// Copyright (c) 2021 Weird Constructor <weirdconstructor@gmail.com>
// This is a part of HexoDSP. Released under (A)GPLv3 or any later.
// See README.md and COPYING for details.

#[allow(non_upper_case_globals)]
mod node_amp;
#[allow(non_upper_case_globals)]
mod node_sin;
#[allow(non_upper_case_globals)]
mod node_out;
#[allow(non_upper_case_globals)]
mod node_test;
#[allow(non_upper_case_globals)]
mod node_tseq;
#[allow(non_upper_case_globals)]
mod node_sampl;

pub mod tracker;
mod satom;
pub mod helpers;

use crate::nodes::NodeAudioContext;
use crate::nodes::NodeExecContext;

use crate::util::AtomicFloat;
use std::sync::Arc;

pub type LedPhaseVals<'a> = &'a [Arc<AtomicFloat>];

pub use satom::*;

use node_amp::Amp;
use node_sin::Sin;
use node_out::Out;
use node_test::Test;
use node_tseq::TSeq;
use node_sampl::Sampl;

pub const MIDI_MAX_FREQ : f32 = 13289.75;

pub const MAX_BLOCK_SIZE : usize = 128;

/// This trait is an interface between the graph functions
/// and the AtomDataModel of the UI.
pub trait GraphAtomData {
    fn get(&self, node_id: usize, param_idx: u32) -> Option<SAtom>;
    fn get_denorm(&self, node_id: usize, param_idx: u32) -> f32;
}

pub type GraphFun = Box<dyn FnMut(&dyn GraphAtomData, bool, f32) -> f32>;

/// This trait represents a DspNode for the [crate::matrix::Matrix]
pub trait DspNode {
    /// Number of outputs this node has.
    fn outputs() -> usize;

    /// Updates the sample rate for the node.
    fn set_sample_rate(&mut self, _srate: f32);

    /// Reset any internal state of the node.
    fn reset(&mut self);

    /// The code DSP function.
    ///
    /// * `ctx` is the audio context, which informs the node about
    /// the number of samples to process. It also provides input/output
    /// ports for the in/out nodes.
    /// * `ectx` is the execution context, which provides global stuff
    /// for all nodes to potentially use. For instance it's used
    /// by the `FbWr` and `FbRd` nodes to share an audio buffer.
    /// * `atoms` are un-smoothed parameters. they can hold integer settings,
    /// samples or even strings.
    /// * `params` are smoother paramters, those who usually have a knob
    /// associated with them.
    /// * `inputs` contain all the possible inputs. In contrast to `params`
    /// these inputs might be overwritten by outputs of other nodes.
    /// * `outputs` are the output buffers of this node.
    fn process<T: NodeAudioContext>(
        &mut self, ctx: &mut T, ectx: &mut NodeExecContext,
        atoms: &[SAtom], params: &[ProcBuf], inputs: &[ProcBuf],
        outputs: &mut [ProcBuf], led: LedPhaseVals);

    /// A function factory for generating a graph for the generic node UI.
    fn graph_fun() -> Option<GraphFun> { None }
}

/// A processing buffer with the exact right maximum size.
#[derive(Clone, Copy)]
pub struct ProcBuf(*mut [f32; MAX_BLOCK_SIZE]);

impl ProcBuf {
    pub fn new() -> Self {
        ProcBuf(Box::into_raw(Box::new([0.0; MAX_BLOCK_SIZE])))
    }

    pub fn null() -> Self {
        ProcBuf(std::ptr::null_mut())
    }
}

impl crate::monitor::MonitorSource for &ProcBuf {
    fn copy_to(&self, len: usize, slice: &mut [f32]) {
        unsafe { slice.copy_from_slice(&(*self.0)[0..len]) }
    }
}

unsafe impl Send for ProcBuf {}
//unsafe impl Sync for HexoSynthShared {}

impl ProcBuf {
    #[inline]
    pub fn write(&mut self, idx: usize, v: f32) {
        unsafe {
            (*self.0)[idx] = v;
        }
    }

