#define SOL_CHECK_ARGUMENTS

#include <catch.hpp>
#include <sol.hpp>
#include <iostream>
#include "test_stack_guard.hpp"


TEST_CASE("environments/get", "Envronments can be taken out of things like Lua functions properly") {
	sol::state lua;
	sol::stack_guard luasg(lua);
	lua.open_libraries(sol::lib::base);

	lua.script("f = function() return test end");
	sol::function f = lua["f"];

	sol::environment env_f(lua, sol::create);
	env_f["test"] = 31;
	sol::set_environment(env_f, f);

	int result = f();
	REQUIRE(result == 31);

	lua.script("g = function() test = 5 end");
	sol::function g = lua["g"];
	sol::environment env_g(lua, sol::create);
	env_g.set_on(g);

	g();
	
	int test = env_g["test"];
	REQUIRE(test == 5);


	sol::object global_test = lua["test"];
	REQUIRE(!global_test.valid());

	lua.script("h = function() end");

	lua.set_function("check_f_env",
		[&lua, &env_f](sol::object target) {
		sol::stack_guard sg(lua);
		sol::environment target_env(sol::env_key, target);
		int test_env_f = env_f["test"];
		int test_target_env = target_env["test"];
		REQUIRE(test_env_f == test_target_env);
		REQUIRE(test_env_f == 31);
		REQUIRE(env_f == target_env);
	}
	);
	lua.set_function("check_g_env",
		[&lua, &env_g](sol::function target) {
		sol::stack_guard sg(lua);
		sol::environment target_env = sol::get_environment(target);
		int test_env_g = env_g["test"];
		int test_target_env = target_env["test"];
		REQUIRE(test_env_g == test_target_env);
		REQUIRE(test_env_g == 5);
		REQUIRE(env_g == target_env);
	}
	);
	lua.set_function("check_h_env",
		[&lua](sol::function target) {
		sol::stack_guard sg(lua);
		sol::environment target_env = sol::get_environment(target);
	}
	);

	REQUIRE_NOTHROW([&lua]() {
		lua.script("check_f_env(f)");
		lua.script("check_g_env(g)");
		lua.script("check_h_env(h)");
	}());
}

TEST_CASE("environments/shadowing", "Environments can properly shadow and fallback on variables") {

	sol::state lua;
	lua["b"] = 2142;

	SECTION("no fallback") {
		sol::environment plain_env(lua, sol::create);
		lua.script("a = 24", plain_env);
		sol::optional<int> maybe_env_a = plain_env["a"];
		sol::optional<int> maybe_global_a = lua["a"];
		sol::optional<int> maybe_env_b = plain_env["b"];
		sol::optional<int> maybe_global_b = lua["b"];
		
		REQUIRE(maybe_env_a != sol::nullopt);
		REQUIRE(maybe_env_a.value() == 24);
		REQUIRE(maybe_env_b == sol::nullopt);

		REQUIRE(maybe_global_a == sol::nullopt);
		REQUIRE(maybe_global_b != sol::nullopt);
		REQUIRE(maybe_global_b.value() == 2142);
	}
	SECTION("fallback") {
		sol::environment env_with_fallback(lua, sol::create, lua.globals());
		lua.script("a = 56", env_with_fallback, sol::default_on_error);
		sol::optional<int> maybe_env_a = env_with_fallback["a"];
		sol::optional<int> maybe_global_a = lua["a"];
		sol::optional<int> maybe_env_b = env_with_fallback["b"];
		sol::optional<int> maybe_global_b = lua["b"];

		REQUIRE(maybe_env_a != sol::nullopt);
		REQUIRE(maybe_env_a.value() == 56);
		REQUIRE(maybe_env_b != sol::nullopt);
		REQUIRE(maybe_env_b.value() == 2142);

		REQUIRE(maybe_global_a == sol::nullopt);
		REQUIRE(maybe_global_b != sol::nullopt);
		REQUIRE(maybe_global_b.value() == 2142);
	}
	SECTION("from name") {
		sol::environment env_with_fallback(lua, sol::create, lua.globals());
		lua["env"] = env_with_fallback;
		sol::environment env = lua["env"];
		lua.script("a = 56", env, sol::default_on_error);
		sol::optional<int> maybe_env_a = env["a"];
		sol::optional<int> maybe_global_a = lua["a"];
		sol::optional<int> maybe_env_b = env["b"];
		sol::optional<int> maybe_global_b = lua["b"];

		REQUIRE(maybe_env_a != sol::nullopt);
		REQUIRE(maybe_env_a.value() == 56);
		REQUIRE(maybe_env_b != sol::nullopt);
		REQUIRE(maybe_env_b.value() == 2142);

		REQUIRE(maybe_global_a == sol::nullopt);
		REQUIRE(maybe_global_b != sol::nullopt);
		REQUIRE(maybe_global_b.value() == 2142);
	}
	SECTION("name with newtable") {
		lua["blank_env"] = sol::new_table(0, 1);
		sol::environment plain_env = lua["blank_env"];
		lua.script("a = 24", plain_env);
		sol::optional<int> maybe_env_a = plain_env["a"];
		sol::optional<int> maybe_global_a = lua["a"];
		sol::optional<int> maybe_env_b = plain_env["b"];
		sol::optional<int> maybe_global_b = lua["b"];

		REQUIRE(maybe_env_a != sol::nullopt);
		REQUIRE(maybe_env_a.value() == 24);
		REQUIRE(maybe_env_b == sol::nullopt);

		REQUIRE(maybe_global_a == sol::nullopt);
		REQUIRE(maybe_global_b != sol::nullopt);
		REQUIRE(maybe_global_b.value() == 2142);
	}
}

TEST_CASE("environments/functions", "see if environments on functions are working properly") {

	SECTION("basic") {
		sol::state lua;

		lua.script("a = function() return 5 end");

		sol::function a = lua["a"];

		int result0 = a();
		REQUIRE(result0 == 5);

		sol::environment env(lua, sol::create);
		sol::set_environment(env, a);

		int result1 = a();
		REQUIRE(result1 == 5);
	}
	SECTION("return environment value") {
		sol::state lua;

		lua.script("a = function() return test end");

		sol::function a = lua["a"];
		sol::environment env(lua, sol::create);
		env["test"] = 5;
		env.set_on(a);

		// the function returns the value from the environment table
		int result = a();
		REQUIRE(result == 5);
	}

	SECTION("set environment value") {
		sol::state lua;
		lua.script("a = function() test = 5 end");

		sol::function a = lua["a"];
		sol::environment env(lua, sol::create);
		sol::set_environment(env, a);

		a();

		// the value can be retrieved from the env table
		int result = env["test"];
		REQUIRE(result == 5);

		// the global environment is not polluted
		auto gtest = lua["test"];
		REQUIRE(!gtest.valid());
	}
}

TEST_CASE("environments/this_environment", "test various situations of pulling out an environment") {
	static std::string code = "return (f(10))";
	
	sol::state lua;

	lua["f"] = [](sol::this_environment te, int x) {
		if (te) {
			sol::environment& env = te;
			return x + static_cast<int>(env["x"]);
		}
		return x;
	};
	
	sol::environment e(lua, sol::create, lua.globals());
	e["x"] = 20;
	SECTION("from Lua script") {
		int value = lua.script(code, e);
		REQUIRE(value == 30);
	}
	SECTION("from C++") {
		sol::function f = lua["f"];
		e.set_on(f);
		int value = f(10);
		REQUIRE(value == 30);
	}
	SECTION("from C++, with no env") {
		sol::function f = lua["f"];
		int value = f(10);
		REQUIRE(value == 10);
	}
}