/*
 * Originally from mbed Microcontroller Library
 * Copyright (c) 2006-2013 ARM Limited
 * Copyright (c) 2014 Intel Corporation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#pragma once

#include <stdio.h>
#include <fcntl.h>

namespace maa {

/** A PWM object, used for interacting with PWM output.
 *
 * Example:
 * @code
 * // Set up PWM object then cycle percentage 0-100.
 *
 * #include "maa.h"
 *
 * PWM pwm(3);
 *
 * int main() {
 *     pwm.period_us(7968750i); //Max Galileo Rev D
 *     pwm.enable(1);
 *
 *     float value = 0;
 *     while(1) {
 *         pwm.write(value);
 *         sleep(0.5);
 *         if(value == 1.0) {
 *             value = 0;
 *         } else {
 *             value = value +0.1;
 *         }
 *     }
 * }
 * @endcode
 */
class PWM {

private:
    int chipid, pin;
    FILE *duty_fp;

    void write_period(int period);
    void write_duty(int duty);
    int setup_duty_fp();
    int get_period();
    int get_duty();

public:

    /** Create an PWM object
     *
     *  @param chipid The chip in which the following pin is on.
     *  @param pin The PWM channel to operate on
     */
    PWM(int chipid, int pin);

    /** Set the ouput duty-cycle percentage, as a float
     *
     *  @param percentage A floating-point value representing percentage of output.
     *    The value should lie between 0.0f (representing on 0%) and 1.0f
     *    Values above or below this range will be set at either 0.0f or 1.0f.
     */
    void write(float percentage);

    /** Read the ouput duty-cycle percentage, as a float
     *
     *  @return percentage A floating-point value representing percentage of output.
     *    The value should lie between 0.0f (representing on 0%) and 1.0f
     *    Values above or below this range will be set at either 0.0f or 1.0f.
     */
    float read();

    /** Set the PWM period as seconds represented in a float
     *
     *  @param seconds Peroid represented as a float in seconds.
     */
    void period(float seconds);

    /** Set period. milli-oseconds.
     *  @param ms milli-seconds for period.
     */
    void period_ms(int ms);

    /** Set period. microseconds
     *  @param ns microseconds as period.
     */
    void period_us(int us);

    /** Set pulsewidth, As represnted by seconds in a (float).
     *  @param seconds The duration of a pulse
     */
    void pulsewidth(float seconds);

     /** Set pulsewidth. Milliseconds
     *  @param ms milliseconds for pulsewidth.
     */
    void pulsewidth_ms(int ms);

      /** Set pulsewidth, microseconds.
     *  @param us microseconds for pulsewidth.
     */
    void pulsewidth_us(int us);

    /** Set the enable status of the PWM pin. None zero will assume on with output being driven.
     *   and 0 will disable the output.
     *  @param enable enable status of pin
     */
    void enable(int enable);

     /** Close and unexport the PWM pin.
     */
    void close();

};
}