///////////////////////////////////////////////////////////////////////////
//  Copyright (C) Wizardry and Steamworks 2014 - 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) 2013 Wizardry and Steamworks - License: GNU GPLv3    //
///////////////////////////////////////////////////////////////////////////
moveTo(vector target, integer bb, key agent) {
    llStopMoveToTarget();
    llTargetRemove(moveTarget);
    vector mePos = llGetPos();
    vector pointTo = target - mePos;
    llOwnerSay("@setrot:" + (string)llAtan2(pointTo.x, pointTo.y) + "=force");
    moveTarget = llTarget(target, 2 + bb);
    float dampening = llVecDist(target, mePos)/3.20;
    if(llGetAgentInfo(agent) & AGENT_ALWAYS_RUN) {
        dampening = llVecDist(target, mePos)/5.13;
        jump move;
    }
@move;
    if(dampening < 0.045) dampening = 0.045;
    llMoveToTarget(target, dampening);
}

///////////////////////////////////////////////////////////////////////////
//    Copyright (C) 2013 Wizardry and Steamworks - License: GNU GPLv3    //
///////////////////////////////////////////////////////////////////////////
wasTellOwner(string type, string message) {
    llOwnerSay("⎣" + type + "⎤: " + message + ".");
}

///////////////////////////////////////////////////////////////////////////
//    Copyright (C) 2014 Wizardry and Steamworks - License: GNU GPLv3    //
///////////////////////////////////////////////////////////////////////////
string wasKeyValueSet(string k, string v, string data) {
    if(llStringLength(k) == 0) return "";
    if(llStringLength(v) == 0) return "";
    if(llStringLength(data) == 0) return k + "=" + v;
    integer i = llListFindList(
        llList2ListStrided(
            llParseString2List(data, ["&", "="], []), 
            0, -1, 2
        ), 
    [ k ]);
    if(i != -1) return llDumpList2String(
        llListReplaceList(
            llParseString2List(data, ["&"], []), 
            [ k + "=" + v ], 
        i, i), 
    "&");
    return data + "&" + k + "=" + v;
}

///////////////////////////////////////////////////////////////////////////
//    Copyright (C) 2015 Wizardry and Steamworks - License: GNU GPLv3    //
///////////////////////////////////////////////////////////////////////////
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 "";
}

///////////////////////////////////////////////////////////////////////////
//    Copyright (C) 2014 Wizardry and Steamworks - License: GNU GPLv3    //
///////////////////////////////////////////////////////////////////////////
string wasKeyValueDelete(string k, string data) {
    if(llStringLength(data) == 0) return "";
    if(llStringLength(k) == 0) return "";
    integer i = llListFindList(
        llList2ListStrided(
            llParseString2List(data, ["&", "="], []), 
            0, -1, 2
        ), 
    [ k ]);
    if(i != -1) return llDumpList2String(
        llDeleteSubList(
            llParseString2List(data, ["&"], []),
        i, i), 
    "&");
    return data;
}

///////////////////////////////////////////////////////////////////////////
//    Copyright (C) 2013 Wizardry and Steamworks - License: GNU GPLv3    //
///////////////////////////////////////////////////////////////////////////
LID(key id) {
    if(id != NULL_KEY && llGetAttached() != 0) {
        llSetLinkPrimitiveParamsFast(2, [PRIM_DESC, wasKeyValueSet("login", (string)((integer)wasKeyValueGet("login", llList2String(llGetLinkPrimitiveParams(2, [PRIM_DESC]), 0))+1), llList2String(llGetLinkPrimitiveParams(2, [PRIM_DESC]), 0))]);
        llResetScript();
    }
    llSetLinkPrimitiveParamsFast(2, [PRIM_DESC, wasKeyValueSet("login", "-1", llList2String(llGetLinkPrimitiveParams(2, [PRIM_DESC]), 0))]);
}

string criteria = "";
key uuid = NULL_KEY;
integer moveTarget = 0;

