#include "wifi_module.hpp"

#include "network_connection.hpp"
#include "util.hpp"

#include <Arduino.h>
#include <string.h>

WiFiModule::WiFiModule(const WiFiModuleOptions &options) noexcept
	: _serial(options.receive_pin, options.transmit_pin)
{
}

void WiFiModule::begin(size_t baudrate) noexcept
{
	_serial.begin(baudrate);
}

auto WiFiModule::get_available() noexcept -> int
{
	return _serial.available();
}

void WiFiModule::reset() noexcept
{
	const auto send_success = _send_serial("AT+RST");

	if (!send_success)
	{
		Serial.println(F("Failed to send command to reset wifi module"));
		return;
	}

	char response[MAX_NETWORK_MODULE_RESPONSE_LENGTH] = "";

	const auto response_status = _read(2000U, response);

	Serial.println(
		response_status == WiFiModuleResponseStatus::OK ? F("Reset wifi module")
														: F("Failed to reset wifi module")
	);
}

auto WiFiModule::connect_to_wifi(const char *ssid, const char *password) noexcept -> bool
{
	const auto cmd = "AT+CWJAP_CUR";

	auto command_length =
		WIFI_CONNECT_COMMAND_BASE_LENGTH + strlen(cmd) + strlen(ssid) + strlen(password);

	auto *command = util::malloc<char>(command_length);

	if (command == nullptr)
	{
		Serial.println(
			F("Heap memory allocation failed for creating a wifi connection command")
		);
		return false;
	}

	snprintf(command, command_length, "%s=\"%s\",\"%s\"", cmd, ssid, password);

	const auto send_success = _send_serial(command);

	if (!send_success)
	{
		Serial.println(F("Failed to send wifi connect command"));
		free(command);
		return false;
	}

	free(command);

	char response[MAX_NETWORK_MODULE_RESPONSE_LENGTH] = "";

	const auto response_status = _read(40000U, response);

	return response_status == WiFiModuleResponseStatus::OK;
}

void WiFiModule::set_wifi_mode(WifiMode wifi_mode) noexcept
{
	const char cmd[] = "AT+CWMODE_CUR";

	const auto command_length = strlen(cmd) + 2U + 1U;

	auto *command = util::malloc<char>(command_length);

	if (command == nullptr)
	{
		return;
	}

	snprintf(command, command_length, "%s=%u", cmd, static_cast<int>(wifi_mode));

	_send_serial(command);

	free(command);

	char response[MAX_NETWORK_MODULE_RESPONSE_LENGTH] = "";

	_read(TIMEOUT_SHORT, response);
}

void WiFiModule::set_multiple_connections_enabled(bool is_enabled) noexcept
{
	const char cmd[] = "AT+CIPMUX";

	auto command_length = strlen(cmd) + 2U + 1U;

	auto *command = util::malloc<char>(command_length);

	if (command == nullptr)
	{
		return;
	}

	snprintf(command, command_length, "%s=%u", cmd, is_enabled ? 1U : 0U);

	_send_serial(command);

	free(command);

	char response[MAX_NETWORK_MODULE_RESPONSE_LENGTH] = "";

	_read(TIMEOUT_SHORT, response);
}

void WiFiModule::set_echo_enabled(bool is_enabled) noexcept
{
	const char cmd[] = "ATE";

	auto command_length = strlen(cmd) + 1U + 1U;

	auto *command = util::malloc<char>(command_length);

	if (command == nullptr)
	{
		return;
	}

	snprintf(command, command_length, "%s%u", cmd, is_enabled ? 1U : 0U);

	_send_serial(command);

	free(command);

	char response[MAX_NETWORK_MODULE_RESPONSE_LENGTH] = "";

	const auto response_status = _read(1500U, response);

