class.lua

-- Lua doesn't natively support OOP, so it needs to be programmed in manually using language constructs

--- @class class
--- @field name string
--- @field super class
--- @field __extend fun(self, subclass: class) called whenever the class is extended
--- @field __name string this class's name
--- @field init fun(self, ...)
local class = {
    __name = "class",
    init = function() end,
    __extend = function() end
}
class.__index = class

function class:__tostring()
    return "class '" .. self.name .. "'"
end

--- Extends a base class
--- @generic T
--- @param self T | class
--- @return T
function class:extend(name)
    local heir = setmetatable({ __name = name, super = self }, self)
    heir.__index = heir
    heir.__call = self.__call
    heir.__tostring = self.__tostring
    self:__extend(heir)
    return heir
end

--- Create a new instance of this class, calling `init` with parameters if it exists
--- @generic T
--- @param self T | class
--- @return T
function class:new(...)
    local instance = setmetatable({}, self)
    self.init(instance, ...)
    return instance
end

class.__call = class.new

--- Create a new instance of this class without calling `init`
--- @generic T
--- @param self T | class
--- @param object? T
--- @return T
function class:create(object)
    return setmetatable(object or {}, self)
end

--- Applies a mixin to the class, allowing code reuse without inheritance
--- @param mixin table
--- @return self
function class:with(mixin)
    for k, f in next, mixin do
        self[k] = f
    end
    return self
end

class.cast = setmetatable

return class