#include <stdio.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdarg.h>
#include <inttypes.h>
#include <sys/types.h>
#include <dirent.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <sqlite3.h>
#include <systemd/sd-bus.h>
#include <sys/inotify.h>

#include "utils.h"
#include "shared.h"
#include "rcm-server-main.h"
#include "rcm-server-kdb.h"
#include "rcm-server-keymap.h"

struct inotify_dir {
	int iwd;
	int dfd;
	int64_t dirid;
	struct list_head list;
};

static LIST_HEAD(inotify_dir_list);

DEFINE_TRIVIAL_CLEANUP_FUNC(sqlite3_stmt *, sqlite3_finalize);
#define _cleanup_finalize_stmt_ _cleanup_(sqlite3_finalizep)

DEFINE_TRIVIAL_CLEANUP_FUNC(sqlite3 *, sqlite3_close);
#define _cleanup_sqlite3_close_ _cleanup_(sqlite3_closep)

static int
_sql_do_prep(sqlite3 *db, sqlite3_stmt **stmt_out, const char *sql, int nbyte, va_list ap)
{
	_cleanup_finalize_stmt_ sqlite3_stmt *stmt = NULL;
	unsigned i;
	int r;

	r = sqlite3_prepare_v2(db, sql, nbyte, &stmt, NULL);
	if (r != SQLITE_OK) {
		fprintf(stderr, "SQL error: %s - %s\n", sql, sqlite3_errmsg(db));
		return -EIO;
	}

	for (i = 0; i < sqlite3_bind_parameter_count(stmt); i++) {
		int type;

		type = va_arg(ap, int);
		switch (type) {
		case SQLITE_INTEGER:
			r = sqlite3_bind_int64(stmt, i + 1, va_arg(ap, int64_t));
			break;
		case SQLITE_TEXT:
			r = sqlite3_bind_text(stmt, i + 1, va_arg(ap, char *), -1, SQLITE_STATIC);
			break;
		default:
			fprintf(stderr, "SQL error: %s - invalid type (%i)\n", sql, type);
			return -EINVAL;
		}

		if (r != SQLITE_OK) {
			fprintf(stderr, "SQL error: %s - %s\n", sql, sqlite3_errmsg(db));
			return -EIO;
		}
	}

	*stmt_out = stmt;
	stmt = NULL;
	return 0;
}

static int
_sql_prep(sqlite3 *db, sqlite3_stmt **stmt_out, const char *sql, int nbyte, ...)
{
	va_list ap;
	int r;

	va_start(ap, nbyte);
	r = _sql_do_prep(db, stmt_out, sql, nbyte, ap);
	va_end(ap);
	return r;
}
#define sql_prep(db, stmt, sql, ...) _sql_prep((db), (stmt), (sql), strlen((sql)) + 1, __VA_ARGS__)

static int
_sql_get_row(sqlite3_stmt *stmt, va_list ap)
{
	unsigned i;
	int64_t *vint;
	const char **vchar;
	int r;


	r = sqlite3_step(stmt);
	if (r == SQLITE_DONE)
		return 0;
	else if (r != SQLITE_ROW)
		return -r;

	for (i = 0; i < sqlite3_column_count(stmt); i++) {
		int type = sqlite3_column_type(stmt, i);

		switch (type) {
		case SQLITE_INTEGER:
			vint = va_arg(ap, int64_t *);
			*vint = sqlite3_column_int64(stmt, i);
			break;
		case SQLITE_TEXT:
			vchar = va_arg(ap, const char **);
			*vchar = (const char *)sqlite3_column_text(stmt, i);
			break;
		default:
			fprintf(stderr, "SQL error: invalid type (%i)\n", type);
			r = -SQLITE_ERROR;
			goto out;
		}
	}

	return 1;

out:
	return r;
}

static int
sql_get_row(sqlite3_stmt *stmt, ...)
{
	va_list ap;
	int r;

	va_start(ap, stmt);
	r = _sql_get_row(stmt, ap);
	va_end(ap);

	return r;
}

static int
sql_get_single_row(sqlite3_stmt *stmt, ...)
{
	va_list ap;
	int r;

	va_start(ap, stmt);
	r = _sql_get_row(stmt, ap);
	va_end(ap);

	if (r < 1)
		return r;

	r = sqlite3_step(stmt);
	if (r != SQLITE_DONE)
		return -EIO;

	return 1;
}

static int
_sql_exec(sqlite3 *db, const char *sql, int nbyte, ...)
{
	_cleanup_finalize_stmt_ sqlite3_stmt *stmt = NULL;
	va_list ap;
	int r;

