Add script command navigateto. Add packet for this command.

Based on rAthena commits:
commit 4f13007fec7f08c265620a71c3bc4806d186c0f1
Author: Lemongrass3110 <lemongrass@kstp.at>
Date:   Sun Mar 6 21:48:47 2016 +0100

commit 809f220b9f5ef70ee062ee56ae6e8d5f56cb5d32
Author: aleos89 <aleos89@users.noreply.github.com>
Date:   Sun Mar 6 16:15:54 2016 -0500

commit 179f73424934d528ebe494dfb66503c182eacb09
Author: aleos89 <aleos89@users.noreply.github.com>
Date:   Sun Mar 6 16:10:15 2016 -0500

5 files changed, 142 insertions, 0 deletions

diff --git a/doc/script_commands.txt b/doc/script_commands.txt
index 04d2c0c16..eb7e0cd9d 100644
--- a/doc/script_commands.txt
+++ b/doc/script_commands.txt
@@ -7204,6 +7204,39 @@ Example:
 	movenpc("Bugga", 100, 20);
 
 ---------------------------------------
+
+*navigateto("<map>"{,<x>,<y>,<flag>,<hide_window>,<monster_id>,<char_id>});
+
+Generates a navigation for attached or specified character. Requires client
+2011-10-10aRagEXE or newer.
+
+The flag specifies how the client will calculate the specific route.
+
+Valid flags are:
+ NAV_NONE - No services
+ NAV_AIRSHIP_ONLY - Airship only
+ NAV_SCROLL_ONLY - Scroll only
+ NAV_AIRSHIP_AND_SCROLL - Airship and Scroll
+ NAV_KAFRA_ONLY - Kafra only
+ NAV_KAFRA_AND_AIRSHIP - Kafra and Airship
+ NAV_KAFRA_AND_SCROLL - Kafra and Scroll
+ NAV_ALL - All services
+
+When flag is not specified, the default value is NAV_KAFRA_AND_AIRSHIP.
+
+The hide_window specifies whether to display (0) or hide (1) the navigation window.
+By default the window is hidden.
+
+You can specify the monster_id in combination with a mapname to make the
+navigation system tell you, that you have reached the desired mob.
+
+Note:
+The client requires custom monster spawns be in the navigation file
+for using the embedded client Navigation feature to work properly. In this
+instance sending the player to the map where the monster spawns is a simpler
+solution rather than sending the map and the monster_id.
+
+---------------------------------------
 //=====================================
 6 - Other Commands
 //=====================================
diff --git a/src/map/clif.c b/src/map/clif.c
index 7e4f6b825..749b3d068 100644
--- a/src/map/clif.c
+++ b/src/map/clif.c
@@ -18861,6 +18861,47 @@ void clif_selectcart(struct map_session_data *sd)
 #endif
 }
 
+/// Starts navigation to the given target on client side
+void clif_navigate_to(struct map_session_data *sd, const char* mapname, uint16 x, uint16 y, uint8 flag, bool hideWindow, uint16 mob_id)
+{
+#if PACKETVER >= 20111010
+	int fd;
+
+	nullpo_retv(sd);
+	nullpo_retv(mapname);
+	fd = sd->fd;
+	WFIFOHEAD(fd, 27);
+	WFIFOW(fd, 0) = 0x8e2;
+
+	// How detailed will our navigation be?
+	if (mob_id > 0) {
+		x = 0;
+		y = 0;
+		WFIFOB(fd, 2) = 3; // monster with destination field
+	} else if (x > 0 && y > 0) {
+		WFIFOB(fd, 2) = 0; // with coordinates
+	} else {
+		x = 0;
+		y = 0;
+		WFIFOB(fd, 2) = 1; // without coordinates(will fail if you are already on the map)
+	}
+
+	// Which services can be used for transportation?
+	WFIFOB(fd, 3) = flag;
+	// If this flag is set, the navigation window will not be opened up
+	WFIFOB(fd, 4) = hideWindow;
+	// Target map
+	safestrncpy((char*)WFIFOP(fd, 5), mapname, MAP_NAME_LENGTH_EXT);
+	// Target x
+	WFIFOW(fd, 21) = x;
+	// Target y
+	WFIFOW(fd, 23) = y;
+	// Target monster ID
+	WFIFOW(fd, 25) = mob_id;
+	WFIFOSET(fd, 27);
+#endif
+}
+
 /**
  * Returns the name of the given bl, in a client-friendly format.
  *
@@ -19704,6 +19745,7 @@ void clif_defaults(void) {
 	clif->selectcart = clif_selectcart;
 	/* */
 	clif->isdisguised = clif_isdisguised;
+	clif->navigate_to = clif_navigate_to;
 	clif->bl_type = clif_bl_type;
 
