/**
 * @brief Example of using a shared memory to pass a mostly fixed set of telemetry
 * data to another process.
 *
 * Note that use of the shared memory reduces precision of the output and
 * increases latency between event and possible reaction.
 */

// Windows stuff.

#define WINVER 0x0500
#define _WIN32_WINNT 0x0500
#include <windows.h>
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <stdarg.h>

// SDK

#include "scssdk_telemetry.h"
#include "eurotrucks2/scssdk_eut2.h"
#include "eurotrucks2/scssdk_telemetry_eut2.h"
#include "amtrucks/scssdk_ats.h"
#include "amtrucks/scssdk_telemetry_ats.h"

#define UNUSED(x)

/**
 * @name Callbacks remembered from the initialization info.
 */
//@{
scs_telemetry_register_for_channel_t register_for_channel = NULL;
scs_telemetry_unregister_from_channel_t unregister_from_channel = NULL;
scs_log_t game_log = NULL;
//@}

/**
 * @brief Prints message to game log.
 */
void log_line(const scs_log_type_t type, const char *const text, ...)
{
	if (! game_log) {
		return;
	}
	char formated[1000];

	va_list args;
	va_start(args, text);
	vsnprintf_s(formated, sizeof(formated), _TRUNCATE, text, args);
	formated[sizeof(formated) - 1] = 0;
	va_end(args);

	game_log(type, formated);
}

const size_t MAX_SUPPORTED_WHEEL_COUNT = 8;

#pragma pack(push)
#pragma pack(1)

/**
 * @brief The layout of the shared memory.
*/
struct telemetry_state_t
{
	scs_u8_t				running;					// Is the telemetry running or it is paused?

	scs_value_dplacement_t	ws_truck_placement;			// SCS_TELEMETRY_TRUCK_CHANNEL_world_placement

	scs_float_t				speedometer_speed;			// SCS_TELEMETRY_TRUCK_CHANNEL_speed
	scs_float_t				rpm;						// SCS_TELEMETRY_TRUCK_CHANNEL_engine_rpm
	scs_s32_t				gear;						// SCS_TELEMETRY_TRUCK_CHANNEL_engine_gear

	scs_float_t				steering;					// SCS_TELEMETRY_TRUCK_CHANNEL_effective_steering
	scs_float_t				throttle;					// SCS_TELEMETRY_TRUCK_CHANNEL_effective_throttle
	scs_float_t				brake;						// SCS_TELEMETRY_TRUCK_CHANNEL_effective_brake
	scs_float_t				clutch;						// SCS_TELEMETRY_TRUCK_CHANNEL_effective_clutch

	scs_value_fvector_t		linear_valocity;			// SCS_TELEMETRY_TRUCK_CHANNEL_local_linear_velocity
	scs_value_fvector_t		angular_velocity;			// SCS_TELEMETRY_TRUCK_CHANNEL_local_angular_velocity
	scs_value_fvector_t		linear_acceleration;		// SCS_TELEMETRY_TRUCK_CHANNEL_local_linear_acceleration
	scs_value_fvector_t		angular_acceleration;		// SCS_TELEMETRY_TRUCK_CHANNEL_local_angular_acceleration
	scs_value_fvector_t		cabin_angular_velocity;		// SCS_TELEMETRY_TRUCK_CHANNEL_cabin_angular_velocity
	scs_value_fvector_t		cabin_angular_acceleration;	// SCS_TELEMETRY_TRUCK_CHANNEL_cabin_angular_acceleration

	scs_u32_t				wheel_count;				// SCS_TELEMETRY_CONFIG_ATTRIBUTE_wheel_count
	scs_float_t				wheel_deflections[MAX_SUPPORTED_WHEEL_COUNT]; // SCS_TELEMETRY_TRUCK_CHANNEL_wheel_susp_deflection
};

#pragma pack(pop)

/**
 * @brief Handle of the memory mapping.
 */
HANDLE memory_mapping = NULL;

/**
 * @brief Block inside the shared memory.
 */
telemetry_state_t *shared_memory = NULL;