	Serial.print(
		response_status == WiFiModuleResponseStatus::OK ? F("Turned ")
														: F("Failed to turn ")
	);
	Serial.print(is_enabled ? F("on") : F("off"));
	Serial.println(F(" AT commands echo"));
}

void WiFiModule::create_tcp_server(size_t port) noexcept
{
	const auto *cmd = "AT+CIPSERVER";

	auto command_length = CREATE_TCP_SERVER_COMMAND_BASE_LENGTH + strlen(cmd);

	auto *command = util::malloc<char>(command_length);

	if (command == nullptr)
	{
		return;
	}

	snprintf(command, command_length, "%s=1,%u", cmd, port);

	_send_serial(command);

	free(command);

	char response[MAX_NETWORK_MODULE_RESPONSE_LENGTH] = "";

	_read(TIMEOUT_MEDIUM, response);
}

auto WiFiModule::test() noexcept -> bool
{
	const auto send_success = _send_serial("AT");

	if (!send_success)
	{
		return false;
	}

	char response[MAX_NETWORK_MODULE_RESPONSE_LENGTH] = "";

	const auto response_status = _read(8000U, response);

	if (response_status == WiFiModuleResponseStatus::TIMEOUT)
	{
		return false;
	}

	return strcmp(response, "") != 0;
}

auto WiFiModule::get_local_ip(char *local_ip_out) noexcept -> const char *
{
	const auto send_success = _send_serial("AT+CIFSR");

	if (!send_success)
	{
		return local_ip_out;
	}

	auto *buf = util::malloc<char>(strlen(local_ip_out) + 1U);

	if (buf == nullptr)
	{
		strcpy(local_ip_out, "Memory allocation failure");
		return local_ip_out;
	}

	strcpy(buf, "");

	const auto response_status = _read(10000U, buf);

	if (response_status != WiFiModuleResponseStatus::OK)
	{
		free(buf);

		sprintf(
			local_ip_out,
			"Response status was not OK. Was %d",
			static_cast<int>(response_status)
		);

		return local_ip_out;
	}

	auto local_ip_end = strstr(buf, "\"\r\n+CIFSR:STAMAC");

	if (local_ip_end == nullptr)
	{
		free(buf);
		strcpy(local_ip_out, "Response parsing error");
		return local_ip_out;
	}

	const auto staip_title_length = 16U; // The length of '+CIFSR:STAIP,"'

	util::substr(buf + staip_title_length, local_ip_end, local_ip_out);

	free(buf);

	return local_ip_out;
}

auto WiFiModule::get_mac_address(char *mac_address_out) noexcept -> const char *
{
	const auto send_success = _send_serial("AT+CIFSR");

	if (!send_success)
	{
		return mac_address_out;
	}

	auto *buf = util::malloc<char>(strlen(mac_address_out) + 1U);

	if (buf == nullptr)
	{
		strcpy(mac_address_out, "Memory allocation failure");
		return mac_address_out;
	}

	strcpy(buf, "");

	const auto response_status = _read(10000U, buf);

	if (response_status != WiFiModuleResponseStatus::OK)
	{
		free(buf);

		sprintf(
			mac_address_out,
			"Response status was not OK. Was %d",
			static_cast<int>(response_status)
		);

		return mac_address_out;
	}

	const auto stamac_title = "CIFSR:STAMAC,\"";

	auto mac_address_start = strstr(buf, stamac_title);

	if (mac_address_start == nullptr)
	{
		free(buf);
		strcpy(mac_address_out, "Response parsing error");
		return mac_address_out;
	}

	mac_address_start += strlen(stamac_title);

	util::substr(mac_address_start, mac_address_start + 17U, mac_address_out);

	free(buf);

	return mac_address_out;
}

auto WiFiModule::read_incoming_request() noexcept -> HTTPRequest
{
	char request_prefix[] = "+IPD,";

	if (get_available() == 0 || !_serial.find(request_prefix))
	{
		return HTTPRequest::create_invalid();
	}

	const auto min_available_bytes = 5;

	// Wait for the data buffer a bit
	while (get_available() < min_available_bytes)
	{
	}

	const auto connection = NetworkConnection(_read_connection_id());

	auto request_data_length = _read_request_data_length();

	const auto request_method = _read_request_method(request_data_length);

