// --------------------------------------------------------------------------------------------------------------------
// <copyright file="HandBrakeUnitConversionHelpers.cs" company="HandBrake Project (https://handbrake.fr)">
//   This file is part of the HandBrake source code - It may be used under the terms of the GNU General Public License.
// </copyright>
// <summary>
//   Defines the HandrakeUnitConversionHelpers type.
// </summary>
// --------------------------------------------------------------------------------------------------------------------

namespace HandBrake.Interop.Interop
{
    using System;
    using System.Collections.Generic;
    using System.Globalization;
    using System.Runtime.InteropServices;

    using HandBrake.Interop.Interop.HbLib;
    using HandBrake.Interop.Interop.Helpers;
    using HandBrake.Interop.Interop.Interfaces.Model;
    using HandBrake.Interop.Interop.Interfaces.Model.Encoders;

    /// <summary>
    /// Converters for various encoding values.
    /// </summary>
    public static class HandBrakeUnitConversionHelpers
    {
        private static readonly Dictionary<double, int> VideoRates;

        /// <summary>
        /// Initializes static members of the HandBrakeUnitConversionHelpers class.
        /// </summary>
        static HandBrakeUnitConversionHelpers()
        {
            if (!HandBrakeUtils.IsInitialised())
            {
                throw new Exception("Please Initialise with HandBrakeUtils.EnsureGlobalInit before using!");
            }

            VideoRates = new Dictionary<double, int>();
            foreach (var framerate in HandBrakeEncoderHelpers.VideoFramerates)
            {
                VideoRates.Add(double.Parse(framerate.Name, CultureInfo.InvariantCulture), framerate.Rate);
            }
        }

        /// <summary>
        /// Convert Framerate to Video Rates
        /// </summary>
        /// <param name="framerate">
        /// The framerate.
        /// </param>
        /// <returns>
        /// The vrate if a valid framerate is passed in.
        /// </returns>
        /// <exception cref="ArgumentException">
        /// Thrown when framerate is invalid.
        /// </exception>
        public static int FramerateToVrate(double framerate)
        {
            if (!VideoRates.ContainsKey(framerate))
            {
                throw new ArgumentException("Framerate not recognized.", "framerate");
            }

            return VideoRates[framerate];
        }
        
        public static int GetFramerateFromName(string name)
        {
            IntPtr frameratePrt = Marshal.StringToHGlobalAnsi(name);

            return HBFunctions.hb_video_framerate_get_from_name(frameratePrt);
        }

        /// <summary>
        /// Converts the PTS amount to a TimeSpan. There may be some accuracy loss here.
        /// </summary>
        /// <param name="pts">
        /// The PTS to convert.
        /// </param>
        /// <returns>
        /// The timespan for it.
        /// </returns>
        public static TimeSpan PtsToTimeSpan(ulong pts)
        {
            return TimeSpan.FromTicks((long)((pts * 10000000) / 90000));
        }

        /// <summary>
        /// Converts the PTS amount to seconds.
        /// </summary>
        /// <param name="pts">
        /// The PTS to convert.
        /// </param>
        /// <returns>
        /// The corresponding number of seconds.
        /// </returns>
        public static double PtsToSeconds(ulong pts)
        {
            return (double)pts / 90000;
        }

        /// <summary>
        /// Converts a native HB encoder structure to an Encoder model.
        /// </summary>
        /// <param name="encoder">
        /// The structure to convert.
        /// </param>
        /// <returns>
        /// The converted model.
        /// </returns>
        internal static HBVideoEncoder NativeToVideoEncoder(hb_encoder_s encoder)
        {
            return new HBVideoEncoder(encoder.muxers, encoder.name, encoder.codec, encoder.short_name);
        }

        /// <summary>
        /// Converts a native HB encoder structure to an Encoder model.
        /// </summary>
        /// <param name="encoder">
        /// The structure to convert.
        /// </param>
        /// <returns>
        /// The converted model.
        /// </returns>
        internal static HBAudioEncoder NativeToAudioEncoder(hb_encoder_s encoder)
        {
            var result = new HBAudioEncoder(
                encoder.muxers,
                HandBrakeEncoderHelpers.GetAudioCompressionLimits(encoder.codec),
                HBFunctions.hb_audio_compression_get_default((uint)encoder.codec),
                HBFunctions.hb_audio_quality_get_default((uint)encoder.codec),
                encoder.name,
                encoder.codec,
                HandBrakeEncoderHelpers.GetAudioQualityLimits(encoder.codec),
                encoder.short_name);

            return result;
        }

        /// <summary>
        /// Converts a native HB rate structure to an HBRate object.
        /// </summary>
        /// <param name="rate">
        /// The structure to convert.
        /// </param>
        /// <returns>
        /// The converted rate object.
        /// </returns>
        internal static HBRate NativeToRate(hb_rate_s rate)
        {
            return new HBRate(rate.name, rate.rate);
        }

        /// <summary>
        /// Converts a native HB mixdown structure to a Mixdown model.
        /// </summary>
        /// <param name="mixdown">
        /// The structure to convert.
        /// </param>
        /// <returns>
        /// The converted model.
        /// </returns>
        internal static HBMixdown NativeToMixdown(hb_mixdown_s mixdown)
        {
            return new HBMixdown(mixdown.name, mixdown.amixdown, mixdown.short_name);
        }

        /// <summary>
        /// Converts a native HB container structure into an HBContainer object.
        /// </summary>
        /// <param name="container">
        /// The structure to convert.
        /// </param>
        /// <returns>
        /// The converted structure.
        /// </returns>
        internal static HBContainer NativeToContainer(hb_container_s container)
        {
            return new HBContainer(container.default_extension, container.name, container.format, container.short_name);
        }

        /// <summary>
        /// Converts a native language structure to a Language object.
        /// </summary>
        /// <param name="language">
        /// The structure to convert.
        /// </param>
        /// <returns>
        /// The converted structure.
        /// </returns>
        internal static Language NativeToLanguage(iso639_lang_t language)
        {
            string englishName = InteropUtilities.ToStringFromUtf8Ptr(language.eng_name);
            string nativeName = InteropUtilities.ToStringFromUtf8Ptr(language.native_name);
            return new Language(englishName, nativeName, language.iso639_2);
        }
    }
}