vector2.lua

local Vector2 = {}
local sqrt = math.sqrt
local acos = math.acos
local abs = math.abs

function Vector2.new(x, y)
    assert(tonumber(x) or (x == nil), "Vector2 coordinates can only be numbers")
    assert(tonumber(x) or (x == nil), "Vector2 coordinates can only be numbers")
    local vec2 = {}
    setmetatable(vec2, Vector2)
    vec2.X = x or 0
    vec2.Y = y or 0
    vec2.Type = "Vector2"
    return vec2
end
--[[
function Vector2:new(x,y)
    return Vector2.new(x,y)
end]]

function Vector2.__index(self, index)
    if index == "Magnitude" then
        local x, y = rawget(self, "X"), rawget(self, "Y")
        return sqrt(x * x + y * y)
    elseif index == "Unit" then
        local x, y = rawget(self, "X"), rawget(self, "Y")
        local len = sqrt(x * x + y * y)
        if len == 0 then
            return self
        end
        return Vector2.new(x / len, y / len)
    end
    return rawget(Vector2, index)
end

function Vector2:Dot(other)
    return self.Y * other.Y + self.X * other.X
end

function Vector2:AngleBetween(other)
    return acos(self.Unit:Dot(other.Unit))
end

function Vector2:IsParallelWith(other)
    return abs(self.Unit:Dot(other.Unit)) == 1
end

function Vector2:__tostring()
    return self.X..", "..self.Y
end


function Vector2.__eq(lhs, rhs)
    assert(rhs.Type == "Vector2", "Cannot compare Vector2 with "..tostring(rhs))
    if lhs.X == rhs.X and lhs.Y == rhs.Y then
        return true
    end
    return false
end


function Vector2.__add(lhs, rhs)
    if type(rhs) == "number" then
        return Vector2.new(lhs.X + rhs, lhs.Y + rhs)
    end
    return Vector2.new(lhs.X + rhs.X, lhs.Y + rhs.Y)
end


function Vector2.__mul(lhs, rhs)
    if type(rhs) == "number" then
        return Vector2.new(lhs.X * rhs, lhs.Y * rhs)
    end
    return Vector2.new(lhs.X * rhs.X, lhs.Y * rhs.Y)
end


function Vector2.__div(lhs, rhs)
    if type(rhs) == "number" then
        return Vector2.new(lhs.X / rhs, lhs.Y / rhs)
    end
    return Vector2.new(lhs.X / rhs.X, lhs.Y / rhs.Y)
end


function Vector2.__sub(lhs, rhs)
    if type(rhs) == "number" then
        return Vector2.new(lhs.X - rhs, lhs.Y - rhs)
    end
    return Vector2.new(lhs.X - rhs.X, lhs.Y - rhs.Y)
end



return Vector2