/*
 *
  ***** BEGIN LICENSE BLOCK *****
 
  Copyright (C) 2009-2017 Olof Hagsand and Benny Holmgren

  This file is part of CLIXON.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

  Alternatively, the contents of this file may be used under the terms of
  the GNU General Public License Version 3 or later (the "GPL"),
  in which case the provisions of the GPL are applicable instead
  of those above. If you wish to allow use of your version of this file only
  under the terms of the GPL, and not to allow others to
  use your version of this file under the terms of Apache License version 2, 
  indicate your decision by deleting the provisions above and replace them with
  the  notice and other provisions required by the GPL. If you do not delete
  the provisions above, a recipient may use your version of this file under
  the terms of any one of the Apache License version 2 or the GPL.

  ***** END LICENSE BLOCK *****
 */

#ifdef HAVE_CONFIG_H
#include "clixon_config.h" /* generated by config & autoconf */
#endif

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <limits.h>
#include <fnmatch.h>
#include <stdint.h>
#include <sys/stat.h>
#include <unistd.h>
#include <dirent.h>
#include <assert.h>
#include <syslog.h>

/* cligen */
#include <cligen/cligen.h>

/* clicon */
#include <clixon/clixon.h>

#include "clixon_xmldb_text.h"

/*! Database locking for candidate and running non-persistent
 * Store an integer for running and candidate containing
 * the session-id of the client holding the lock.
 */
static int _running_locked = 0;
static int _candidate_locked = 0;
static int _startup_locked = 0;

/*! Translate from symbolic database name to actual filename in file-system
 * @param[in]   h        Clicon handle
 * @param[in]   db       Symbolic database name, eg "candidate", "running"
 * @param[out]  filename Filename. Unallocate after use with free()
 * @retval      0        OK
 * @retval     -1        Error
 * @note Could need a way to extend which databases exists, eg to register new.
 * The currently allowed databases are: 
 *   candidate, tmp, running, result
 * The filename reside in CLICON_XMLDB_DIR option
 */
static int
db2file(clicon_handle h, 
	char         *db,
	char        **filename)
{
    int   retval = -1;
    cbuf *cb;
    char *dir;

    if ((cb = cbuf_new()) == NULL){
	clicon_err(OE_XML, errno, "cbuf_new");
	goto done;
    }
    if ((dir = clicon_xmldb_dir(h)) == NULL){
	clicon_err(OE_XML, errno, "CLICON_XMLDB_DIR not set");
	goto done;
    }
    if (strcmp(db, "running") != 0 && 
	strcmp(db, "candidate") != 0 && 
	strcmp(db, "startup") != 0 && 
	strcmp(db, "tmp") != 0){
	clicon_err(OE_XML, 0, "Unexpected database: %s", db);
	goto done;
    }
    cprintf(cb, "%s/%s_db", dir, db);
    if ((*filename = strdup4(cbuf_get(cb))) == NULL){
	clicon_err(OE_UNIX, errno, "strdup");
	goto done;
    }
    retval = 0;
 done:
    if (cb)
	cbuf_free(cb);
    return retval;
}

/*! Get content of database using xpath. return a set of matching sub-trees
 * The function returns a minimal tree that includes all sub-trees that match
 * xpath.
 * @param[in]  dbname Name of database to search in (filename including dir path
 * @param[in]  xpath  String with XPATH syntax. or NULL for all
 * @param[in]  yspec  Yang specification
 * @param[out] xtop   Single XML tree which xvec points to. Free with xml_free()
 * @param[out] xvec   Vector of xml trees. Free after use.
 * @param[out] xlen   Length of vector.
 * @retval     0      OK
 * @retval     -1     Error
 * @code
 *   cxobj   *xt;
 *   cxobj  **xvec;
 *   size_t   xlen;
 *   yang_spec *yspec = clicon_dbspec_yang(h);
 *   if (xmldb_get("running", "/interfaces/interface[name="eth"]", 
 *                 &xt, &xvec, &xlen) < 0)
 *      err;
 *   for (i=0; i<xlen; i++){
 *      xn = xv[i];
 *      ...
 *   }
 *   xml_free(xt);
 *   free(xvec);
 * @endcode
 * @note if xvec is given, then purge tree, if not return whole tree.
 * @see xpath_vec
 * @see xmldb_get
 */
int
text_get(clicon_handle h,
	  char         *db, 
	  char         *xpath,
	  cxobj       **xtop,
	  cxobj      ***xvec0,
	  size_t       *xlen0)
{
    int             retval = -1;

    retval = 0;
    // done:
    return retval;