    #[inline]
    pub fn write_from(&mut self, slice: &[f32]) {
        unsafe {
            (*self.0)[0..slice.len()].copy_from_slice(slice);
        }
    }

    #[inline]
    pub fn read(&self, idx: usize) -> f32 { unsafe { (*self.0)[idx] } }

    #[inline]
    pub fn fill(&mut self, v: f32) {
        unsafe {
            (*self.0).fill(v);
        }
    }

    pub fn free(&self) {
        if !self.0.is_null() {
            drop(unsafe { Box::from_raw(self.0) });
        }
    }
}

impl std::fmt::Debug for ProcBuf {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        unsafe {
            write!(f, "ProcBuf(")?;
            if self.0.is_null() {
                write!(f, "NULL ")?;
            } else {
                for i in 0..MAX_BLOCK_SIZE {
                    write!(f, "{:5.4} ", (*self.0)[i])?;
                }
            }
            write!(f, ")")
        }
    }
}

impl std::fmt::Display for ProcBuf {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        unsafe {
            write!(f, "ProcBuf(0: {})", (*self.0)[0])
        }
    }
}

//#[derive(Debug, Clone, Copy)]
//enum UIParamDesc {
//    Knob    { width: usize, prec: usize, unit: &'static str },
//    Setting { labels: &'static [&'static str], unit: &'static str },
//}


#[derive(Debug, Clone, Copy, PartialOrd, PartialEq)]
pub enum UIType {
    Generic,
    LfoA,
    EnvA,
    OscA,
}

#[derive(Debug, Clone, Copy, PartialOrd, PartialEq)]
pub enum UICategory {
    None,
    Osc,
    Mod,
    NtoM,
    Signal,
    CV,
    IOUtil,
}

macro_rules! n_id { ($x: expr) => { $x } }
macro_rules! d_id { ($x: expr) => { $x } }

macro_rules! define_lin {
    ($n_id: ident $d_id: ident $min: expr, $max: expr) => {
        macro_rules! $n_id { ($x: expr) => {
            (($x - $min) / ($max - $min) as f32).abs()
        } }

        macro_rules! $d_id { ($x: expr) => {
            $min * (1.0 - $x) + $max * $x
        } }
    }
}

macro_rules! define_exp {
    ($n_id: ident $d_id: ident $min: expr, $max: expr) => {
        macro_rules! $n_id { ($x: expr) => {
            (($x - $min) / ($max - $min) as f32).abs().sqrt()
        } }
        macro_rules! $d_id { ($x: expr) => {
            { let x : f32 = $x * $x; $min * (1.0 - x) + $max * x }
        } }
    }
}

macro_rules! define_exp4 {
    ($n_id: ident $d_id: ident $min: expr, $max: expr) => {
        macro_rules! $n_id { ($x: expr) => {
            (($x - $min) / ($max - $min)).abs().sqrt().sqrt()
        } }
        macro_rules! $d_id { ($x: expr) => {
            { let x : f32 = $x * $x * $x * $x; $min * (1.0 - x) + $max * x }
        } }
    }
}

macro_rules! n_pit { ($x: expr) => {
    ((($x as f32).max(0.01) / 440.0).log2() / 10.0)
//    ((($x as f32).max(0.01) / 440.0).log2() / 5.0)
} }

macro_rules! d_pit { ($x: expr) => {
    {
        let note : f32 = ($x as f32) * 10.0;
        440.0 * (2.0_f32).powf(note)
    }
} }