	// Read request path
	char request_path[REQUEST_PATH_MAX_LENGTH] = "";
	_read_to(&request_path[0], sizeof(request_path) - 1U, ' ', TIMEOUT_MEDIUM);

	request_data_length -= strlen(request_path) + 1U;

	// Read request HTTP version
	char http_version[REQUEST_HTTP_VERSION_MAX_LENGTH] = "";
	_read_to(&http_version[0], sizeof(http_version) - 1U, '\r', TIMEOUT_MEDIUM);

	request_data_length -= strlen(http_version) + 1U;

	// Skip the newline
	while (get_available() == 0)
	{
	}
	_serial.read();
	request_data_length -= 1U;

	auto request_data = util::malloc<char>(request_data_length + 1U);

	if (request_data == nullptr)
	{
		return HTTPRequest::create_invalid();
	}

	strcpy(request_data, "");

	_read_bytes(request_data, request_data_length, TIMEOUT_LONG);

	free(request_data);

	return HTTPRequest(
		connection,
		request_method,
		http_version,
		request_path,
		0,		// request_data_length,
		nullptr // request_data
	);
}

auto WiFiModule::close_connection(NetworkConnection &connection) noexcept -> bool
{
	const auto *cmd = "AT+CIPCLOSE";

	auto command_length = CLOSE_CONNECTION_COMMAND_BASE_LENGTH + strlen(cmd);

	auto *command = util::malloc<char>(command_length);

	if (command == nullptr)
	{
		Serial.println(
			F("Heap memory allocation failed for creating close connection command")
		);
		return false;
	}

	snprintf(command, command_length, "%s=%u", cmd, connection.id());

	_send_serial(command);

	free(command);

	char response[MAX_NETWORK_MODULE_RESPONSE_LENGTH] = "";

	const auto response_status = _read(4000U, response);

	if (response_status != WiFiModuleResponseStatus::OK)
	{
		Serial.print(F("Failed to close connection to "));
		Serial.println(connection.id());
		Serial.println(response);
		return false;
	}

	connection.set_is_closed(true);

	Serial.print(F("Closed connection to "));
	Serial.println(connection.id());

	return true;
}

auto WiFiModule::send_response(
	const NetworkConnection &connection,
	size_t status_code,
	const char **headers,
	size_t headers_cnt,
	const char *body
) noexcept -> bool
{
	const auto *cmd = "AT+CIPSEND";

	auto tot_headers_lengths = 0U;

	for (size_t index = 0U; index < headers_cnt; index++)
	{
		tot_headers_lengths += strlen(headers[index]) + 2U;
	}

	const auto data_length = strlen_P(RESPONSE_HTTP_VERSION) + 1 +
							 RESPONSE_STATUS_CODE_LENGTH + 4 + strlen(body) +
							 tot_headers_lengths;

	auto command_length = SEND_RESPONSE_COMMAND_BASE_LENGTH + strlen(cmd) + data_length;

	auto *command = util::malloc<char>(command_length);

	if (command == nullptr)
	{
		Serial.println(
			F("Heap memory allocation failed for creating send response command")
		);
		return false;
	}

	snprintf(command, command_length, "%s=%u,%u", cmd, connection.id(), data_length);

	_send_serial(command);

	free(command);

	char response[MAX_NETWORK_MODULE_RESPONSE_LENGTH] = "";

	_read(TIMEOUT_MEDIUM, response);

	_serial.print(reinterpret_cast<const __FlashStringHelper *>(RESPONSE_HTTP_VERSION));
	_serial.print(F(" "));
	_serial.print(status_code);
	_serial.print(F("\r\n"));

	// Print headers
	for (size_t index = 0U; index < headers_cnt; index++)
	{
		_serial.print(headers[index]);
		_serial.print(F("\r\n"));
	}

	_serial.print(F("\r\n"));
	_serial.print(body);

	strcpy(response, "");