}


/*! Modify database provided an xml tree and an operation
 *
 * @param[in]  h      CLICON handle
 * @param[in]  db     running or candidate
 * @param[in]  xt     xml-tree. Top-level symbol is dummy
 * @param[in]  op     OP_MERGE: just add it. 
 *                    OP_REPLACE: first delete whole database
 *                    OP_NONE: operation attribute in xml determines operation
 * @param[in]  api_path According to restconf (Sec 3.5.1.1 in [restconf-draft 13])
 * @retval     0      OK
 * @retval     -1     Error
 * The xml may contain the "operation" attribute which defines the operation.
 * @code
 *   cxobj     *xt;
 *   if (clicon_xml_parse_str("<a>17</a>", &xt) < 0)
 *     err;
 *   if (xmldb_put(h, "running", OP_MERGE, NULL, xt) < 0)
 *     err;
 * @endcode
 * @see xmldb_put_xkey  for single key
 */
int
text_put(clicon_handle       h,
       char               *db, 
       enum operation_type op,
       char               *api_path,
       cxobj              *xt) 
{
    int        retval = -1;
    retval = 0;
    // done:
    return retval;
}

/*! Raw dump of database, just keys and values, no xml interpretation 
 * @param[in]  f       File
 * @param[in]  dbfile  File-name of database. This is a local file
 * @param[in]  rxkey   Key regexp, eg "^.*$"
 * @note This function can only be called locally.
 */
int
text_dump(FILE         *f,
	char         *dbfilename, 
	char         *rxkey)
{
    int             retval = -1;

    retval = 0;
    // done:
    return retval;
}

/*! Copy database from db1 to db2
 * @param[in]  h     Clicon handle
 * @param[in]  from  Source database copy
 * @param[in]  to    Destination database
 * @retval -1  Error
 * @retval  0  OK
  */
int 
text_copy(clicon_handle h, 
	char         *from,
	char         *to)
{
    int           retval = -1;
    retval = 0;
    // done:
    return retval;
}

/*! Lock database
 * @param[in]  h    Clicon handle
 * @param[in]  db   Database
 * @param[in]  pid  Process id
 * @retval -1  Error
 * @retval  0  OK
  */
int 
text_lock(clicon_handle h, 
	char         *db,
	int           pid)
{
    if (strcmp("running", db) == 0)
	_running_locked = pid;
    else if (strcmp("candidate", db) == 0)
	_candidate_locked = pid;
    else if (strcmp("startup", db) == 0)
	_startup_locked = pid;
    clicon_debug(1, "%s: locked by %u",  db, pid);
    return 0;
}

/*! Unlock database
 * @param[in]  h   Clicon handle
 * @param[in]  db  Database
 * @param[in]  pid  Process id
 * @retval -1  Error
 * @retval  0  OK
 * Assume all sanity checks have been made
 */
int 
text_unlock(clicon_handle h, 
	  char         *db,
	  int           pid)
{
    if (strcmp("running", db) == 0)
	_running_locked = 0;
    else if (strcmp("candidate", db) == 0)
	_candidate_locked = 0;
    else if (strcmp("startup", db) == 0)
	_startup_locked = 0;
    return 0;
}

/*! Unlock all databases locked by pid (eg process dies) 
 * @param[in]    h   Clicon handle
 * @param[in]    pid Process / Session id
 * @retval -1    Error
 * @retval   0   Ok
 */
int 
text_unlock_all(clicon_handle h, 
	      int           pid)
{
    if (_running_locked == pid)
	_running_locked = 0;
    if (_candidate_locked == pid)
	_candidate_locked = 0;
    if (_startup_locked == pid)
	_startup_locked = 0;
    return 0;
}

/*! Check if database is locked
 * @param[in]    h   Clicon handle
 * @param[in]    db  Database
 * @retval -1    Error
 * @retval   0   Not locked
 * @retval  >0   Id of locker
  */
int 
text_islocked(clicon_handle h, 
	    char         *db)
{
    if (strcmp("running", db) == 0)
	return (_running_locked);
    else if (strcmp("candidate", db) == 0)
	return(_candidate_locked);
    else if (strcmp("startup", db) == 0)
	return(_startup_locked);
    return 0;
}