	va_start(ap, nbyte);
	r = _sql_do_prep(db, &stmt, sql, nbyte, ap);
	va_end(ap);

	if (r < 0 )
		return r;

	r = sqlite3_step(stmt);

	if (r != SQLITE_DONE) {
		fprintf(stderr, "sql_exec: unexpected return code (%i) for query %s\n", r, sql);
		return -EIO;
	}

	return 0;
}
#define sql_exec(db, sql, ...) _sql_exec((db), (sql), strlen((sql)) + 1, __VA_ARGS__)

static uint64_t
mtime_in_nsec(struct stat *stat)
{
	return (uint64_t)stat->st_atim.tv_sec * 1000000000 +
	       (uint64_t)stat->st_atim.tv_nsec;
}

static int
get_directory(sqlite3 *db, const char *path, int64_t *dirid, uint64_t *mtime)
{
	_cleanup_finalize_stmt_ sqlite3_stmt *stmt = NULL;
	int r;

	r = sql_prep(db, &stmt,
		     "SELECT dirid, mtime FROM directories WHERE abspath = :PATH;",
		     SQLITE_TEXT, path);
	if (r < 0)
		return r;

	r = sql_get_single_row(stmt, dirid, mtime);
	return r;
}

static void
kdb_check_file(struct manager *mgr, int dfd, int64_t dirid, int64_t fileid, const char *filename, uint64_t db_mtime)
{
	struct stat stat;
	uint64_t file_mtime;
	_cleanup_keymap_free_ struct keymap *keymap = NULL;
	int r;

	printf("%s: check file %s (id %" PRIi64 " dir %" PRIi64 " dirfd %i db_mtime %" PRIu64 ")\n",
	       __FUNCTION__, filename, fileid, dirid, dfd, db_mtime);

	if (dfd < 0 || !filename) {
		printf("Invalid");
		return;
	}

	if (fstatat(dfd, filename, &stat, AT_SYMLINK_NOFOLLOW) < 0) {
		fprintf(stderr, "\tfstatat(%s) - failed: %m\n", filename);
		goto out;
	}

	if ((stat.st_mode & S_IFMT) != S_IFREG) {
		printf("\t%s - not a regular file\n", filename);
		goto out;
	}

	file_mtime = mtime_in_nsec(&stat);
	if (fileid >= 0) {
		if (file_mtime <= db_mtime) {
			printf("\t%s - file not older than db entry, skipped\n", filename);
			return;
		}

		r = sql_exec(mgr->db,
			     "DELETE FROM keymap WHERE fileid = :FILEID;",
			     SQLITE_INTEGER, fileid);
		if (r < 0) {
			printf("\t%s - failed to clean out old entries\n", filename);
			goto out;
		}
	}

	keymap = keymap_read(dfd, ".", filename);
	if (!keymap) {
		printf("\t%s - unable to parse keymap, skipped\n", filename);
		goto out;
	}

	if (fileid >= 0) {
		r = sql_exec(mgr->db, "UPDATE files SET name = :NAME, desc = :DESC, scanned = 1, mtime = :MTIME"
			     " WHERE fileid = :FILEID",
			     SQLITE_TEXT, keymap->name, SQLITE_TEXT, keymap->description,
			     SQLITE_INTEGER, file_mtime, SQLITE_INTEGER, fileid);
		if (r < 0) {
			printf("\t%s - failed to update old file entry\n", filename);
			goto out;
		}
		
	} else {
		r = sql_exec(mgr->db, "INSERT INTO files (dirid, filename, name, desc, scanned, mtime)"
			     " VALUES (:DIRID, :FILENAME, :NAME, :DESC, 1, :MTIME);",
			     SQLITE_INTEGER, dirid, SQLITE_TEXT, filename,
			     SQLITE_TEXT, keymap->name, SQLITE_TEXT, keymap->description,
			     SQLITE_INTEGER, file_mtime);
		if (r < 0) {
			printf("\t%s - failed to create new file entry\n", filename);
			goto out;
		}

		fileid = sqlite3_last_insert_rowid(mgr->db);
	}

	for (unsigned i = 0; i < keymap->keycode_count; i++) {
		printf("\t%s - inserting entry %u/%u 0x%08" PRIx64 ":0x%08" PRIx64 ":0x%08" PRIx64 "\n",
		       filename, i, keymap->keycode_count,
		       (int64_t)keymap->keycodes[i].protocol,
		       (int64_t)keymap->keycodes[i].scancode,
		       (int64_t)keymap->keycodes[i].lik->value);

