--  Programmed by Jedidiah Barber
--  Released into the public domain


with

    Ada.Numerics.Long_Elementary_Functions,
    Ada.Text_IO,
    Interfaces,
    Portaudio.Streams;


procedure Sine_Block is


    package Num renames Ada.Numerics;
    package Elem renames Ada.Numerics.Long_Elementary_Functions;
    package TIO renames Ada.Text_IO;
    package Paud renames Portaudio;
    package Pstm renames Portaudio.Streams;


    Play_Time   : constant Paud.Time         := 5.0;
    Sample_Rate : constant Paud.Hertz        := 44100.0;
    Channels    : constant Natural           := 2;
    Per_Buffer  : constant Pstm.Frame_Amount := 1024;

    --  Note how this array specifies the bounds in the initial value rather than the type.
    --  This is important because otherwise the aliasing would cause subtype mismatch errors.
    Sample_Array : aliased Pstm.Float_32_Array := (1 .. Natural (Per_Buffer) * Channels => 0.0);
    Sample_Buffer : Pstm.Buffer := Pstm.Wrap (Sample_Array, Per_Buffer, Channels);

    type Table_Index is mod 200;
    Sine_Table : array (Table_Index) of Interfaces.IEEE_Float_32;

    Left_Phase, Right_Phase : Table_Index := 0;
    Left_Increment          : Table_Index := 1;
    Right_Increment         : Table_Index := 3;

    Buffer_Count : Natural;

    Sine_Stream : Pstm.Audio_Stream;


begin


    TIO.Put_Line ("PortAudio Test: output sine wave. " &
        "Sample Rate = " & Paud.Hertz_Image (Sample_Rate) & ", " &
        "Buffer Size =" & Pstm.Frame_Amount'Image (Per_Buffer));

    for Index in Table_Index loop
        Sine_Table (Index) := Interfaces.IEEE_Float_32
            (Elem.Sin (Long_Float (Index) / Long_Float (Table_Index'Last_Valid) * Num.Pi * 2.0));
    end loop;

    Sine_Stream.Open_Default_Blocking
       (Input_Channels  => 0,
        Output_Channels => Channels,
        Format          => Pstm.Float_32_Format,
        Sample_Rate     => Sample_Rate,
        Buffer_Frames   => Per_Buffer);

    TIO.Put_Line ("Play 3 times, higher each time.");

    for Round in Integer range 1 .. 3 loop
        TIO.Put_Line ("Play for " & Paud.Image (Play_Time) & " seconds.");

        Sine_Stream.Start;

        Buffer_Count := Integer (Play_Time) * Integer (Sample_Rate) / Integer (Per_Buffer);
        for Fill in Integer range 1 .. Buffer_Count loop

            for Index in Pstm.Frame_Amount range 1 .. Per_Buffer loop
                Sample_Buffer.Put (Index, 1, Sine_Table (Left_Phase));
                Sample_Buffer.Put (Index, 2, Sine_Table (Right_Phase));
                Left_Phase := Left_Phase + Left_Increment;
                Right_Phase := Right_Phase + Right_Increment;
            end loop;

            Sine_Stream.Write_Blocking (Sample_Buffer, Per_Buffer);

        end loop;

        Sine_Stream.Stop;

        Left_Increment := Left_Increment + 1;
        Right_Increment := Right_Increment + 1;

        delay 1.0;
    end loop;

    Sine_Stream.Close;

    TIO.Put_Line ("Test finished.");


end Sine_Block;