default {
    state_entry() {
        // LID™ reasoning - http://grimore.org/fuss:lsl#log-in_detection_with_attachments
        // if LID™, then login = 1
        // else login = 0 - script running | parameter undefined
        if((integer)wasKeyValueGet("login", llGetObjectDesc()) > 0) {
            llSetLinkPrimitiveParamsFast(2, [PRIM_DESC, wasKeyValueSet("login", "0", llList2String(llGetLinkPrimitiveParams(2, [PRIM_DESC]), 0))]);
            state check;
            return;
        }
        llSetLinkPrimitiveParamsFast(2, [PRIM_DESC, wasKeyValueSet("login", "0", llList2String(llGetLinkPrimitiveParams(2, [PRIM_DESC]), 0))]);
        state check;
    }
    // LID™ reasoning - http://grimore.org/fuss:lsl#log-in_detection_with_attachments
    // order: on_rez -> attach
    //
    // if object attached, then login := login+1
    // else login := -1
    attach(key id) {
        // attached
        if(id != NULL_KEY && llGetAttached() != 0) {
            llSetLinkPrimitiveParamsFast(2, [PRIM_DESC, wasKeyValueSet("login", (string)((integer)wasKeyValueGet("login", llList2String(llGetLinkPrimitiveParams(2, [PRIM_DESC]), 0))+1), llList2String(llGetLinkPrimitiveParams(2, [PRIM_DESC]), 0))]);
            // Reset script for llGetCreator() bugture.
            llResetScript();
        }
        // detached
        llSetLinkPrimitiveParamsFast(2, [PRIM_DESC, wasKeyValueSet("login", "-1", llList2String(llGetLinkPrimitiveParams(2, [PRIM_DESC]), 0))]);
    }
    // login = 1 after object attached
    //       = -1 after object detached
    on_rez(integer num) {
        llResetScript();
    }
    changed(integer change) {
        llResetScript();
    }
}
 
state check {
    state_entry() {
        // alarm for seekng RLV
        llSetTimerEvent(25);
        integer channel = 10+(integer)llFrand(10);
        llListen(channel, "", llGetOwner(), "");
        llOwnerSay("@version=" + (string)channel);
    }
    timer() {
        llSetTimerEvent(0);
        // alarm triggered, we don't have RLV
        wasTellOwner("follow", "This gizmo requires a RLV-enabled viewer.");
        return;
    }
    listen(integer channel, string name, key id, string message) {
        llSetTimerEvent(0);
        // we have RLV
        state seek;
    }
    on_rez(integer num) {
        llResetScript();
    }
    changed(integer change) {
        llResetScript();
    }
    // LID™ - http://grimore.org/fuss:lsl#log-in_detection_with_attachments
    attach(key id) {
        LID(id);
    }
}

state seek {
    state_entry() {
        uuid = (key) wasKeyValueGet("follow", llList2String(llGetLinkPrimitiveParams(2, [PRIM_DESC]), 0));
        if(uuid != "") state follow;
        if(criteria != "") {
            llSensorRepeat("", "", AGENT, 65, TWO_PI, 1);
            // alarm for searching agent matching criteria
            llSetTimerEvent(5);
        }
        llListen(0, "", llGetOwner(), "");
    }
    listen(integer channel, string name, key id, string message) {
        list cmd = llParseString2List(message, [" "], []);
        if(llList2String(cmd, 0) != "@follow") {
            cmd = [];
            return;
        }
        criteria = llList2String(cmd, 1);
        llSensorRepeat("", "", AGENT, 65, TWO_PI, 1);
        // alarm for searching agent matching criteria
        llSetTimerEvent(5);
    }
    timer() {
        wasTellOwner("follow", "Could not find avatar to follow...");
        llResetScript();
    }
    sensor(integer num) {
        --num;
        do {
            list name = llParseString2List(llDetectedName(num), ["."], []);
            do {
                string nib = llList2String(name, 0);
                if(llSubStringIndex(llToLower(nib), llToLower(criteria)) != -1) {
                    wasTellOwner("follow", "Target agent found...");
                    uuid = llDetectedKey(num);
                    llSetLinkPrimitiveParamsFast(
                        2, 
                        [PRIM_DESC, 
                            wasKeyValueSet(
                                "follow", 
                                (string)uuid, 
                                llList2String(
                                    llGetLinkPrimitiveParams(
                                        2, 
                                        [PRIM_DESC]
                                    ), 
                                    0
                                )
                            )
                        ]
                    );
                    criteria = "";
                    wasTellOwner("follow", "Starting follow...");
                    state follow;
                }
                name = llDeleteSubList(name, 0, 0);
            } while(llGetListLength(name) != 0);
        } while(--num>-1);
    }
    on_rez(integer num) {
        llResetScript();
    }
    changed(integer change) {
        llResetScript();
    }
    // LID™ - http://grimore.org/fuss:lsl#log-in_detection_with_attachments
    attach(key id) {
        LID(id);
    }
}

