/*       +------------------------------------+
 *       | Inspire Internet Relay Chat Daemon |
 *       +------------------------------------+
 *
 *  InspIRCd: (C) 2002-2009 InspIRCd Development Team
 * See: http://wiki.inspircd.org/Credits
 *
 * This program is free but copyrighted software; see
 *	    the file COPYING for details.
 *
 * ---------------------------------------------------
 */

#include "inspircd.h"
#include "m_sqlv2.h"
#include "m_sqlutils.h"
#include "m_hash.h"

/* $ModDesc: Allows storage of oper credentials in an SQL table */
/* $ModDep: m_sqlv2.h m_sqlutils.h m_hash.h */

typedef std::map<irc::string, Module*> hashymodules;

class ModuleSQLOper : public Module
{
	LocalStringExt saved_user;
	LocalStringExt saved_pass;
	Module* SQLutils;
	std::string databaseid;
	std::string hashtype;
	parameterlist names;

public:
	ModuleSQLOper() : saved_user("sqloper_user", this), saved_pass("sqloper_pass", this)
	{
		OnRehash(NULL);

		SQLutils = ServerInstance->Modules->Find("m_sqlutils.so");
		if (!SQLutils)
			throw ModuleException("Can't find m_sqlutils.so. Please load m_sqlutils.so before m_sqloper.so.");

		Implementation eventlist[] = { I_OnRehash, I_OnPreCommand, I_OnLoadModule };
		ServerInstance->Modules->Attach(eventlist, this, 3);
		ServerInstance->Modules->AddService(saved_user);
		ServerInstance->Modules->AddService(saved_pass);
	}

	bool OneOfMatches(const char* host, const char* ip, const char* hostlist)
	{
		std::stringstream hl(hostlist);
		std::string xhost;
		while (hl >> xhost)
		{
			if (InspIRCd::Match(host, xhost, ascii_case_insensitive_map) || InspIRCd::MatchCIDR(ip, xhost, ascii_case_insensitive_map))
			{
				return true;
			}
		}
		return false;
	}

	virtual void OnRehash(User* user)
	{
		ConfigReader Conf;

		databaseid = Conf.ReadValue("sqloper", "dbid", 0); /* Database ID of a database configured for the service provider module */
		hashtype = Conf.ReadValue("sqloper", "hash", 0);
	}

	virtual ModResult OnPreCommand(std::string &command, std::vector<std::string> &parameters, User *user, bool validated, const std::string &original_line)
	{
		if ((validated) && (command == "OPER"))
		{
			if (LookupOper(user, parameters[0], parameters[1]))
			{
				/* Returning true here just means the query is in progress, or on it's way to being
				 * in progress. Nothing about the /oper actually being successful..
				 * If the oper lookup fails later, we pass the command to the original handler
				 * for /oper by calling its Handle method directly.
				 */
				return MOD_RES_DENY;
			}
		}
		return MOD_RES_PASSTHRU;
	}

	bool LookupOper(User* user, const std::string &username, const std::string &password)
	{
		ServiceProvider* prov = ServerInstance->Modules->FindService(SERVICE_DATA, "SQL");
		if (prov)
		{
			Module* target = prov->creator;
			HashProvider* hash = ServerInstance->Modules->FindDataService<HashProvider>("hash/" + hashtype);

			/* Make an MD5 hash of the password for using in the query */
			std::string md5_pass_hash = hash ? hash->hexsum(password) : password;

			/* We generate our own sum here because some database providers (e.g. SQLite) dont have a builtin md5/sha256 function,
			 * also hashing it in the module and only passing a remote query containing a hash is more secure.
			 */
			SQLrequest req = SQLrequest(this, target, databaseid,
					SQLquery("SELECT username, password, hostname, type FROM ircd_opers WHERE username = '?' AND password='?'") % username % md5_pass_hash);

