/*
 * ngIRCd -- The Next Generation IRC Daemon
 * Copyright (c)2001-2014 Alexander Barton (alex@barton.de) and Contributors.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * Please read the file COPYING, README and AUTHORS for more information.
 */

#include "portab.h"

/**
 * @file
 * Handler for IRC capability ("CAP") commands
 */

#include <assert.h>
#include <string.h>
#include <strings.h>

#include "conn.h"
#include "channel.h"
#include "client-cap.h"
#include "irc-write.h"
#include "log.h"
#include "login.h"
#include "messages.h"
#include "parse.h"

#include "irc-cap.h"

/* Local functions */

/**
 * Set CAP negotiation status and mark client as "supports capabilities".
 *
 * @param Client The client to handle.
 */
static void
Set_CAP_Negotiation(CLIENT *Client)
{
	assert(Client != NULL);

	if (Client_Type(Client) != CLIENT_USER)
		Client_CapAdd(Client, CLIENT_CAP_PENDING);
	Client_CapAdd(Client, CLIENT_CAP_SUPPORTED);
}

/**
 * Parse capability string and return numeric flag value.
 *
 * @param Args The string containing space-separated capability names.
 * @return Changed capability flags or 0 on error.
 */
static int
Parse_CAP(int Capabilities, char *Args)
{
	static char tmp[COMMAND_LEN];
	char *ptr;

	assert(Args != NULL);

	strlcpy(tmp, Args, sizeof(tmp));

	ptr = strtok(tmp, " ");
	while (ptr) {
		if (*ptr == '-') {
			/* drop capabilities */
			ptr++;
			if (strcmp(ptr, "multi-prefix") == 0)
				Capabilities &= ~CLIENT_CAP_MULTI_PREFIX;
			else
				return -1;
		} else {
			/* request capabilities */
			if (strcmp(ptr, "multi-prefix") == 0)
				Capabilities |= CLIENT_CAP_MULTI_PREFIX;
			else
				return -1;
		}
		ptr = strtok(NULL, " ");
	}

	return Capabilities;
}

/**
 * Return textual representation of capability flags.
 *
 * Please note: this function returns a pointer to a global buffer and
 * therefore isn't thread safe!
 *
 * @param Capabilities Capability flags (bitmask).
 * @return Pointer to textual representation.
 */
static char *
Get_CAP_String(int Capabilities)
{
	static char txt[COMMAND_LEN];

	txt[0] = '\0';

	if (Capabilities & CLIENT_CAP_MULTI_PREFIX)
		strlcat(txt, "multi-prefix ", sizeof(txt));

	return txt;
}

/**
 * Handler for the IRCv3 sub-command "CAP LS".
 *
 * @param Client The client from which this command has been received.
 * @param Arg Command argument or NULL.
 * @return CONNECTED or DISCONNECTED.
 */
static bool
Handle_CAP_LS(CLIENT *Client, UNUSED char *Arg)
{
	assert(Client != NULL);

	Set_CAP_Negotiation(Client);

	return IRC_WriteStrClient(Client,
				  "CAP %s LS :multi-prefix",
				  Client_ID(Client));
}

/**
 * Handler for the IRCv3 sub-command "CAP LIST".
 *
 * @param Client The client from which this command has been received.
 * @param Arg Command argument or NULL.
 * @return CONNECTED or DISCONNECTED.
 */
static bool
Handle_CAP_LIST(CLIENT *Client, UNUSED char *Arg)
{
	assert(Client != NULL);

	return IRC_WriteStrClient(Client, "CAP %s LIST :%s", Client_ID(Client),
				  Get_CAP_String(Client_Cap(Client)));
}

/**
 * Handler for the IRCv3 sub-command "CAP REQ".
 *
 * @param Client The client from which this command has been received.
 * @param Arg Command argument.
 * @return CONNECTED or DISCONNECTED.
 */
static bool
Handle_CAP_REQ(CLIENT *Client, char *Arg)
{
	int new_cap;

	assert(Client != NULL);
	assert(Arg != NULL);

