using System.Device.I2c;


namespace Libs_SequentMicrosystems
{
    public class RTDStackLevelReader
    {
        public readonly byte DEVICE_ADDRESS = 0x40;
        public readonly byte RTD_RESISTANCE_ADD = 59;

        /// <summary>
        /// Read Single Resistance
        /// </summary>
        /// <param name="stack">Level on Stack 0-7</param>
        /// <param name="channel">Chanel on stack layer 1-8</param>
        /// <returns>Resistance of selected element</returns>
        /// <exception cref="ArgumentException"></exception>
        /// <exception cref="IOException"></exception>
        public float Get(byte stack, byte channel)
        {
            if (stack < 0 || stack > 7)
                throw new ArgumentException("Invalid stack level");

            if (channel < 1 || channel > 8)
                throw new ArgumentException("Invalid channel number");

            float val = -273.15f;

            try
            {
                using (I2cDevice i2c = I2cDevice.Create(new I2cConnectionSettings(1, DEVICE_ADDRESS + stack)))
                {
                    byte[] buffer = new byte[4];
                    i2c.WriteByte((byte)(RTD_RESISTANCE_ADD + (4 * (channel - 1))));
                    i2c.Read(buffer);
                    val = BitConverter.ToSingle(buffer, 0);
                }
            }
            catch (IOException e)
            {
                throw new IOException($"Fail to communicate with the RTD card with message: \"{e.Message}\"");
            }

            if (val < 0)
            {
                val = 0;
            }

            return val;
        }

        /// <summary>
        /// Get data from all inputs on stack level
        /// </summary>
        /// <param name="stack">Number of level in stack</param>
        /// <param name="precision">Number of decimals numbers of measured resistance</param>
        /// <returns>Measured resistances of all inputs</returns>
        public float[] GetStack(byte stack, byte precision = 2)
        {
            float[] chanels = new float[8]; //initialize float array

            chanels[0] = (float)Math.Round(Get(stack, 1), precision); //write readed value from input to array
            chanels[1] = (float)Math.Round(Get(stack, 2), precision);
            chanels[2] = (float)Math.Round(Get(stack, 3), precision);
            chanels[3] = (float)Math.Round(Get(stack, 4), precision);
            chanels[4] = (float)Math.Round(Get(stack, 5), precision);
            chanels[5] = (float)Math.Round(Get(stack, 6), precision);
            chanels[6] = (float)Math.Round(Get(stack, 7), precision);
            chanels[7] = (float)Math.Round(Get(stack, 8), precision);

            return chanels; //return array
        }


    }
}