#ifndef ESP32DISPLAYTEST_LIB_COMMANDER_COMMANDER_H_
#define ESP32DISPLAYTEST_LIB_COMMANDER_COMMANDER_H_

#include <functional>
#include <utility>
#include <vector>
#include <WString.h>
#include <WiFiServer.h>
#include <AsyncTCP.h>
#include <Stream.h>


class CmdString : public String {

 public:
  CmdString(const char *cstr = "") : String(cstr){}
  CmdString(const String& str) : String(str){}


  template<typename T>
  bool ReadInto(T *out) const {
	static_assert(!std::is_same<T, int64_t>::value, "64-bit not supported");
	static_assert(!std::is_same<T, uint64_t>::value, "64-bit not supported");
	static_assert(std::is_integral<T>::value, "integer type required");

	if (isEmpty()) return false;
	int64_t res;
	int i = 0;

	if (!std::is_unsigned<T>::value) {
	  bool negative = false;
	  if (this->charAt(0) == '-') {
		i = 1;
		negative = true;
		if (length() < 2) return false;
	  }

	  char ch = this->charAt(i);
	  if (ch >= '0' && ch <= '9') {
		res = ch - '0';
		if (negative) {
		  res = -res;
		}
	  } else {
		return false;
	  };
	  i += 1;
	}

	for (; i < length(); i++) {
	  char ch = this->charAt(i);
	  if (ch >= '0' && ch <= '9') {
		uint8_t digit = ch - '0';
		res *= 10;
		res += digit;
		if (res > std::numeric_limits<T>::max() || res < std::numeric_limits<T>::min()) {
		  return false;
		}
	  } else {
		return false;
	  }
	}

	*out = res;
	return true;
  }
};




class Commander;

class Command;

class CommanderClient;

class SerialCommanderClient;

class WifiCommanderClient;

class Command {
  friend class CommanderClient;

 protected:
  String name_;
  String description_;
  std::function<void(std::vector<CmdString>, CommanderClient *)> handler_;
  std::vector<Command> commands_;

  bool shell_;

  String prompt_ = "> ";
  String welcome_message_ = "";

  Command(const String &name, std::function<void(std::vector<CmdString>, CommanderClient *)> handler, bool shell)
	  : handler_(std::move(handler)), shell_(shell) {
	int space_index = name.indexOf(' ');
	if (space_index == -1) {
	  name_ = name;
	  description_ = "";
	} else {
	  name_ = name.substring(0, space_index);
	  description_ = name.substring(space_index);
	}
  }

  const Command* Dispatch(std::vector<CmdString> cmdline, CommanderClient *client) const;

  void DefaultHandler(const std::vector<CmdString> &cmdline, CommanderClient *client) const;

  void DefaultHelpHandler(CommanderClient *client) const;

 public:
  Command *RegisterCommand(const String &name,
						   const std::function<void(const std::vector<CmdString> &,
													CommanderClient *)> &handler);

  Command *RegisterCommandWithShell(const String &name);

  void SetPrompt(const String &prompt);

  void SetWelcomeMessage(const String &message);

};

class Commander : public Command {
  friend CommanderClient;
 private:
  bool enable_wifi_ = false;
  bool enable_serial_ = false;
  uint16_t port_ = 0;
  AsyncServer *tcp_server_{};
  std::vector<WifiCommanderClient> wifi_clients_;
  SerialCommanderClient *serial_client_{};

  bool running_ = false;

  static Commander *serial_instance_;

  TaskHandle_t task_handle_{};

 public:

  Commander() : Command("", Commander::DefaultFallbackHandler, false) {}

  using Command::RegisterCommand;
  using Command::RegisterCommandWithShell;

  void EnableSerial();
  void EnableWifi(uint16_t port);

  void SetFallbackHandler(const std::function<void(const std::vector<CmdString> &,
												   CommanderClient *)> &handler);

  void Begin();

  void Stop();

 private:
  void WifiOnClient(AsyncClient *client);

  void SerialReceive();

  [[noreturn]] void Task();

  static void SerialReceiveHandler();

  static void WifiOnClientHandler(void *thisarg, AsyncClient *client);

  [[noreturn]] static void TaskFn(void *thisarg);

  static void DefaultFallbackHandler(std::vector<CmdString> cmd, CommanderClient *client) {

  }
};

class CommanderClient : public Stream {
 protected:
  std::vector<const Command *> shell_stack_;

  bool in_command_ = false;

  String buffer_ = "";

  std::vector<CmdString> current_line_;
  bool in_quotes_ = false;
  bool in_escape_ = false;
  bool previous_was_cr_ = false;

  TaskHandle_t task_handle_ = nullptr;

  void BufferAppend(const String &str);

  void BufferAppend(char ch);

  void DipatchCurrentCommandLine();

  void ProcessCommandLine();

  const String &GetPrompt();
  const String &GetWelcomeMessage();

  virtual void Task() = 0;

  static void TaskFn(void *thisarg) {
	((CommanderClient *)thisarg)->Task();
  }

 public:
  explicit CommanderClient(Commander *commander) {
	shell_stack_.push_back(commander);
  }

  virtual void Begin() {
	xTaskCreate(CommanderClient::TaskFn, "commander client", 10000, this, 1, &this->task_handle_);
  }

  CmdString ReadLine();

  template<typename T>
  bool ReadLine(T *out) {
	static_assert(!std::is_same<T, int64_t>::value, "64-bit not supported");
	static_assert(!std::is_same<T, uint64_t>::value, "64-bit not supported");
	static_assert(std::is_integral<T>::value, "integer type required");

	CmdString line = ReadLine();
	if (line.isEmpty()) return false;
	int64_t res;
	int i = 0;

	if (!std::is_unsigned<T>::value) {
	  bool negative = false;
	  if (line[0] == '-') {
		i = 1;
		negative = true;
		if (line.length() < 2) return false;
	  }

	  char ch = line[i];
	  if (ch >= '0' && ch <= '9') {
		res = ch - '0';
		if (negative) {
		  res = -res;
		}
	  } else {
		return false;
	  };
	  i += 1;
	}

	for (; i < line.length(); i++) {
	  char ch = line[i];
	  if (ch >= '0' && ch <= '9') {
		uint8_t digit = ch - '0';
		res *= 10;
		res += digit;
		if (res > std::numeric_limits<T>::max() || res < std::numeric_limits<T>::min()) {
		  return false;
		}
	  } else {
		return false;
	  }
	}

	*out = res;
	return true;
  }

};

class SerialCommanderClient : public CommanderClient {

  static SerialCommanderClient *single_instance_;

 public:
  explicit SerialCommanderClient(Commander *commander);

  void OnReceive();

  size_t write(uint8_t byte) override;
  int available() override;
  int read() override;
  int peek() override;
  void flush() override;

  void Begin() override {
	CommanderClient::Begin();
	Serial.onReceive(SerialCommanderClient::OnReceiveHandler);
  }

  [[noreturn]] void Task() override;

  static void OnReceiveHandler() {
	single_instance_->OnReceive();
  }
};

class WifiCommanderClient : public CommanderClient {
  AsyncClient *async_client_;
 public:
  explicit WifiCommanderClient(Commander *commander, AsyncClient *client);

  void OnData(void *data, size_t len);

  size_t write(uint8_t byte) override;
  int available() override;
  int read() override;
  int peek() override;
  void flush() override;

  void Task() {};

 private:
  static void OnDataHandler(void *thisarg, AsyncClient *, void *data, size_t len);
};

#endif //ESP32DISPLAYTEST_LIB_COMMANDER_COMMANDER_H_