//          norm-fun      denorm-min
//                 denorm-fun  denorm-max
define_exp!{n_gain d_gain 0.0, 2.0}
define_exp!{n_att  d_att  0.0, 1.0}

define_exp!{n_declick d_declick 0.0, 50.0}

// A note about the input-indicies:
//
// Atoms and Input parameters share the same global ID space
// because thats how the client of the Matrix API needs to refer to
// them. Beyond the Matrix API the atom data is actually split apart
// from the parameters, because they are not smoothed.
//
// The index there only matters for addressing the atoms in the global atom vector.
//
// But the actually second index here is for referring to the atom index
// relative to the absolute count of atom data a Node has.
// It is used by the [Matrix] to get the global ParamId for the atom data
// when iterating through the atoms of a Node and initializes the default data
// for new nodes.
macro_rules! node_list {
    ($inmacro: ident) => {
        $inmacro!{
            nop => Nop,
            amp => Amp UIType::Generic UICategory::Signal
             // node_param_idx
             //   name             denorm_fun norm norm denorm
             //         norm_fun              min  max  default
               (0 inp   n_id       d_id      -1.0, 1.0, 0.0)
               (1 gain  n_gain     d_gain     0.0, 1.0, 1.0)
               (2 att   n_att      d_att      0.0, 1.0, 1.0)
               {3 0 neg_att setting(1) 0  1}
               [0 sig],
            tseq => TSeq UIType::Generic UICategory::CV
               (0 clock n_id       d_id       0.0, 1.0, 0.0)
               {1 0 cmode setting(1) 0  2}
               [0 trk1]
               [1 trk2]
               [2 trk3]
               [3 trk4]
               [4 trk5]
               [5 trk6],
            sampl => Sampl UIType::Generic UICategory::Osc
               (0 freq  n_pit      d_pit     -1.0, 1.0, 440.0)
               (1 trig  n_id       n_id      -1.0, 1.0, 0.0)
               (2 offs  n_id       n_id       0.0, 1.0, 0.0)
               (3 len   n_id       n_id       0.0, 1.0, 1.0)
               (4 dcms  n_declick  d_declick  0.0, 1.0, 3.14)
               {5 0 sample audio_unloaded("") 0 0}
               {6 1 pmode  setting(0)         0 1}
               {7 2 dclick setting(0)         0 1}
               [0 sig],
            sin => Sin UIType::Generic UICategory::Osc
               (0 freq  n_pit      d_pit     -1.0, 1.0, 440.0)
               [0 sig],
            out => Out UIType::Generic UICategory::IOUtil
               (0  ch1   n_id      d_id      -1.0, 1.0, 0.0)
               (1  ch2   n_id      d_id      -1.0, 1.0, 0.0)
             // node_param_idx
             // | atom_idx
             // | | name constructor min max
             // | | |    |       defa/lt_/value
             // | | |    |       |  |   /
               {2 0 mono setting(0) 0  1},
            test => Test UIType::Generic UICategory::IOUtil
               (0 f     n_id      d_id       0.0, 1.0, 0.5)
               {1 0 s    setting(0) 0  10},
        }
    }
}

#[allow(non_snake_case)]
#[allow(non_upper_case_globals)]
pub mod labels {
    pub mod Test {
        pub const s : [&'static str; 11] = [
            "Zero", "One", "Two", "Three", "Four",
            "Five", "Six", "Seven", "Eigth", "Nine", "Ten"
        ];
    }

    pub mod Out {
        pub const mono : [&'static str; 2] = ["Mono", "Stereo"];
    }

    pub mod Amp {
        pub const neg_att : [&'static str; 2] = ["Allow", "Clip"];
    }

    pub mod TSeq {
        pub const cmode : [&'static str; 3] = ["RowT", "PatT", "Phase"];
    }

    pub mod Sampl {
        pub const sample : [&'static str; 0] = [];
        pub const dclick : [&'static str; 2] = ["Off", "On"];
        pub const pmode  : [&'static str; 2] = ["Loop", "OneShot"];
    }
}

