using IStation.Epanet.Enums;
using IStation.Epanet.Network.Structures;
using System.Diagnostics;

namespace IStation.Epanet.Network
{

    ///<summary>Units report properties & conversion support class</summary>
    public class FieldsMap
    {
        ///<summary>Report fields properties.</summary>
        private readonly Dictionary<FieldType, Field> _fields = new Dictionary<FieldType, Field>();
        ///<summary>Fields units values.</summary>
        private readonly Dictionary<FieldType, double> _units = new Dictionary<FieldType, double>();

        ///<summary>Init fields default configuration</summary>
        public FieldsMap()
        {
            try
            {

                foreach (FieldType type in Enum.GetValues(typeof(FieldType)))
                    _fields[type] = new Field(type);

                GetField(FieldType.FRICTION).Precision = 3;

                for (var i = FieldType.DEMAND; i <= FieldType.QUALITY; i++)
                    GetField(i).Enabled = true;

                for (var i = FieldType.FLOW; i <= FieldType.HEADLOSS; i++)
                    GetField(i).Enabled = true;
            }
            catch (EnException e)
            {
                Debug.Print(e.ToString());
            }
        }

        ///<summary>Get report field properties from type.</summary>
        /// <param name="fieldType">Field type.</param>
        /// <returns>Report field.</returns>
        /// <remarks>
        /// Throws <see cref="EnException"/> 
        /// If specified type not found.
        /// </remarks>
        public Field GetField(FieldType fieldType)
        {
            if (!_fields.TryGetValue(fieldType, out Field value))
                throw new EnException(ErrorCode.Err201, fieldType.ParseStr());

            return value;
        }

        ///<summary>Get conversion value from field type.</summary>
        /// <param name="fieldType">Field type.</param>
        /// <returns>Conversion units value (from user units to system units).</returns>
        /// <remarks>
        /// Throws <see cref="EnException"/> If specified type not found.
        /// </remarks>
        public double GetUnits(FieldType fieldType)
        {
            if (!_units.TryGetValue(fieldType, out double value))
                throw new EnException(ErrorCode.Err201, fieldType.ParseStr());

            return value;
        }

        ///<summary>Update fields and units, after loading the INP.</summary>
        public void Prepare(
            UnitsType targetUnits,
            FlowUnitsType flowFlag,
            PressUnitsType pressFlag,
            QualType qualFlag,
            string chemUnits,
            double spGrav,
            TimeSpan hstep)
        {

            double dcf,
                   ccf,
                   qcf,
                   hcf,
                   pcf,
                   wcf;

            if (targetUnits == UnitsType.SI)
            {

                GetField(FieldType.DEMAND).Units = flowFlag.ToString();
                GetField(FieldType.ELEV).Units = Keywords.u_METERS;
                GetField(FieldType.HEAD).Units = Keywords.u_METERS;

                GetField(FieldType.PRESSURE).Units = pressFlag == PressUnitsType.METERS
                    ? Keywords.u_METERS
                    : Keywords.u_KPA;

                GetField(FieldType.LENGTH).Units = Keywords.u_METERS;
                GetField(FieldType.DIAM).Units = Keywords.u_MMETERS;
                GetField(FieldType.FLOW).Units = flowFlag.ToString();
                GetField(FieldType.VELOCITY).Units = Keywords.u_MperSEC;
                GetField(FieldType.HEADLOSS).Units = "m" + Keywords.u_per1000M;
                GetField(FieldType.FRICTION).Units = "";
                GetField(FieldType.POWER).Units = Keywords.u_KW;

                dcf = 1000.0 * Constants.MperFT;
                qcf = Constants.LPSperCFS;
                switch (flowFlag)
                {
                    case FlowUnitsType.Lpm:
                        qcf = Constants.LPMperCFS;
                        break;
                    case FlowUnitsType.Mld:
                        qcf = Constants.MLDperCFS;
                        break;
                    case FlowUnitsType.Cmh:
                        qcf = Constants.CMHperCFS;
                        break;
                    case FlowUnitsType.Cmd:
                        qcf = Constants.CMDperCFS;
                        break;
                }

                hcf = Constants.MperFT;
                if (pressFlag == PressUnitsType.METERS) pcf = Constants.MperFT * spGrav;
                else pcf = Constants.KPAperPSI * Constants.PSIperFT * spGrav;
                wcf = Constants.KWperHP;
            }
            else
            {
                GetField(FieldType.DEMAND).Units = flowFlag.ToString();
                GetField(FieldType.ELEV).Units = Keywords.u_FEET;
                GetField(FieldType.HEAD).Units = Keywords.u_FEET;

