//    OpenVPN -- An application to securely tunnel IP networks
//               over a single port, with support for SSL/TLS-based
//               session authentication and key exchange,
//               packet encryption, packet authentication, and
//               packet compression.
//
//    Copyright (C) 2012-2020 OpenVPN Inc.
//
//    This program is free software: you can redistribute it and/or modify
//    it under the terms of the GNU Affero General Public License Version 3
//    as published by the Free Software Foundation.
//
//    This program is distributed in the hope that it will be useful,
//    but WITHOUT ANY WARRANTY; without even the implied warranty of
//    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//    GNU Affero General Public License for more details.
//
//    You should have received a copy of the GNU Affero General Public License
//    along with this program in the COPYING file.
//    If not, see <http://www.gnu.org/licenses/>.

#pragma once

namespace openvpn {
  class DSDict {
    public:
      OPENVPN_EXCEPTION(dsdict_error);
    
      DSDict(CF::DynamicStore& sc_arg, const std::string& sname_arg, const std::string& dskey_arg)
	: sc(sc_arg),
	  sname(sname_arg),
	  dskey(dskey_arg),
	  dict(CF::DynamicStoreCopyDict(sc_arg, dskey)) { }

      bool dirty() const
      {
	return mod.defined() ? !CFEqual(dict(), mod()) : false;
      }

      bool push_to_store()
      {
	if (dirty())
	  {
	    const CF::String keystr = CF::string(dskey);
	    if (SCDynamicStoreSetValue(sc(), keystr(), mod()))
	      {
		OPENVPN_LOG("DSDict: updated " << dskey);
		return true;
	      }
	    else
	      OPENVPN_LOG("DSDict: ERROR updating " << dskey);
	  }
	return false;
      }

      bool remove_from_store()
      {
        if (dirty())
          throw dsdict_error("internal error: remove_from_store called on modified dict");
        const CF::String keystr = CF::string(dskey);
        if (SCDynamicStoreRemoveValue(sc(), keystr()))
          {
            OPENVPN_LOG("DSDict: removed " << dskey);
            return true;
          }
        else
          {
            OPENVPN_LOG("DSDict: ERROR removing " << dskey);
            return false;
          }
      }

      void will_modify()
      {
        if (!mod.defined())
          mod = CF::mutable_dict_copy(dict);
      }

      void mod_reset()
      {
        mod = CF::mutable_dict();
      }

      void backup_orig(const std::string& key, const bool wipe_orig=true)
      {
	const CF::String k = CF::string(key);
	const CF::String orig = orig_key(key);
	if (!CFDictionaryContainsKey(dict(), orig()))
	  {
	    const CF::String delval = delete_value();
	    CFTypeRef v = CFDictionaryGetValue(dict(), k());
	    if (!v)
	      v = delval();
	    will_modify();
	    CFDictionarySetValue(mod(), orig(), v);
	  }
        if (wipe_orig)
	  {
	    will_modify();
	    CFDictionaryRemoveValue(mod(), k());
	  }
      }

      void restore_orig()
      {
	const CFIndex size = CFDictionaryGetCount(dict());
	std::unique_ptr<const void *[]> keys(new const void *[size]);
	std::unique_ptr<const void *[]> values(new const void *[size]);
	CFDictionaryGetKeysAndValues(dict(), keys.get(), values.get());
	const CF::String orig_prefix = orig_key("");
	const CFIndex orig_prefix_len = CFStringGetLength(orig_prefix());
	const CF::String delval = delete_value();
	for (CFIndex i = 0; i < size; ++i)
	  {
	    const CF::String key = CF::string_cast(keys[i]);
	    if (CFStringHasPrefix(key(), orig_prefix()))
	      {
		const CFIndex key_len = CFStringGetLength(key());
		if (key_len > orig_prefix_len)
		  {
		    const CFRange r = CFRangeMake(orig_prefix_len, key_len - orig_prefix_len);
		    const CF::String k(CFStringCreateWithSubstring(kCFAllocatorDefault, key(), r));
		    const CFTypeRef v = values[i];
		    const CF::String vstr = CF::string_cast(v);
		    will_modify();
		    if (vstr.defined() && CFStringCompare(vstr(), delval(), 0) == kCFCompareEqualTo)
		      CFDictionaryRemoveValue(mod(), k());
		    else
		      CFDictionaryReplaceValue(mod(), k(), v);
		    CFDictionaryRemoveValue(mod(), key());
		  }
	      }
	  }
      }

      std::string to_string() const
      {
	std::ostringstream os;
	os << "*** DSDict " << dskey << std::endl;
	std::string orig = CF::description(dict());
	string::trim_crlf(orig);
	os << "ORIG " << orig << std::endl;
	if (dirty())
	  {
	    std::string modstr = CF::description(mod());
	    string::trim_crlf(modstr);
	    os << "MODIFIED " << modstr << std::endl;
	  }
	return os.str();
      }
      
      static CF::DynamicStore ds_create(const std::string& sname)
      {
	CF::String sn = CF::string(sname);
	return CF::DynamicStore(SCDynamicStoreCreate(kCFAllocatorDefault, sn(), nullptr, nullptr));
      }
      
      static bool signal_network_reconfiguration(const std::string& sname)
      {
	const char *key = "Setup:/Network/Global/IPv4";
	CF::DynamicStore sc = ds_create(sname);
	const CF::String cfkey = CF::string(key);
	OPENVPN_LOG("DSDict: SCDynamicStoreNotifyValue " << key);
	return bool(SCDynamicStoreNotifyValue(sc(), cfkey()));
      }

      CF::DynamicStore sc;
      const std::string sname;
      const std::string dskey;
      const CF::Dict dict;
      CF::MutableDict mod;

    private:
      CF::String orig_key(const std::string& key) const
      {
	return CF::string(sname + "Orig" + key);
      }

      CF::String delete_value() const
      {
	return CF::string(sname + "DeleteValue");
      }
    };
}