#include "game_server/NetworkProtocol.h"
#include "LocationState.h"
#include <cstdlib>
#include <iostream>
#include <string>

namespace {

void require(bool condition, const char* message)
{
	if (condition) return;
	std::cerr << "NetworkProtocolTests: " << message << '\n';
	std::exit(EXIT_FAILURE);
}

} // namespace

int main()
{
	FRG::LocationNetworkState locationState;
	nlohmann::json savedLocationState;
	locationState.save(savedLocationState);
	const nlohmann::json original{
		{"schemaVersion", 2},
		{"campaignId", "battle_zone_multiplayer"},
		{"players", {{"player", {{"hp", 200.0}}}}},
		{"locations", {{"uni_exterior", {{"state", savedLocationState}}}}}
	};
	FRG::InitialStateMessage initial;
	initial.state = original;
	initial.assignedPlayerId = "player";
	initial.snapshotTick = 42;
	initial.compatibilityFingerprint = "lockstep-v2:battle_zone_multiplayer";
	const std::string message = FRG::makeInitialStateMessage(initial);
	FRG::InitialStateMessage parsed;
	std::string error;
	require(
		FRG::parseInitialStateMessage(message, parsed, error),
		"valid initial-state envelope was rejected");
	require(parsed.state == original, "state payload did not round trip");
	require(parsed.snapshotTick == 42, "snapshot tick did not round trip");
	require(
		parsed.assignedPlayerId == "player",
		"assigned player did not round trip");
	require(
		!parsed.state["locations"]["uni_exterior"]["state"].contains("cameraAzimuth") &&
		!parsed.state["locations"]["uni_exterior"]["state"].contains("cameraInclination"),
		"local camera state leaked into the network payload");

	FRG::DestinationInputMessage input;
	input.clientSequence = 7;
	input.target = Eigen::Vector3f(1.234f, 0.f, -5.678f);
	FRG::DestinationInputMessage parsedInput;
	require(
		FRG::parseDestinationInputMessage(
			FRG::makeDestinationInputMessage(input), parsedInput, error),
		"destination input did not round trip");
	require(
		parsedInput.clientSequence == 7 &&
		parsedInput.target.isApprox(Eigen::Vector3f(1.23f, 0.f, -5.68f)),
		"destination input was not normalized");

	FRG::TickMessage tick;
	tick.tickId = 43;
	tick.commands.push_back(FRG::ScheduledDestinationCommand{
		1, "player", parsedInput.target});
	tick.commands.push_back(FRG::ScheduledCharacterEnabledCommand{
		2, "uni_exterior", "player2", true});
	tick.stateHash = "0123456789abcdef";
	FRG::TickMessage parsedTick;
	require(
		FRG::parseTickMessage(
			FRG::makeTickMessage(tick), parsedTick, error),
		"tick message did not round trip");
	require(
		parsedTick.tickId == 43 && parsedTick.commands.size() == 2 &&
		std::holds_alternative<FRG::ScheduledCharacterEnabledCommand>(
			parsedTick.commands[1]) &&
		std::get<FRG::ScheduledCharacterEnabledCommand>(
			parsedTick.commands[1]).enabled,
		"tick contents did not round trip");

	require(
		!FRG::parseInitialStateMessage(
			R"({"protocolVersion":1,"type":"initial_state","payload":{}})",
			parsed, error),
		"unknown protocol version was accepted");
	require(
		!FRG::parseDestinationInputMessage(
			R"({"protocolVersion":2,"type":"command","payload":{}})",
			parsedInput, error),
		"unknown message type was accepted");
	require(
		!FRG::parseInitialStateMessage("not json", parsed, error),
		"malformed JSON was accepted");
	require(
		!FRG::parseDestinationInputMessage(
			R"({"protocolVersion":2,"type":"destination_input","payload":{"clientSequence":1,"target":[1e999,0,0]}})",
			parsedInput, error),
		"non-finite destination was accepted");
	std::string errorCode;
	std::string errorDetail;
	require(
		FRG::parseErrorMessage(
			FRG::makeErrorMessage("server_full", "No slot"),
			errorCode, errorDetail) &&
		errorCode == "server_full" && errorDetail == "No slot",
		"error message did not round trip");

	nlohmann::json hashState = original;
	hashState["savedAt"] = "first";
	const std::string firstHash = FRG::canonicalStateHash(hashState);
	hashState["savedAt"] = "second";
	require(
		firstHash == FRG::canonicalStateHash(hashState),
		"persistence timestamp changed deterministic hash");

	FRG::LockstepTimeline timeline(2);
	const std::uint64_t firstSequence =
		timeline.schedule("player", Eigen::Vector3f(1.f, 0.f, 1.f));
	const std::uint64_t secondSequence =
		timeline.schedule("player_2", Eigen::Vector3f(2.f, 0.f, 2.f));
	const FRG::TickMessage emptyTick = timeline.advance();
	require(
		emptyTick.tickId == 1 && emptyTick.commands.empty(),
		"input-delay tick was not empty");
	const FRG::TickMessage commandTick = timeline.advance();
	require(
		commandTick.tickId == 2 && commandTick.commands.size() == 2 &&
		std::get<FRG::ScheduledDestinationCommand>(
			commandTick.commands[0]).commandSequence == firstSequence &&
		std::get<FRG::ScheduledDestinationCommand>(
			commandTick.commands[1]).commandSequence == secondSequence,
		"scheduled commands were not finalized in stable order");

	timeline.scheduleCharacterEnabled("uni_exterior", "player2", true);
	const FRG::TickMessage presenceTick = timeline.advance();
	require(
		presenceTick.commands.size() == 1 &&
		std::holds_alternative<FRG::ScheduledCharacterEnabledCommand>(
			presenceTick.commands[0]),
		"character enabled command was not scheduled for the next tick");

	return EXIT_SUCCESS;
}