using Microsoft.Xna.Framework.Audio;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace RPGamesEngine.src {
    class SoundEngine {

        public static Dictionary<string, SoundEffect> sfx = new Dictionary<string, SoundEffect>();

        public static Dictionary<string, SoundEffect> music = new Dictionary<string, SoundEffect>();
        public static Dictionary<string, SoundEffectInstance> musicInstances = new Dictionary<string, SoundEffectInstance>();
        public static Dictionary<string, float> fadingMusic = new Dictionary<string, float>();

        private static float sfxVolume = 1;
        private static float musicVolume = 1;

        public static void addSoundEffect(string name, string path) {
            name = name.ToLower();

            FileStream fs = new FileStream(path, FileMode.Open);
            SoundEffect newSound = SoundEffect.FromStream(fs);
            sfx.Add(name, newSound);
            fs.Dispose();
        }

        public static void addMusic(string name, string path) {
            name = name.ToLower();

            FileStream fs = new FileStream(path, FileMode.Open);
            SoundEffect newMusic = SoundEffect.FromStream(fs);
            music.Add(name, newMusic);
            fs.Dispose();
        }

        public static void playSound(string name, float volume = 1) {
            name = name.ToLower();

            SoundEffect effect = sfx[name];
            SoundEffectInstance effectInstance = effect.CreateInstance();
            effectInstance.Volume = volume * sfxVolume;
            effectInstance.Play();
        }

        public static void playMusic(string name, float volume = 1, bool startFromBeginning = true, bool loop = true, float fade = 0F) {
            name = name.ToLower();

            // prevent crash from music that doesn't exist
            if (!music.ContainsKey(name)) {
                Console.Out.WriteLine("Music not Found: " + name);
                return;
            }

            // either make new effect instance or grab pre - existing one for music
            SoundEffectInstance effectInstance;
            if (musicInstances.ContainsKey(name)) {
                // grab music from pre - existing instances
                effectInstance = musicInstances[name];

                // apply settings
                effectInstance.Volume = volume * musicVolume;
                effectInstance.IsLooped = loop;

                // continue pre - existing music unless otherwise specified
                if (!startFromBeginning) effectInstance.Resume();
                else { effectInstance.Play(); }
            }
            else {
                // add music to pre - existing instances
                SoundEffect effect = music[name];
                effectInstance = effect.CreateInstance();
                musicInstances.Add(name, effectInstance);

                // apply settings and play from beginning
                effectInstance.Volume = volume * musicVolume;
                effectInstance.IsLooped = loop;
                effectInstance.Play();
            }

            // process fade capabilities
            if (fade != 0F) {
                startMusicFade(name, fade);
            }
        }

        // start or change the fade of a song
        public static void startMusicFade(string name, float rate = 1.0F) {
            name = name.ToLower();

            // prevent crash from music that doesn't exist
            if (!music.ContainsKey(name)) {
                Console.Out.WriteLine("Music not Found: " + name);
                return;
            }
            // prevent crash from music instance that doesn't exist
            if (!musicInstances.ContainsKey(name)) {
                Console.Out.WriteLine("Music instance not Found: " + name);
                return;
            }

            if (rate > 0 && musicVolume == 0) {
                musicInstances[name].Volume = 0;
                musicInstances[name].Resume();
                return;
            }

            float actualRate = rate / 60F; // convert the rate (amount per second) to the rate per tick

            if (fadingMusic.ContainsKey(name)) fadingMusic.Remove(name);
            fadingMusic.Add(name, actualRate);
        }

        public static void continueMusicFade() {

            // loop throgh each music track being faded
            List<String> toRemove = new List<String>();

            foreach (KeyValuePair<string, float> entry in fadingMusic) {
                float newVolume = musicInstances[entry.Key].Volume + entry.Value * musicVolume;

                // stop fading if rade is finished
                if (newVolume < 0F) {
                    musicInstances[entry.Key].Volume = 0F;
                    toRemove.Add(entry.Key);

                    // pause music that is at 0% volume
                    musicInstances[entry.Key].Pause();
                }
                else if (newVolume > 1F * musicVolume) {
                    musicInstances[entry.Key].Volume = 1F * musicVolume;
                    toRemove.Add(entry.Key);
                }
                // normal change of volume
                else {
                    musicInstances[entry.Key].Volume = newVolume;
                }

            }

            // finish removal of completed fades
            foreach (string name in toRemove) { fadingMusic.Remove(name); }
        }

        public static void updateSFXVolume(float newVolume) {
            if (newVolume < 0 || newVolume > 1) return;

            sfxVolume = newVolume;
        }
        public static void updateMusicVolume(float newVolume) {
            if (newVolume < 0 || newVolume > 1) return;

            foreach (KeyValuePair<string, SoundEffectInstance> entry in musicInstances) {
                if (fadingMusic.Keys.Contains(entry.Key)) continue;
                musicInstances[entry.Key].Volume = newVolume;
            }
            musicVolume = newVolume;
        }

        // getters
        public static float getSFXVolume() { return sfxVolume; }
        public static float getMusicVolume() { return musicVolume; }
    }
}