		r = sql_exec(mgr->db, "INSERT INTO keymap (fileid, protocol, scancode, keycode)"
			     " VALUES (:FILEID, :PROTOCOL, :SCANCODE, :KEYCODE);",
			     SQLITE_INTEGER, fileid,
			     SQLITE_INTEGER, (int64_t)keymap->keycodes[i].protocol,
			     SQLITE_INTEGER, (int64_t)keymap->keycodes[i].scancode,
			     SQLITE_INTEGER, (int64_t)keymap->keycodes[i].lik->value);
		if (r < 0) {
			printf("\t%s - failed to insert keymap entry\n", filename);
			goto out;
		}
	}

	printf("%s - inserted into db with %u entries\n", filename, keymap->keycode_count);
	return;

out:
	if (fileid >= 0) {
		printf("\t%s - Deleting row from DB\n", filename);
		sql_exec(mgr->db,
			 "DELETE FROM files WHERE fileid = :FILEID;",
			 SQLITE_INTEGER, fileid);
	}
}

int
kdb_add_directory(struct manager *mgr, const char *path)
{
	sqlite3 *db = mgr->db;
	_cleanup_free_ char *abspath = NULL;
	_cleanup_free_ struct inotify_dir *in_dir = NULL;
	_cleanup_closedir_ DIR *dir = NULL;
	_cleanup_finalize_stmt_ sqlite3_stmt *stmt = NULL;
	struct dirent *dent;
	struct stat stat;
	uint64_t mtime;
	uint64_t old_mtime;
	int64_t dirid;
	int dfd;
	int r;

	abspath = realpath(path, NULL);
	if (!abspath) {
		r = -errno;
		fprintf(stderr, "realpath(%s) failed: %m\n", path);
		goto out;
	}

	printf("Scanning directory: %s (%s)\n", abspath, path);

	in_dir = malloc(sizeof(*in_dir));
	if (!in_dir) {
		r = -ENOMEM;
		fprintf(stderr, "malloc failed: %m\n");
		goto out;
	}
	in_dir->iwd = -1;
	in_dir->dfd = -1;
	in_dir->dirid = -1;

	dfd = open(abspath, O_RDONLY | O_CLOEXEC | O_DIRECTORY);
	if (dfd < 0) {
		r = -errno;
		fprintf(stderr, "open(%s) failed: %m\n", abspath);
		goto out;
	}
	in_dir->dfd = dfd;

	dfd = fcntl(in_dir->dfd, F_DUPFD_CLOEXEC);
	if (dfd < 0) {
		r = -errno;
		fprintf(stderr, "fcntl(%i, F_DUPFD_CLOEXEC) failed: %m\n", in_dir->dfd);
		goto out;
	}

	dir = fdopendir(dfd);
	if (!dir) {
		close(dfd);
		r = -errno;
		fprintf(stderr, "fdopendir(%i) failed: %m\n", dfd);
		goto out;
	}

	if (fstat(dirfd(dir), &stat) < 0) {
		r = -errno;
		fprintf(stderr, "fstat(%s) failed: %s\n", abspath, strerror(errno));
		goto out;
	}

	mtime = mtime_in_nsec(&stat);

	r = inotify_add_watch(mgr->db_ifd, abspath, IN_CLOSE_WRITE | IN_CREATE | IN_DELETE | IN_MOVE | IN_ONLYDIR);
	if (r < 0) {
		r = -errno;
		fprintf(stderr, "inotify_add_watch(%s) failed: %m\n", abspath);
		goto out;
	}
	in_dir->iwd = r;

	r = get_directory(db, abspath, &dirid, &old_mtime);
	if (r < 0) {
		fprintf(stderr, "get_directory(%s) failed: %i\n", abspath, r);
		goto out;

	} else if (r == 0) {
		printf("Adding new directory: %s\n", abspath);

		r = sql_exec(db,
			     "INSERT INTO directories (abspath, mtime) VALUES (:PATH, 0);",
			     SQLITE_TEXT, abspath);
		if (r < 0)
			goto out;

		dirid = (int64_t)sqlite3_last_insert_rowid(db);
		old_mtime = 0;

