/*
 *
  ***** 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 *****

 *
 * Translation between database specs
 *   yang_spec                   CLIgen parse_tree
 *  +-------------+   yang2cli    +-------------+
 *  |             | ------------> | cli         |
 *  | list{key A;}|               | syntax      |
 *  +-------------+               +-------------+
 */
#ifdef HAVE_CONFIG_H
#include "clixon_config.h" /* generated by config & autoconf */
#endif


#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <assert.h>
#include <fcntl.h>
#include <sys/param.h>


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

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

#include "clixon_cli_api.h"
#include "cli_plugin.h"
#include "cli_generate.h"

/* This is the default callback function. But this is typically overwritten */
#define GENERATE_CALLBACK "overwrite_me"

/* variable expand function */
#define GENERATE_EXPAND_XMLDB "expand_dbvar"

/*=====================================================================
 * YANG generate CLI
 *=====================================================================*/
/*
 This is an example yang module:
module m {
  container x {
    list m1 {
      key "a";
      leaf a {
        type string;
      }
      leaf b {
        type string;
      }
    }
  }
}

You can see which CLISPEC it generates via clixon_cli -D 1:
Jan  2 11:17:58: yang2cli: buf
}   x,cli_set("/x");{
      m1         (<a:string>|<a:string expand_dbvar("candidate /x/m1/%s/a")>),cli_set("/x/m1/%s");
{
         b (<b:string>|<b:string expand_dbvar("candidate /x/m1/%s/b")>),cli_set("/x/m1/%s/b");
      }
   }
*/

/*! Create cligen variable expand entry with xmlkey format string as argument
 * @param[in]  h      clicon handle
 * @param[in]  ys     yang_stmt of the node at hand
 * @param[in]  cvtype Type of the cligen variable
 * @param[in]  cb0    The string where the result format string is inserted.
 * @param[in]  options 
 * @param[in]  fraction_digits

 * @see expand_dbvar  This is where the expand string is used
 * @note XXX only fraction_digits handled,should also have mincv, maxcv, pattern
 */
static int
cli_expand_var_generate(clicon_handle h, 
			yang_stmt    *ys, 
			enum cv_type  cvtype,
			cbuf         *cb0,
			int           options,
			uint8_t       fraction_digits)
{
    int   retval = -1;
    char *api_path_fmt = NULL;

    if (yang2api_path_fmt(ys, 1, &api_path_fmt) < 0)
	goto done;
    cprintf(cb0, "|<%s:%s",  ys->ys_argument, 
	    cv_type2str(cvtype));
    if (options & YANG_OPTIONS_FRACTION_DIGITS)
	cprintf(cb0, " fraction-digits:%u", fraction_digits);
    cprintf(cb0, " %s(\"candidate\",\"%s\")>",
	    GENERATE_EXPAND_XMLDB,
	    api_path_fmt);
    retval = 0;
 done:
    if (api_path_fmt)
	free(api_path_fmt);
    return retval;
}

/*! Create callback with api_path format string as argument
 * @param[in]  h   clicon handle
 * @param[in]  ys  yang_stmt of the node at hand
 * @param[in]  cb0 The string where the result format string is inserted.
 * @see cli_dbxml  This is where the xmlkeyfmt string is used
 */
static int
cli_callback_generate(clicon_handle h, 
		      yang_stmt    *ys, 
		      cbuf         *cb0)
{
    int        retval = -1;
    char      *api_path_fmt = NULL;

    if (yang2api_path_fmt(ys, 0, &api_path_fmt) < 0)
	goto done;
    cprintf(cb0, ",%s(\"%s\")", GENERATE_CALLBACK, 
	    api_path_fmt);
    retval = 0;
 done:
    if (api_path_fmt)
	free(api_path_fmt);
    return retval;
}

static int yang2cli_stmt(clicon_handle h, yang_stmt    *ys, 
			 cbuf         *cb0,    
			 enum genmodel_type gt,
			 int           level);

/*! Check for completion (of already existent values), ranges (eg range[min:max]) and
 * patterns, (eg regexp:"[0.9]*").
 */
static int
yang2cli_var_sub(clicon_handle h,
		 yang_stmt    *ys, 
		 cbuf         *cb0,    
		 char         *helptext,
		 enum cv_type  cvtype,
		 yang_stmt    *ytype,  /* resolved type */
		 int           options,
		 cg_var       *mincv,
		 cg_var       *maxcv,
		 char         *pattern,
		 uint8_t       fraction_digits
    )
{
    int           retval = -1;
    char         *type;
    char         *r;
    yang_stmt    *yi = NULL;
    int           i = 0;
    char         *cvtypestr;
    int           completion;

