using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Autodesk.Revit.DB;

namespace COME4Revit
{
   /// <summary>
    /// Provides static functions to convert unit
    /// </summary>
    static class Unit
    {
        #region Methods
        /// <summary>
        /// Convert the value get from RevitAPI to the value indicated by DisplayUnitType
        /// </summary>
        /// <param name="to">DisplayUnitType indicates unit of target value</param>
        /// <param name="value">value get from RevitAPI</param>
        /// <returns>Target value</returns>
        public static double CovertFromAPI(DisplayUnitType to, double value)
        {
            return value *= ImperialDutRatio(to);
        }

        /// <summary>
        /// Convert a value indicated by DisplayUnitType to the value used by RevitAPI
        /// </summary>
        /// <param name="value">Value to be converted</param>
        /// <param name="from">DisplayUnitType indicates the unit of the value to be converted</param>
        /// <returns>Target value</returns>
        public static double CovertToAPI(double value, DisplayUnitType from )
        {
            return value /= ImperialDutRatio(from);
        }

        /// <summary>
        /// Get ratio between value in RevitAPI and value to display indicated by DisplayUnitType
        /// </summary>
        /// <param name="dut">DisplayUnitType indicates display unit type</param>
        /// <returns>Ratio </returns>
        private static double ImperialDutRatio(DisplayUnitType dut) 
        {
            switch (dut)
            {
                case DisplayUnitType.DUT_DECIMAL_FEET: return 1;
                case DisplayUnitType.DUT_FEET_FRACTIONAL_INCHES: return 1;
                case DisplayUnitType.DUT_DECIMAL_INCHES: return 12;
                case DisplayUnitType.DUT_FRACTIONAL_INCHES: return 12;
                case DisplayUnitType.DUT_METERS: return 0.3048;
                case DisplayUnitType.DUT_CENTIMETERS: return 30.48;
                case DisplayUnitType.DUT_MILLIMETERS: return 304.8;
                case DisplayUnitType.DUT_METERS_CENTIMETERS: return 0.3048;
                case DisplayUnitType.DUT_SQUARE_METERS: return 0.092904;     // 1평방피트->1평방미터
                default: return 1;
            }
        }
        #endregion
    }
}