// Copyright (c) 2021 Weird Constructor <weirdconstructor@gmail.com>
// This file is a part of HexoDSP. Released under GPL-3.0-or-later.
// See README.md and COPYING for details.

use crate::nodes::{NodeAudioContext, NodeExecContext};
use crate::dsp::{NodeId, SAtom, ProcBuf, DspNode, LedPhaseVals, NodeContext};

/// A simple amplifier
#[derive(Debug, Clone)]
pub struct FbWr {
    fb_index:   u8,
}

impl FbWr {
    pub fn new(nid: &NodeId) -> Self {
        Self {
            fb_index: nid.instance() as u8,
        }
    }
    pub const inp : &'static str =
        "FbWr inp\nSignal input\nRange: (-1..1)\n";

    pub const DESC : &'static str =
"Feedback Delay Writer\n\n\
HexoSynth does not allow direct feedback cycles in it's graph.\n\
To make feedback possible anyways the 'FbWr' and 'FbRd' nodes are provided.\n\
This node allows you to write a signal into the corresponsing signal delay buffer.\n\
Use 'FbRd' for using the signal.\n\
The delay is 3.14ms.";
    pub const HELP : &'static str =
r#"Feedback Delay Writer

HexoSynth does not allow direct feedback cycles in it's graph.
To make feedback possible anyways the 'FbWr' and 'FbRd' nodes are provided.
This node allows you to send a signal into the corresponsing 'FbWr' signal
delay.

The instance id of the node defines which FbWr and FbRd are connected.
That means 'FbRd 0' is connected to the corresponding 'FbWr 0'. You can use
the signal multiple times by connecting the 'FbRd 0' 'sig' port to multiple
inputs.

The delay is always 3.14ms, regardless of the sampling rate the synthesizer
is running at.
"#;
}

impl DspNode for FbWr {
    fn outputs() -> usize { 0 }

    fn set_sample_rate(&mut self, _srate: f32) { }
    fn reset(&mut self) { }

    #[inline]
    fn process<T: NodeAudioContext>(
        &mut self, ctx: &mut T, ectx: &mut NodeExecContext,
        _nctx: &NodeContext,
        _atoms: &[SAtom], inputs: &[ProcBuf],
        _outputs: &mut [ProcBuf], ctx_vals: LedPhaseVals)
    {
        use crate::dsp::{inp};

        let inp  = inp::FbWr::inp(inputs);

        for frame in 0..ctx.nframes() {
            ectx.feedback_delay_buffers[self.fb_index as usize]
                .write(inp.read(frame));
        }

        ctx_vals[0].set(inp.read(ctx.nframes() - 1));
    }
}


/// A simple amplifier
#[derive(Debug, Clone)]
pub struct FbRd {
    fb_index:   u8,
}

impl FbRd {
    pub fn new(nid: &NodeId) -> Self {
        Self {
            fb_index: nid.instance() as u8,
        }
    }
    pub const atv : &'static str =
        "FbRd atv\nAttenuate or invert input.\n\
         Use this to adjust the feedback amount.\nRange: (-1..1)\n";
    pub const sig : &'static str =
        "FbRd sig\nFeedback signal output.\nRange: (-1..1)\n";

    pub const DESC : &'static str =
"Feedback Delay Reader\n\n\
HexoSynth does not allow direct feedback cycles in it's graph.\n\
To make feedback possible anyways the 'FbWr' and 'FbRd' nodes are provided.\n\
This node allows you to tap into the corresponsing 'FbWr' signal delay \
for feedback.\n\
The delay is 3.14ms.";
    pub const HELP : &'static str =
r#"Feedback Delay Reader

HexoSynth does not allow direct feedback cycles in it's graph.
To make feedback possible anyways the 'FbWr' and 'FbRd' nodes are provided.
This node allows you to tap into the corresponsing 'FbWr' signal delay for
feedback.

The instance id of the node defines which FbWr and FbRd are connected.
That means 'FbRd 0' is connected to the corresponding 'FbWr 0'. You can use
the signal multiple times by connecting the 'FbRd 0' 'sig' port to multiple
inputs.

The delay is always 3.14ms, regardless of the sampling rate the synthesizer
is running at.

The 'atv' parameter is a convenience parameter to allow attenuating or
even inverting the signal.
"#;
}

impl DspNode for FbRd {
    fn outputs() -> usize { 1 }

    fn set_sample_rate(&mut self, _srate: f32) { }
    fn reset(&mut self) { }

    #[inline]
    fn process<T: NodeAudioContext>(
        &mut self, ctx: &mut T, ectx: &mut NodeExecContext,
        _nctx: &NodeContext,
        _atoms: &[SAtom], inputs: &[ProcBuf],
        outputs: &mut [ProcBuf], ctx_vals: LedPhaseVals)
    {
        use crate::dsp::{out, inp, denorm};

        let atv  = inp::FbRd::atv(inputs);
        let sig  = out::FbRd::sig(outputs);

        let mut last_val = 0.0;
        for frame in 0..ctx.nframes() {
            last_val =
                ectx.feedback_delay_buffers[self.fb_index as usize]
                    .read();
            last_val *= denorm::FbRd::atv(atv, frame);
            sig.write(frame, last_val);
        }

        ctx_vals[0].set(last_val);
    }
}
