require("tprint")
local Proxies = {
  __mode = "k",

  load = function(self, tbl)
    local proxy = self[tbl]
    local lib = GetPluginVariable(proxy.id, "Library")

    if lib == nil then
      error("[LoadPPI]: Unable to load interface for plugin " .. (proxy.id or "<invalid ID>"), 0)
    end

    self[tbl].library = loadstring(lib)()
    return proxy.library
  end,
}
setmetatable(Proxies, Proxies)

local Proxy = {
  new = function(id)
    local proxy = {
      id = id,
      library = false,

      __metatable = false,

      __newindex = function(tbl, idx, val)
        (Proxies[tbl].library or Proxies:load(tbl))[idx] = val
      end,

      __index = function(tbl, idx)
        return (Proxies[tbl].library or Proxies:load(tbl))[idx]
      end,
    }
    local tbl = setmetatable({}, proxy)
    Proxies[tbl] = proxy
    return tbl
  end,
}

-- Creates new Proxies for a plugin library
local Loader = {
  __metatable = false,

  __newindex = function()
    error("Please don't modify this table.")
  end,

  __index = {
    load = function(id)
      if type(id) ~= "string" then
        error("Plugin ID must be a string.")
      end

      return Proxy.new(id)
    end,
  },
}

-- Returns a new read-only loader.
return setmetatable({}, Loader)