/**
 * @brief Deinitialize the shared memory objects.
 */
void deinitialize_shared_memory(void)
{
	if (shared_memory) {
		UnmapViewOfFile(shared_memory);
		shared_memory = NULL;
	}

	if (memory_mapping) {
		CloseHandle(memory_mapping);
		memory_mapping = NULL;
	}
}

/**
 * @brief Initialize the shared memory objects.
 */
bool initialize_shared_memory(void)
{
	// Setup the mapping.

	const DWORD memory_size = sizeof(telemetry_state_t);
	memory_mapping = CreateFileMappingA(INVALID_HANDLE_VALUE, NULL, PAGE_READWRITE | SEC_COMMIT, 0, memory_size, "SCSTelemetryExample");
	if (! memory_mapping) {
		log_line(SCS_LOG_TYPE_error, "Unable to create shared memory %08X", GetLastError());
		deinitialize_shared_memory();
		return false;
	}
	if (GetLastError() == ERROR_ALREADY_EXISTS) {
		log_line(SCS_LOG_TYPE_error, "Shared memory is already in use.");
		deinitialize_shared_memory();
		return false;
	}

	shared_memory = static_cast<telemetry_state_t *>(MapViewOfFile(memory_mapping, FILE_MAP_ALL_ACCESS, 0, 0, 0));
	if (! shared_memory) {
		log_line(SCS_LOG_TYPE_error, "Unable to map the view %08X", GetLastError());
		deinitialize_shared_memory();
		return false;
	}

	// Defaults in the structure.

	memset(shared_memory, 0, memory_size);

	// We are always initialized in the paused state.

	shared_memory->running = 0;

	// No wheels until we get corresponding configuration message.

	shared_memory->wheel_count = 0;
	return true;
}

/**
 * @brief Float storage callback.
 *
 * Can be used together with SCS_TELEMETRY_CHANNEL_FLAG_no_value in which case it
 * will store zero if the value is not available.
 */
SCSAPI_VOID telemetry_store_float(const scs_string_t name, const scs_u32_t index, const scs_value_t *const value, const scs_context_t context)
{
	assert(context);
	scs_float_t *const storage = static_cast<scs_float_t *>(context);

	if (value) {
		assert(value->type == SCS_VALUE_TYPE_float);
		*storage = value->value_float.value;
	}
	else {
		*storage = 0.0f;
	}
}

/**
 * @brief s32 storage callback.
 *
 * Can be used together with SCS_TELEMETRY_CHANNEL_FLAG_no_value in which case it
 * will store zero if the value is not available.
 */
SCSAPI_VOID telemetry_store_s32(const scs_string_t name, const scs_u32_t index, const scs_value_t *const value, const scs_context_t context)
{
	assert(context);
	scs_s32_t *const storage = static_cast<scs_s32_t *>(context);

	if (value) {
		assert(value->type == SCS_VALUE_TYPE_s32);
		*storage = value->value_s32.value;
	}
	else {
		*storage = 0;
	}
}

/**
 * @brief Orientation storage callback.
 *
 * Can be used together with SCS_TELEMETRY_CHANNEL_FLAG_no_value in which case it
 * will store zero if the value is not available.
 */
SCSAPI_VOID telemetry_store_orientation(const scs_string_t name, const scs_u32_t index, const scs_value_t *const value, const scs_context_t context)
{
	assert(context);
	scs_value_euler_t *const storage = static_cast<scs_value_euler_t *>(context);

	if (value) {
		assert(value->type == SCS_VALUE_TYPE_euler);
		*storage = value->value_euler;
	}
	else {
		storage->heading = 0.0f;
		storage->pitch = 0.0f;
		storage->roll = 0.0f;
	}
}

