/*-
 * Copyright (c) 2004 Jacques A. Vidrine
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 */
#include <sys/param.h>

#include <algorithm>
#include <cctype>
#include <cerrno>
#include <cstdlib>
#include <fstream>
#include <iostream>
#include <map>
#include <memory>
#include <sstream>
#include <stack>
#include <string>
#include <vector>

#include <unistd.h>

#include <vuxml/vuxml.hh>
#include <vuxml/constants.hh>
#include <vuxml/parser.hh>
#include <vuxml/handlers.hh>


using namespace vuxml;


BasicHandler::BasicHandler(EntryProcessor &proc)
    : parser_(0), proc_(proc), state_(&F_docroot)
#define CLASS BasicHandler
#include <vuxml/state_init.hh>
#include <vuxml/state_head.hh>
#include <vuxml/basic_state.hh>
#include <vuxml/state_undef.hh>
{
#if defined(DEBUG_STATE)
#include <vuxml/state_debug.hh>
#include <vuxml/state_head.hh>
#include <vuxml/basic_state.hh>
#include <vuxml/state_undef.hh>
#endif
}


BasicHandler::~BasicHandler()
{
}


XMLState *
BasicHandler::signalError_(const char *msg)
{
	parser_->signalError(msg);
	return &F_ignore;
}


XMLState *
BasicHandler::docroot_child(const Element &element)
{
	if (element.id() != T_vuxml)
		return signalError_("Not a VuXML document.");
	return &F_vuxml;
}


XMLState *
BasicHandler::vuxml_child(const Element &element)
{
	if (element.id() != T_vuln)
		return signalError_("Expected `vuln' element.");
	return &F_vuln0;
}


XMLState *
BasicHandler::vuxml_end(const Element &element)
{
	if (element.id() != T_vuxml)
		return &F_dead;
	return state_;
}


XMLState *
BasicHandler::vuln0_child(const Element &element)
{
	if (element.id() == T_topic)
		return &F_topic;
	else if (element.id() == T_cancelled)
		return &F_cxl;
	else
		return signalError_("Expected `topic' element.");
}


namespace {
bool isValidVidCharacter(char c) {
	using std::islower;
	using std::isdigit;
	return (islower(c) || isdigit(c) || c == '-');
}
}


void
BasicHandler::vuln0_start(const Element & __unused element,
    Attributes &attr)
{
	entry_.reset(new Entry);
	std::string vid = killspace(attr["vid"]);
	if (vid.size() == 0) {
		signalError_("Empty or missing `vid' attribute.");
		return;
	}
	std::transform(vid.begin(), vid.end(), vid.begin(), ::tolower);
	std::string::const_iterator p = std::find_if(vid.begin(), vid.end(),
	    std::not1(std::ptr_fun(isValidVidCharacter)));
	if (p != vid.end()) {
		signalError_("Malformed `vid' attribute.");
		return;
	}
	entry_->setVid(vid);
}


void
BasicHandler::tmp_start(const Element & __unused element,
    Attributes & __unused attr)
{
	tmp_ = std::string();
}


void
BasicHandler::tmp_characters(std::string &pcdata)
{
	tmp_ += pcdata;
}


XMLState *
BasicHandler::topic_end(const Element & __unused element)
{
	entry_->setTopic(killspace(tmp_));
	return &F_vuln1;
}


XMLState *
BasicHandler::vuln1_child(const Element &element)
{
	if (element.id() != T_affects)
		return signalError_("Expected `affects' element.");
	return &F_affects;
}


XMLState *
BasicHandler::affects_child(const Element &element)
{
	switch (element.id()) {
	case T_package:
		return &F_package;
	case T_system:
		return &F_system;
	default:
		return signalError_("Expected `package' or `system' element.");
	}
}


XMLState *
BasicHandler::affects_end(const Element &element)
{
	if (element.id() != T_affects)
		return &F_dead;
	return &F_vuln2;
}


