#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <assert.h>
#include <string.h>
#include <libgen.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <errno.h>
#include <pwd.h>
#include <grp.h>



#include <libxml/tree.h>
#include <libxml/parser.h>
#include <libxml/xpath.h>
#include <libxml/xpathInternals.h>
#include <libxml/relaxng.h>

#include <libxslt/xslt.h>
#include <libxslt/xsltInternals.h>
#include <libxslt/transform.h>
#include <libxslt/xsltutils.h>

#include "util.h"

#define XMLCHARLEN 255
#define MAXSTR XMLCHARLEN
/* If a default namespace is defined
 *  
 * IMPORTANT: XPath 1.0 has no concept of a default namespace. Unprefixed
 * names in XPath only match names which have no namespace.  So, if the
 * document uses a default namespace, it is required to associate a non-empty
 * prefix with the default namespace via register-namespace  and add that
 * prefix to names in XPath expressions intended to match nodes in the default
 * namespace.
 */
xmlChar *default_namespace_prefix = (xmlChar *) "def";

#define XSLT_METADATA_NAMESPACE (xmlChar *) "http://freeipa.org/xsl/metadata/1.0"
#define XSLT_METADATA_NAMESPACE_PREFIX (xmlChar *) "md"
#define XPATH_OUTPUT_HANDLER (xmlChar *) "//md:output_handler/*"


char *get_output_handler_parameter(xmlNode *node, const char *name, const char *default_value, const int required) {
    char *value;

    DEBUG(3,("Search for attribute '%s'.\n",name));
    value = (char *) xmlGetProp(node, (xmlChar *) name);
    if (required == 1) {
        CHECK_NULL_FATAL(value, ("Cannot find required attribute '%s' for output handler.\n", name));
        DEBUG(3,("Found required attribute '%s' with value '%s'.\n",name, value));
    } else if (required == 0 ) {
        if (value == NULL) {
            DEBUG(3,("Optional attribute '%s' not found, using default '%s'.\n",name, default_value));
            if (default_value != NULL ) value=strdup(default_value);
        } else {
            DEBUG(3,("Found optional attribute '%s' with value '%s'.\n",name, value));
        }
    } else {
        DEBUG(0,("I am not allowed to be here, aborting ...\n"));
        exit(-1);
    }

    return value;
}

int output_handler_file(xmlNode *node, const xmlDocPtr doc, const char *xslt_file_name) {
    char *name;
    char *owner;
    char *group;
    char *permission;
    char *param_name;
    char *param_value;
    struct stat stat_buffer;
    char *dir_name;
    char *tmp_file_name;
    char *buffer;
    int ret;
    int fd;
    struct passwd *pwd_info;
    struct group *grp_info;
    xsltStylesheetPtr parsed_stylesheet = NULL;
    xmlDocPtr res;

    name=get_output_handler_parameter(node, "name", NULL, 1);
   
    buffer=strdup(name);
    CHECK_NULL_RETURN(buffer ,("strdup failed\n"));
    dir_name=dirname(buffer); 
    if( (ret=stat(dir_name, &stat_buffer)) == -1) {
        DEBUG(0,("stat on %s failed: %s\n",dir_name, strerror(errno)));
        free(name);
        return(-1);
    }
    if(!S_ISDIR(stat_buffer.st_mode)) {
        DEBUG(0,("%s is not a directory!\n",dir_name));
        free(name);
        return(-1);
    } 
    free(buffer);

    if( (ret=lstat(name, &stat_buffer)) == -1) {
        DEBUG(0,("stat on %s failed: %s\n",name, strerror(errno)));
        free(name);
        return(-1);
    }
    if(!S_ISREG(stat_buffer.st_mode)) {
        DEBUG(0,("%s is not a regular file!\n",name));
        free(name);
        return(-1);
    } 
     
    owner=get_output_handler_parameter(node, "owner", "root", 0);
    pwd_info=getpwnam(owner);
    CHECK_NULL_RETURN(pwd_info, ("Cannot find user %s.\n", owner));
    group=get_output_handler_parameter(node, "group", "root", 0);
    grp_info=getgrnam(group);
    CHECK_NULL_RETURN(grp_info, ("Cannot find group %s.\n", group));
   
    permission=get_output_handler_parameter(node, "permission", "0400", 0);
    param_name=get_output_handler_parameter(node, "param_name", NULL, 0);
    param_value=get_output_handler_parameter(node, "param_value", NULL, 0);