	_read(TIMEOUT_MEDIUM, response);

	return true;
}

auto WiFiModule::_send_serial(const char *command) noexcept -> bool
{
	auto full_command_length = strlen(command) + 2U + 1U;

	auto *full_command = util::malloc<char>(full_command_length);

	if (full_command == nullptr)
	{
		// NOLINTNEXTLINE(readability-simplify-boolean-expr)
		return false;
	}

	snprintf(full_command, full_command_length, "%s\r\n", command);

	_serial.print(full_command);

	free(full_command);

	return true;
}

auto WiFiModule::_read_connection_id() noexcept -> int8_t
{
	const auto connection_id = _serial.read() - ASCII_TO_CHAR;

	// Skip the comma
	_serial.read();

	return static_cast<int8_t>(connection_id);
}

auto WiFiModule::_read_request_data_length() noexcept -> size_t
{
	char data_length_buf[REQUEST_DATA_LENGTH_BUF_SIZE] = "";

	_read_to(&data_length_buf[0], sizeof(data_length_buf) - 1U, ':', TIMEOUT_SHORT);

	return static_cast<size_t>(strtoul(data_length_buf, nullptr, NUMBER_BASE));
}

auto WiFiModule::_read_request_method(size_t &request_data_length) noexcept
	-> HTTPRequestMethod
{
	char request_method_buf[REQUEST_METHOD_STR_MAX_LENGTH] = "";

	_read_to(
		&request_method_buf[0],
		sizeof(request_method_buf) - 1U,
		' ',
		TIMEOUT_MEDIUM
	);

	const auto request_method = str_to_http_request_method(request_method_buf);

	request_data_length -= strlen(request_method_buf) + 1U;

	return request_method;
}

auto WiFiModule::_read(uint64_t timeout, char *response_out) noexcept
	-> WiFiModuleResponseStatus
{
	const auto start_time = millis();
	size_t index = 0U;
	bool has_end = false;
	auto status = WiFiModuleResponseStatus::TIMEOUT;

	while (!has_end && (start_time + timeout) > millis())
	{
		while (_serial.available() != 0)
		{
			char character = _read_byte();

			if (has_end)
			{
				continue;
			}

			const auto end_pos = index + 1U;

			response_out[index] = character;
			response_out[end_pos] = '\0';

			if (util::str_ends_with(response_out, end_pos, "OK"))
			{
				status = WiFiModuleResponseStatus::OK;
				has_end = true;
			}

			if (util::str_ends_with(response_out, end_pos, "ERROR"))
			{
				status = WiFiModuleResponseStatus::ERROR;
				has_end = true;
			}

			if (util::str_ends_with(response_out, end_pos, "FAIL"))
			{
				status = WiFiModuleResponseStatus::FAIL;
				has_end = true;
			}

			index++;
		}
	}

	return status;
}

void WiFiModule::_read_to(
	char *buffer_out,
	size_t length, // NOLINT(bugprone-easily-swappable-parameters)
	char stop_char,
	uint64_t timeout
) noexcept
{
	auto position = 0U;
	const auto start_time = millis();

	while (position < length && (start_time + timeout) > millis())
	{
		if (get_available() == 0)
		{
			continue;
		}

		auto character = _read_byte();

		if (character == stop_char)
		{
			break;
		}

		buffer_out[position++] = character;
	}

	buffer_out[position] = '\0';
}

// NOLINTNEXTLINE(bugprone-easily-swappable-parameters)
void WiFiModule::_read_bytes(char *buffer_out, size_t length, uint64_t timeout) noexcept
{
	const auto original_length = length;

	auto position = 0U;
	const auto start_time = millis();

	while (position != length && (start_time + timeout) > millis())
	{
		if (get_available() == 0)
		{
			continue;
		}

		char character = _read_byte();

		buffer_out[position++] = character;

		if (character == '\n' && position != original_length)
		{
			length -= 2U;
		}
	}

	buffer_out[position] = '\0';
}

auto WiFiModule::_read_byte() noexcept -> char
{
	return static_cast<char>(_serial.read());
}