XMLState *
BasicHandler::package_child(const Element &element)
{
	switch (element.id()) {
	case T_name:
		push_state(state_);
		return &F_name;
	case T_range:
		push_state(state_);
		return &F_range;
	default:
		return signalError_("Expected `name' or `range' element.");
	}
}


void
BasicHandler::package_start(const Element & __unused element,
    Attributes & __unused attr)
{
	entry_->addAffectedSet();
}


XMLState *
BasicHandler::package_end(const Element &element)
{
	if (element.id() != T_package && element.id() != T_system)
		return &F_dead;
	return &F_affects;
}


XMLState *
BasicHandler::name_end(const Element & __unused element)
{
	entry_->addAffectedName(killspace(tmp_));
	return pop_state();
}


XMLState *
BasicHandler::range_child(const Element &element)
{
	switch (element.id()) {
	case T_gt:
	case T_ge:
	case T_lt:
	case T_le:
	case T_eq:
		return &F_rangeop;
	default:
		return signalError_("Expected range operator element.");
	}
}


void
BasicHandler::range_start(const Element & __unused element,
    Attributes & __unused attr)
{
	range_ = VersionRange();
}


XMLState *
BasicHandler::range_end(const Element & __unused element)
{
	entry_->addAffectedRange(range_);
	return pop_state();
}


XMLState *
BasicHandler::rangeop_end(const Element &element)
{
	tmp_ = killspace(tmp_);
	switch (element.id()) {
	case T_gt:
		range_.lo_closed = false;
		// fallthrough
	case T_ge:
		range_.lo = tmp_;
		break;
	case T_lt:
		range_.hi_closed = false;
		// fallthrough
	case T_le:
		range_.hi = tmp_;
		break;
	case T_eq:
		range_.hi = range_.lo = tmp_;
		break;
	default:
		throw except("Internal error: rangeop_end, bad element");
	}
	return &F_range;
}



namespace {
class appendAttribute : public std::unary_function<void,
    std::pair<const std::string, std::string> &> {
private:
  std::string &s_;
public:
  appendAttribute(std::string &s) : s_(s) {}
  void operator()(std::pair<const std::string, std::string> &item) {
	  s_ += ' ';
	  s_ += item.first;
	  s_ += "=\"";
	  s_ += xmlescape(item.second);
	  s_ += '"';
  }
};
}


XMLState *
BasicHandler::vuln2_child(const Element &element)
{
	if (element.id() != T_description)
		return signalError_("Expected `description' element.");
	return &F_description;
}


void
BasicHandler::description_start(const Element &element, Attributes &attr)
{
	std::string s;
	switch (element.id()) {
	case T_description:
		break;
	case T_XHTML_BODY:
		break;
	case T_XHTML:
		s += '<';
		s += element.name();
		if (element.id() == T_XHTML_BODY) {
			s += " xmlns=\"";
			s += XHTML_NAMESPACE;
			s += '"';
		}
		std::for_each(attr.begin(), attr.end(), appendAttribute(s));
		s += '>';
		entry_->appendDescription(s);
		break;
	default:
		signalError_("Expected element in XHTML namespace.");
		break;
	}
}


void
BasicHandler::description_characters(std::string &pcdata)
{
	entry_->appendDescription(xmlescape(pcdata));
}


XMLState *
BasicHandler::description_end(const Element &element)
{
	if (element.id() == T_description)
		return &F_vuln3;
	else if (element.id() == T_XHTML_BODY)
		return state_;
	std::string s;
	s += "</";
	s += element.name();
	s += '>';
	entry_->appendDescription(s);
	return state_;
}


XMLState *
BasicHandler::vuln3_child(const Element &element)
{
	if (element.id() != T_references)
		return signalError_("Expected `references' element.");
	return &F_references;
}


XMLState *
BasicHandler::references_child(const Element &element)
{
	switch (element.id()) {
	case T_url:
	case T_cvename:
	case T_freebsdsa:
	case T_bid:
	case T_certsa:
	case T_certvu:
	case T_mlist:
	case T_uscertsa:
	case T_uscertta:
	case T_freebsdpr:
		return &F_reference;
	default:
		return signalError_("Expected a reference element.");
	}
}


XMLState *
BasicHandler::references_end(const Element &element)
{
	if (element.id() != T_references)
		return &F_dead;
	return &F_vuln4;
}