			/* When we get the query response from the service provider we will be given an ID to play with,
			 * just an ID number which is unique to this query. We need a way of associating that ID with a User
			 * so we insert it into a map mapping the IDs to users.
			 * Thankfully m_sqlutils provides this, it will associate a ID with a user or channel, and if the user quits it removes the
			 * association. This means that if the user quits during a query we will just get a failed lookup from m_sqlutils - telling
			 * us to discard the query.
			 */
			AssociateUser(this, SQLutils, req.id, user).Send();

			saved_user.set(user, username);
			saved_pass.set(user, password);

			return true;
		}
		else
		{
			ServerInstance->Logs->Log("m_sqloper",SPARSE, "WARNING: Couldn't find SQL provider module. NOBODY will be able to oper up unless their o:line is statically configured");
			return false;
		}
	}

	void OnRequest(Request& request)
	{
		if (strcmp(SQLRESID, request.id) == 0)
		{
			SQLresult* res = static_cast<SQLresult*>(&request);

			User* user = GetAssocUser(this, SQLutils, res->id).S().user;
			UnAssociate(this, SQLutils, res->id).S();

			if (user)
			{
				std::string* tried_user = saved_user.get(user);
				std::string* tried_pass = saved_pass.get(user);
				if (res->error.Id() == SQL_NO_ERROR)
				{
					if (res->Rows())
					{
						/* We got a row in the result, this means there was a record for the oper..
						 * now we just need to check if their host matches, and if it does then
						 * oper them up.
						 *
						 * We now (previous versions of the module didn't) support multiple SQL
						 * rows per-oper in the same way the config file does, all rows will be tried
						 * until one is found which matches. This is useful to define several different
						 * hosts for a single oper.
						 *
						 * The for() loop works as SQLresult::GetRowMap() returns an empty map when there
						 * are no more rows to return.
						 */

						for (SQLfieldMap& row = res->GetRowMap(); row.size(); row = res->GetRowMap())
						{
							if (OperUser(user, row["hostname"].d, row["type"].d))
							{
								/* If/when one of the rows matches, stop checking and return */
								saved_user.unset(user);
								saved_pass.unset(user);
							}
							if (tried_user && tried_pass)
							{
								LoginFail(user, *tried_user, *tried_pass);
								saved_user.unset(user);
								saved_pass.unset(user);
							}
						}
					}
					else
					{
						/* No rows in result, this means there was no oper line for the user,
						 * we should have already checked the o:lines so now we need an
						 * "insufficient awesomeness" (invalid credentials) error
						 */
						if (tried_user && tried_pass)
						{
							LoginFail(user, *tried_user, *tried_pass);
							saved_user.unset(user);
							saved_pass.unset(user);
						}
					}
				}
				else
				{
					/* This one shouldn't happen, the query failed for some reason.
					 * We have to fail the /oper request and give them the same error
					 * as above.
					 */
					if (tried_user && tried_pass)
					{
						LoginFail(user, *tried_user, *tried_pass);
						saved_user.unset(user);
						saved_pass.unset(user);
					}

				}
			}
		}
	}

	void LoginFail(User* user, const std::string &username, const std::string &pass)
	{
		Command* oper_command = ServerInstance->Parser->GetHandler("OPER");

		if (oper_command)
		{
			std::vector<std::string> params;
			params.push_back(username);
			params.push_back(pass);
			oper_command->Handle(params, user);
		}
		else
		{
			ServerInstance->Logs->Log("m_sqloper",DEBUG, "BUG: WHAT?! Why do we have no OPER command?!");
		}
	}

	bool OperUser(User* user, const std::string &pattern, const std::string &type)
	{
		OperIndex::iterator iter = ServerInstance->Config->oper_blocks.find(" " + type);
		if (iter == ServerInstance->Config->oper_blocks.end())
			return false;
		OperInfo* ifo = iter->second;

		std::string hostname(user->ident);

		hostname.append("@").append(user->host);

		if (OneOfMatches(hostname.c_str(), user->GetIPString(), pattern.c_str()))
		{
			/* Opertype and host match, looks like this is it. */

			user->Oper(ifo);
			return true;
		}

		return false;
	}

	Version GetVersion()
	{
		return Version("Allows storage of oper credentials in an SQL table", VF_VENDOR);
	}

};

MODULE_INIT(ModuleSQLOper)