/**
 * @brief Vector storage callback.
 *
 * Can be used together with SCS_TELEMETRY_CHANNEL_FLAG_no_value in which case it
 * will store zero if the value is not available.
 */
SCSAPI_VOID telemetry_store_fvector(const scs_string_t name, const scs_u32_t index, const scs_value_t *const value, const scs_context_t context)
{
	assert(context);
	scs_value_fvector_t *const storage = static_cast<scs_value_fvector_t *>(context);

	if (value) {
		assert(value->type == SCS_VALUE_TYPE_fvector);
		*storage = value->value_fvector;
	}
	else {
		storage->x = 0.0f;
		storage->y = 0.0f;
		storage->z = 0.0f;
	}
}

/**
 * @brief Placement storage callback.
 *
 * Can be used together with SCS_TELEMETRY_CHANNEL_FLAG_no_value in which case it
 * will store zeros if the value is not available.
 */
SCSAPI_VOID telemetry_store_dplacement(const scs_string_t name, const scs_u32_t index, const scs_value_t *const value, const scs_context_t context)
{
	assert(context);
	scs_value_dplacement_t *const storage = static_cast<scs_value_dplacement_t *>(context);

	if (value) {
		assert(value->type == SCS_VALUE_TYPE_dplacement);
		*storage = value->value_dplacement;
	}
	else {
		storage->position.x = 0.0;
		storage->position.y = 0.0;
		storage->position.z = 0.0;
		storage->orientation.heading = 0.0f;
		storage->orientation.pitch = 0.0f;
		storage->orientation.roll = 0.0f;
	}
}

/**
 * @brief Finds attribute with specified name in the configuration structure.
 *
 * Returns NULL if the attribute was not found or if it is not of the expected type.
 */
const scs_named_value_t *find_attribute(const scs_telemetry_configuration_t &configuration, const char *const name, const scs_u32_t index, const scs_value_type_t expected_type)
{
	for (const scs_named_value_t *current = configuration.attributes; current->name; ++current) {
		if ((current->index != index) || (strcmp(current->name, name) != 0)) {
			continue;
		}
		if (current->value.type == expected_type) {
			return current;
		}
		log_line(SCS_LOG_TYPE_error, "Attribute %s has unexpected type %u", name, static_cast<unsigned>(current->value.type));
		break;
	}
	return NULL;
}

/**
 * @brief Called whenever the game pauses or unpauses its telemetry output.
 */
SCSAPI_VOID telemetry_pause(const scs_event_t event, const void *const UNUSED(event_info), const scs_context_t UNUSED(context))
{
	shared_memory->running = (event == SCS_TELEMETRY_EVENT_started) ? 1 : 0;
}

/**
 * @brief Called whenever configuration changes.
 */
SCSAPI_VOID telemetry_configuration(const scs_event_t event, const void *const event_info, const scs_context_t UNUSED(context))
{
	// We currently only care for the truck telemetry info.

	const struct scs_telemetry_configuration_t *const info = static_cast<const scs_telemetry_configuration_t *>(event_info);
	if (strcmp(info->id, SCS_TELEMETRY_CONFIG_truck) != 0) {
		return;
	}

	// Determine number of wheels up to the number supported by our memory structure.

	const scs_named_value_t *const wheel_count_attr = find_attribute(*info, SCS_TELEMETRY_CONFIG_ATTRIBUTE_wheel_count, SCS_U32_NIL, SCS_VALUE_TYPE_u32);
	size_t wheel_count = wheel_count_attr ? wheel_count_attr->value.value_u32.value : 0;
	if (wheel_count > MAX_SUPPORTED_WHEEL_COUNT) {
		wheel_count = MAX_SUPPORTED_WHEEL_COUNT;
	}

	// Update the wheel-related channel registrations to match.

	while (shared_memory->wheel_count > wheel_count) {
		--shared_memory->wheel_count;
		shared_memory->wheel_deflections[shared_memory->wheel_count] = 0.0f;
		unregister_from_channel(SCS_TELEMETRY_TRUCK_CHANNEL_wheel_susp_deflection, shared_memory->wheel_count, SCS_VALUE_TYPE_float);
	}
	while (shared_memory->wheel_count < wheel_count) {
		register_for_channel(SCS_TELEMETRY_TRUCK_CHANNEL_wheel_susp_deflection, shared_memory->wheel_count, SCS_VALUE_TYPE_float, SCS_TELEMETRY_CHANNEL_FLAG_none, telemetry_store_float, (shared_memory->wheel_deflections + shared_memory->wheel_count));
		++shared_memory->wheel_count;
	}
}

