local Class = {}
Class.__index = Class

function copy(array)
    local new = {}
    for i, v in pairs(array) do
        new[i] = v
    end
    return new
end

function Class.__newindex(self, key, value)
    if key == "extends" then
        local meta = getmetatable(self)
        meta.__index = function(this, key)
            return rawget(self, key) or rawget(value, key) or rawget(module, key)
        end
        return setmetatable(self, meta)
    else
        rawset(self, key, value)
    end
end

function Class.__call(self, ...)
    local new = setmetatable(copy(self), getmetatable(self))
    if new.init then
        new:init(...)
    end
    return new
end

setmetatable(Class, {__call = function() return setmetatable({}, Class) end})

function getByClassName(name)
    for i, v in pairs(environment) do
        if v._COMPILE_CODE:find(name:gsub("%s+", "")) then
            return i
        end
    end
    return false
end

local keywords = {
    ["func(.-)%((.-)%)%s*{%s*(.-)};"] = function(name, args, block)
        environment[getByClassName(name)][name] = loadstring("return function(self ".. (args:find("%S") and "," or "") .. args ..") "..block.." end")()
    end,
    ["override func(.-)%((.-)%)%s*{%s*(.-)};"] = function(name, args, block)
        if not environment[getByClassName(name)][name] then
            error("Cannot override a funciton that does not exist.")
        end
        environment[getByClassName(name)][name] = loadstring("return function(self ".. (args:find("%S") and "," or "") .. args ..") "..block.." end")()
    end,
    ["var(.-)=(.-);"] = function(name, value)
        environment[getByClassName(name)][name] = value
    end
}

function run(code)
    environment = {}
    local extenders = {}
    code = code:gsub("class (.-)%->(.-)<%-", function(name, block)
        if name:find("extends") then
            local save = name:match("extends (%a+)")
            name = name:gsub("extends (%a+)", "")
            extenders[name:gsub("%s+", "")] = save
        end
        return ("environment._NAME = {_COMPILE_CODE = " .. "[[" .. "%s" .. "]]}"):gsub("_NAME", tostring(name)):format(block)
    end)
    loadstring(code)()
    for i, v in pairs(keywords) do
        code:gsub(i, v)
    end
    for className, class in pairs(environment) do
        getfenv()[className] = Class()
        for key, value in pairs(class) do
            getfenv()[className][key:gsub("%s+", "")] = value
        end
    end
    for className, class in pairs(getfenv()) do
        if extenders[className] then
            class.extends = getfenv()[extenders[className]]
        end
    end
end

run([[

    class UIPhysics ->
        func isOn(other) {
            return
                self.x + self.sx > other.x and
                self.y + self.sy > other.y and
                other.x + other.sx > self.x and
                other.y + other.sy > self.y
        };
        func area() {
            return self.sx * self.sy
        };
    <-

    class Body extends UIPhysics ->
        func init(pos, size) {
            self.x = pos.X
            self.sx = size.X
            self.y = pos.Y
            self.sy = size.Y
        };
    <-

]])

local square = Body(Vector2.new(0, 0), Vector2.new(50, 50))
print(square:area())