/*
 * This file is part of OpenTTD.
 * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
 * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */

/** @file script_admin_json.cpp Tests for the Squirrel -> JSON conversion in ScriptAdmin. */

#include "../stdafx.h"

#include "../3rdparty/catch2/catch.hpp"

#include "../game/game_instance.hpp"
#include "../script/api/script_admin.hpp"
#include "../script/api/script_event_types.hpp"
#include "../script/script_instance.hpp"
#include "../script/squirrel.hpp"

#include "../3rdparty/fmt/format.h"

#include <squirrel.h>

/**
 * A controller to start enough so we can use Squirrel for testing.
 *
 * To run Squirrel, we need an Allocator, so malloc/free works.
 * For functions that log, we need an ActiveInstance, so the logger knows where
 * to send the logs to.
 *
 * By instantiating this class, both are set correctly. After that you can
 * use Squirrel without issues.
 */
class TestScriptController {
public:
	GameInstance game{};
	ScriptObject::ActiveInstance active{&game};

	Squirrel engine{"test"};
	ScriptAllocatorScope scope{&engine};
};

/**
 * Small wrapper around ScriptAdmin.
 *
 * MakeJSON is protected; so for tests, we make a public function with
 * which we call into the protected one. This prevents accidental use
 * by the rest of the code, while still being able to test it.
 */
class TestScriptAdmin : public ScriptAdmin {
public:
	static std::optional<std::string> MakeJSON(std::string_view squirrel)
	{
		auto vm = sq_open(1024);
		/* sq_compile creates a closure with our snipper, which is a table.
		 * Add "return " to get the table on the stack. */
		std::string buffer = fmt::format("return {}", squirrel);

		/* Insert an (empty) class for testing. */
		sq_pushroottable(vm);
		sq_pushstring(vm, "DummyClass", -1);
		sq_newclass(vm, SQFalse);
		sq_newslot(vm, -3, SQFalse);
		sq_pop(vm, 1);

		/* Compile the snippet. */
		REQUIRE(sq_compilebuffer(vm, buffer.c_str(), buffer.size(), "test", SQTrue) == SQ_OK);
		/* Execute the snippet, capturing the return value. */
		sq_pushroottable(vm);
		REQUIRE(sq_call(vm, 1, SQTrue, SQTrue) == SQ_OK);
		/* Ensure the snippet pushed a table on the stack. */
		REQUIRE(sq_gettype(vm, -1) == OT_TABLE);

		/* Feed the snippet into the MakeJSON function. */
		std::string json;
		if (!ScriptAdmin::MakeJSON(vm, -1, SQUIRREL_MAX_DEPTH, json)) {
			sq_close(vm);
			return std::nullopt;
		}

		sq_close(vm);
		return json;
	}

	/**
	 * Validate ScriptEventAdminPort can convert JSON to Squirrel.
	 *
	 * This function is not actually part of ScriptAdmin, but we will use MakeJSON,
	 * and as such need to be inside this class.
	 *
	 * The easiest way to do validate, is to first use ScriptEventAdminPort (the function
	 * we are testing) to convert the JSON to a Squirrel table. Then to use MakeJSON
	 * to convert it back to JSON.
	 *
	 * Sadly, Squirrel has no way to easily compare if two tables are identical, so we
	 * use the JSON -> Squirrel -> JSON method to validate the conversion. But mind you,
	 * a failure in the final JSON might also mean a bug in MakeJSON.
	 *
	 * @param json The JSON-string to convert to Squirrel
	 * @return The Squirrel table converted to a JSON-string.
	 */
	static std::optional<std::string> TestScriptEventAdminPort(const std::string &json)
	{
		auto vm = sq_open(1024);

		/* Run the conversion JSON -> Squirrel (this will now be on top of the stack). */
		ScriptEventAdminPort(json).GetObject(vm);
		if (sq_gettype(vm, -1) == OT_NULL) {
			sq_close(vm);
			return std::nullopt;
		}
		REQUIRE(sq_gettype(vm, -1) == OT_TABLE);

		std::string squirrel_json;
		REQUIRE(ScriptAdmin::MakeJSON(vm, -1, SQUIRREL_MAX_DEPTH, squirrel_json) == true);

		sq_close(vm);
		return squirrel_json;
	}

};

TEST_CASE("Squirrel -> JSON conversion")
{
	TestScriptController controller;

