///////////////////////////////////////////////////////////////////////////
//  Copyright (C) Wizardry and Steamworks 2021 - License: GNU GPLv3      //
//  Please see: http://www.gnu.org/licenses/gpl.html for legal details,  //
//  rights of fair usage, the disclaimer and warranty conditions.        //
///////////////////////////////////////////////////////////////////////////

///////////////////////////////////////////////////////////////////////////
//    Copyright (C) 2015 Wizardry and Steamworks - License: CC BY 2.0    //
///////////////////////////////////////////////////////////////////////////
string wasKeyValueGet(string k, string data) {
    if(llStringLength(data) == 0) return "";
    if(llStringLength(k) == 0) return "";
    list a = llParseStringKeepNulls(data, ["&", "="], []);
    integer i = llListFindList(llList2ListStrided(a, 0, -1, 2), [ k ]);
    if(i != -1) return llList2String(a, 2*i+1);
    return "";
}

key sitting = NULL_KEY;
vector destination = ZERO_VECTOR;
integer channel = 0;

default {
    state_entry() {
        channel = (integer)("0x8" + llGetSubString(llGetOwner(), 0, 6));
        llListen(channel, "", "", "");
        llSetTimerEvent(10);
    }
    listen(integer num, string name, key id, string message) {
        if(message == "DIE") {
            llDie();
        }
        destination = (vector)wasKeyValueGet("destination", message);
        sitting = (key)wasKeyValueGet("avatar", message);
        if(destination == ZERO_VECTOR || sitting == NULL_KEY)  {
            return;
        }
        state configured;
    }
    timer() {
        llDie();
    }
    on_rez(integer num) {
        llResetScript();
    }
}

state configured {
    state_entry() {
        llSitTarget(<0,0,1>, ZERO_ROTATION);
        llSetClickAction(CLICK_ACTION_SIT);
        llSetTimerEvent(10);
    }
    changed(integer change) {
        if(change & CHANGED_LINK) {
            key agent = llAvatarOnSitTarget();
            if(agent == NULL_KEY) {
                llUnSit(agent);
                return;
            }
            if(agent == sitting) {
                llWhisper(channel, "OK");
                state teleport;
            }
            llInstantMessage(agent, 
                "Sorry, the teleporter is currently in use by: " + 
                    llList2String(
                        llParseString2List(
                            llKey2Name(sitting), 
                            [" "], 
                            []
                        ),
                        0
                    )
            );
            llUnSit(agent);
            return;
        }
    }
    timer() {
        llDie();
    }
    on_rez(integer num) {
        llResetScript();
    }
}
 
state teleport {
    state_entry() {
        // set timeout
        llSetTimerEvent(10);
        // clear sit position and action
        llSetRegionPos(destination);
        // request to set camera
        llRequestPermissions(sitting, PERMISSION_CONTROL_CAMERA);
    }
    run_time_permissions(integer perm) {
        // set the camera so the viewer follows the agent
        // this works if the viewer is not zoomed-in on
        // the teleport pad
        if(perm & PERMISSION_CONTROL_CAMERA) {
            llSetCameraParams([
                CAMERA_ACTIVE, 1,
                CAMERA_BEHINDNESS_ANGLE, 45.0,
                CAMERA_BEHINDNESS_LAG, 0.5,
                CAMERA_DISTANCE, 8.0,
                CAMERA_FOCUS_LAG, 0.05 ,
                CAMERA_FOCUS_LOCKED, TRUE,
                CAMERA_FOCUS_THRESHOLD, 0.0,
                CAMERA_PITCH, 20.0,
                CAMERA_POSITION_LAG, 0.1,
                CAMERA_POSITION_LOCKED, TRUE,
                CAMERA_POSITION_THRESHOLD, 0.0,
                CAMERA_FOCUS_OFFSET, <3,0,2>
            ]);
            llClearCameraParams();
        }
        llSetTimerEvent(0.1);
    }
    timer() {
        key agent = llAvatarOnSitTarget();
        if(agent != NULL_KEY) {
            llUnSit(agent);
        }
        llDie();
    }
    on_rez(integer num) {
        llResetScript();
    }
}