impl UICategory {
    #[allow(unused_assignments)]
    pub fn get_node_ids<F: FnMut(NodeId)>(&self, mut skip: usize, mut fun: F) {
        macro_rules! make_cat_lister {
            ($s1: ident => $v1: ident,
                $($str: ident => $variant: ident
                    UIType:: $gui_type: ident
                    UICategory:: $ui_cat: ident
                    $(($in_idx: literal $para: ident
                       $n_fun: ident $d_fun: ident
                       $min: expr, $max: expr, $def: expr))*
                    $({$in_at_idx: literal $at_idx: literal $atom: ident
                       $at_fun: ident ($at_init: tt)
                       $amin: literal $amax: literal})*
                    $([$out_idx: literal $out: ident])*
                    ,)+
            ) => {
                $(if UICategory::$ui_cat == *self {
                    if skip == 0 {
                        fun(NodeId::$variant(0));
                    } else {
                        skip -= 1
                    }
                })+
            }
        }

        node_list!{make_cat_lister};
    }
}

macro_rules! make_node_info_enum {
    ($s1: ident => $v1: ident,
        $($str: ident => $variant: ident
            UIType:: $gui_type: ident
            UICategory:: $ui_cat: ident
            $(($in_idx: literal $para: ident
               $n_fun: ident $d_fun: ident
               $min: expr, $max: expr, $def: expr))*
            $({$in_at_idx: literal $at_idx: literal $atom: ident
               $at_fun: ident ($at_init: expr)
               $amin: literal $amax: literal})*
            $([$out_idx: literal $out: ident])*
            ,)+
    ) => {
        /// Holds information about the node type that was allocated.
        /// It stores the names of inputs, output and atoms for uniform
        /// access.
        ///
        /// The [crate::NodeConfigurator] allocates and holds instances
        /// of this type for access by [NodeId].
        /// See also [crate::NodeConfigurator::node_by_id] and
        /// [crate::Matrix::info_for].
        #[derive(Debug, Clone)]
        pub enum NodeInfo {
            $v1,
            $($variant((NodeId, crate::dsp::ni::$variant))),+
        }

        impl NodeInfo {
            /// Allocates a new [NodeInfo] from a [NodeId].
            /// Usually you access [NodeInfo] in the UI thread via
            /// [crate::NodeConfigurator::node_by_id]
            /// or [crate::Matrix::info_for].
            pub fn from_node_id(nid: NodeId) -> NodeInfo {
                match nid {
                    NodeId::$v1           => NodeInfo::$v1,
                    $(NodeId::$variant(_) => NodeInfo::$variant((nid, crate::dsp::ni::$variant::new()))),+
                }
            }
        }

        /// Refers to an input paramter or atom of a specific
        /// [Node] referred to by a [NodeId].
        ///
        /// To obtain a [ParamId] you use one of these:
        /// * [NodeId::atom_param_by_idx]
        /// * [NodeId::inp_param_by_idx]
        /// * [NodeId::param_by_idx]
        /// * [NodeId::inp_param]
        ///
        /// To obtain an input and output index for a port use:
        /// * [NodeId::inp]
        /// * [NodeId::out]
        ///
        ///```
        /// use hexodsp::*;
        /// let freq_param = NodeId::Sin(2).inp_param("freq").unwrap();
        ///
        /// assert!(!freq_param.is_atom());
        ///
        /// // Access the min/max values of this paramter:
        /// assert_eq!(freq_param.param_min_max().unwrap(), (-1.0, 1.0));
        ///
        /// // Access the default value:
        /// assert_eq!(freq_param.as_atom_def().f(), 0.0);
        ///
        /// // Normalize a value (convert frequency to the 0.0 to 1.0 range)
        /// assert_eq!(freq_param.norm(220.0), -0.1);
        ///
        /// // Denormalize a value (convert 0.0 to 1.0 range to frequency)
        /// assert_eq!(freq_param.denorm(-0.1), 220.0);
        ///```
        #[derive(Debug, Clone, Copy, PartialOrd, PartialEq, Eq, Ord, Hash)]
        pub struct ParamId {
            name: &'static str,
            node: NodeId,
            idx:  u8,
        }

        impl ParamId {
            pub fn none() -> Self {
                Self {
                    name: "NOP",
                    node: NodeId::Nop,
                    idx: 0,
                }
            }

            pub fn node_id(&self) -> NodeId       { self.node }
            pub fn inp(&self)     -> u8           { self.idx }
            pub fn name(&self)    -> &'static str { self.name }

