/*
 * Copyright (C) 2005 Junio C Hamano
 */
#include "cache.h"
#include "commit.h"
#include "fetch.h"

static int use_link = 0;
static int use_symlink = 0;
static int use_filecopy = 1;

static char *path; /* "Remote" git repository */

void prefetch(unsigned char *sha1)
{
}

static struct packed_git *packs = NULL;

static void setup_index(unsigned char *sha1)
{
        struct packed_git *new_pack;
        char filename[PATH_MAX];
        strcpy(filename, path);
        strcat(filename, "/objects/pack/pack-");
        strcat(filename, sha1_to_hex(sha1));
        strcat(filename, ".idx");
        new_pack = parse_pack_index_file(sha1, filename);
        new_pack->next = packs;
        packs = new_pack;
}

static int setup_indices(void)
{
        DIR *dir;
        struct dirent *de;
        char filename[PATH_MAX];
        unsigned char sha1[20];
        sprintf(filename, "%s/objects/pack/", path);
        dir = opendir(filename);
        if (!dir)
                return -1;
        while ((de = readdir(dir)) != NULL) {
                int namelen = strlen(de->d_name);
                if (namelen != 50 || 
                    strcmp(de->d_name + namelen - 5, ".pack"))
                        continue;
                get_sha1_hex(de->d_name + 5, sha1);
                setup_index(sha1);
        }
        closedir(dir);
        return 0;
}

static int copy_file(const char *source, const char *dest, const char *hex)
{
        if (use_link) {
                if (!link(source, dest)) {
                        pull_say("link %s\n", hex);
                        return 0;
                }
                /* If we got ENOENT there is no point continuing. */
                if (errno == ENOENT) {
                        fprintf(stderr, "does not exist %s\n", source);
                        return -1;
                }
        }
        if (use_symlink) {
                struct stat st;
                if (stat(source, &st)) {
                        fprintf(stderr, "cannot stat %s: %s\n", source,
                                strerror(errno));
                        return -1;
                }
                if (!symlink(source, dest)) {
                        pull_say("symlink %s\n", hex);
                        return 0;
                }
        }
        if (use_filecopy) {
                int ifd, ofd, status;
                struct stat st;
                void *map;
                ifd = open(source, O_RDONLY);
                if (ifd < 0 || fstat(ifd, &st) < 0) {
                        if (ifd >= 0)
                                close(ifd);
                        fprintf(stderr, "cannot open %s\n", source);
                        return -1;
                }
                map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, ifd, 0);
                close(ifd);
                if (map == MAP_FAILED) {
                        fprintf(stderr, "cannot mmap %s\n", source);
                        return -1;
                }
                ofd = open(dest, O_WRONLY | O_CREAT | O_EXCL, 0666);
                status = ((ofd < 0) ||
                          (write(ofd, map, st.st_size) != st.st_size));
                munmap(map, st.st_size);
                if (ofd >= 0)
                        close(ofd);
                if (status)
                        fprintf(stderr, "cannot write %s\n", dest);
                else
                        pull_say("copy %s\n", hex);
                return status;
        }
        fprintf(stderr, "failed to copy %s with given copy methods.\n", hex);
        return -1;
}

static int fetch_pack(const unsigned char *sha1)
{
        struct packed_git *target;
        char filename[PATH_MAX];
        if (setup_indices())
                return -1;
        target = find_sha1_pack(sha1, packs);
        if (!target)
                return error("Couldn't find %s: not separate or in any pack", 
                             sha1_to_hex(sha1));
        if (get_verbosely) {
                fprintf(stderr, "Getting pack %s\n",
                        sha1_to_hex(target->sha1));
                fprintf(stderr, " which contains %s\n",
                        sha1_to_hex(sha1));
        }
        sprintf(filename, "%s/objects/pack/pack-%s.pack", 
                path, sha1_to_hex(target->sha1));
        copy_file(filename, sha1_pack_name(target->sha1),
                  sha1_to_hex(target->sha1));
        sprintf(filename, "%s/objects/pack/pack-%s.idx", 
                path, sha1_to_hex(target->sha1));
        copy_file(filename, sha1_pack_index_name(target->sha1),
                  sha1_to_hex(target->sha1));
        install_packed_git(target);
        return 0;
}

static int fetch_file(const unsigned char *sha1)
{
        static int object_name_start = -1;
        static char filename[PATH_MAX];
        char *hex = sha1_to_hex(sha1);
        const char *dest_filename = sha1_file_name(sha1);

        if (object_name_start < 0) {
                strcpy(filename, path); /* e.g. git.git */
                strcat(filename, "/objects/");
                object_name_start = strlen(filename);
        }
        filename[object_name_start+0] = hex[0];
        filename[object_name_start+1] = hex[1];
        filename[object_name_start+2] = '/';
        strcpy(filename + object_name_start + 3, hex + 2);
        return copy_file(filename, dest_filename, hex);
}

int fetch(unsigned char *sha1)
{
        return fetch_file(sha1) && fetch_pack(sha1);
}

int fetch_ref(char *ref, unsigned char *sha1)
{
        static int ref_name_start = -1;
        static char filename[PATH_MAX];
        static char hex[41];
        int ifd;

        if (ref_name_start < 0) {
                sprintf(filename, "%s/refs/", path);
                ref_name_start = strlen(filename);
        }
        strcpy(filename + ref_name_start, ref);
        ifd = open(filename, O_RDONLY);
        if (ifd < 0) {
                close(ifd);
                fprintf(stderr, "cannot open %s\n", filename);
                return -1;
        }
        if (read(ifd, hex, 40) != 40 || get_sha1_hex(hex, sha1)) {
                close(ifd);
                fprintf(stderr, "cannot read from %s\n", filename);
                return -1;
        }
        close(ifd);
        pull_say("ref %s\n", sha1_to_hex(sha1));
        return 0;
}

static const char local_pull_usage[] =
"git-local-fetch [-c] [-t] [-a] [-d] [-v] [-w filename] [--recover] [-l] [-s] [-n] commit-id path";

/* 
 * By default we only use file copy.
 * If -l is specified, a hard link is attempted.
 * If -s is specified, then a symlink is attempted.
 * If -n is _not_ specified, then a regular file-to-file copy is done.
 */
int main(int argc, char **argv)
{
        char *commit_id;
        int arg = 1;

        while (arg < argc && argv[arg][0] == '-') {
                if (argv[arg][1] == 't')
                        get_tree = 1;
                else if (argv[arg][1] == 'c')
                        get_history = 1;
                else if (argv[arg][1] == 'a') {
                        get_all = 1;
                        get_tree = 1;
                        get_history = 1;
                }
                else if (argv[arg][1] == 'l')
                        use_link = 1;
                else if (argv[arg][1] == 's')
                        use_symlink = 1;
                else if (argv[arg][1] == 'n')
                        use_filecopy = 0;
                else if (argv[arg][1] == 'v')
                        get_verbosely = 1;
                else if (argv[arg][1] == 'w')
                        write_ref = argv[++arg];
                else
                        usage(local_pull_usage);
                arg++;
        }
        if (argc < arg + 2)
                usage(local_pull_usage);
        commit_id = argv[arg];
        path = argv[arg + 1];

        if (pull(commit_id))
                return 1;

        return 0;
}