    /* TODO: create backup copy */

    tmp_file_name=(char *) malloc(strlen(name)+7);
    CHECK_NULL_RETURN(tmp_file_name,("malloc failed."));
    strcpy(tmp_file_name, name);
    strcat(tmp_file_name, ".XXXXXX");
    fd=mkstemp(tmp_file_name);
    if (fd==-1) {
        DEBUG(0,("mkstemp failed with template %s: %s\n",tmp_file_name, strerror(errno)));
        free(name);
        return(-1);
    }

    ret=fchmod(fd, (mode_t) strtol(permission, NULL, 8));
    CHECK_MINUS_ONE_RETURN(ret, ("Cannot chmod temporary file to %s: %s\n", permission, strerror(errno)));

    ret=fchown(fd, pwd_info->pw_uid, grp_info->gr_gid);
    CHECK_MINUS_ONE_RETURN(ret, ("Cannot chown temporary file to %s:%s: %s\n", owner, group, strerror(errno)));
 
    parsed_stylesheet = xsltParseStylesheetFile((xmlChar *) xslt_file_name);
    CHECK_NULL_FATAL(parsed_stylesheet, ("Cannot parse stylesheet!\n"));

    res = xsltApplyStylesheet(parsed_stylesheet, doc, NULL);
    CHECK_NULL_FATAL(res, ("Cannot apply stylesheet!\n"));
    ret = xsltSaveResultToFd(fd, res, parsed_stylesheet);
    if (ret == -1) {
        DEBUG(0, ("Cannot save result!\n"));
        exit(1);
    }
    xmlFreeDoc(res);
    xsltFreeStylesheet(parsed_stylesheet);

    close(fd);
    ret=rename(tmp_file_name, name);
    CHECK_MINUS_ONE_RETURN(ret, ("Cannot rename %s to %s: %s\n", tmp_file_name, name, strerror(errno) ));

    free(tmp_file_name);

    free(name);
    free(owner);
    free(group);
    free(permission);
    free(param_name);
    free(param_value);
    return(0);
}

int output_handler_exec_with_args(xmlNode *node, const xmlDocPtr doc, const char *xslt_file_name) {
    char *command;
    char *arguments;
    char *user;
    char *group;
    char *param_name;
    char *param_value;
    int ret;
    struct stat stat_buffer;
    struct passwd *pwd_info;
    struct group *grp_info;
    xsltStylesheetPtr parsed_stylesheet = NULL;
    xmlDocPtr res;
    xmlChar *result_string;
    int result_length;
    char *cur;
    char *end_of_line;
    
    command=get_output_handler_parameter(node, "command", NULL, 1);

    if( (ret=stat(command, &stat_buffer)) == -1) {
        DEBUG(0,("stat on %s failed: %s\n",command, strerror(errno)));
        free(command);
        return(-1);
    }


    arguments=get_output_handler_parameter(node, "arguments", NULL, 0);

    user=get_output_handler_parameter(node, "user", "nobody", 0);
    pwd_info=getpwnam(user);
    CHECK_NULL_RETURN(pwd_info, ("Cannot find user %s.\n", user));

    group=get_output_handler_parameter(node, "group", "nogroup", 0);
    grp_info=getgrnam(group);
    CHECK_NULL_RETURN(grp_info, ("Cannot find group %s.\n", group));

    param_name=get_output_handler_parameter(node, "param_name", NULL, 0);
    param_value=get_output_handler_parameter(node, "param_value", NULL, 0);

    parsed_stylesheet = xsltParseStylesheetFile((xmlChar *) xslt_file_name);
    CHECK_NULL_FATAL(parsed_stylesheet, ("Cannot parse stylesheet!\n"));

    res = xsltApplyStylesheet(parsed_stylesheet, doc, NULL);
    CHECK_NULL_FATAL(res, ("Cannot apply stylesheet!\n"));
    ret = xsltSaveResultToString(&result_string, &result_length, res, parsed_stylesheet);
    if (ret == -1) {
        DEBUG(0, ("Cannot save result!\n"));
        exit(1);
    }
    xmlFreeDoc(res);
    xsltFreeStylesheet(parsed_stylesheet);

    cur=(char *)result_string;
    DEBUG(3,("last argument to %s: |%s|\n",command, cur));
    while ( (end_of_line = strchr(cur, '\n'))!=NULL ) {
        *end_of_line='\0';
        DEBUG(3,("argument to %s: |%s|\n",command, cur));
        cur=end_of_line+1;
    };

    free(result_string);

    free(command);
    free(arguments);
    free(user);
    free(group);
    free(param_name);
    free(param_value);
    return(0);
}

int print_all_attributes(xmlNode *node) {
    xmlAttr *cur;

    cur=node->properties;
    while(cur!=NULL) {
        DEBUG(3, ("found attribute '%s' with value '%s'.\n", cur->name, XML_GET_CONTENT(cur->children)));
        cur=cur->next;
    }
    return(0);
}