    /* enumeration already gives completion */
    if (cvtype == CGV_VOID){
	retval = 0;
	goto done;
    }
    type = ytype?ytype->ys_argument:NULL;
    if (type)
	completion = clicon_cli_genmodel_completion(h) &&
	    strcmp(type, "enumeration") != 0 && 
	    strcmp(type, "bits") != 0;
    else
	completion = clicon_cli_genmodel_completion(h);

    if (completion)
	cprintf(cb0, "(");
    cvtypestr = cv_type2str(cvtype);
    cprintf(cb0, "<%s:%s", ys->ys_argument, cvtypestr);
#if 0
    if (type && (strcmp(type, "identityref") == 0)){
	yang_stmt      *ybase;
	if ((ybase = yang_find((yang_node*)ytype, Y_BASE, NULL)) != NULL){
	    cprintf(cb0, " choice:"); 
	    i = 0;
	    /* for every found identity derived from base-type , do: */
	    {
		if (yi->ys_keyword != Y_ENUM && yi->ys_keyword != Y_BIT)
		    continue;
		if (i)
		    cprintf(cb0, "|"); 
		cprintf(cb0, "%s", yi->ys_argument); 
		i++;
	    }
	}

    }
#endif
    if (type && (strcmp(type, "enumeration") == 0 || strcmp(type, "bits") == 0)){
	cprintf(cb0, " choice:"); 
	i = 0;
	while ((yi = yn_each((yang_node*)ytype, yi)) != NULL){
	    if (yi->ys_keyword != Y_ENUM && yi->ys_keyword != Y_BIT)
		continue;
	    if (i)
		cprintf(cb0, "|"); 
	    cprintf(cb0, "%s", yi->ys_argument); 
	    i++;
	}
    }
    if (options & YANG_OPTIONS_FRACTION_DIGITS)
	cprintf(cb0, " fraction-digits:%u", fraction_digits);
    if (options & (YANG_OPTIONS_RANGE|YANG_OPTIONS_LENGTH)){
	cprintf(cb0, " %s[", (options&YANG_OPTIONS_RANGE)?"range":"length");
	if (mincv){
	    if ((r = cv2str_dup(mincv)) == NULL){
		clicon_err(OE_UNIX, errno, "cv2str_dup");
		goto done;
	    }
	    cprintf(cb0, "%s:", r);
	    free(r);
	}
	if (maxcv != NULL){
	    if ((r = cv2str_dup(maxcv)) == NULL){
		clicon_err(OE_UNIX, errno, "cv2str_dup");
		goto done;
	    }

	}
	else{ /* Cligen does not have 'max' keyword in range so need to find actual
		 max value of type if yang range expression is 0..max */
	    if ((r = cvtype_max2str_dup(cvtype)) == NULL){
		clicon_err(OE_UNIX, errno, "cvtype_max2str");
		goto done;
	    }
	}
	cprintf(cb0, "%s]", r);
	free(r);
    }
    if (options & YANG_OPTIONS_PATTERN)
	cprintf(cb0, " regexp:\"%s\"", pattern);

    cprintf(cb0, ">");
    if (helptext)
	cprintf(cb0, "(\"%s\")", helptext);
    if (completion){
#if 0
	if (type && (strcmp(type, "leafref") == 0)){
	    yang_stmt *ypath;
	    /* XXX only for absolute xpath */
	    if ((ypath = yang_find((yang_node*)ytype, Y_PATH, NULL)) == NULL){
		clicon_err(OE_XML, 0, "leafref should have path sub");
		goto done;
	    }
	    clicon_debug(1, "%s ypath:%s\n", __FUNCTION__, ypath->ys_argument);
	    cprintf(cb0, "|<%s:%s",  ys->ys_argument, 
		    cv_type2str(cvtype));
	    cprintf(cb0, " %s(\"candidate\",\"%s\")>",
		    GENERATE_EXPAND_XMLDB,
		    ypath->ys_argument);
	}
	else
#endif
	    if (cli_expand_var_generate(h, ys, cvtype, cb0, 
					options, fraction_digits) < 0)
		goto done;
	if (helptext)
	    cprintf(cb0, "(\"%s\")", helptext);
	cprintf(cb0, ")");
    }
    retval = 0;
  done:
    return retval;
}