/**
 * @brief Telemetry API initialization function.
 *
 * See scssdk_telemetry.h
 */
SCSAPI_RESULT scs_telemetry_init(const scs_u32_t version, const scs_telemetry_init_params_t *const params)
{
	// We currently support only one version of the API.

	if (version != SCS_TELEMETRY_VERSION_1_00) {
		return SCS_RESULT_unsupported;
	}
	const scs_telemetry_init_params_v100_t *const version_params = static_cast<const scs_telemetry_init_params_v100_t *>(params);
	game_log = version_params->common.log;

	// Check application version.

	log_line(SCS_LOG_TYPE_message, "Game '%s' %u.%u", version_params->common.game_id, SCS_GET_MAJOR_VERSION(version_params->common.game_version), SCS_GET_MINOR_VERSION(version_params->common.game_version));

	if (strcmp(version_params->common.game_id, SCS_GAME_ID_EUT2) == 0) {

		// Below the minimum version there might be some missing features (only minor change) or
		// incompatible values (major change).

		if (version_params->common.game_version < SCS_TELEMETRY_EUT2_GAME_VERSION_1_03) { // Fixed the wheels.count attribute
			log_line(SCS_LOG_TYPE_error, "Too old version of the game");
			game_log = NULL;
			return SCS_RESULT_unsupported;
		}

		if (version_params->common.game_version < SCS_TELEMETRY_EUT2_GAME_VERSION_1_07) { // Fixed the angular acceleration calculation
			log_line(SCS_LOG_TYPE_warning, "This version of the game has less precise output of angular acceleration of the cabin");
		}

		// Future versions are fine as long the major version is not changed.

		const scs_u32_t IMPLEMENTED_VERSION = SCS_TELEMETRY_EUT2_GAME_VERSION_CURRENT;
		if (SCS_GET_MAJOR_VERSION(version_params->common.game_version) > SCS_GET_MAJOR_VERSION(IMPLEMENTED_VERSION)) {
			log_line(SCS_LOG_TYPE_warning, "Too new major version of the game, some features might behave incorrectly");
		}
	}
	else if (strcmp(version_params->common.game_id, SCS_GAME_ID_ATS) == 0) {

		// Below the minimum version there might be some missing features (only minor change) or
		// incompatible values (major change).

		const scs_u32_t MINIMAL_VERSION = SCS_TELEMETRY_ATS_GAME_VERSION_1_00;
		if (version_params->common.game_version < MINIMAL_VERSION) {
			log_line(SCS_LOG_TYPE_warning, "WARNING: Too old version of the game, some features might behave incorrectly");
		}

		// Future versions are fine as long the major version is not changed.

		const scs_u32_t IMPLEMENTED_VERSION = SCS_TELEMETRY_ATS_GAME_VERSION_CURRENT;
		if (SCS_GET_MAJOR_VERSION(version_params->common.game_version) > SCS_GET_MAJOR_VERSION(IMPLEMENTED_VERSION)) {
			log_line(SCS_LOG_TYPE_warning, "WARNING: Too new major version of the game, some features might behave incorrectly");
		}
	}
	else {
		log_line(SCS_LOG_TYPE_warning, "Unsupported game, some features or values might behave incorrectly");
	}

	// Register for events. Note that failure to register those basic events
	// likely indicates invalid usage of the api or some critical problem. As the
	// example requires all of them, we can not continue if the registration fails.

	const bool events_registered =
		(version_params->register_for_event(SCS_TELEMETRY_EVENT_paused, telemetry_pause, NULL) == SCS_RESULT_ok) &&
		(version_params->register_for_event(SCS_TELEMETRY_EVENT_started, telemetry_pause, NULL) == SCS_RESULT_ok) &&
		(version_params->register_for_event(SCS_TELEMETRY_EVENT_configuration, telemetry_configuration, NULL) == SCS_RESULT_ok)
	;
	if (! events_registered) {

