using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace AudioGainTestCS
{
    /// <summary>
    /// This application automatically adjusts the record level (input volume)
    /// as you use speech recognition. A mismatched record level can be 
    /// disastrous if you're going to use speech recognition. Note that for
    /// this demo, I'm using a DictationGrammar, but it works with any grammar.
    /// 
    /// The key is the WaveLibMixer.dll, which you can find on CodeProject. 
    /// This library lets you get and set levels and other controls associated with
    /// audio devices.
    /// 
    /// The SpeechRecognitionEngine raises an event on a regular interval passing in
    /// the volume at the input device. When you are not speaking this level is close
    /// to zero. When you are shouting it's closer to 99.
    /// 
    /// Given the volume of speech over time and the ability to control the record level
    /// dynamically, well... it's pretty darned easy to automatically adjust the
    /// microphone for the speaker.
    /// 
    /// Don't get caught without this nice little tool!
    /// 
    /// Carl
    /// </summary>
    public partial class MainWindow : Window
    {
        // -- Add a reference to System.Speech
        private System.Speech.Recognition.SpeechRecognitionEngine speech = new System.Speech.Recognition.SpeechRecognitionEngine();
    
        // -- Add a reference to WaveLibMixer.dll, which you can find at:
        //    http://www.codeproject.com/Articles/11695/Audio-Library-Part-I-Windows-Mixer-Control
        private WaveLib.AudioMixer.MixerLine audioLine;
    
        private Int32 peakLevel;

        public MainWindow()
        {
            InitializeComponent();
            this.Loaded+=new RoutedEventHandler(MainWindow_Loaded);
            speech.AudioLevelUpdated+=new EventHandler<System.Speech.Recognition.AudioLevelUpdatedEventArgs>(speech_AudioLevelUpdated);
            speech.SpeechRecognized+=new EventHandler<System.Speech.Recognition.SpeechRecognizedEventArgs>(speech_SpeechRecognized);
            Slider1.ValueChanged += new RoutedPropertyChangedEventHandler<double>(Slider1_ValueChanged);
        }

   
        private void MainWindow_Loaded(object sender, System.Windows.RoutedEventArgs e) {
            // -- Create a new input mixer object to control an audio input device
            WaveLib.AudioMixer.Mixer audioMixer = new WaveLib.AudioMixer.Mixer(WaveLib.AudioMixer.MixerType.Recording);
            // -- Open the default recording device
            audioMixer.DeviceId = audioMixer.DeviceIdDefault;
            // -- Does the mixer have lines? It ought to...
            if ((audioMixer.Lines.Count > 0)) {
                // -- Select the first line, which is usually the Master Volume
                audioLine = audioMixer.Lines[0];
                // -- Does that line have a Volume control? It really ought to...
                if (audioLine.ContainsVolume) {
                    // -- Set the input volume (record level) to 50%
                    audioLine.Volume = audioLine.VolumeMax / 2;
                    // -- Set up the slider min/max and value based on the volume
                    Slider1.Minimum = audioLine.VolumeMin;
                    Slider1.Maximum = audioLine.VolumeMax;
                    Slider1.Value = audioLine.Volume;
                }
                else {
                    // -- Jeez... lame.
                    Slider1.IsEnabled = false;
                }
            }

            // -- The progress bar is used as an audio meter. 
            //    The speech recognition engine gives us a volume value from 0 to 99.
            //    So we set the ProgressBar min and max accordingly
            ProgressBar1.Minimum = 0;
            ProgressBar1.Maximum = 99;
            // -- Set the speech synthesizer to use the default audio input device
            speech.SetInputToDefaultAudioDevice();
            // -- Tell the speech synthesizer to recognize plain speech, not commands.
            speech.LoadGrammar(new System.Speech.Recognition.DictationGrammar());
            // -- Start recognizing
            speech.RecognizeAsync(System.Speech.Recognition.RecognizeMode.Multiple);
        }
    
        private void speech_AudioLevelUpdated(object sender, System.Speech.Recognition.AudioLevelUpdatedEventArgs e) {
            // -- This is an event handler that happens on a regular interval.
            //    The e.AudioLevel is a value from 0 to 99 representing the 
            //    volume of the talker's voice in almost real-time.
            // -- Setting the progressbar value to this level creates an audio meter.
            ProgressBar1.Value = e.AudioLevel;
            // -- If the volume is over 70% loud, knock the slider down a bit
            //    which will in turn drop the record level
            if ((e.AudioLevel > 70)) {
                Slider1.Value -= 1000;
            }
            // -- Keep track of the peak level for this sentence.
            if ((e.AudioLevel > peakLevel)) {
                peakLevel = e.AudioLevel;
            }
        }
    
        private void speech_SpeechRecognized(object sender, System.Speech.Recognition.SpeechRecognizedEventArgs e) {
            // -- This event handler fires after the talker speaks a sentence.
            //    e.Result.Text contains the text that they have spoken.
            // -- In this case, I'm capitalizing the sentence, adding a period at the end, 
            //    and displaying the text in a text box.
            TextBox1.Text = (e.Result.Text.Substring(0, 1).ToUpper() 
                        + (e.Result.Text.Substring(1) + "."));
            if ((peakLevel < 20)) {
                Slider1.Value += 3000;
            }
            // -- Reset the peak level
            peakLevel = 0;
        }

        void Slider1_ValueChanged(object sender, RoutedPropertyChangedEventArgs<double> e)
        {
            // -- When the value of the slider changes, 
            //    set the audio input volume (the record level) to that value.
            //    This can happen when the user moves the slider, or some code
            //    sets the Slider1.Value 
            if (audioLine != null)
            {
                audioLine.Volume = (int)Slider1.Value;
            }
        }    
    }
}