/*! Translate a yang leaf to cligen variable
 * Make a type lookup and complete a cligen variable expression such as <a:string>.
 * One complication is yang union, that needs a recursion since it consists of sub-types.
 * eg type union{ type int32; type string } --> (<x:int32>| <x:string>)
 */
static int
yang2cli_var(clicon_handle h,
	     yang_stmt    *ys, 
	     cbuf         *cb0,    
	     char         *helptext)
{
    int retval = -1;
    char         *type;  /* orig type */
    yang_stmt    *yrestype; /* resolved type */
    char         *restype; /* resolved type */
    cg_var       *mincv = NULL; 
    cg_var       *maxcv = NULL;
    char         *pattern = NULL;
    yang_stmt    *yt = NULL;
    yang_stmt    *yrt;
    uint8_t       fraction_digits = 0;
    enum cv_type  cvtype;
    int           options = 0;
    int           i;

    if (yang_type_get(ys, &type, &yrestype, 
		      &options, &mincv, &maxcv, &pattern, &fraction_digits) < 0)
	goto done;
    restype = yrestype?yrestype->ys_argument:NULL;
    if (clicon_type2cv(type, restype, &cvtype) < 0)
	goto done;
    /* Note restype can be NULL here for example with unresolved hardcoded uuid */
    if (restype && strcmp(restype, "union") == 0){ 
	/* Union: loop over resolved type's sub-types */
	cprintf(cb0, "(");
	yt = NULL;
	i = 0;
	while ((yt = yn_each((yang_node*)yrestype, yt)) != NULL){
	    if (yt->ys_keyword != Y_TYPE)
		continue;
	    if (i++)
		cprintf(cb0, "|");
	    if (yang_type_resolve(ys, yt, &yrt, 
				  &options, &mincv, &maxcv, &pattern, &fraction_digits) < 0)
		goto done;
	    restype = yrt?yrt->ys_argument:NULL;
	    if (clicon_type2cv(type, restype, &cvtype) < 0)
		goto done;
	    if ((retval = yang2cli_var_sub(h, ys, cb0, helptext, cvtype, yrt,
					   options, mincv, maxcv, pattern, fraction_digits)) < 0)

		goto done;

	}
	cprintf(cb0, ")");
    }
    else
	if ((retval = yang2cli_var_sub(h, ys, cb0, helptext, cvtype, yrestype,
				    options, mincv, maxcv, pattern, fraction_digits)) < 0)
	    goto done;

    retval = 0;
  done:
    return retval;
}

/*!
 * @param[in]  h         Clicon handle
 * @param[in]  callback  If set, include a "; cli_set()" callback, otherwise not.
 */
static int
yang2cli_leaf(clicon_handle h, 
	      yang_stmt    *ys, 
	      cbuf         *cbuf,
	      enum genmodel_type gt,
	      int           level,
	      int           callback)
{
    yang_stmt    *yd;  /* description */
    int           retval = -1;
    char         *helptext = NULL;
    char         *s;

    /* description */
    if ((yd = yang_find((yang_node*)ys, Y_DESCRIPTION, NULL)) != NULL){
	if ((helptext = strdup(yd->ys_argument)) == NULL){
	    clicon_err(OE_UNIX, errno, "strdup");
	    goto done;
	}
	if ((s = strstr(helptext, "\n\n")) != NULL)
	    *s = '\0';
    }
    cprintf(cbuf, "%*s", level*3, "");
    if (gt == GT_VARS|| gt == GT_ALL){
	cprintf(cbuf, "%s", ys->ys_argument);
	if (helptext)
	    cprintf(cbuf, "(\"%s\")", helptext);
	cprintf(cbuf, " ");
	yang2cli_var(h, ys, cbuf, helptext);
    }
    else
	yang2cli_var(h, ys, cbuf, helptext);
    if (callback){
	if (cli_callback_generate(h, ys, cbuf) < 0)
	    goto done;
	cprintf(cbuf, ";\n");
    }

    retval = 0;
  done:
    if (helptext)
	free(helptext);
    return retval;
}

static int
yang2cli_container(clicon_handle h, 
		   yang_stmt    *ys, 
		   cbuf         *cbuf,
		   enum genmodel_type gt,
		   int           level)
{
    yang_stmt    *yc;
    yang_stmt    *yd;
    int           i;
    int           retval = -1;
    char         *helptext = NULL;
    char         *s;