int find_output_handler(const xmlDocPtr doc, const char *xslt_file_name) {
    int i;
    xmlXPathContextPtr xpath_context;
    xmlXPathObjectPtr xpath_obj;
    xmlDocPtr xslt_doc;

    xslt_doc = xmlParseFile(xslt_file_name);
    CHECK_NULL_FATAL(xslt_doc, ("Cannot parse file %s!\n", xslt_file_name));

    xpath_context = xmlXPathNewContext(xslt_doc);
    CHECK_NULL_FATAL(xpath_context, ("Error: unable to create new XPath context\n"));

    if (xmlXPathRegisterNs(xpath_context, XSLT_METADATA_NAMESPACE_PREFIX, XSLT_METADATA_NAMESPACE) != 0) {
        DEBUG(0,
              ("Error: unable to register NS with prefix=\"%s\" and href=\"%s\"\n",
               XSLT_METADATA_NAMESPACE_PREFIX, XSLT_METADATA_NAMESPACE));
        xmlXPathFreeContext(xpath_context);
        return (0);
    }

    xpath_obj = xmlXPathEvalExpression(XPATH_OUTPUT_HANDLER, xpath_context);
    if (xpath_obj == NULL) {
        DEBUG(0,
              ("Error: unable to evaluate xpath expression \"%s\"\n",
               XPATH_OUTPUT_HANDLER));
        xmlXPathFreeContext(xpath_context);
        return (0);
    }

    if (xmlXPathNodeSetIsEmpty(xpath_obj->nodesetval)) {
        DEBUG(0, ("Nothing found for %s\n", XPATH_OUTPUT_HANDLER));
        xmlXPathFreeObject(xpath_obj);
        xmlXPathFreeContext(xpath_context);
        return (0);
    } 

    for (i=0; i<xmlXPathNodeSetGetLength(xpath_obj->nodesetval); i++) {
        DEBUG(3, ("found output_handler: %s\n",(char *) xpath_obj->nodesetval->nodeTab[i]->name));
        print_all_attributes(xpath_obj->nodesetval->nodeTab[i]);
        if ( xmlStrEqual(xpath_obj->nodesetval->nodeTab[i]->name, (xmlChar *) "file" )) {
            output_handler_file(xpath_obj->nodesetval->nodeTab[i], doc, xslt_file_name);
        } else if ( xmlStrEqual(xpath_obj->nodesetval->nodeTab[i]->name, (xmlChar *) "exec_with_args" )) {
            output_handler_exec_with_args(xpath_obj->nodesetval->nodeTab[i], doc, xslt_file_name);
        } else {
            DEBUG(0, ("Unknow outout handler '%s'.\n", xpath_obj->nodesetval->nodeTab[i]->name));
            xmlXPathFreeObject(xpath_obj);
            xmlXPathFreeContext(xpath_context);
            return (-1);
        }
    }


    xmlXPathFreeObject(xpath_obj);
    xmlXPathFreeContext(xpath_context);
    return 0;
}

char *find_value_by_xpath(xmlDocPtr doc, xmlChar * xpath_expr, xmlChar * prefix,
                          xmlChar * namespace)
{

    xmlXPathContextPtr xpath_context;
    xmlXPathObjectPtr xpath_obj;
    char *result = NULL;

    /* Create xpath evaluation context */
    xpath_context = xmlXPathNewContext(doc);
    CHECK_NULL_FATAL(xpath_context,
                     ("Error: unable to create new XPath context\n"));
    /* Register a namespace */
    if (xmlXPathRegisterNs(xpath_context, prefix, namespace) != 0) {
        DEBUG(0,
              ("Error: unable to register NS with prefix=\"%s\" and href=\"%s\"\n",
               prefix , namespace));
        xmlXPathFreeContext(xpath_context);
        return (NULL);
    }
    /* Evaluate xpath expression */
    xpath_obj = xmlXPathEvalExpression(xpath_expr, xpath_context);
    if (xpath_obj == NULL) {
        DEBUG(0,
              ("Error: unable to evaluate xpath expression \"%s\"\n",
               xpath_expr));
        xmlXPathFreeContext(xpath_context);
        return (NULL);
    }

    if (xmlXPathNodeSetIsEmpty(xpath_obj->nodesetval)) {
        DEBUG(0, ("Nothing found for %s\n", xpath_expr));
        xmlXPathFreeObject(xpath_obj);
        xmlXPathFreeContext(xpath_context);
        return (NULL);
    } else if (xmlXPathNodeSetGetLength(xpath_obj->nodesetval) != 1) {
        DEBUG(0, ("More than one node found for %s!", xpath_expr));
        xmlXPathFreeObject(xpath_obj);
        xmlXPathFreeContext(xpath_context);
        return (NULL);
    } else {
        result =
            (char *) xmlNodeListGetString(doc,
                                          xpath_obj->nodesetval->nodeTab[0]->
                                          xmlChildrenNode, 1);
    }


    xmlXPathFreeObject(xpath_obj);
    xmlXPathFreeContext(xpath_context);
    return result;