                GetField(FieldType.PRESSURE).Units = Keywords.u_PSI;
                GetField(FieldType.LENGTH).Units = Keywords.u_FEET;
                GetField(FieldType.DIAM).Units = Keywords.u_INCHES;
                GetField(FieldType.FLOW).Units = flowFlag.ToString();
                GetField(FieldType.VELOCITY).Units = Keywords.u_FTperSEC;
                GetField(FieldType.HEADLOSS).Units = "ft" + Keywords.u_per1000FT;
                GetField(FieldType.FRICTION).Units = "";
                GetField(FieldType.POWER).Units = Keywords.u_HP;


                dcf = 12.0;
                qcf = 1.0;

                switch (flowFlag)
                {
                    case FlowUnitsType.Gpm:
                        qcf = Constants.GPMperCFS;
                        break;
                    case FlowUnitsType.Mgd:
                        qcf = Constants.MGDperCFS;
                        break;
                    case FlowUnitsType.Imgd:
                        qcf = Constants.IMGDperCFS;
                        break;
                    case FlowUnitsType.Afd:
                        qcf = Constants.AFDperCFS;
                        break;
                }

                hcf = 1.0;
                pcf = Constants.PSIperFT * spGrav;
                wcf = 1.0;
            }

            GetField(FieldType.QUALITY).Units = "";
            ccf = 1.0;

            switch (qualFlag)
            {
                case QualType.Chem:
                    ccf = 1.0 / Constants.LperFT3;
                    GetField(FieldType.QUALITY).Units = chemUnits;
                    GetField(FieldType.REACTRATE).Units = chemUnits + Keywords.t_PERDAY;
                    break;
                case QualType.Age:
                    GetField(FieldType.QUALITY).Units = Keywords.u_HOURS;
                    break;
                case QualType.Trace:
                    GetField(FieldType.QUALITY).Units = Keywords.u_PERCENT;
                    break;
            }

            SetUnits(FieldType.DEMAND, qcf);
            SetUnits(FieldType.ELEV, hcf);
            SetUnits(FieldType.HEAD, hcf);
            SetUnits(FieldType.PRESSURE, pcf);
            SetUnits(FieldType.QUALITY, ccf);
            SetUnits(FieldType.LENGTH, hcf);
            SetUnits(FieldType.DIAM, dcf);
            SetUnits(FieldType.FLOW, qcf);
            SetUnits(FieldType.VELOCITY, hcf);
            SetUnits(FieldType.HEADLOSS, hcf);
            SetUnits(FieldType.LINKQUAL, ccf);
            SetUnits(FieldType.REACTRATE, ccf);
            SetUnits(FieldType.FRICTION, 1.0);
            SetUnits(FieldType.POWER, wcf);
            SetUnits(FieldType.VOLUME, hcf * hcf * hcf);

            if (hstep.TotalSeconds < 1800)
            {
                SetUnits(FieldType.TIME, 1.0 / 60.0);
                GetField(FieldType.TIME).Units = Keywords.u_MINUTES;
            }
            else
            {
                SetUnits(FieldType.TIME, 1.0 / 3600.0);
                GetField(FieldType.TIME).Units = Keywords.u_HOURS;
            }
        }

        /// <summary>Revert system units to user units.</summary>
        ///  <param name="fieldType">Field type.</param>
        /// <param name="value">Value to be converted.</param>
        /// <returns>Value in user units.</returns>
        public double RevertUnit(FieldType fieldType, double value)
        {
            return fieldType == (FieldType)(-1)
                ? value
                : value * GetUnits(fieldType);
        }

        public double ConvertUnitToSystem(FieldType fieldType, double value)
        {
            return value / GetUnits(fieldType);
        }

        ///<summary>Set conversion value from field type.</summary>
        /// <param name="fieldType">Field type.</param>
        /// <param name="value">Field value.</param>
        private void SetUnits(FieldType fieldType, double value)
        {
            _units[fieldType] = value;
        }

    }

}