/*
    Copyright (c) 2015-2016 Sodaq.  All rights reserved.

    This file is part of Sodaq_nbIOT.

    Sodaq_nbIOT is free software: you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as
    published by the Free Software Foundation, either version 3 of
    the License, or(at your option) any later version.

    Sodaq_nbIOT is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    GNU Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with Sodaq_nbIOT.  If not, see
    <http://www.gnu.org/licenses/>.
*/

#ifndef _SODAQ_AT_DEVICE_h
#define _SODAQ_AT_DEVICE_h

#include <Arduino.h>
#include <stdint.h>
#include <Stream.h>
#include "Sodaq_OnOffBee.h"

// Response type (returned by readResponse() and parser methods).
enum ResponseTypes {
    ResponseNotFound = 0,
    ResponseOK = 1,
    ResponseError = 2,
    ResponsePrompt = 3,
    ResponseTimeout = 4,
    ResponseEmpty = 5,
    ResponsePendingExtra = 6,
};

// IP type
typedef uint32_t IP_t;

// callback for changing the baudrate of the modem stream.
typedef void (*BaudRateChangeCallbackPtr)(uint32_t newBaudrate);

#define SODAQ_AT_DEVICE_DEFAULT_READ_MS 5000 // Used in readResponse()

class Sodaq_AT_Device
{
  public:
    // Constructor
    Sodaq_AT_Device();
    virtual ~Sodaq_AT_Device() {}

    // Sets the onoff instance
    void setOnOff(Sodaq_OnOffBee& onoff) { _onoff = &onoff; }

    // Turns the modem on and returns true if successful.
    bool on();

    // Turns the modem off and returns true if successful.
    bool off();

    // Sets the optional "Diagnostics and Debug" stream.
    void setDiag(Stream& stream) { _diagStream = &stream; }
    void setDiag(Stream* stream) { _diagStream = stream; }

    // Sets the size of the input buffer.
    // Needs to be called before init().
    void setInputBufferSize(size_t value) { this->_inputBufferSize = value; };

    // Returns the default baud rate of the modem.
    // To be used when initializing the modem stream for the first time.
    virtual uint32_t getDefaultBaudrate() = 0;

    // Enables the change of the baud rate to a higher speed when the modem is ready to do so.
    // Needs a callback in the main application to re-initialize the stream.
    void enableBaudrateChange(BaudRateChangeCallbackPtr callback) { _baudRateChangeCallbackPtr = callback; };

  protected:
    // The stream that communicates with the device.
    Stream* _modemStream;

    // The (optional) stream to show debug information.
    Stream* _diagStream;
    bool _disableDiag;

    // The size of the input buffer. Equals SODAQ_GSM_MODEM_DEFAULT_INPUT_BUFFER_SIZE
    // by default or (optionally) a user-defined value when using USE_DYNAMIC_BUFFER.
    size_t _inputBufferSize;

    // Flag to make sure the buffers are not allocated more than once.
    bool _isBufferInitialized;

    // The buffer used when reading from the modem. The space is allocated during init() via initBuffer().
    char* _inputBuffer;

    // The on-off pin power controller object.
    Sodaq_OnOffBee* _onoff;

    // The callback for requesting baudrate change of the modem stream.
    BaudRateChangeCallbackPtr _baudRateChangeCallbackPtr;

    // This flag keeps track if the next write is the continuation of the current command
    // A Carriage Return will reset this flag.
    bool _appendCommand;

    // Keep track when connect started. Use this to record various status changes.
    uint32_t _startOn;

    // Initializes the input buffer and makes sure it is only initialized once.
    // Safe to call multiple times.
    void initBuffer();

    // Returns true if the modem is ON (and replies to "AT" commands without timing out)
    virtual bool isAlive() = 0;

    // Returns true if the modem is on.
    bool isOn() const;

    // Sets the modem stream.
    void setModemStream(Stream& stream);

    // Returns a character from the modem stream if read within _timeout ms or -1 otherwise.
    int timedRead(uint32_t timeout = 1000) const;

    // Fills the given "buffer" with characters read from the modem stream up to "length"
    // maximum characters and until the "terminator" character is found or a character read
    // times out (whichever happens first).
    // The buffer does not contain the "terminator" character or a null terminator explicitly.
    // Returns the number of characters written to the buffer, not including null terminator.
    size_t readBytesUntil(char terminator, char* buffer, size_t length, uint32_t timeout = 1000);

    // Fills the given "buffer" with up to "length" characters read from the modem stream.
    // It stops when a character read times out or "length" characters have been read.
    // Returns the number of characters written to the buffer.
    size_t readBytes(uint8_t* buffer, size_t length, uint32_t timeout = 1000);

    // Reads a line from the modem stream into the "buffer". The line terminator is not
    // written into the buffer. The buffer is terminated with null.
    // Returns the number of bytes read, not including the null terminator.
    size_t readLn(char* buffer, size_t size, uint32_t timeout = 1000);

    // Reads a line from the modem stream into the input buffer.
    // Returns the number of bytes read.
    size_t readLn() { return readLn(_inputBuffer, _inputBufferSize); };

    // Write a byte
    size_t writeByte(uint8_t value);

    // Write the command prolog (just for debugging
    void writeProlog();

    size_t print(const __FlashStringHelper*);
    size_t print(const String&);
    size_t print(const char[]);
    size_t print(char);
    size_t print(unsigned char, int = DEC);
    size_t print(int, int = DEC);
    size_t print(unsigned int, int = DEC);
    size_t print(long, int = DEC);
    size_t print(unsigned long, int = DEC);
    size_t print(double, int = 2);
    size_t print(const Printable&);

    size_t println(const __FlashStringHelper*);
    size_t println(const String& s);
    size_t println(const char[]);
    size_t println(char);
    size_t println(unsigned char, int = DEC);
    size_t println(int, int = DEC);
    size_t println(unsigned int, int = DEC);
    size_t println(long, int = DEC);
    size_t println(unsigned long, int = DEC);
    size_t println(double, int = 2);
    size_t println(const Printable&);
    size_t println(void);

    virtual ResponseTypes readResponse(char* buffer, size_t size, size_t* outSize, uint32_t timeout = SODAQ_AT_DEVICE_DEFAULT_READ_MS) = 0;
};

#endif