	CHECK(TestScriptAdmin::MakeJSON(R"sq({ test = null })sq") == R"json({ "test": null })json");
	CHECK(TestScriptAdmin::MakeJSON(R"sq({ test = 1 })sq") == R"json({ "test": 1 })json");
	CHECK(TestScriptAdmin::MakeJSON(R"sq({ test = -1 })sq") == R"json({ "test": -1 })json");
	CHECK(TestScriptAdmin::MakeJSON(R"sq({ test = true })sq") == R"json({ "test": true })json");
	CHECK(TestScriptAdmin::MakeJSON(R"sq({ test = "a" })sq") == R"json({ "test": "a" })json");
	CHECK(TestScriptAdmin::MakeJSON(R"sq({ test = [ ] })sq") == R"json({ "test": [  ] })json");
	CHECK(TestScriptAdmin::MakeJSON(R"sq({ test = [ 1 ] })sq") == R"json({ "test": [ 1 ] })json");
	CHECK(TestScriptAdmin::MakeJSON(R"sq({ test = [ 1, "a", true, { test = 1 }, [], null ] })sq") == R"json({ "test": [ 1, "a", true, { "test": 1 }, [  ], null ] })json");
	CHECK(TestScriptAdmin::MakeJSON(R"sq({ test = { } })sq") == R"json({ "test": {  } })json");
	CHECK(TestScriptAdmin::MakeJSON(R"sq({ test = { test = 1 } })sq") == R"json({ "test": { "test": 1 } })json");
	CHECK(TestScriptAdmin::MakeJSON(R"sq({ test = { test = 1, test = 2 } })sq") == R"json({ "test": { "test": 2 } })json");
	CHECK(TestScriptAdmin::MakeJSON(R"sq({ test = { test = 1, test2 = [ 2 ] } })sq") == R"json({ "test": { "test": 1, "test2": [ 2 ] } })json");

	/* Cases that should fail, as we cannot convert a class to JSON. */
	CHECK(TestScriptAdmin::MakeJSON(R"sq({ test = DummyClass })sq") == std::nullopt);
	CHECK(TestScriptAdmin::MakeJSON(R"sq({ test = [ 1, DummyClass ] })sq") == std::nullopt);
	CHECK(TestScriptAdmin::MakeJSON(R"sq({ test = { test = 1, test2 = DummyClass } })sq") == std::nullopt);
}

TEST_CASE("JSON -> Squirrel conversion")
{
	TestScriptController controller;

	CHECK(TestScriptAdmin::TestScriptEventAdminPort(R"json({ "test": null })json") == R"json({ "test": null })json");
	CHECK(TestScriptAdmin::TestScriptEventAdminPort(R"json({ "test": 1 })json") == R"json({ "test": 1 })json");
	CHECK(TestScriptAdmin::TestScriptEventAdminPort(R"json({ "test": -1 })json") == R"json({ "test": -1 })json");
	CHECK(TestScriptAdmin::TestScriptEventAdminPort(R"json({ "test": true })json") == R"json({ "test": true })json");
	CHECK(TestScriptAdmin::TestScriptEventAdminPort(R"json({ "test": "a" })json") == R"json({ "test": "a" })json");
	CHECK(TestScriptAdmin::TestScriptEventAdminPort(R"json({ "test": [] })json") == R"json({ "test": [  ] })json");
	CHECK(TestScriptAdmin::TestScriptEventAdminPort(R"json({ "test": [ 1 ] })json") == R"json({ "test": [ 1 ] })json");
	CHECK(TestScriptAdmin::TestScriptEventAdminPort(R"json({ "test": [ 1, "a", true, { "test": 1 }, [], null ] })json") == R"json({ "test": [ 1, "a", true, { "test": 1 }, [  ], null ] })json");
	// BUG -- This should work, but doesn't.
	// CHECK(TestScriptAdmin::TestScriptEventAdminPort(R"json({ "test": {} })json") == R"json({ "test": {  } })json");
	CHECK(TestScriptAdmin::TestScriptEventAdminPort(R"json({ "test": { "test": 1 } })json") == R"json({ "test": { "test": 1 } })json");
	CHECK(TestScriptAdmin::TestScriptEventAdminPort(R"json({ "test": { "test": 2 } })json") == R"json({ "test": { "test": 2 } })json");
	CHECK(TestScriptAdmin::TestScriptEventAdminPort(R"json({ "test": { "test": 1, "test2": [ 2 ] } })json") == R"json({ "test": { "test": 1, "test2": [ 2 ] } })json");

	/* Check if spaces are properly ignored. */
	CHECK(TestScriptAdmin::TestScriptEventAdminPort(R"json({"test":1})json") == R"json({ "test": 1 })json");
	CHECK(TestScriptAdmin::TestScriptEventAdminPort(R"json({"test":        1})json") == R"json({ "test": 1 })json");

	/* Cases that should fail, as it is invalid JSON. */
	CHECK(TestScriptAdmin::TestScriptEventAdminPort(R"json({"test":test})json") == std::nullopt);
	CHECK(TestScriptAdmin::TestScriptEventAdminPort(R"json({ "test": 1 )json") == std::nullopt); // Missing closing }
	CHECK(TestScriptAdmin::TestScriptEventAdminPort(R"json(  "test": 1})json") == std::nullopt); // Missing opening {
	CHECK(TestScriptAdmin::TestScriptEventAdminPort(R"json({ "test" = 1})json") == std::nullopt);
	CHECK(TestScriptAdmin::TestScriptEventAdminPort(R"json({ "test": [ 1 })json") == std::nullopt); // Missing closing ]
	CHECK(TestScriptAdmin::TestScriptEventAdminPort(R"json({ "test": 1 ] })json") == std::nullopt); // Missing opening [
}