#include <sys/types.h>
#include <dirent.h>
#include "cache.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, 0755)) {
			if (errno == EEXIST) {
				struct stat st;
				if (len > state->base_dir_len && state->force && !unlink(buf) && !mkdir(buf, 0755))
					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, int force)
{
	int fd;

	mode = (mode & 0100) ? 0777 : 0666;
	fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
	if (fd < 0) {
		if (errno == EISDIR && force) {
			remove_subtree(path);
			fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
		}
	}
	return fd;
}

static int write_entry(struct cache_entry *ce, const char *path, struct checkout *state)
{
	int fd;
	void *new;
	unsigned long size;
	long wrote;
	char type[20];
	char target[1024];

	new = read_sha1_file(ce->sha1, type, &size);
	if (!new || strcmp(type, "blob")) {
		if (new)
			free(new);
		return error("git-checkout-cache: unable to read sha1 file of %s (%s)",
			path, sha1_to_hex(ce->sha1));
	}
	switch (ntohl(ce->ce_mode) & S_IFMT) {
	case S_IFREG:
		fd = create_file(path, ntohl(ce->ce_mode), state->force);
		if (fd < 0) {
			free(new);
			return error("git-checkout-cache: 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-cache: unable to write file %s", path);
		break;
	case S_IFLNK:
		memcpy(target, new, size);
		target[size] = '\0';
		if (symlink(target, path)) {
			free(new);
			return error("git-checkout-cache: unable to create symlink %s (%s)",
				path, strerror(errno));
		}
		free(new);
		break;
	default:
		free(new);
		return error("git-checkout-cache: 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)
{
	struct stat st;
	static char path[MAXPATHLEN+1];
	int len = state->base_dir_len;

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

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

		/*
		 * 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);
	} else if (state->not_new) 
		return 0;
	create_directories(path, state);
	return write_entry(ce, path, state);
}