--// When you can't trust #table
local function getTableCount(tbl)
    local c = 0;
    if tbl == nil then return 0; end
    for k,v in pairs(tbl) do
      c=c+1;
    end
    return c;
end

--//feed it table of latitude=\longitude= and get back Y= X= ;for use with inPolygon();
-- ie you can feed it a zone.area and then just use result as input to inPolygon.
local function fnConvertLatLonToYXtable(lltable)
    if (lltable ~=nil and getTableCount(lltable) > 0) then
        local retval = {}
        local tcount = getTableCount(lltable);
        for i=1, getTableCount(lltable) do
            table.insert(retval,{y=lltable[i].latitude,x=lltable[i].longitude});  --lowercase required.
        end
        if #retval > 0 then
            return retval;
        else
            print('fnConvertLatLonToYXtable():: generated table has no data, returning nil.');
            return nil;
        end
    else
        print('fnConvertLatLonToYXtable():: table missing or zero entries, returning nil.');
        return nil;
    end
end


--This totally may not work in some very specific cases?? 
--I may have to just live with it.  Think it may fail when zone crosses 179|180|-179 globe split in pacific or polar regions?
--https://stackoverflow.com/questions/31730923/check-if-point-lies-in-polygon-lua#31744797
--lots of samples out there but none it seems when comes to core-lua and handling all geo cases properly.
--Wonder if related to polar regions in the game. 

local function insidePolygon(polygon, point)
    local oddNodes = false
    local j = #polygon
    for i = 1, #polygon do
        if (polygon[i].y < point.y and polygon[j].y >= point.y or polygon[j].y < point.y and polygon[i].y >= point.y) then
            if (polygon[i].x + ( point.y - polygon[i].y ) / (polygon[j].y - polygon[i].y) * (polygon[j].x - polygon[i].x) < point.x) then
                oddNodes = not oddNodes;
            end
        end
        j = i;
    end
    return oddNodes 
end


print('---- Sample tests ----');
--//Table representing the polygon to check.
local poly={
{y=-2.17371659770207, x=-4.86607715718033},
{y=-2.11459848946334, x=-3.18048722275834},
{y=-3.77456725501735, x=-3.23996283292925},
{y=-3.68063657943523, x=-5.15867707489552},
{y=-2.7429662365217, x=-5.60898162815377}
}

--//table that simulates an zone's .area return value of RP's
local tmpZoneDotAreaReplica={
{name='RP-bla1',latitude=-2.17371659770207, longitude=-4.86607715718033},
{name='RP-bla2',latitude=-2.11459848946334, longitude=-3.18048722275834},
{name='RP-bla3',latitude=-3.77456725501735, longitude=-3.23996283292925},
{name='RP-bla4',latitude=-3.68063657943523, longitude=-5.15867707489552},
{name='RP-bla5',latitude=-2.7429662365217, longitude=-5.60898162815377}
}

local middle = {y=-3.00439118080036, x=-4.08700082745286};
local edge = {y=-3.54497201361856, x=-4.24574572930585};
local random = {y=-2.30874447451051, x=-3.5247459460433};
local outside = {y=2.02568621285042,x=4.57013931632061};

--//test when using nonavzone.area return value that is table of RP's.
local ctbl = fnConvertLatLonToYXtable(tmpZoneDotAreaReplica);
if(ctbl) then
    local pt  = {y=-2.30874447451051, x=-3.5247459460433};
    if insidePolygon(ctbl,pt) then print('pt inside area.') else print('pt outside area') end
end

if insidePolygon(poly,middle) then print('point inside area.') else print('point outside area') end
if insidePolygon(poly,edge) then print('point inside area.') else print('point outside area') end
if insidePolygon(poly,random) then print('point inside area.') else print('point outside area') end
if insidePolygon(poly,outside) then print('point inside area.') else print('point outside area') end