using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using YLScsDrawing.Drawing3d;

namespace ArdupilotMega.HIL
{
    public class QuadCopter : Aircraft
    {
        const float ft2m = (float)(1.0 / 3.2808399);
        const float rad2deg = (float)(180 / Math.PI);
        const float deg2rad = (float)(1.0 / rad2deg);
        const float kts2fps = (float)1.68780986;

        int framecount = 0;
        DateTime seconds = DateTime.Now;

        double[] motor_speed = null;

        double hover_throttle;
        double terminal_velocity;

        Vector3d old_position;


        //# scaling from total motor power to Newtons. Allows the copter
        //# to hover against gravity when each motor is at hover_throttle
        double thrust_scale;

        DateTime last_time;

        public QuadCopter()
        {
            mass = 1.0;// # Kg
            frame_height = 0.1;
            motor_speed = new double[] { 0.0, 0.0, 0.0, 0.0 };
            hover_throttle = 0.37;
            terminal_velocity = 30.0;

            thrust_scale = (mass * gravity) / (4.0 * hover_throttle);

            last_time = DateTime.Now;
        }

        double scale_rc(int sn, float servo, float min, float max)
        {
            float min_pwm = 1000;
            float max_pwm = 2000;
                 //'''scale a PWM value'''       # default to servo range of 1000 to 2000  
            if (MainV2.comPort.param.Count > 0)
            {
                min_pwm = int.Parse(MainV2.comPort.param["RC3_MIN"].ToString());
                max_pwm = int.Parse(MainV2.comPort.param["RC3_MAX"].ToString());
            }

             float p = (servo - min_pwm) / (max_pwm - min_pwm);

             float v = min + p * (max - min);

             if (v < min)
             v = min  ;
             if (v > max)
             v = max  ;
             return v;
         }

        public void update(ref double[] servos, ArdupilotMega.GCSViews.Simulation.FGNetFDM fdm)
        { 
            for (int i = 0; i < servos.Length; i++)
            {
                if (servos[i] <= 0.0)
                {
                    motor_speed[i] = 0;
                }
                else
                {
                    motor_speed[i] = scale_rc(i,(float)servos[i], 0.0f, 1.0f);
                    //servos[i] = motor_speed[i];
                }
            }
            double[] m = motor_speed;

            /*
            roll = 0;
            pitch = 0;
            yaw = 0;
            roll_rate = 0;
            pitch_rate = 0;
            yaw_rate = 0;
            */

//            Console.WriteLine("\nin m {0:0.000000} {1:0.000000} {2:0.000000} {3:0.000000}", m[0], m[1], m[2], m[3]);
//            Console.WriteLine("in vel {0:0.000000} {1:0.000000} {2:0.000000}", velocity.X, velocity.Y, velocity.Z);
            //Console.WriteLine("in r {0:0.000000} p {1:0.000000} y {2:0.000000}    - r {3:0.000000} p {4:0.000000} y {5:0.000000}", roll, pitch, yaw, roll_rate, pitch_rate, yaw_rate);
            

//            m[0] *= 0.5;

            //# how much time has passed?
            DateTime t = DateTime.Now;
            TimeSpan delta_time = t - last_time; // 0.02
            last_time = t;

            if (delta_time.TotalMilliseconds > 100) // somethings wrong / debug
            {
                delta_time = new TimeSpan(0, 0, 0, 0, 20);
            }

            //# rotational acceleration, in degrees/s/s
            double roll_accel = (m[1] - m[0]) * 5000.0;
            double pitch_accel = (m[2] - m[3]) * 5000.0;
            double yaw_accel = -((m[2] + m[3]) - (m[0] + m[1])) * 400.0;

           // Console.WriteLine("roll {0} {1} {2}", roll_accel, roll_rate, roll);

            //# update rotational rates
            roll_rate += roll_accel * delta_time.TotalSeconds;
            pitch_rate += pitch_accel * delta_time.TotalSeconds;
            yaw_rate += yaw_accel * delta_time.TotalSeconds;

           // Console.WriteLine("roll {0} {1} {2}", roll_accel, roll_rate, roll);

            //# update rotation
            roll += roll_rate * delta_time.TotalSeconds;
            pitch += pitch_rate * delta_time.TotalSeconds;
            yaw += yaw_rate * delta_time.TotalSeconds;

//            Console.WriteLine("roll {0} {1} {2}", roll_accel, roll_rate, roll);

            //Console.WriteLine("r {0:0.0} p {1:0.0} y {2:0.0}    - r {3:0.0} p {4:0.0} y {5:0.0}  ms {6:0.000}", roll, pitch, yaw, roll_rate, pitch_rate, yaw_rate, delta_time.TotalSeconds);

            //# air resistance
            Vector3d air_resistance = -velocity * (gravity / terminal_velocity);

            //# normalise rotations
            normalise();

            double thrust = (m[0] + m[1] + m[2] + m[3]) * thrust_scale;//# Newtons
            double accel = thrust / mass;

            //Console.WriteLine("in {0:0.000000} {1:0.000000} {2:0.000000} {3:0.000000}", roll, pitch, yaw, accel);

            Vector3d accel3D = RPY_to_XYZ(roll, pitch, yaw, accel);
            //Console.WriteLine("accel3D " + accel3D.X + " " + accel3D.Y + " " + accel3D.Z);
            accel3D += new Vector3d(0, 0, -gravity);
            accel3D += air_resistance;