	Set_CAP_Negotiation(Client);

	new_cap = Parse_CAP(Client_Cap(Client), Arg);

	if (new_cap < 0)
		return IRC_WriteStrClient(Client, "CAP %s NAK :%s",
					  Client_ID(Client), Arg);

	Client_CapSet(Client, new_cap);
	return IRC_WriteStrClient(Client, "CAP %s ACK :%s",
				  Client_ID(Client), Arg);
}

/**
 * Handler for the IRCv3 sub-command "CAP ACK".
 *
 * @param Client The client from which this command has been received.
 * @param Arg Command argument.
 * @return CONNECTED or DISCONNECTED.
 */
static bool
Handle_CAP_ACK(UNUSED CLIENT *Client, UNUSED char *Arg)
{
	assert(Client != NULL);
	assert(Arg != NULL);

	return CONNECTED;
}

/**
 * Handler for the IRCv3 sub-command "CAP CLEAR".
 *
 * @param Client The client from which this command has been received.
 * @return CONNECTED or DISCONNECTED.
 */
static bool
Handle_CAP_CLEAR(CLIENT *Client)
{
	int cap_old;

	assert(Client != NULL);

	cap_old = Client_Cap(Client);
	if (cap_old & CLIENT_CAP_MULTI_PREFIX)
		Client_CapDel(Client, CLIENT_CAP_MULTI_PREFIX);

	return IRC_WriteStrClient(Client, "CAP %s ACK :%s", Client_ID(Client),
				  Get_CAP_String(cap_old));
}

/**
 * Handler for the IRCv3 sub-command "CAP END".
 *
 * @param Client The client from which this command has been received.
 * @return CONNECTED or DISCONNECTED.
 */
static bool
Handle_CAP_END(CLIENT *Client)
{
	assert(Client != NULL);

	if (Client_Type(Client) != CLIENT_USER) {
		/* User is still logging in ... */
		Client_CapDel(Client, CLIENT_CAP_PENDING);

		if (Client_Type(Client) == CLIENT_WAITCAPEND) {
			/* Only "CAP END" was missing: log in! */
			return Login_User(Client);
		}
	}

	return CONNECTED;
}

/* Global functions */

/**
 * Handler for the IRCv3 command "CAP".
 *
 * @param Client The client from which this command has been received.
 * @param Req Request structure with prefix and all parameters.
 * @return CONNECTED or DISCONNECTED.
 */
GLOBAL bool
IRC_CAP(CLIENT *Client, REQUEST *Req)
{
	assert(Client != NULL);
	assert(Req != NULL);

	LogDebug("Got \"%s %s\" command from \"%s\" ...",
		 Req->command, Req->argv[0], Client_ID(Client));

	if (Req->argc == 1) {
		if (strcasecmp(Req->argv[0], "CLEAR") == 0)
			return Handle_CAP_CLEAR(Client);
		if (strcasecmp(Req->argv[0], "END") == 0)
			return Handle_CAP_END(Client);
	}
	if (Req->argc >= 1 && Req->argc <= 2) {
		if (strcasecmp(Req->argv[0], "LS") == 0)
			return Handle_CAP_LS(Client, Req->argv[1]);
		if (strcasecmp(Req->argv[0], "LIST") == 0)
			return Handle_CAP_LIST(Client, Req->argv[1]);
	}
	if (Req->argc == 2) {
		if (strcasecmp(Req->argv[0], "REQ") == 0)
			return Handle_CAP_REQ(Client, Req->argv[1]);
		if (strcasecmp(Req->argv[0], "ACK") == 0)
			return Handle_CAP_ACK(Client, Req->argv[1]);
	}

	return IRC_WriteErrClient(Client, ERR_INVALIDCAP_MSG,
				  Client_ID(Client), Req->argv[0]);
}

/* -eof- */