/*
 * @file GPIO.h
 * @author Derek Molloy
 * @version 0.1
 *
 * Created on: 29 Apr 2014
 * Copyright (c) 2014 Derek Molloy (www.derekmolloy.ie)
 * Made available for the book "Exploring BeagleBone"
 * See: www.exploringbeaglebone.com
 * Licensed under the EUPL V.1.1
 *
 * This Software is provided to You under the terms of the European
 * Union Public License (the "EUPL") version 1.1 as published by the
 * European Union. Any use of this Software, other than as authorized
 * under this License is strictly prohibited (to the extent such use
 * is covered by a right of the copyright holder of this Software).
 *
 * This Software is provided under the License on an "AS IS" basis and
 * without warranties of any kind concerning the Software, including
 * without limitation merchantability, fitness for a particular purpose,
 * absence of defects or errors, accuracy, and non-infringement of
 * intellectual property rights other than copyright. This disclaimer
 * of warranty is an essential part of the License and a condition for
 * the grant of any rights to this Software.
 *
 * For more details, see http://www.derekmolloy.ie/
 */

#pragma once

#include <string>
#include <fstream>

class gpio
{
public:
    enum direction
    {
        input, output
    };
    enum value
    {
        low = 0, high = 1
    };
    enum edge
    {
        none, rising, falling, both
    };

private:
    static constexpr const char* base_path = "/sys/class/gpio/";
    /// The GPIO number of the object
    int number_;
    /// The name of the GPIO
    std::string name_;
    /// The full path to the GPIO
    std::string path_;

    /// Write a string to a file.
    static int write(const std::string& path, const std::string& filename, const std::string& value);
    /// Write an integer to a file.
    static int write(const std::string& path, const std::string& filename, int value);
    /// Read a string from a file.
    static std::string read(const std::string& path, const std::string& filename);

public:
    explicit gpio(int number);
    int get_number() const
    {
        return number_;
    }

    // General Input and Output Settings
    int set_direction(direction);
    direction get_direction() const;
    int set_value(value);
    int toggle_output();
    value get_value() const;
    int set_active_low(bool is_low = true);
    int set_active_high(); //default
    
    // Advanced OUTPUT: Faster write by keeping the stream alive (~20X)
    int stream_open();
    int stream_write(value);
    int stream_close();

    // Advanced INPUT: Detect input edges; threaded and non-threaded
    int set_edge_type(edge);
    edge get_edge_type() const;

    ~gpio();

private:
    int export_gpio();
    int unexport_gpio();
    std::ofstream stream_;
};