}

int main(int argc, char **argv)
{

    xmlDocPtr doc;
    xmlNodePtr root_node;
    xmlChar *default_namespace;
    xmlChar xpath_expr[XMLCHARLEN];
    char *rng_file_name;
    char *xslt_file_name;
    xmlRelaxNGValidCtxtPtr rng_context;
    xmlDocPtr xslt_doc;
//    xsltStylesheetPtr parsed_stylesheet = NULL;
//    xmlDocPtr res;
//    int ret;

    if (argc != 2) {
        DEBUG(0,
              ("missing or to many arguments, I expect a single filename!\n"));
        exit(1);
    }

    doc = xmlParseFile(argv[1]);
    CHECK_NULL_FATAL(doc, ("Cannot parse document %s!\n", argv[1]));

    /* find the default namespace */
    root_node = xmlDocGetRootElement(doc);
    CHECK_NULL_FATAL(root_node,
                     ("Cannot find root node of document %s!\n", argv[1]));
    if (xmlStrncasecmp(root_node->name, (xmlChar *) "IPA", XMLCHARLEN) != 0) {
        DEBUG(0,
              ("Name of root node of document %s has to be 'ipa'!\n", argv[1]));
        exit(1);
    }
    CHECK_NULL_FATAL(root_node->ns->href,
                     ("Root node of document %s must define a namespace!\n",
                      argv[1]));
    default_namespace = xmlStrndup(root_node->ns->href, XMLCHARLEN);
    CHECK_NULL_FATAL(default_namespace, ("Cannot copy namespace!\n"));
    DEBUG(3, ("Default namespace of %s is %s\n", argv[1], default_namespace));

    /* extract XSTLfile and RNGfile from document using XPath */
    xmlStrPrintf(xpath_expr, XMLCHARLEN, (xmlChar *) "//%s:XSLTfile",
                 default_namespace_prefix);
    xslt_file_name =
        find_value_by_xpath(doc, xpath_expr, default_namespace_prefix,
                            default_namespace);
    CHECK_NULL_FATAL(xslt_file_name, ("Name of XSLT file not found.\n"));
    DEBUG(3, ("Found name of XSLT file: %s\n", xslt_file_name));

    xmlStrPrintf(xpath_expr, XMLCHARLEN, (xmlChar *) "//%s:RNGfile",
                 default_namespace_prefix);
    rng_file_name =
        find_value_by_xpath(doc, xpath_expr, default_namespace_prefix,
                            default_namespace);
    CHECK_NULL_FATAL(rng_file_name,
                     ("Name of RELANX NG schema file not found.\n"));
    DEBUG(3, ("Found name of RELAX NG schema file: %s\n", rng_file_name));



    /* validate the document */
    rng_context =
        xmlRelaxNGNewValidCtxt(xmlRelaxNGParse
                               (xmlRelaxNGNewParserCtxt(rng_file_name)));
    CHECK_NULL_FATAL(rng_context, ("Failed to create RNG context\n"));
    if (xmlRelaxNGValidateDoc(rng_context, doc) == 0) {
        DEBUG(0, ("The document is valid.\n"));
    } else {
        DEBUG(0, ("Error during validation.\n"));
        exit(1);
    }

    xmlRelaxNGFreeValidCtxt(rng_context);
    free(rng_file_name);


    /* read the xslt file */
    xslt_doc = xmlParseFile(xslt_file_name);
    CHECK_NULL_FATAL(xslt_doc, ("Cannot parse file %s!\n", xslt_file_name));

    find_output_handler(doc, xslt_file_name);

/*
    parsed_stylesheet = xsltParseStylesheetDoc(xslt_doc);
    CHECK_NULL_FATAL(parsed_stylesheet, ("Cannot parse stylesheet %s!\n", xslt_file_name));
    res = xsltApplyStylesheet(parsed_stylesheet, doc, NULL);
    CHECK_NULL_FATAL(xslt_doc,
                     ("Cannot apply stylesheet %s!\n", xslt_file_name));
    ret = xsltSaveResultToFile(stdout, res, parsed_stylesheet);
    if (ret == -1) {
        DEBUG(0, ("Cannot save result!\n"));
        exit(1);
    }
    xmlFreeDoc(res);

    xsltFreeStylesheet(parsed_stylesheet);
*/
    free(xslt_file_name);

    xmlFreeDoc(doc);




    return (0);
}