		// Registrations created by unsuccessful initialization are
		// cleared automatically so we can simply exit.

		log_line(SCS_LOG_TYPE_error, "Unable to register event callbacks");
		game_log = NULL;
		return SCS_RESULT_generic_error;
	}

	// Initialize the shared memory.

	if (! initialize_shared_memory()) {
		log_line(SCS_LOG_TYPE_error, "Unable to initialize shared memory");
		game_log = NULL;
		return SCS_RESULT_generic_error;
	}

	// Register all changes we are interested in. Note that some wheel-related channels will be initialized when we
	// receive a configuration event. The channel might be missing if the game does not support it (SCS_RESULT_not_found)
	// or if does not support the requested type (SCS_RESULT_unsupported_type). For purpose of this example we ignore
	// the failures so the unsupported channels will remain at theirs default value.

#define register_channel(name, index, type, field) version_params->register_for_channel(SCS_TELEMETRY_##name, index, SCS_VALUE_TYPE_##type, SCS_TELEMETRY_CHANNEL_FLAG_no_value, telemetry_store_##type, &shared_memory->field);

	register_channel(TRUCK_CHANNEL_world_placement,				SCS_U32_NIL, dplacement,	ws_truck_placement);

	register_channel(TRUCK_CHANNEL_speed,						SCS_U32_NIL, float,			speedometer_speed);
	register_channel(TRUCK_CHANNEL_engine_rpm,					SCS_U32_NIL, float,			rpm);
	register_channel(TRUCK_CHANNEL_engine_gear,					SCS_U32_NIL, s32,			gear);

	register_channel(TRUCK_CHANNEL_effective_steering,			SCS_U32_NIL, float,			steering);
	register_channel(TRUCK_CHANNEL_effective_throttle,			SCS_U32_NIL, float,			throttle);
	register_channel(TRUCK_CHANNEL_effective_brake,				SCS_U32_NIL, float,			brake);
	register_channel(TRUCK_CHANNEL_effective_clutch,			SCS_U32_NIL, float,			clutch);

	register_channel(TRUCK_CHANNEL_local_linear_velocity,		SCS_U32_NIL, fvector,		linear_valocity);
	register_channel(TRUCK_CHANNEL_local_angular_velocity,		SCS_U32_NIL, fvector,		angular_velocity);
	register_channel(TRUCK_CHANNEL_local_linear_acceleration,	SCS_U32_NIL, fvector,		linear_acceleration);
	register_channel(TRUCK_CHANNEL_local_angular_acceleration,	SCS_U32_NIL, fvector,		angular_acceleration);
	register_channel(TRUCK_CHANNEL_cabin_angular_velocity,		SCS_U32_NIL, fvector,		cabin_angular_velocity);
	register_channel(TRUCK_CHANNEL_cabin_angular_acceleration,	SCS_U32_NIL, fvector,		cabin_angular_acceleration);

#undef register_channel

	// Remember other the functions we will use in the future.

	register_for_channel = version_params->register_for_channel;
	unregister_from_channel = version_params->unregister_from_channel;

	// We are done.

	log_line(SCS_LOG_TYPE_message, "Memory telemetry example initialized");
	return SCS_RESULT_ok;
}

/**
 * @brief Telemetry API deinitialization function.
 *
 * See scssdk_telemetry.h
 */
SCSAPI_VOID scs_telemetry_shutdown(void)
{
	// Any cleanup needed. The registrations will be removed automatically
	// so there is no need to do that manually.

	deinitialize_shared_memory();

	unregister_from_channel = NULL;
	register_for_channel = NULL;
	game_log = NULL;
}

// Cleanup

BOOL APIENTRY DllMain(
	HMODULE module,
	DWORD  reason_for_call,
	LPVOID reseved
)
{
	return TRUE;
}

// EOF //