-- Function to move unit semi randomly up to a limit of distance from start, in bearing of optional choosing
-- and to optionally set depth or altitude semi randomly
-- side: (string) side name of unit; REQUIRED
-- ship: (string) name of unit;  REQUIRED
-- distance: (number) max nm distance to randomly try. 1-12000; default = 100
-- bmin: (number) min bearing to try from 1-360; default 1
-- bmax: (number) max bearing to try from 1-360; default 360
-- mindepth:(negative number) when searching for a location for a sub or ship apply this minimum -elevation check; default -2meters
-- randomalt: (boolean) defaults to false
--
-- To users:
-- Script function is primarly meant to be placed with other 'global' scripts in a scenario-onstartup\load event.
-- so that you run it once and use it everywhere, though technically speaking you can use it as a fragment.

function placeUnitRandomly(side, ship, distance, bmin, bmax, mindepth,randomalt)
    if (side == nil or side=='') or (ship == nil or ship =='') then
      print('placeUnitRandomly() missing side or ship or unit name. Aborting call.');
      return
    end

    if (bmin == nil or bmin < 0 or bmin > 360) then bmin = 1 end --if missing or invaid use 1 as default
    if (bmax == nil or bmax < 0 or bmax > 360) then bmax = 360 end -- if missing or invalid use 360 as default
    if (mindepth == nil or mindepth < -10000 or mindepth > 0) then mindepth = -2 end -- if missing or invalid use -2m default
    if (distance == nil or distance < 1 or distance > 12000) then distance = 100 end -- if missing or invalid use 100nm default
    randomalt = randomalt or false;
    math.randomseed(os.time());

    local u = ScenEdit_GetUnit({name=ship});
    if u ~= nil then
        for i = 1,25 do
          local d = math.random(1,distance);
          local b = math.random(bmin,bmax);
          local point = ScenEdit_AddReferencePoint( {side=side, name='possible' .. tostring(i), RelativeTo=ship, bearing=b ,distance=d });
          -- using addRP's ability to set the points bearing and distance relative to an existing unit as the new location for the unit
          ScenEdit_DeleteReferencePoint ({side=side, name='possible' .. tostring(i)}); --should be ok to delete, just need the values
          elevation = World_GetElevation({latitude=point.latitude, longitude=point.longitude}); -- get elevation of new RP to see if it is suitable
          --print(elevation)
          if u.type == 'Aircraft' then 
            --print('moving an aircraft')
            u.latitude = point.latitude;
            u.longitude = point.longitude;
            if (randomalt) then 
                local ralt = math.random(305,10975.7); -- ~ 1000 to 36000 ft
                u.altitude = ralt; --set alt
                ScenEdit_SetUnit({side=side, unitname=ship, moveto=true,altitude=ralt}) --set desired alt to current.
            end
            return; --exit as we are done
          elseif (u.type == 'Facility' and u.subtype ~= '4001') then
            if (elevation > 0) then
                -- facility that is not sosus bottom array? and needs to be above ground level; could be other subtypes to flag??.
                --print('moving an non submerged facility')
                u.latitude = point.latitude;
                u.longitude = point.longitude;
                return --exit as we are done only if elevation was > 0'
            end
          elseif (elevation < mindepth) then -- check if the new points depth is ok, if so assign the unit to the RPs lat/long
            --print('moving an ship, sub or submerged facility')
            u.latitude = point.latitude;
            u.longitude = point.longitude;
            if (randomalt and u.type == 'Submarine') then
                if (elevation < -450 ) then elevation = -450 end; --cap max depth at like ~1475ft when it's much deeper.
                if (elevation >= mindepth) then mindepth = -3 end; --reset min depth to like 10ft if elevation > min depth; change to 0 if want chance of surfaced subs.
                local ralt = math.random(elevation,mindepth);  --grab rando betweeen bottom and mindepth;
                --print('changing altitude on ' .. ship .. ' to ' .. tostring(ralt) );
                u.altitude = ralt; --set alt
                ScenEdit_SetUnit({side=side, unitname=ship,moveto=true, depth=(ralt * -1)}); --set desired depth to current depth req postive
            end
            return; --exit as we are done
          end 
        end
        print ('unit was not able to find a suitable spot for placement, ship not moved'); -- if we got here then we've exceeded try count.
    else
        print("Unit does not exist");
    end
--endfunc
end


local side = 'US';
--local ship = 'A-100 Premier [Il-476]' --can be group or individual ship or sub aircraft;
--local ship = 'SSN 774 Virginia [Flight I]'; --sub max depth ~1475
--local ship = 'Bottom Fixed Array (SOSUS)'; facility subtype 4001;
--local ship = 'DDG 96 Bainbridge [Arleigh Burke Flight IIA]'; --ship
local ship = 'Bunker (ACINT SOSUS Station)'; --facility subtype 3001
--local ship = 'Flight 18'; --group of 2 a-100 aircraft

local distance = 150; -- max distance in miles away from starting point
local bearignMin = 1; -- you can control the direction by adjusting the min and max bearing
local bearingMax = 360;-- 1 and 360 is anywhere around, 90,180 would be anywhere below etc.
local minDepth = -300 --meters, negative

placeUnitRandomly(side, ship, distance, bearignMin, bearingMax, minDepth,true) -- call the function and pass in ALL the parameters 
--placeUnitRandomly(side, ship, distance, bearignMin, bearingMax, minDepth) -- call the function leave out last param. 
--placeUnitRandomly(side, ship, distance) -- call the function use defaults except for distance. 
--placeUnitRandomly(side, ship) -- call the function leave out stuff let it use ALL defaults. 
--placeUnitRandomly(side, ship, nil, bearignMin, bearingMax) -- call the function use defaults for some not others. 
--placeUnitRandomly(side, ship, nil, nil, nil,nil ,true) --use defaults but enable random alt.