            /// Returns true if the [ParamId] has been associated with
            /// the atoms of a Node, and not the paramters. Even if the
            /// Atom is a `param()`.
            pub fn is_atom(&self) -> bool {
                match self.node {
                    NodeId::$v1           => false,
                    $(NodeId::$variant(_) => {
                        match self.idx {
                            $($in_idx    => false,)*
                            $($in_at_idx => true,)*
                            _            => false,
                        }
                    }),+
                }
            }

            pub fn param_min_max(&self) -> Option<(f32, f32)> {
                match self.node {
                    NodeId::$v1           => None,
                    $(NodeId::$variant(_) => {
                        match self.idx {
                            $($in_idx => Some(($min, $max)),)*
                            _         => None,
                        }
                    }),+
                }
            }

            pub fn setting_lbl(&self, lbl_idx: usize) -> Option<&'static str> {
                match self.node {
                    NodeId::$v1           => None,
                    $(NodeId::$variant(_) => {
                        match self.idx {
                            $($in_at_idx =>
                                if lbl_idx < crate::dsp::labels::$variant::$atom.len() {
                                    Some(crate::dsp::labels::$variant::$atom[lbl_idx])
                                } else {
                                    None
                                },)*
                            _  => None,
                        }
                    }),+
                }
            }

            pub fn setting_min_max(&self) -> Option<(i64, i64)> {
                match self.node {
                    NodeId::$v1           => None,
                    $(NodeId::$variant(_) => {
                        match self.idx {
                            $($in_at_idx => Some(($amin, $amax)),)*
                            _            => None,
                        }
                    }),+
                }
            }

            pub fn as_atom_def(&self) -> SAtom {
                match self.node {
                    NodeId::$v1           => SAtom::param(0.0),
                    $(NodeId::$variant(_) => {
                        match self.idx {
                            $($in_idx    => SAtom::param(crate::dsp::norm_def::$variant::$para()),)*
                            $($in_at_idx => SAtom::$at_fun($at_init),)*
                            _            => SAtom::param(0.0),
                        }
                    }),+
                }
            }

            pub fn norm_def(&self) -> f32 {
                match self.node {
                    NodeId::$v1           => 0.0,
                    $(NodeId::$variant(_) => {
                        match self.idx {
                            $($in_idx => crate::dsp::norm_def::$variant::$para(),)*
                            _ => 0.0,
                        }
                    }),+
                }
            }

            pub fn norm(&self, v: f32) -> f32 {
                match self.node {
                    NodeId::$v1           => 0.0,
                    $(NodeId::$variant(_) => {
                        match self.idx {
                            $($in_idx => crate::dsp::norm_v::$variant::$para(v),)*
                            _ => 0.0,
                        }
                    }),+
                }
            }

            pub fn denorm(&self, v: f32) -> f32 {
                match self.node {
                    NodeId::$v1           => 0.0,
                    $(NodeId::$variant(_) => {
                        match self.idx {
                            $($in_idx => crate::dsp::denorm_v::$variant::$para(v),)*
                            _ => 0.0,
                        }
                    }),+
                }
            }
        }

        /// This enum is a collection of all implemented modules (aka nodes)
        /// that are implemented. The associated `u8` index is the so called
        /// _instance_ of the corresponding [Node] type.
        ///
        /// This is the primary way in this library to refer to a specific node
        /// in the node graph that is managed by [crate::NodeConfigurator]
        /// and executed by [crate::NodeExecutor].
        ///
        /// To see how to actually use this, refer to the documentation
        /// of [crate::Cell], where you will find an example.
        #[derive(Debug, Clone, Copy, PartialOrd, PartialEq, Eq, Ord, Hash)]
        pub enum NodeId {
            $v1,
            $($variant(u8)),+
        }