            //# new velocity vector
            velocity += accel3D * delta_time.TotalSeconds;
            this.accel = accel3D;

            //# new position vector
            old_position = new Vector3d(position);
            position += velocity * delta_time.TotalSeconds;

//            Console.WriteLine(fdm.agl + " "+ fdm.altitude);

            //Console.WriteLine("Z {0} halt {1}  < gl {2} fh {3}" ,position.Z , home_altitude , ground_level , frame_height);

            if (home_latitude == 0)
            {
                this.home_latitude = fdm.latitude * rad2deg;
                this.home_longitude = fdm.longitude * rad2deg;
                this.home_altitude = fdm.altitude * ft2m;
                this.ground_level = this.home_altitude;

                this.altitude = fdm.altitude * ft2m;
                this.latitude = fdm.latitude * rad2deg;
                this.longitude = fdm.longitude * rad2deg;
            }

            //# constrain height to the ground
            if (position.Z + home_altitude < ground_level + frame_height)
            {
                if (old_position.Z + home_altitude > ground_level + frame_height)
                {
//                    Console.WriteLine("Hit ground at {0} m/s", (-velocity.Z));
                }
                velocity = new Vector3d(0, 0, 0);
                roll_rate = 0;
                pitch_rate = 0;
                yaw_rate = 0;
                roll = 0;
                pitch = 0;
                position = new Vector3d(position.X, position.Y,
                                               ground_level + frame_height - home_altitude + 0);
               // Console.WriteLine("here " + position.Z);
            } 

            //# update lat/lon/altitude
            update_position();

            // send to apm
            ArdupilotMega.MAVLink.__mavlink_gps_raw_t gps = new ArdupilotMega.MAVLink.__mavlink_gps_raw_t();

            ArdupilotMega.MAVLink.__mavlink_attitude_t att = new ArdupilotMega.MAVLink.__mavlink_attitude_t();

            ArdupilotMega.MAVLink.__mavlink_vfr_hud_t asp = new ArdupilotMega.MAVLink.__mavlink_vfr_hud_t();

            att.roll = (float)roll * deg2rad;
            att.pitch = (float)pitch * deg2rad;
            att.yaw = (float)yaw * deg2rad;
            att.rollspeed = (float)roll_rate * deg2rad;
            att.pitchspeed = (float)pitch_rate * deg2rad;
            att.yawspeed = (float)yaw_rate * deg2rad;

            gps.alt = ((float)(altitude));
            gps.fix_type = 3;
            gps.v = ((float)Math.Sqrt((velocity.X * velocity.X) + (velocity.Y * velocity.Y)));
            gps.hdg = (float)(((Math.Atan2(velocity.Y, velocity.X) * rad2deg) + 360) % 360); ;
            gps.lat = ((float)latitude);
            gps.lon = ((float)longitude);
            gps.usec = ((ulong)DateTime.Now.Ticks);

            asp.airspeed = gps.v;

            MainV2.comPort.generatePacket(ArdupilotMega.MAVLink.MAVLINK_MSG_ID_ATTITUDE, att);

            MAVLink.__mavlink_raw_pressure_t pres = new MAVLink.__mavlink_raw_pressure_t();
            double calc = (101325 * Math.Pow(1 - 2.25577 * Math.Pow(10, -5) * gps.alt, 5.25588));
            pres.press_diff1 = (short)(int)(calc); // 0 alt is 0 pa

            MainV2.comPort.generatePacket(ArdupilotMega.MAVLink.MAVLINK_MSG_ID_RAW_PRESSURE, pres);

            MainV2.comPort.generatePacket(ArdupilotMega.MAVLink.MAVLINK_MSG_ID_VFR_HUD, asp);

            if (framecount % 10 == 0)
            {// 50 / 10 = 5 hz
                MainV2.comPort.generatePacket(ArdupilotMega.MAVLink.MAVLINK_MSG_ID_GPS_RAW, gps);
                //Console.WriteLine(DateTime.Now.Millisecond + " GPS" );
            }

            framecount++;
        }

        public static Vector3d RPY_to_XYZ(double roll, double pitch, double yaw, double length)
        {
            Vector3d v = new Vector3d(0, 0, length);
            v = new_rotate_euler(-deg2rad * (pitch), 0, -deg2rad * (roll)) * v;
            v = new_rotate_euler(0, deg2rad * (yaw), 0) * v;
            return v;
        }

        static Quaternion new_rotate_euler(double heading, double attitude, double bank)
        {
            Quaternion Q = new Quaternion();
            double c1 = Math.Cos(heading / 2);
            double s1 = Math.Sin(heading / 2);
            double c2 = Math.Cos(attitude / 2);
            double s2 = Math.Sin(attitude / 2);
            double c3 = Math.Cos(bank / 2);
            double s3 = Math.Sin(bank / 2);

            Q.W = c1 * c2 * c3 - s1 * s2 * s3;
            Q.X = s1 * s2 * c3 + c1 * c2 * s3;
            Q.Y = s1 * c2 * c3 + c1 * s2 * s3;
            Q.Z = c1 * s2 * c3 - s1 * c2 * s3;
            return Q;
        }
    }
}
