#include "wifi_module.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
{
	_send_serial("AT+RST");

	char response[MAX_NETWORK_MODULE_RESPONSE_LENGTH] = "";

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

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

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

	auto command_length = strlen(cmd) + strlen(ssid) + strlen(password) + 6U + 1U;

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

	if (command == nullptr)
	{
		Serial.println("Memory allocation failed for creating full 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("Failed to send connection command");
		return false;
	}

	free(command);

	char response[MAX_NETWORK_MODULE_RESPONSE_LENGTH] = "";

	const auto response_status = _read(20000U, 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);

	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);

	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);

	// Serial.println(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);

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

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

	auto command_length = strlen(cmd) + 7U + 1U;

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

	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);

	// Serial.println(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(5000U, 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 *command = "AT+CIFSR";

	const auto send_success = _send_serial(command);

	if (!send_success)
	{
		return local_ip_out;
	}

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

	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;
	}

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

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

	const auto min_available_bytes = 5;

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

	const auto connection_id = _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 nullptr;
	}

	strcpy(request_data, "");

	_read_bytes(request_data, request_data_length, TIMEOUT_LONG);

	return new HTTPRequest(
		connection_id,
		request_method,
		http_version,
		request_path,
		request_data_length,
		request_data
	);
}

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

	auto command_length = strlen(cmd) + 50U + 1U;

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

	if (command == nullptr)
	{
		Serial.println("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("Closed connection to ");
		Serial.println(connection_id);
	}
	else
	{
		Serial.print("Failed to close connection to ");
		Serial.println(connection_id);
		return false;
	}

	return true;
}

auto WiFiModule::send_response(size_t connection_id, const char *data) noexcept -> bool
{
	const auto *cmd = "AT+CIPSEND";

	const auto data_length = strlen(data);

	auto command_length = strlen(cmd) + 50U + data_length + 1U;

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

	if (command == nullptr)
	{
		Serial.println("Memory allocation failed for creating close connection 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(data);

	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)
	{
		return false;
	}

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

	_serial.print(full_command);

	// Serial.print("Sent command: ");
	// Serial.println(full_command);

	free(full_command);

	return true;
}

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

	// Skip the comma
	_serial.read();

	return connection_id;
}

size_t WiFiModule::_read_request_data_length() noexcept
{
	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, 10));
}

HTTPRequestMethod WiFiModule::_read_request_method(size_t &request_data_length) noexcept
{
	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();

	bool has_end = false;
	auto status = WiFiModuleResponseStatus::TIMEOUT;

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

			strncat(response_out, &character, 1U);

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

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

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

	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());
}