state follow {
    state_entry() {
        llRequestPermissions(llGetOwner(), PERMISSION_TAKE_CONTROLS);
        llSensorRepeat("", uuid, AGENT, 65, TWO_PI, 1);
        llListen(0, "", llGetOwner(), "");
    }
    listen(integer channel, string name, key id, string message) {
        list cmd = llParseString2List(message, [" "], []);
        if(llList2String(cmd, 0) != "@follow" && llList2String(cmd, 0) != "@unfollow") {
            cmd = [];
            return;
        }
        if(llList2String(cmd, 0) == "@unfollow") {
            wasTellOwner("follow", "Stopping follow...");
        }
        llSetLinkPrimitiveParamsFast(
            2, 
            [PRIM_DESC, 
                wasKeyValueDelete(
                    "follow", 
                    llList2String(
                        llGetLinkPrimitiveParams(
                            2, 
                            [PRIM_DESC]
                        ), 
                    0
                    )
                )
            ]
        );
        if(llList2String(cmd, 0) == "@follow") {
            criteria = llList2String(cmd, 1);
            llSetTimerEvent(0);
            state seek;
        }
        llResetScript();
    }
    run_time_permissions(integer perm) {
        if(perm & PERMISSION_TAKE_CONTROLS) {
            llTakeControls(
                CONTROL_FWD |
                CONTROL_BACK |
                CONTROL_LEFT |
                CONTROL_RIGHT |
                CONTROL_ROT_LEFT |
                CONTROL_ROT_RIGHT |
                CONTROL_UP |
                CONTROL_DOWN |
                CONTROL_LBUTTON |
                CONTROL_ML_LBUTTON, TRUE, TRUE);
            return;
        }
        wasTellOwner("follow", "Could not get control permissions. Restarting script.");
        llResetScript();
    }
    sensor(integer num) {
        --num;
        do {
            vector pos = llDetectedPos(num);
            if(llVecDist(pos, llGetPos()) < 5) {
                llStopMoveToTarget();
                llTargetRemove(moveTarget);
                return;
            }
            if(llGetAgentInfo(uuid) & AGENT_IN_AIR) return;
            moveTo(
                pos,
                (integer)(llVecDist(llList2Vector(llGetBoundingBox(uuid), 1), 
                llList2Vector(llGetBoundingBox(uuid), 0))/2.0),
                uuid
            );
            return;
        } while(--num>-1);
    }
    at_target(integer tnum, vector targetpos, vector ourpos) {
        llStopMoveToTarget();
        llTargetRemove(moveTarget);
    }
    control(key id, integer level, integer edge) {
        // while key is held down, don't move the avatar
        if(level & ~edge == 0) return;
        llStopMoveToTarget();
        llTargetRemove(moveTarget);
        llReleaseControls();
        llSetTimerEvent(0);
        state move;
    }
    on_rez(integer num) {
        llResetScript();
    }
    changed(integer change) {
        llResetScript();
    }
    // LID™ - http://grimore.org/fuss:lsl#log-in_detection_with_attachments
    attach(key id) {
        LID(id);
    }
}

state move {
    state_entry() {
        llRequestPermissions(llGetOwner(), PERMISSION_TAKE_CONTROLS);
    }
    run_time_permissions(integer perm) {
        if(perm & PERMISSION_TAKE_CONTROLS == 0) {
            wasTellOwner("follow", "Could not get control permissions. Restarting script.");
            llResetScript();
        }
        llTakeControls(
            CONTROL_FWD |
            CONTROL_BACK |
            CONTROL_LEFT |
            CONTROL_RIGHT |
            CONTROL_ROT_LEFT |
            CONTROL_ROT_RIGHT |
            CONTROL_UP |
            CONTROL_DOWN |
            CONTROL_LBUTTON |
            CONTROL_ML_LBUTTON, TRUE, TRUE);
    }
    control(key id, integer level, integer edge) {
        // alarm 
        llSetTimerEvent(1);
    }
    timer() {
        llSetTimerEvent(0);
        llReleaseControls();
        state follow;
    }
    on_rez(integer num) {
        llResetScript();
    }
    changed(integer change) {
        llResetScript();
    }
    // LID™ - http://grimore.org/fuss:lsl#log-in_detection_with_attachments
    attach(key id) {
        LID(id);
    }
}