/*! Check if db exists 
 * @param[in]  h   Clicon handle
 * @param[in]  db  Database
 * @retval -1  Error
 * @retval  0  No it does not exist
 * @retval  1  Yes it exists
 */
int 
text_exists(clicon_handle h, 
	  char         *db)
{
    int           retval = -1;
    char         *filename = NULL;
    struct stat  sb;

    if (db2file(h, db, &filename) < 0)
	goto done;
    if (lstat(filename, &sb) < 0)
	retval = 0;
    else
	retval = 1;
 done:
    if (filename)
	free(filename);
    return retval;
}

/*! Delete database. Remove file 
 * @param[in]  h   Clicon handle
 * @param[in]  db  Database
 * @retval -1  Error
 * @retval  0  OK
 */
int 
text_delete(clicon_handle h, 
	  char         *db)
{
    int           retval = -1;

    retval = 0;
    // done:
    return retval;
}

/*! Initialize database 
 * @param[in]  h   Clicon handle
 * @param[in]  db  Database
 * @retval  0  OK
 * @retval -1  Error
 */
int 
text_init(clicon_handle h, 
	  char         *db)
{
    int           retval = -1;

    retval = 0;
    // done:
    return retval;
}

/*! plugin init function */
int
text_plugin_exit(void)
{
    return 0;
}

static const struct xmldb_api api;

/*! plugin init function */
void *
clixon_xmldb_plugin_init(int version)
{
    if (version != XMLDB_API_VERSION){
	clicon_err(OE_DB, 0, "Invalid version %d expected %d", 
		   version, XMLDB_API_VERSION);
	goto done;
    }
    return (void*)&api;
 done:
    return NULL;
}

static const struct xmldb_api api = {
    1,
    XMLDB_API_MAGIC,
    clixon_xmldb_plugin_init,
    text_plugin_exit,
    text_get,
    text_put,
    text_dump,
    text_copy,
    text_lock,
    text_unlock,
    text_unlock_all,
    text_islocked,
    text_exists,
    text_delete,
    text_init,
};


#if 0 /* Test program */
/*
 * Turn this on to get an xpath test program 
 * Usage: clicon_xpath [<xpath>] 
 * read xml from input
 * Example compile:
 gcc -g -o xmldb -I. -I../clixon ./clixon_xmldb.c -lclixon -lcligen
*/

static int
usage(char *argv0)
{
    fprintf(stderr, "usage:\n%s\tget <db> <yangdir> <yangmod> [<xpath>]\t\txml on stdin\n", argv0);
    fprintf(stderr, "\tput <db> <yangdir> <yangmod> set|merge|delete\txml to stdout\n");
    exit(0);
}

int
main(int argc, char **argv)
{
    cxobj      *xt;
    cxobj      *xn;
    char       *xpath;
    enum operation_type      op;
    char       *cmd;
    char       *db;
    char       *yangdir;
    char       *yangmod;
    yang_spec  *yspec = NULL;
    clicon_handle h;

    if ((h = clicon_handle_init()) == NULL)
	goto done;
    clicon_log_init("xmldb", LOG_DEBUG, CLICON_LOG_STDERR);
    if (argc < 4){
	usage(argv[0]);
	goto done;
    }
    cmd = argv[1];
    db = argv[2];
    yangdir = argv[3];
    yangmod = argv[4];
    db_init(db);
    if ((yspec = yspec_new()) == NULL)
	goto done
    if (yang_parse(h, yangdir, yangmod, NULL, yspec) < 0)
	goto done;
    if (strcmp(cmd, "get")==0){
	if (argc < 5)
	    usage(argv[0]);
	xpath = argc>5?argv[5]:NULL;
	if (xmldb_get(h, db, xpath, &xt, NULL, NULL) < 0)
	    goto done;
	clicon_xml2file(stdout, xt, 0, 1);	
    }
    else
    if (strcmp(cmd, "put")==0){
	if (argc != 6)
	    usage(argv[0]);
	if (clicon_xml_parse_file(0, &xt, "</clicon>") < 0)
	    goto done;
	if (xml_rootchild(xt, 0, &xn) < 0)
	    goto done;
	if (strcmp(argv[5], "set") == 0)
	    op = OP_REPLACE;
	else 	
	    if (strcmp(argv[4], "merge") == 0)
	    op = OP_MERGE;
	else 	if (strcmp(argv[5], "delete") == 0)
	    op = OP_REMOVE;
	else
	    usage(argv[0]);
	if (xmldb_put(h, db, op, NULL, xn) < 0)
	    goto done;
    }
    else
	usage(argv[0]);
    printf("\n");
 done:
    return 0;
}

#endif /* Test program */