        impl std::fmt::Display for NodeId {
            fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
                match self {
                    NodeId::$v1           => write!(f, "{}", stringify!($s1)),
                    $(NodeId::$variant(i) => write!(f, "{} {}", stringify!($str), i)),+
                }
            }
        }

        impl NodeId {
            pub fn to_instance(&self, instance: usize) -> NodeId {
                match self {
                    NodeId::$v1           => NodeId::$v1,
                    $(NodeId::$variant(_) => NodeId::$variant(instance as u8)),+
                }
            }

            pub fn graph_fun(&self) -> Option<GraphFun> {
                match self {
                    NodeId::$v1           => None,
                    $(NodeId::$variant(_) => crate::dsp::$variant::graph_fun()),+
                }
            }

            pub fn eq_variant(&self, other: &NodeId) -> bool {
                match self {
                    NodeId::$v1           => *other == NodeId::$v1,
                    $(NodeId::$variant(_) =>
                        if let NodeId::$variant(_) = other { true }
                        else { false }),+
                }
            }

            pub fn from_node_info(ni: &NodeInfo) -> NodeId {
                match ni {
                    NodeInfo::$v1           => NodeId::$v1,
                    $(NodeInfo::$variant(_) => NodeId::$variant(0)),+
                }
            }

            pub fn name(&self) -> &'static str {
                match self {
                    NodeId::$v1           => stringify!($s1),
                    $(NodeId::$variant(_) => stringify!($str)),+
                }
            }

            pub fn from_str(name: &str) -> Self {
                match name {
                    stringify!($s1)    => NodeId::$v1,
                    $(stringify!($str) => NodeId::$variant(0)),+,
                    _                  => NodeId::Nop,
                }
            }

            pub fn ui_type(&self) -> UIType {
                match self {
                    NodeId::$v1           => UIType::Generic,
                    $(NodeId::$variant(_) => UIType::$gui_type),+
                }
            }

            pub fn ui_category(&self) -> UICategory {
                match self {
                    NodeId::$v1           => UICategory::None,
                    $(NodeId::$variant(_) => UICategory::$ui_cat),+
                }
            }

            /// This maps the atom index of the node to the absolute
            /// ParamId in the GUI (and in the [crate::matrix::Matrix]).
            /// The Atom/Param duality is a bit weird because they share
            /// the same ID namespace for the UI. But in the actual
            /// backend, they are split. So the actual splitting happens
            /// in the [crate::matrix::Matrix].
            pub fn atom_param_by_idx(&self, idx: usize) -> Option<ParamId> {
                match self {
                    NodeId::$v1           => None,
                    $(NodeId::$variant(_) => {
                        match idx {
                            $($at_idx => Some(ParamId {
                                node: *self,
                                name: stringify!($atom),
                                idx:  $in_at_idx,
                            }),)*
                            _ => None,
                        }
                    }),+
                }
            }

            pub fn inp_param_by_idx(&self, idx: usize) -> Option<ParamId> {
                match self {
                    NodeId::$v1           => None,
                    $(NodeId::$variant(_) => {
                        match idx {
                            $($in_idx => Some(ParamId {
                                node: *self,
                                name: stringify!($para),
                                idx:  $in_idx,
                            }),)*
                            _ => None,
                        }
                    }),+
                }
            }

            pub fn param_by_idx(&self, idx: usize) -> Option<ParamId> {
                match self {
                    NodeId::$v1           => None,
                    $(NodeId::$variant(_) => {
                        match idx {
                            $($in_idx => Some(ParamId {
                                node: *self,
                                name: stringify!($para),
                                idx:  $in_idx,
                            }),)*
                            $($in_at_idx => Some(ParamId {
                                node: *self,
                                name: stringify!($atom),
                                idx:  $in_at_idx,
                            }),)*
                            _ => None,
                        }
                    }),+
                }
            }

