#define FUSE_USE_VERSION 26

#include <sys/types.h>
#include <sqlite3.h>
#include <pthread.h>
#include <string.h>
#include <stdarg.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <fuse.h>
#include <pwd.h>
#include <tcl.h>

#ifndef APPFS_CACHEDIR
#define APPFS_CACHEDIR "/var/cache/appfs"
#endif

#ifdef DEBUG
#define APPFS_DEBUG(x...) { fprintf(stderr, "[debug] %s:%i:%s: ", __FILE__, __LINE__, __func__); fprintf(stderr, x); fprintf(stderr, "\n"); }
#else
#define APPFS_DEBUG(x...) /**/
#endif

static pthread_key_t interpKey;

struct appfs_thread_data {
	sqlite3 *db;
	const char *cachedir;
	time_t boottime;
	const char *platform;
	struct {
		int writable;
	} options;
};

struct appfs_thread_data globalThread;

typedef enum {
	APPFS_PATHTYPE_INVALID,
	APPFS_PATHTYPE_FILE,

	obj->_next = *head_p;
	*head_p = obj;

	return(0);
	
}

static uid_t appfs_get_fsuid(void) {
	struct fuse_context *ctx;

	ctx = fuse_get_context();
	if (ctx == NULL) {
		return(1);
	}

	return(ctx->uid);
}

static const char *appfs_get_homedir(uid_t fsuid) {
	struct passwd entry, *result;
	struct stat stbuf;
	char buf[1024], *retval;
	int gpu_ret, stat_ret;

	gpu_ret = getpwuid_r(fsuid, &entry, buf, sizeof(buf), &result);
	if (gpu_ret != 0) {
		APPFS_DEBUG("getpwuid_r(%llu, ...) returned in failure", (unsigned long long) fsuid);

		return(NULL);
	}

	if (result == NULL) {
		APPFS_DEBUG("getpwuid_r(%llu, ...) returned NULL result", (unsigned long long) fsuid);

		return(NULL);
	}

	if (result->pw_dir == NULL) {
		APPFS_DEBUG("getpwuid_r(%llu, ...) returned NULL home directory", (unsigned long long) fsuid);

		return(NULL);
	}

	stat_ret = stat(result->pw_dir, &stbuf);
	if (stat_ret != 0) {
		APPFS_DEBUG("stat(%s) returned in failure", result->pw_dir);

		return(NULL);
	}

	if (stbuf.st_uid != fsuid) {
		APPFS_DEBUG("UID mis-match on user %llu's home directory (%s).  It's owned by %llu.",
		    (unsigned long long) fsuid,
		    result->pw_dir,
		    (unsigned long long) stbuf.st_uid
		);

		return(NULL);
	}

	retval = sqlite3_mprintf("%s", result->pw_dir);

	return(retval);
}

static struct appfs_children *appfs_getchildren_fs(struct appfs_children *in_children, const char *fspath) {
	APPFS_DEBUG("Searching %s", fspath);

	return(in_children);
}

static struct appfs_children *appfs_getchildren(const char *hostname, const char *package_hash, const char *path, int *children_count_p) {
	struct appfs_children *head = NULL;
	char *sql, *filebuf, *homedir = NULL;
	int sqlite_ret;
	uid_t fsuid;

	if (children_count_p == NULL) {
		return(NULL);
	}

	appfs_update_index(hostname);
	appfs_update_manifest(hostname, package_hash);

	if (sqlite_ret != SQLITE_OK) {
		APPFS_DEBUG("Call to sqlite3_exec failed.");

		appfs_free_list_children(head);

		return(NULL);
	}

	if (globalThread.options.writable) {
		/* Determine user of process accessing this file */
		fsuid = appfs_get_fsuid();

		/* Check filesystem paths for updated files */
		/** Check the global directory (/etc) **/
		filebuf = sqlite3_mprintf("/etc/appfs/%s/%s", package_hash, path);
		if (filebuf == NULL) {
			APPFS_DEBUG("Call to sqlite3_mprintf failed.");

			return(NULL);
		}

		head = appfs_getchildren_fs(head, filebuf);

		sqlite3_free(filebuf);

		/** Check the user's directory, if we are not root **/
		if (fsuid != 0) {
			homedir = (char *) appfs_get_homedir(fsuid);
		}

		if (homedir != NULL) {
			filebuf = sqlite3_mprintf("%z/.appfs/%s/%s", homedir, package_hash, path);

			if (filebuf == NULL) {
				APPFS_DEBUG("Call to sqlite3_mprintf failed.");

				return(NULL);
			}

			head = appfs_getchildren_fs(head, filebuf);

			sqlite3_free(filebuf);
		}
	}

	if (head != NULL) {
		*children_count_p = head->counter + 1;
	} else {
		*children_count_p = 0;
	}

	return(head);
}

static int appfs_sqlite3_query_cb(void *_cb_handle, int columns, char **values, char **names) {
	struct appfs_sqlite3_query_cb_handle *cb_handle;

	memset(stbuf, 0, sizeof(struct stat));

	stbuf->st_mtime = pathinfo.time;
	stbuf->st_ctime = pathinfo.time;
	stbuf->st_atime = pathinfo.time;
	stbuf->st_ino   = pathinfo.inode;
	stbuf->st_mode  = 0;

	switch (pathinfo.type) {
		case APPFS_PATHTYPE_DIRECTORY:
			stbuf->st_mode = S_IFDIR | 0555;
			stbuf->st_nlink = 2 + pathinfo.typeinfo.dir.childcount;
			break;
		case APPFS_PATHTYPE_FILE:

			stbuf->st_size = pathinfo.typeinfo.symlink.size;
			break;
		case APPFS_PATHTYPE_INVALID:
			res = -EIO;

			break;
	}

	if (globalThread.options.writable) {
		stbuf->st_mode |= 0222;
	}

	return res;
}

static int appfs_fuse_readdir(const char *path, void *buf, fuse_fill_dir_t filler, off_t offset, struct fuse_file_info *fi) {
	struct appfs_pathinfo pathinfo;
	struct appfs_children *children, *child;

	const char *cachedir = APPFS_CACHEDIR;
	char dbfilename[1024];
	int pthread_ret, snprintf_ret, sqlite_ret;

	globalThread.cachedir = cachedir;
	globalThread.boottime = time(NULL);
	globalThread.platform = "linux-x86_64";
	globalThread.options.writable = 1;

	pthread_ret = pthread_key_create(&interpKey, NULL);
	if (pthread_ret != 0) {
		fprintf(stderr, "Unable to create TSD key for Tcl.  Aborting.\n");

		return(1);
	}