    cprintf(cbuf, "%*s%s", level*3, "", ys->ys_argument);
    if ((yd = yang_find((yang_node*)ys, Y_DESCRIPTION, NULL)) != NULL){
	if ((helptext = strdup(yd->ys_argument)) == NULL){
	    clicon_err(OE_UNIX, errno, "strdup");
	    goto done;
	}
	if ((s = strstr(helptext, "\n\n")) != NULL)
	    *s = '\0';
	cprintf(cbuf, "(\"%s\")", helptext);
    }
    if (cli_callback_generate(h, ys, cbuf) < 0)
	goto done;
    cprintf(cbuf, ";{\n");
    for (i=0; i<ys->ys_len; i++)
	if ((yc = ys->ys_stmt[i]) != NULL)
	    if (yang2cli_stmt(h, yc, cbuf, gt, level+1) < 0)
		goto done;
    cprintf(cbuf, "%*s}\n", level*3, "");
    retval = 0;
  done:
    if (helptext)
	free(helptext);
    return retval;
}

static int
yang2cli_list(clicon_handle h, 
	      yang_stmt    *ys, 
	      cbuf         *cbuf,
	      enum genmodel_type gt,
	      int           level)
{
    yang_stmt    *yc;
    yang_stmt    *yd;
    yang_stmt    *ykey;
    yang_stmt    *yleaf;
    int           i;
    cg_var       *cvi;
    char         *keyname;
    cvec         *cvk = NULL; /* vector of index keys */
    int           retval = -1;
    char         *helptext = NULL;
    char         *s;

    cprintf(cbuf, "%*s%s", level*3, "", ys->ys_argument);
    if ((yd = yang_find((yang_node*)ys, Y_DESCRIPTION, NULL)) != NULL){
	if ((helptext = strdup(yd->ys_argument)) == NULL){
	    clicon_err(OE_UNIX, errno, "strdup");
	    goto done;
	}
	if ((s = strstr(helptext, "\n\n")) != NULL)
	    *s = '\0';
	cprintf(cbuf, "(\"%s\")", helptext);
    }
    /* Loop over all key variables */
    if ((ykey = yang_find((yang_node*)ys, Y_KEY, NULL)) == NULL){
	clicon_err(OE_XML, 0, "List statement \"%s\" has no key", ys->ys_argument);
	goto done;
    }
    /* The value is a list of keys: <key>[ <key>]*  */
    if ((cvk = yang_arg2cvec(ykey, " ")) == NULL)
	goto done;
    cvi = NULL;
    /* Iterate over individual keys  */
    while ((cvi = cvec_each(cvk, cvi)) != NULL) {
	keyname = cv_string_get(cvi);
	if ((yleaf = yang_find((yang_node*)ys, Y_LEAF, keyname)) == NULL){
	    clicon_err(OE_XML, 0, "List statement \"%s\" has no key leaf \"%s\"", 
		       ys->ys_argument, keyname);
	    goto done;
	}
	/* Print key variable now, and skip it in loop below 
	   Note, only print callback on last statement
	 */
	if (yang2cli_leaf(h, yleaf, cbuf, gt==GT_VARS?GT_NONE:gt, level+1, 
			  cvec_next(cvk, cvi)?0:1) < 0)
	    goto done;
    }

    cprintf(cbuf, "{\n");
    for (i=0; i<ys->ys_len; i++)
	if ((yc = ys->ys_stmt[i]) != NULL){
	    /*  cvk is a cvec of strings containing variable names
		yc is a leaf that may match one of the values of cvk.
	     */
	    cvi = NULL;
	    while ((cvi = cvec_each(cvk, cvi)) != NULL) {
		keyname = cv_string_get(cvi);
		if (strcmp(keyname, yc->ys_argument) == 0)
		    break;
	    }
	    if (cvi != NULL)
		continue;
	    if (yang2cli_stmt(h, yc, cbuf, gt, level+1) < 0)
		goto done;
	}
    cprintf(cbuf, "%*s}\n", level*3, "");
    retval = 0;
  done:
    if (helptext)
	free(helptext);
    if (cvk)
	cvec_free(cvk);
    return retval;
}
/*! Generate cli code for yang choice statement

