitpid failed (%s)", strerror(errno));
                        goto error_die;
                }
                if (WIFSIGNALED(status)) {
                        int sig = WTERMSIG(status);
                        error("git-index-pack died of signal %d", sig);
                        goto error_die;
                }
                if (!WIFEXITED(status)) {
                        error("git-index-pack died of unnatural causes %d",
                              status);
                        goto error_die;
                }
                code = WEXITSTATUS(status);
                if (code) {
                        error("git-index-pack died with error code %d", code);
                        goto error_die;
                }
                if (err)
                        goto error_die;
                break;
        }
        hash[40] = 0;
        if (get_sha1_hex(hash, sha1)) {
                error("git-index-pack reported nonsense '%s'", hash);
                goto error_die;
        }
        /* Now we have pack in pack_tmp_name[], and
         * idx in idx[]; rename them to their final names.
         */
        snprintf(final, sizeof(final),
                 "%s/pack/pack-%s.pack", get_object_directory(), hash);
        move_temp_to_file(pack_tmp_name, final);
        chmod(final, 0444);
        snprintf(final, sizeof(final),
                 "%s/pack/pack-%s.idx", get_object_directory(), hash);
        move_temp_to_file(idx, final);
        chmod(final, 0444);
        return 0;

 error_die:
        unlink(idx);
        unlink(pack_tmp_name);
        exit(1);
}

static pid_t setup_sideband(int sideband, const char *me, int fd[2], int xd[2])
{
        pid_t side_pid;

        if (!sideband) {
                fd[0] = xd[0];
                fd[1] = xd[1];
                return 0;
        }
        /* xd[] is talking with upload-pack; subprocess reads from
         * xd[0], spits out band#2 to stderr, and feeds us band#1
         * through our fd[0].
         */
        if (pipe(fd) < 0)
                die("%s: unable to set up pipe", me);
        side_pid = fork();
        if (side_pid < 0)
                die("%s: unable to fork off sideband demultiplexer", me);
        if (!side_pid) {
                /* subprocess */
                close(fd[0]);
                if (xd[0] != xd[1])
                        close(xd[1]);
                if (recv_sideband(me, xd[0], fd[1], 2))
                        exit(1);
                exit(0);
        }
        close(xd[0]);
        close(fd[1]);
        fd[1] = xd[1];
        return side_pid;
}

int receive_unpack_pack(int xd[2], const char *me, int quiet, int sideband)
{
        int status;
        pid_t pid, side_pid;
        int fd[2];

        side_pid = setup_sideband(sideband, me, fd, xd);
        pid = fork();
        if (pid < 0)
                die("%s: unable to fork off git-unpack-objects", me);
        if (!pid) {
                dup2(fd[0], 0);
                close(fd[0]);
                close(fd[1]);
                execl_git_cmd("unpack-objects", quiet ? "-q" : NULL, NULL);
                die("git-unpack-objects exec failed");
        }
        close(fd[0]);
        close(fd[1]);
        while (waitpid(pid, &status, 0) < 0) {
                if (errno != EINTR)
                        die("waiting for git-unpack-objects: %s",
                            strerror(errno));
        }
        if (WIFEXITED(status)) {
                int code = WEXITSTATUS(status);
                if (code)
                        die("git-unpack-objects died with error code %d",
                            code);
                return 0;
        }
        if (WIFSIGNALED(status)) {
                int sig = WTERMSIG(status);
                die("git-unpack-objects died of signal %d", sig);
        }
        die("git-unpack-objects died of unnatural causes %d", status);
}

/*
 * We average out the download speed over this many "events", where
 * an event is a minimum of about half a second. That way, we get
 * a reasonably stable number.
 */
#define NR_AVERAGE (4)

/*
 * A "binary msec" is a power-of-two-msec, aka 1/1024th of a second.
 * Keeping the time in that format means that "bytes / msecs" means
 * the same as kB/s (modulo rounding).
 *
 * 1000512 is a magic number (usecs in a second, rounded up by half
 * of 1024, to make "rounding" come out right ;)
 */
#define usec_to_binarymsec(x) ((int)(x) / (1000512 >> 10))

int receive_keep_pack(int xd[2], const char *me, int quiet, int sideband)
{
        char tmpfile[PATH_MAX];
        int ofd, ifd, fd[2];
        unsigned long total;
        static struct timeval prev_tv;
        struct average {
                unsigned long bytes;
                unsigned long time;
        } download[NR_AVERAGE] = { {0, 0}, };
        unsigned long avg_bytes, avg_time;
        int idx = 0;

        setup_sideband(sideband, me, fd, xd);

        ifd = fd[0];
        snprintf(tmpfile, sizeof(tmpfile),
                 "%s/pack/tmp-XXXXXX", get_object_directory());
        ofd = mkstemp(tmpfile);
        if (ofd < 0)
                return error("unable to create temporary file %s", tmpfile);

        gettimeofday(&prev_tv, NULL);
        total = 0;
        avg_bytes = 0;
        avg_time = 0;
        while (1) {
                char buf[8192];
                ssize_t sz, wsz, pos;
                sz = read(ifd, buf, sizeof(buf));
                if (sz == 0)
                        break;
                if (sz < 0) {
                        if (errno != EINTR && errno != EAGAIN) {
                                error("error reading pack (%s)", strerror(errno));
                                close(ofd);
                                unlink(tmpfile);
                                return -1;
                        }
                        sz = 0;
                }
                pos = 0;
                while (pos < sz) {
                        wsz = write(ofd, buf + pos, sz - pos);
                        if (wsz < 0) {
                                error("error writing pack (%s)",
                                      strerror(errno));
                                close(ofd);
                                unlink(tmpfile);
                                return -1;
                        }
                        pos += wsz;
                }
                total += sz;
                if (!quiet) {
                        static unsigned long last;
                        struct timeval tv;
                        unsigned long diff = total - last;
                        /* not really "msecs", but a power-of-two millisec (1/1024th of a sec) */
                        unsigned long msecs;

                        gettimeofday(&tv, NULL);
                        msecs = tv.tv_sec - prev_tv.tv_sec;
                        msecs <<= 10;
                        msecs += usec_to_binarymsec(tv.tv_usec - prev_tv.tv_usec);

                        if (msecs > 500) {
                                prev_tv = tv;
                                last = total;

                                /* Update averages ..*/
                                avg_bytes += diff;
                                avg_time += msecs;
                                avg_bytes -= download[idx].bytes;
                                avg_time -= download[idx].time;
                                download[idx].bytes = diff;
                                download[idx].time = msecs;
                                idx++;
                                if (idx >= NR_AVERAGE)
                                        idx = 0;

                                fprintf(stderr, "%4lu.%03luMB  (%lu kB/s)      \r",
                                        total >> 20,
                                        1000*((total >> 10) & 1023)>>10,
                                        avg_bytes / avg_time );
                        }
                }
        }
        close(ofd);
        return finish_pack(tmpfile, me);
}