// Copyright 2014-2017 ClassicalSharp | Licensed under BSD-3
using System;
using System.Collections.Generic;
using System.IO;

namespace ClassicalSharp.Audio {

	public class Sound {
		public int SampleRate, BitsPerSample, Channels;
		public byte[] Data;
	}
	
	public class Soundboard {
		
		public byte[] Data;
		Dictionary<string, List<Sound>> allSounds = new Dictionary<string, List<Sound>>();
		Random rnd = new Random();
		
		const StringComparison comp = StringComparison.OrdinalIgnoreCase;
		public void Init(string group, string[] files) {
			for (int i = 0; i < files.Length; i++) {
				string name = Path.GetFileNameWithoutExtension(files[i]);
				if (!name.StartsWith(group, comp)) continue;
				
				// Convert dig_grass1.wav to grass
				name = Utils.ToLower(name.Substring(group.Length));
				name = name.Substring(0, name.Length - 1);
				
				List<Sound> sounds = null;
				if (!allSounds.TryGetValue(name, out sounds)) {
					sounds = new List<Sound>();
					allSounds[name] = sounds;
				}
				
				try {
					Sound snd = ReadWave(files[i]);
					sounds.Add(snd);
				} catch (Exception ex) {
					ErrorHandler.LogError("Soundboard.ReadWave()", ex);
				}
			}
		}
		
		public Sound PickRandomSound(SoundType type) {
			if (type == SoundType.None)  return null;
			string name = soundNames[(int)type];
			
			List<Sound> sounds;
			if (!allSounds.TryGetValue(name, out sounds)) return null;
			return sounds[rnd.Next(sounds.Count)];
		}
		
		Sound ReadWave(string file) {
			using (FileStream fs = File.OpenRead(file))
				using (BinaryReader r = new BinaryReader(fs))
			{
				CheckFourCC(r, "RIFF");
				r.ReadInt32(); // file size, but we don't care
				CheckFourCC(r, "WAVE");
				Sound snd = new Sound();
				
				CheckFourCC(r, "fmt ");
				int size = r.ReadInt32();
				if (r.ReadUInt16() != 1)
					throw new InvalidDataException("Only PCM audio is supported.");
				size -= 2;
				
				snd.Channels = r.ReadUInt16(); size -= 2;
				snd.SampleRate = r.ReadInt32(); size -= 4;
				r.ReadInt32(); r.ReadUInt16(); size -= 6;
				snd.BitsPerSample = r.ReadUInt16(); size -= 2;
				if (size > 0)
					fs.Seek(size, SeekOrigin.Current);
				
				CheckFourCC(r, "data");
				size = r.ReadInt32();
				byte[] data = r.ReadBytes(size);
				snd.Data = data;
				return snd;
			}
		}
		
		void CheckFourCC(BinaryReader r, string fourCC) {
			if (r.ReadByte() != (byte)fourCC[0] || r.ReadByte() != (byte)fourCC[1]
			   || r.ReadByte() != (byte)fourCC[2] || r.ReadByte() != (byte)fourCC[3])
				throw new InvalidDataException("Expected " + fourCC + " fourcc");
		}
		
		static string[] soundNames;
		static Soundboard() {
			soundNames = Enum.GetNames(typeof(SoundType));
			for (int i = 0; i < soundNames.Length; i++)
				soundNames[i] = soundNames[i].ToLower();
		}
	}
}