  Example:
  choice interface-type {
         container ethernet { ... }
         container fddi { ... }
  }
  @Note Removes 'meta-syntax' from cli syntax. They are not shown when xml is 
  translated to cli. and therefore input-syntax != output syntax. Which is bad
 */
static int
yang2cli_choice(clicon_handle h, 
		yang_stmt    *ys, 
		cbuf         *cbuf,
		enum genmodel_type gt,
		int           level)
{
    int           retval = -1;
    yang_stmt    *yc;
    int           i;

    for (i=0; i<ys->ys_len; i++)
	if ((yc = ys->ys_stmt[i]) != NULL){
	    switch (yc->ys_keyword){
	    case Y_CASE:
		if (yang2cli_stmt(h, yc, cbuf, gt, level+2) < 0)
		    goto done;
		break;
	    case Y_CONTAINER:
	    case Y_LEAF:
	    case Y_LEAF_LIST:
	    case Y_LIST:
	    default:
		if (yang2cli_stmt(h, yc, cbuf, gt, level+1) < 0)
		    goto done;
		break;
	    }
	}
    retval = 0;
  done:
    return retval;
}


/*! Translate yang-stmt to CLIgen syntax.
 */
static int
yang2cli_stmt(clicon_handle h, 
	      yang_stmt    *ys, 
	      cbuf         *cbuf,
	      enum genmodel_type gt,
	      int           level /* indentation level for pretty-print */
    )
{
    yang_stmt    *yc;
    int           retval = -1;
    int           i;

    if (yang_config(ys)){
	switch (ys->ys_keyword){
	case Y_GROUPING:
	case Y_RPC:
	case Y_AUGMENT:
	    return 0;
	    break;
	case Y_CONTAINER:
	    if (yang2cli_container(h, ys, cbuf, gt, level) < 0)
		goto done;
	    break;
	case Y_LIST:
	    if (yang2cli_list(h, ys, cbuf, gt, level) < 0)
		goto done;
	    break;
	case Y_CHOICE:
	    if (yang2cli_choice(h, ys, cbuf, gt, level) < 0)
		goto done;
	    break;
	case Y_LEAF_LIST:
	case Y_LEAF:
	    if (yang2cli_leaf(h, ys, cbuf, gt, level, 1) < 0)
		goto done;
	    break;
	default:
	    for (i=0; i<ys->ys_len; i++)
		if ((yc = ys->ys_stmt[i]) != NULL)
		    if (yang2cli_stmt(h, yc, cbuf, gt, level+1) < 0)
			goto done;
	    break;
	}
    }

    retval = 0;
  done:
    return retval;

}

/*! Translate from a yang specification into a CLIgen syntax.
 *
 * Print a CLIgen syntax to cbuf string, then parse it.
 * @param gt - how to generate CLI: 
 *             VARS: generate keywords for regular vars only not index
 *             ALL:  generate keywords for all variables including index
 */
int
yang2cli(clicon_handle h, 
	 yang_spec *yspec, 
	 parse_tree *ptnew, 
	 enum genmodel_type gt)
{
    cbuf           *cbuf;
    int             i;
    int             retval = -1;
    yang_stmt      *ymod = NULL;
    cvec           *globals;       /* global variables from syntax */

    if ((cbuf = cbuf_new()) == NULL){
	clicon_err(OE_XML, errno, "%s: cbuf_new", __FUNCTION__);
	goto done;
    }
    /* Traverse YANG specification: loop through statements */
    for (i=0; i<yspec->yp_len; i++)
	if ((ymod = yspec->yp_stmt[i]) != NULL){
	    if (yang2cli_stmt(h, ymod, cbuf, gt, 0) < 0)
		goto done;
	}
    clicon_debug(1, "%s: buf\n%s\n", __FUNCTION__, cbuf_get(cbuf));
    /* Parse the buffer using cligen parser. XXX why this?*/
    if ((globals = cvec_new(0)) == NULL)
	goto done;
    /* load cli syntax */
    if (cligen_parse_str(cli_cligen(h), cbuf_get(cbuf), 
			 "yang2cli", ptnew, globals) < 0)
	goto done;
    cvec_free(globals);
    /* Resolve the expand callback functions in the generated syntax.
       This "should" only be GENERATE_EXPAND_XMLDB
       handle=NULL for global namespace, this means expand callbacks must be in
       CLICON namespace, not in a cli frontend plugin.
    */
    if (cligen_expandv_str2fn(*ptnew, (expandv_str2fn_t*)clixon_str2fn, NULL) < 0)     
	goto done;

    retval = 0;
  done:
    cbuf_free(cbuf);
    return retval;
}