	} else {
		printf("Marking files in directory %s for a rescan\n", abspath);

		r = sql_exec(db,
			     "UPDATE files SET scanned = 0 WHERE dirid = :ID;",
			     SQLITE_INTEGER, dirid);
		if (r < 0)
			goto out;
	}

	in_dir->dirid = dirid;

	if (mtime > old_mtime) {
		/* Look for added files */
		printf("Directory %s modified, scanning for new files\n", abspath);
		errno = 0;

		while ((dent = readdir(dir)) != NULL) {
			if (dent->d_name[0] == '\0' || dent->d_name[0] == '.') {
				printf("\t%s - skipped\n", dent->d_name);
				errno = 0;
				continue;
			}

			switch (dent->d_type) {
			case DT_UNKNOWN:
				if (fstatat(dirfd(dir), dent->d_name, &stat, AT_SYMLINK_NOFOLLOW) < 0) {
					fprintf(stderr, "\tfstatat(%s) - failed: %s\n", dent->d_name, strerror(errno));
					errno = 0;
					continue;
				}

				if ((stat.st_mode & S_IFMT) != S_IFREG) {
					printf("\t%s - not a regular file\n", dent->d_name);
					errno = 0;
					continue;
				}

				/* fall through */

			case DT_REG:
				printf("\t%s - add (possibly) to DB\n", dent->d_name);
				r = sql_exec(db,
					     "INSERT OR IGNORE INTO"
					     " files (dirid, filename, name, scanned, mtime)"
					     " VALUES (:DIRID, :FILENAME, '', 0, 0);",
					     SQLITE_INTEGER, dirid,
					     SQLITE_TEXT, dent->d_name);
				if (r < 0)
					goto out;

				break;

			default:
				printf("\t%s - not a regular file\n", dent->d_name);
				break;
			}

			errno = 0;
		}

		if (errno != 0)
			fprintf(stderr, "readdir error: %s\n", strerror(errno));
	}

	/* check all files in db */
	r = sql_prep(db, &stmt,
		     "SELECT fileid, filename, mtime FROM files WHERE dirid = :DIRID AND scanned = 0;",
		     SQLITE_INTEGER, dirid);
	if (r < 0)
		goto out;
	else {
		int64_t fileid;
		char *filename;
		uint64_t mtime;

		while ((r = sql_get_row(stmt, &fileid, &filename, &mtime)) > 0)
			kdb_check_file(mgr, in_dir->dfd, dirid, fileid, filename, mtime);

		if (r < 0)
			goto out;
	}

	/* delete files not found during scan */
	r = sql_exec(db,
		     "DELETE FROM files WHERE dirid = :DIRID AND scanned = 0;",
		     SQLITE_INTEGER, dirid);
	if (r < 0)
		goto out;

	list_add(&in_dir->list, &inotify_dir_list);
	in_dir = NULL;
	return 0;

out:
	if (in_dir && in_dir->iwd >= 0)
		inotify_rm_watch(mgr->db_ifd, in_dir->iwd);
	if (in_dir && in_dir->dfd >= 0)
		close(in_dir->dfd);

	return r;
}

static int
create_tables(sqlite3 *db)
{
	int r;

	r = sql_exec(db,
		     "CREATE TABLE IF NOT EXISTS directories("
		     "  dirid	INTEGER PRIMARY KEY NOT NULL,"
		     "  abspath	TEXT UNIQUE NOT NULL,"
		     "  mtime	INTEGER NOT NULL"
		     ");", NULL);
	if (r != SQLITE_OK)
		goto out;

	r = sql_exec(db,
		     "CREATE TABLE IF NOT EXISTS files("
		     "  dirid	INTEGER NOT NULL REFERENCES directories(dirid) ON UPDATE CASCADE ON DELETE CASCADE,"
		     "  fileid	INTEGER PRIMARY KEY NOT NULL,"
		     "  filename	TEXT NOT NULL,"
		     "  name	TEXT NOT NULL,"
		     "  desc	TEXT,"
		     "  scanned	BOOLEAN NOT NULL CHECK (scanned IN (0,1)),"
		     "  mtime	INTEGER NOT NULL,"
		     "  UNIQUE(dirid, filename)"
		     ");", NULL);
	if (r != SQLITE_OK)
		goto out;

	r = sql_exec(db,
		     "CREATE TABLE IF NOT EXISTS keymap("
		     "  fileid	INTEGER NOT NULL REFERENCES files(fileid) ON UPDATE CASCADE ON DELETE CASCADE,"
		     "  protocol	INTEGER NOT NULL,"
		     "  scancode	INTEGER NOT NULL,"
		     "  keycode	INTEGER NOT NULL,"
		     "  UNIQUE(protocol, scancode)"
		     ");", NULL);
	if (r != SQLITE_OK)
		goto out;

	return SQLITE_OK;

out:
	return r;
}

static int
enable_foreign_keys(sqlite3 *db)
{
	sqlite3_stmt *stmt;
	bool supported = false;
	int r;

	sql_exec(db, "PRAGMA foreign_keys = ON;", NULL);