 	/*------------------------
diff --git a/src/map/clif.h b/src/map/clif.h
index 8f6950666..3203a3e66 100644
--- a/src/map/clif.h
+++ b/src/map/clif.h
@@ -1111,6 +1111,7 @@ struct clif_interface {
 	void (*ackmergeitems) (int fd, struct map_session_data *sd);
 	/* */
 	bool (*isdisguised) (struct block_list* bl);
+	void (*navigate_to) (struct map_session_data *sd, const char* mapname, uint16 x, uint16 y, uint8 flag, bool hideWindow, uint16 mob_id);
 	unsigned char (*bl_type) (struct block_list *bl);
 	/*------------------------
 	 *- Parse Incoming Packet
diff --git a/src/map/script.c b/src/map/script.c
index 2633c1e5f..f8754660c 100644
--- a/src/map/script.c
+++ b/src/map/script.c
@@ -20507,6 +20507,48 @@ BUILDIN(pcre_match)
 }
 
 /**
+ * navigateto("<map>"{,<x>,<y>,<flag>,<hide_window>,<monster_id>,<char_id>});
+ */
+BUILDIN(navigateto)
+{
+#if PACKETVER >= 20111010
+	struct map_session_data* sd;
+	const char *mapname;
+	uint16 x = 0;
+	uint16 y = 0;
+	uint16 monster_id = 0;
+	uint8 flag = NAV_KAFRA_AND_AIRSHIP;
+	bool hideWindow = true;
+
+	mapname = script_getstr(st, 2);
+
+	if (script_hasdata(st, 3))
+		x = script_getnum(st, 3);
+	if (script_hasdata(st, 4))
+		y = script_getnum(st, 4);
+	if (script_hasdata(st, 5))
+		flag = (uint8)script_getnum(st, 5);
+	if (script_hasdata(st, 6))
+		hideWindow = script_getnum(st, 6) ? true : false;
+	if (script_hasdata(st, 7))
+		monster_id = script_getnum(st, 7);
+
+	if (script_hasdata(st, 8)) {
+		sd = map->charid2sd(script_getnum(st, 8));
+	} else {
+		sd = script->rid2sd(st);
+	}
+
+	clif->navigate_to(sd, mapname, x, y, flag, hideWindow, monster_id);
+
+	return true;
+#else
+	ShowError("Navigation system works only with packet version >= 20111010");
+	return false;
+#endif
+}
+
+/**
  * Adds a built-in script function.
  *
  * @param buildin Script function data
@@ -21175,6 +21217,9 @@ void script_parse_builtin(void) {
 		BUILDIN_DEF(purchaseok,""),
 		BUILDIN_DEF(shopcount, "i"),
 
+		/* Navigation */
+		BUILDIN_DEF(navigateto, "s??????"),
+
 		BUILDIN_DEF(channelmes, "ss"),
 		BUILDIN_DEF(showscript, "s?"),
 		BUILDIN_DEF(mergeitem,""),
@@ -21329,6 +21374,16 @@ void script_hardcoded_constants(void)
 	script->set_constant("EQP_SHADOW_ACC_R", EQP_SHADOW_ACC_R, false, false);
 	script->set_constant("EQP_SHADOW_ACC_L", EQP_SHADOW_ACC_L, false, false);
 
+	script->constdb_comment("Navigation constants, use with *navigateto*");
+	script->set_constant("NAV_NONE", NAV_NONE, false, false);
+	script->set_constant("NAV_AIRSHIP_ONLY", NAV_AIRSHIP_ONLY, false, false);
+	script->set_constant("NAV_SCROLL_ONLY", NAV_SCROLL_ONLY, false, false);
+	script->set_constant("NAV_AIRSHIP_AND_SCROLL", NAV_AIRSHIP_AND_SCROLL, false, false);
+	script->set_constant("NAV_KAFRA_ONLY", NAV_KAFRA_ONLY, false, false);
+	script->set_constant("NAV_KAFRA_AND_AIRSHIP", NAV_KAFRA_AND_AIRSHIP, false, false);
+	script->set_constant("NAV_KAFRA_AND_SCROLL", NAV_KAFRA_AND_SCROLL, false, false);
+	script->set_constant("NAV_ALL", NAV_ALL, false, false);
+
 	script->constdb_comment("Renewal");
 #ifdef RENEWAL
 	script->set_constant("RENEWAL", 1, false, false);
diff --git a/src/map/script.h b/src/map/script.h
index c4c082263..a69000991 100644
--- a/src/map/script.h
+++ b/src/map/script.h
@@ -338,6 +338,17 @@ enum {
 	MF_NOVIEWID
 };
 
+enum navigation_service {
+	NAV_NONE               = 0,
+	NAV_AIRSHIP_ONLY       = 1,
+	NAV_SCROLL_ONLY        = 10,
+	NAV_AIRSHIP_AND_SCROLL = NAV_AIRSHIP_ONLY + NAV_SCROLL_ONLY, //11
+	NAV_KAFRA_ONLY         = 100,
+	NAV_KAFRA_AND_AIRSHIP  = NAV_KAFRA_ONLY + NAV_AIRSHIP_ONLY, // 101
+	NAV_KAFRA_AND_SCROLL   = NAV_KAFRA_ONLY + NAV_SCROLL_ONLY, // 110
+	NAV_ALL                = NAV_AIRSHIP_ONLY + NAV_SCROLL_ONLY + NAV_KAFRA_ONLY // 111-255
+};
+
 /**
  * Structures
  **/