using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.IO.Ports;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace TinyFPGA_VisualProgrammer
{
    public class JSON_BoardMeta
    {
        public string name { get; set; }
        public string fpga { get; set; }
        public string hver { get; set; }
        public string uuid { get; set; }
    }

    public class JSON_BootMeta
    {
        public string bootloader { get; set; }
        public string bver { get; set; }
        public string update { get; set; }
        public JSON_AddrMap addrmap { get; set; }
    }

    public class JSON_AddrMap
    {
        public string bootloader { get; set; }
        public string userimage { get; set; }
        public string userdata { get; set; }
    }

    public class TinyProg
    {
        SerialController pPort = null;
        byte SecurePage_bitOffset = 0x00;
        byte SecurePage_writeCmd = 0x00;
        byte SecurePage_readCmd = 0x00;
        byte SecurePage_eraseCmd = 0x00;
        TinyMeta tinyMeta = null;

        public bool TinyFPGAIsConnected { get; private set; }

        public TinyProg(SerialController p)
        {
            TinyFPGAIsConnected = false;
            if (p != null)
                pPort = p;
        }


        public void CheckTinyPresence()
        {
            WakeCmd();
            byte[] flash_id = RetrieveFlashID();
            if (flash_id.Length >= 3)
            {
                if (flash_id[0] == 0x9D && flash_id[2] == 0x60)
                {
                    // ISSI
                    SecurePage_bitOffset = 4;
                    SecurePage_writeCmd = 0x62;
                    SecurePage_readCmd = 0x68;
                    SecurePage_eraseCmd = 0x64;
                }
                else
                {
                    // Adesto
                    SecurePage_bitOffset = 0;
                    SecurePage_writeCmd = 0x42;
                    SecurePage_readCmd = 0x48;
                    SecurePage_eraseCmd = 0x44;
                }
            }

            tinyMeta = new TinyMeta(this);
            if (tinyMeta.BoardMeta != null)
                TinyFPGAIsConnected = true;
            else
                TinyFPGAIsConnected = false;
        }

        public JSON_BoardMeta GetBoardData()
        {
            return tinyMeta.BoardMeta;
        }

        public JSON_BootMeta GetBootData()
        {
            return tinyMeta.BootMeta;
        }

        byte[] SendCommand(byte opcode, byte[] addr, byte[] datas, uint read_len = 0)
        {
            if (addr == null)
                addr = new byte[] { };
            if (datas == null)
                datas = new byte[] { };

            byte[] _ret = new byte[read_len];
            byte[] cmdSequence = new byte[sizeof(byte) + sizeof(ushort) + sizeof(ushort) + sizeof(byte) + addr.Length + datas.Length];
            int i;

            /*
             * Prepare datas container
             */
            cmdSequence[0] = 0x01;

            ushort seqSize = (ushort)(1 + addr.Length + datas.Length);
            cmdSequence[1] = (byte)(seqSize & 0xFF);                    // LSB
            cmdSequence[2] = (byte)((seqSize >> 8) & 0xFF);

            cmdSequence[3] = (byte)(read_len & 0xFF);                   // LSB
            cmdSequence[4] = (byte)((read_len >> 8) & 0xFF);

            cmdSequence[5] = opcode;
            i = 6;
            foreach (byte ab in addr)
                cmdSequence[i++] = ab;
            i = 6 + addr.Length;
            foreach (byte d in datas)
                cmdSequence[i++] = d;

            /*
             * Send datas container through serial line
             */
            //pPort.clearBuffer();
            pPort.SendBytes(cmdSequence, cmdSequence.Length);

            if (read_len > 0)
                _ret = pPort.WaitForBytes((int)read_len);

            return _ret;
        }

        public void WakeCmd()
        {
            SendCommand(0xab, null, null);
        }

        byte[] RetrieveFlashID()
        {
            return SendCommand(0x9f, null, null, 3);
        }

        void FlashWriteEnable()
        {
            SendCommand(0x06, null, null);
        }

        void FlashWriteDisable()
        {
            SendCommand(0x04, null, null);
        }

        byte RetrieveStatus()
        {
            return SendCommand(0x05, null, null, 1)[0];
        }

        void WaitWhileBusy()
        {
            while ((RetrieveStatus() & 1) == 1) { }
        }

        void EraseSecureRegPage(uint page)
        {
            FlashWriteEnable();
            SendCommand(SecurePage_eraseCmd, BitConverter.GetBytes((page & 0xFFFF) << 8 + SecurePage_bitOffset), null);
            WaitWhileBusy();
        }

        void ProgramSecureRegPage(uint page, byte[] data)
        {
            FlashWriteEnable();
            SendCommand(SecurePage_writeCmd, BitConverter.GetBytes((page & 0xFFFF) << 8 + SecurePage_bitOffset), data);
            WaitWhileBusy();
        }

        public string ReadSecureRegPage(uint page)
        {
            return Encoding.UTF8.GetString(SendCommand(SecurePage_readCmd, BitConverter.GetBytes((page & 0xFFFF) << 8 + SecurePage_bitOffset), new byte[] { 0x00 }, 255)).Insert(0, "{");
        }
    }

    public class TinyMeta
    {
        TinyProg tProg;
        //JSONRoot JSON_root;
        public JSON_BoardMeta BoardMeta { get; private set; }
        public JSON_BootMeta BootMeta { get; private set; }

        public TinyMeta(TinyProg tProg)
        {
            this.tProg = tProg;
            tProg.WakeCmd();
            ReadMetadata();
        }

        void ReadMetadata()
        {
            string rawJSON;

            rawJSON = tProg.ReadSecureRegPage(1).Substring(13, 107);
            BoardMeta = JsonConvert.DeserializeObject<JSON_BoardMeta>(rawJSON);     // Read 1st register, contain boardmeta
            Thread.Sleep(200);

            rawJSON = tProg.ReadSecureRegPage(2).Substring(12, 209);
            BootMeta = JsonConvert.DeserializeObject<JSON_BootMeta>(rawJSON);     // Read 2nd register, contain bootmeta
            Thread.Sleep(200);
            //tProg.ReadSecureRegPage(3);     // Read 3rd register, contain nothing
        }
    }
}