using System;
using System.Collections.Generic;
using System.Text;
using System.Threading;
using RPi.I2C.Net;

class I2C_PWM
{
	const int    __MODE1              = 0x00;
	const int    __MODE2              = 0x01;
	const int    __SUBADR1            = 0x02;
	const int    __SUBADR2            = 0x03;
	const int    __SUBADR3            = 0x04;
	const int    __PRESCALE           = 0xFE;
	const int    __LED0_ON_L          = 0x06;
	const int    __LED0_ON_H          = 0x07;
	const int    __LED0_OFF_L         = 0x08;
	const int    __LED0_OFF_H         = 0x09;
	const int    __ALL_LED_ON_L       = 0xFA;
	const int    __ALL_LED_ON_H       = 0xFB;
	const int    __ALL_LED_OFF_L      = 0xFC;
	const int    __ALL_LED_OFF_H      = 0xFD;

//  # Bits
	const int    __RESTART            = 0x80;
	const int    __SLEEP              = 0x10;
	const int    __ALLCALL            = 0x01;
	const int    __INVRT              = 0x10;
	const int    __OUTDRV             = 0x04;

	int address;
	I2CBus bus;	

	public I2C_PWM(int a_address)
	{
		address=a_address;
		bus = I2CBus.Open();
		if (bus==null)
		{
			log("Cannot connect to I2C, Address = "+a_address.ToString());
			return;
		}
        setAllPWM(0, 0);
        write8(__MODE2, __OUTDRV);
        write8(__MODE1, __ALLCALL);
        Thread.Sleep(5); //                                      # wait for oscillator
        
        byte mode1 = readU8(self.__MODE1);
        mode1 = mode1 & ~self.__SLEEP; //                 # wake up (reset sleep)
        write8(self.__MODE1, mode1);
        Thread.Sleep(5); //                                      # wait for oscillator
    }
	public SetPWMFreq(int freq)
	{
//    "Sets the PWM frequency"
   		double  prescaleval = 25000000.0;//    # 25MHz
	    prescaleval /= 4096.0;//       # 12-bit
	    prescaleval /= double(freq);
		prescaleval -= 1.0;
	    prescale = Math.floor(prescaleval + 0.5);

	    byte oldmode = readU8(self.__MODE1);
	    byte newmode = (oldmode & 0x7F) | 0x10 ; //             # sleep
	    write8(__MODE1, newmode); //        # go to sleep
	    write8(__PRESCALE, int(math.floor(prescale)));
	    write8(__MODE1, oldmode);
        Thread.Sleep(5); //                                      # wait for oscillator
	    write8(__MODE1, oldmode | 0x80);
	}
	public SetPWM(int pwm_channel, int value)
	{
		int on = 0; // change it if you need to start PWM cycle with phase delay
		int off = a_value;
		write8(__LED0_ON_L+4*channel, on & 0xFF);
	    write8(__LED0_ON_H+4*channel, on >> 8);
	    write8(__LED0_OFF_L+4*channel, off & 0xFF);
    	write8(__LED0_OFF_H+4*channel, off >> 8);
	}
	public SetAllPWM(int a_value)
	{
		int on = 0; // change it if you need to start PWM cycle with phase delay
		int off = a_value;
	    // "Sets all PWM channels"
	    write8(__ALL_LED_ON_L, on & 0xFF);
	    write8(__ALL_LED_ON_H, on >> 8);
	    write8(__ALL_LED_OFF_L, off & 0xFF);
	    write8(__ALL_LED_OFF_H, off >> 8);
	}

	private void write8(int address, byte b);
	{
		bus.WriteByte(address,b);
	}

	private byte readU8(int address);
	{
		byte[] buff = bus.ReadBytes(address,1);
		if (buff!=null && buff.Length>0)
		{
			return buff[0];
		}
		else
		{
			log("ERROR Reading byte from address "+address.ToString());
			return 0;
		}
	}

	private void log (string msg)
	{
		Console.Write(msg);
	}
}