XMLState *
BasicHandler::reference_end(const Element &element)
{
	entry_->addReference(element.name(), killspace(tmp_));
	return &F_references;
}


XMLState *
BasicHandler::vuln4_child(const Element &element)
{
	if (element.id() != T_dates)
		return signalError_("Expected `dates' element.");
	return &F_dates0;
}


XMLState *
BasicHandler::dates0_child(const Element &element)
{
	if (element.id() != T_discovery)
		return signalError_("Expected `discovery' element.");
	return &F_discovery;
}


XMLState *
BasicHandler::discovery_end(const Element & __unused element)
{
	entry_->setDiscoveryDate(killspace(tmp_));
	return &F_dates1;
}


XMLState *
BasicHandler::dates1_child(const Element &element)
{
	if (element.id() != T_entry)
		return signalError_("Expected `entry' element.");
	return &F_entry;
}


XMLState *
BasicHandler::entry_end(const Element & __unused element)
{
	entry_->setEntryDate(killspace(tmp_));
	return &F_dates2;
}


XMLState *
BasicHandler::dates2_child(const Element &element)
{
	if (element.id() != T_modified)
		return signalError_("Expected `modified' element.");
	return &F_modified;
}


XMLState *
BasicHandler::modified_end(const Element & __unused element)
{
	entry_->setModifiedDate(killspace(tmp_));
	return &F_dates3;
}


XMLState *
BasicHandler::dates2_end(const Element &element)
{
	if (element.id() != T_dates)
		return &F_dead;
	return &F_vuln5;
}


XMLState *
BasicHandler::vuln5_end(const Element &element)
{
	if (element.id() == T_vuln) {
		proc_(*entry_);
		return &F_vuxml;
	}
	return state_;
}


XMLState *
BasicHandler::cxl_end(const Element &element)
{
	return &F_vuln5;
}


void
BasicHandler::setParser(Parser &parser)
{
	parser_ = &parser;
}


XMLState *
BasicHandler::top_state()
{
	return state_stack_.top();
}


XMLState *
BasicHandler::pop_state()
{
	XMLState *s = state_stack_.top();
	state_stack_.pop();
	return s;
}


void
BasicHandler::push_state(XMLState *state)
{
	state_stack_.push(state);
}


void
BasicHandler::startElement(std::string &xmlns, std::string &name,
    Attributes &attr)
{
	Element element(xmlns, name);
#if defined(DEBUG_STATE)
	LOG << "child state=" << static_cast<void *>(state_) << '\n';
#endif
	state_ = state_->child(element);
#if defined(DEBUG_STATE)
	LOG << "start state=" << static_cast<void *>(state_) << '\n';
#endif
	state_->start(element, attr);
}


void
BasicHandler::characters(std::string &pcdata)
{
#if defined(DEBUG_STATE)
	LOG << "characters state=" << static_cast<void *>(state_) << '\n';
#endif
	state_->characters(pcdata);
}


void
BasicHandler::endElement(std::string &xmlns, std::string &name)
{
	Element element(xmlns, name);
#if defined(DEBUG_STATE)
	LOG << "end state=" << static_cast<void *>(state_) << '\n';
#endif
	state_ = state_->end(element);
}


XMLState *
BasicHandler::dead_child(const Element & __unused element)
{
	return signalError_("Start of element unexpected.");
}


void
BasicHandler::dead_start(const Element & __unused element,
    Attributes & __unused attr)
{
	signalError_("Attributes unexpected.");
}


void
BasicHandler::dead_characters(std::string & __unused pcdata)
{
	signalError_("Character data unexpected.");
}


XMLState *
BasicHandler::dead_end(const Element & __unused element)
{
	return signalError_("End of element unexpected.");
}


XMLState *
BasicHandler::ignore_child(const Element & __unused element)
{
	return state_;
}


void
BasicHandler::ignore_start(const Element & __unused element,
    Attributes & __unused attr)
{
}


void
BasicHandler::ignore_characters(std::string & __unused pcdata)
{
}


XMLState *
BasicHandler::ignore_end(const Element & __unused element)
{
	return state_;
}