local ast = require("ast")
local Overloadable = ast.abstract.Overloadable

local operator_priority = require("common").operator_priority

local LuaFunction
LuaFunction = ast.abstract.Runtime(Overloadable) {
	type = "lua function",

	parameters = nil, -- ParameterTuple
	func = nil, -- lua function
	format_priority = operator_priority["$_"],

	init = function(self, parameters, func)
		self.parameters = parameters
		self.func = func
	end,

	traverse = function(self, fn, ...)
		fn(self.parameters, ...)
	end,

	_format = function(self, ...)
		if self.parameters.assignment then
			return "$"..self.parameters:format(...).."; <lua function>"
		else
			return "$"..self.parameters:format(...).." <lua function>"
		end
	end,

	compatible_with_arguments = function(self, state, args)
		return args:match_parameter_tuple(state, self.parameters)
	end,
	format_parameters = function(self, state)
		return self.parameters:format(state)
	end,
	call_dispatched = function(self, state, args)
		local lua_args = { state }

		state.scope:push()

		args:bind_parameter_tuple(state, self.parameters)
		for _, param in ipairs(self.parameters.list) do
			table.insert(lua_args, state.scope:get(param.identifier))
		end

		state.scope:pop()

		local r = self.func(table.unpack(lua_args))
		assert(r, "lua function returned no value")
		return r
	end,

	_eval = function(self, state)
		return LuaFunction:new(self.parameters:eval(state), self.func)
	end,

	to_lua = function(self, state)
		return self.func
	end,
}

return LuaFunction