	r = sql_prep(db, &stmt, "PRAGMA foreign_keys;", NULL);
	if (r == SQLITE_OK) {
		int64_t value;

		r = sql_get_single_row(stmt, &value);
		if (r > 0 && value > 0)
			supported = true;
	}

	sqlite3_finalize(stmt);
	return supported ? SQLITE_OK : SQLITE_ERROR;
}

static int
inotify_read(sd_event_source *s, int fd, uint32_t revents, void *userdata)
{
	struct manager *mgr = userdata;
	char buf[sizeof(struct inotify_event) + NAME_MAX + 1] __attribute__ ((aligned(__alignof__(struct inotify_event))));
	struct inotify_event *ev = (struct inotify_event *)buf;
	ssize_t r;

	if (revents & EPOLLHUP) {
		fprintf(stderr, "kdb inotify connection closed!\n");
		return 0;
	}

	if (!(revents & EPOLLIN)) {
		fprintf(stderr, "unexpected udev event: %" PRIu32 "\n", revents);
		return 0;
	}

	while ((r = read(mgr->db_ifd, buf, sizeof(buf))) > 0) {
		struct inotify_dir *idir;
		sqlite3_stmt *stmt;
		int64_t fileid;
		uint64_t mtime;

		printf("Read inotify event:\n");
		printf("\tWD: %i\n", ev->wd);
		printf("\tMask: %08" PRIx32 "\n", ev->mask);
		printf("\tCookie: %08" PRIx32 "\n", ev->cookie);
		printf("\tLen: %" PRIu32 "\n", ev->len);
		printf("\tName: %s\n", ev->name);

		list_for_each_entry(idir, &inotify_dir_list, list) {

			if (idir->iwd != ev->wd)
				continue;

			printf("\tSQL dirid: %" PRIi64 "\n", idir->dirid);
			r = sql_prep(mgr->db, &stmt,
				     "SELECT fileid, mtime FROM files WHERE dirid = :DIRID AND filename = :FILENAME;",
				     SQLITE_INTEGER, idir->dirid, SQLITE_TEXT, ev->name);
			if (r < 0)
				break;

			fileid = -1;
			mtime = 0;
			r = sql_get_row(stmt, &fileid, &mtime);
			sqlite3_finalize(stmt);
			if (r < 0)
				break;

			printf("\tSQL fileid: %" PRIi64 "\n", fileid);
			printf("\tSQL mtime: %" PRIu64 "\n", mtime);
			kdb_check_file(mgr, idir->dfd, idir->dirid, fileid, ev->name, mtime);
			break;
		}
	}

	return 1;
};

int
kdb_init(struct manager *mgr, const char *path)
{
	_cleanup_close_ int ifd = -1;
	_cleanup_event_source_unref_ sd_event_source *ev = NULL;
	_cleanup_sqlite3_close_ sqlite3 *db = NULL;
	int r;

	ifd = inotify_init1(IN_NONBLOCK | IN_CLOEXEC);
	if (ifd < 0) {
		r = errno;
		fprintf(stderr, "Failed to create inotify instance: %s\n", strerror(r));
		return -r;
	}

	r = sd_event_add_io(mgr->event, &ev, ifd, EPOLLIN, inotify_read, mgr);
	if (r < 0) {
		fprintf(stderr, "Failed to add kdb inotify instance to event loop: %m\n");
		return r;
	}

	r = sqlite3_open_v2(path, &db, SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, NULL);
	if (r != SQLITE_OK) {
		fprintf(stderr, "Can't open database: (%i) %s\n", r, sqlite3_errmsg(db));
		return -1;
	}

	r = enable_foreign_keys(db);
	if (r != SQLITE_OK) {
		fprintf(stderr, "Failed to enable foreign keys\n");
		return -1;
	}

	r = create_tables(db);
	if (r != SQLITE_OK) {
		fprintf(stderr, "Failed to create tables\n");
		return -1;
	}

	mgr->db_ifd_ev = ev;
	mgr->db = db;
	mgr->db_ifd = ifd;
	ev = NULL;
	db = NULL;
	ifd = -1;
	return 0;
}

void
kdb_close(struct manager *mgr)
{
	struct inotify_dir *idir;
	struct inotify_dir *tmp;

	list_for_each_entry_safe(idir, tmp, &inotify_dir_list, list) {
		if (idir->dfd >= 0)
			close(idir->dfd);
		list_del(&idir->list);
		free(idir);
	}

	sqlite3_close(mgr->db);
	close(mgr->db_ifd);
	sd_event_source_unref(mgr->db_ifd_ev);
}