-- This function assumes only 4pts in the feed rps param and disttbl tables.
-- copy and adjust as needed for different shapes and designs etc.
-- when providing thebear and therange override params slat,slon,tlat,tlon can all be nil.
-- otherwise they are required.
local function handle4pBoxPTzone(slat,slon,tlat,tlon,rps,disttbl,pct,thebear,therange)
    if thebear ==nil then thebear = Tool_Bearing({latitude=slat, longitude=slon},{latitude=tlat, longitude=tlon}); end
    if therange ==nil then therange = Tool_Range({latitude=slat, longitude=slon},{latitude=tlat, longitude=tlon}); end
    local centerpoint = World_GetPointFromBearing({latitude=slat,longitude=slon,BEARING=thebear,DISTANCE=(therange * pct)})
    local,retval1,retval2,adjbear,bFlag = false,nil,0,false;
    for k,v in pairs(rps) do
       if k == 1 then adjbear = (thebear + (k * 45)) %360; --original bearing 45d offset from that starting point
       else adjbear = (adjbear + 90)%360;  end  --90d offset from ^starting point or later.. lastpoint.
        local therp = World_GetPointFromBearing({latitude=centerpoint.latitude,longitude=centerpoint.longitude,BEARING=adjbear,DISTANCE=disttbl[k]});
         --a simple v.latitude,v.longitude=therp.latitude,therp.longitude here will not actually update it,must use setrefpt. 
        retval1,retval2 = pcall(ScenEdit_SetReferencePoint,{guid=v.guid,side=v.side,latitude=therp.latitude,longitude=therp.longitude});
        if retval1 ==false then print("Error updating ref point: " .. tostring(retval2)); bFlag = true; end
    end
    if bFlag then return false; else return true;end
end

local function UpdatePatrolMissionRPSourceToTarget(mname,mside,sname,sside,tname,tside,pct,nenm,senm,swnm,nwnm,pznm)
    if mname ==nil or mside == nil or tname ==nil or tside ==nil or sname==nil or sside==nil then 
        print("One or more of missionname,missionside,sourcename,sourceside,targetname,targetside params are missing."); return;
    end
    if pct == nil then pct = 0.50;end  if pznm == nil then pznm = 50.0;end
    if nenm == nil then nenm = 50.0;end  if senm == nil then senm = 50.0;end
    if swnm == nil then swnm = 50.0;end  if nwnm == nil then nwnm = 50.0;end
    local m = ScenEdit_GetMission(mside,mname);
    local s = ScenEdit_GetUnit({name=sname,side=sside});
    local t = ScenEdit_GetUnit({name=tname,side=tside});
    if m==nil or t==nil or s==nil then print("Could not get mission or source or target."); return end --sanity check.

    local tmparea = {};
    if (m.patrolmission.PatrolZone ~=nil) and #m.patrolmission.PatrolZone == 4 then
        for i =1,#m.patrolmission.PatrolZone do
          tmparea[i] = m.patrolmission.PatrolZone[i].name
        end
        local ppoints = ScenEdit_GetReferencePoints({side=m.side, area=tmparea});
        handle4pBoxPTzone(s.latitude,s.longitude,t.latitude,t.longitude,ppoints,{nenm,senm,swnm,nwnm},pct)
    end
    if (m.patrolmission.ProsecutionZone ~=nil) and #m.patrolmission.ProsecutionZone == 4 then
        tmparea = {};
        for i =1,#m.patrolmission.ProsecutionZone do
          tmparea[i] = m.patrolmission.ProsecutionZone[i].name
        end
        local ppoints = ScenEdit_GetReferencePoints({side=m.side, area=tmparea})
        handle4pBoxPTzone(s.latitude,s.longitude,t.latitude,t.longitude,ppoints,{nenm+pznm,senm+pznm,swnm+pznm,nwnm+pznm},pct)
    end
end

--call update to a square box centered 50% distance to target with 50nm extra add on for prosecution rp's if any.
UpdatePatrolMissionRPSourceToTarget("Testy","China","Shandong Carrier Strike Group","China","Abraham Lincoln Strike Group","United States",0.50,100,100,100,100,50);

--call update to a polygon centered 40% distance to target with 30nm extra add on for prosecution rp's if any.
UpdatePatrolMissionRPSourceToTarget("Testy","China","Shandong Carrier Strike Group","China","Abraham Lincoln Strike Group","United States",0.40,125,50,50,125,30);