#include <sys/types.h>
#include <dirent.h>
#include "cache.h"
#include "blob.h"

static void create_directories(const char *path, struct checkout *state)
{
        int len = strlen(path);
        char *buf = xmalloc(len + 1);
        const char *slash = path;

        while ((slash = strchr(slash+1, '/')) != NULL) {
                len = slash - path;
                memcpy(buf, path, len);
                buf[len] = 0;
                if (mkdir(buf, 0777)) {
                        if (errno == EEXIST) {
                                struct stat st;
                                if (len > state->base_dir_len && state->force && !unlink(buf) && !mkdir(buf, 0777))
                                        continue;
                                if (!stat(buf, &st) && S_ISDIR(st.st_mode))
                                        continue; /* ok */
                        }
                        die("cannot create directory at %s", buf);
                }
        }
        free(buf);
}

static void remove_subtree(const char *path)
{
        DIR *dir = opendir(path);
        struct dirent *de;
        char pathbuf[PATH_MAX];
        char *name;
        
        if (!dir)
                die("cannot opendir %s", path);
        strcpy(pathbuf, path);
        name = pathbuf + strlen(path);
        *name++ = '/';
        while ((de = readdir(dir)) != NULL) {
                struct stat st;
                if ((de->d_name[0] == '.') &&
                    ((de->d_name[1] == 0) ||
                     ((de->d_name[1] == '.') && de->d_name[2] == 0)))
                        continue;
                strcpy(name, de->d_name);
                if (lstat(pathbuf, &st))
                        die("cannot lstat %s", pathbuf);
                if (S_ISDIR(st.st_mode))
                        remove_subtree(pathbuf);
                else if (unlink(pathbuf))
                        die("cannot unlink %s", pathbuf);
        }
        closedir(dir);
        if (rmdir(path))
                die("cannot rmdir %s", path);
}

static int create_file(const char *path, unsigned int mode)
{
        mode = (mode & 0100) ? 0777 : 0666;
        return open(path, O_WRONLY | O_CREAT | O_EXCL, mode);
}

static int write_entry(struct cache_entry *ce, char *path, struct checkout *state, int to_tempfile)
{
        int fd;
        void *new;
        unsigned long size;
        long wrote;
        char type[20];

        new = read_sha1_file(ce->sha1, type, &size);
        if (!new || strcmp(type, blob_type)) {
                if (new)
                        free(new);
                return error("git-checkout-index: unable to read sha1 file of %s (%s)",
                        path, sha1_to_hex(ce->sha1));
        }
        switch (ntohl(ce->ce_mode) & S_IFMT) {
        case S_IFREG:
                if (to_tempfile) {
                        strcpy(path, ".merge_file_XXXXXX");
                        fd = mkstemp(path);
                } else
                        fd = create_file(path, ntohl(ce->ce_mode));
                if (fd < 0) {
                        free(new);
                        return error("git-checkout-index: unable to create file %s (%s)",
                                path, strerror(errno));
                }
                wrote = write(fd, new, size);
                close(fd);
                free(new);
                if (wrote != size)
                        return error("git-checkout-index: unable to write file %s", path);
                break;
        case S_IFLNK:
                if (to_tempfile) {
                        strcpy(path, ".merge_link_XXXXXX");
                        fd = mkstemp(path);
                        if (fd < 0) {
                                free(new);
                                return error("git-checkout-index: unable to create "
                                                 "file %s (%s)", path, strerror(errno));
                        }
                        wrote = write(fd, new, size);
                        close(fd);
                        free(new);
                        if (wrote != size)
                                return error("git-checkout-index: unable to write file %s",
                                        path);
                } else {
                        wrote = symlink(new, path);
                        free(new);
                        if (wrote)
                                return error("git-checkout-index: unable to create "
                                                 "symlink %s (%s)", path, strerror(errno));
                }
                break;
        default:
                free(new);
                return error("git-checkout-index: unknown file mode for %s", path);
        }

        if (state->refresh_cache) {
                struct stat st;
                lstat(ce->name, &st);
                fill_stat_cache_info(ce, &st);
        }
        return 0;
}

int checkout_entry(struct cache_entry *ce, struct checkout *state, char *topath)
{
        static char path[PATH_MAX + 1];
        struct stat st;
        int len = state->base_dir_len;

        if (topath)
                return write_entry(ce, topath, state, 1);

        memcpy(path, state->base_dir, len);
        strcpy(path + len, ce->name);

        if (!lstat(path, &st)) {
                unsigned changed = ce_match_stat(ce, &st, 1);
                if (!changed)
                        return 0;
                if (!state->force) {
                        if (!state->quiet)
                                fprintf(stderr, "git-checkout-index: %s already exists\n", path);
                        return -1;
                }

                /*
                 * We unlink the old file, to get the new one with the
                 * right permissions (including umask, which is nasty
                 * to emulate by hand - much easier to let the system
                 * just do the right thing)
                 */
                unlink(path);
                if (S_ISDIR(st.st_mode)) {
                        if (!state->force)
                                return error("%s is a directory", path);
                        remove_subtree(path);
                }
        } else if (state->not_new)
                return 0;
        create_directories(path, state);
        return write_entry(ce, path, state, 0);
}