            pub fn inp_param(&self, name: &str) -> Option<ParamId> {
                match self {
                    NodeId::$v1           => None,
                    $(NodeId::$variant(_) => {
                        match name {
                            $(stringify!($para) => Some(ParamId {
                                node: *self,
                                name: stringify!($para),
                                idx:  $in_idx,
                            }),)*
                            $(stringify!($atom) => Some(ParamId {
                                node: *self,
                                name: stringify!($atom),
                                idx:  $in_at_idx,
                            }),)*
                            _ => None,
                        }
                    }),+
                }
            }

            pub fn inp(&self, name: &str) -> Option<u8> {
                match self {
                    NodeId::$v1           => None,
                    $(NodeId::$variant(_) => {
                        match name {
                            $(stringify!($para) => Some($in_idx),)*
                            _ => None,
                        }
                    }),+
                }
            }

            pub fn out_name_by_idx(&self, idx: u8) -> Option<&'static str> {
                match self {
                    NodeId::$v1           => None,
                    $(NodeId::$variant(_) => {
                        match idx {
                            $($out_idx => Some(stringify!($out)),)*
                            _ => None,
                        }
                    }),+
                }
            }

            pub fn out(&self, name: &str) -> Option<u8> {
                match self {
                    NodeId::$v1           => None,
                    $(NodeId::$variant(_) => {
                        match name {
                            $(stringify!($out) => Some($out_idx),)*
                            _ => None,
                        }
                    }),+
                }
            }

            pub fn instance(&self) -> usize {
                match self {
                    NodeId::$v1           => 0,
                    $(NodeId::$variant(i) => *i as usize),+
                }
            }
        }

        #[allow(non_snake_case)]
        pub mod denorm_v {
            $(pub mod $variant {
                $(#[inline] pub fn $para(x: f32) -> f32 { $d_fun!(x) })*
            })+
        }

        #[allow(non_snake_case)]
        pub mod norm_def {
            $(pub mod $variant {
                $(#[inline] pub fn $para() -> f32 { $n_fun!($def) })*
            })+
        }

        #[allow(non_snake_case)]
        pub mod norm_v {
            $(pub mod $variant {
                $(#[inline] pub fn $para(v: f32) -> f32 { $n_fun!(v) })*
            })+
        }

        #[allow(non_snake_case)]
        pub mod denorm {
            $(pub mod $variant {
                $(#[inline] pub fn $para(buf: &crate::dsp::ProcBuf, frame: usize) -> f32 {
                    $d_fun!(buf.read(frame))
                })*
            })+
        }

        #[allow(non_snake_case)]
        pub mod inp_dir {
            $(pub mod $variant {
                $(#[inline] pub fn $para(buf: &crate::dsp::ProcBuf, frame: usize) -> f32 {
                    buf.read(frame)
                })*
            })+
        }

        #[allow(non_snake_case)]
        pub mod inp {
            $(pub mod $variant {
                $(#[inline] pub fn $para(inputs: &[crate::dsp::ProcBuf]) -> &crate::dsp::ProcBuf {
                    &inputs[$in_idx]
                })*
            })+
        }

        #[allow(non_snake_case)]
        pub mod at {
            $(pub mod $variant {
                $(#[inline] pub fn $atom(atoms: &[crate::dsp::SAtom]) -> &crate::dsp::SAtom {
                    &atoms[$at_idx]
                })*
            })+
        }

        #[allow(non_snake_case)]
        pub mod out_dir {
            $(pub mod $variant {
                $(#[inline] pub fn $out(outputs: &mut [crate::dsp::ProcBuf], frame: usize, v: f32) {
                    outputs[$out_idx].write(frame, v);
                })*
            })+
        }

        #[allow(non_snake_case)]
        pub mod out {
            $(pub mod $variant {
                $(#[inline] pub fn $out(outputs: &mut [crate::dsp::ProcBuf]) -> &mut crate::dsp::ProcBuf {
                    &mut outputs[$out_idx]
                })*
            })+
        }

        mod ni {
            $(
                #[derive(Debug, Clone)]
                pub struct $variant {
                    inputs:         Vec<&'static str>,
                    atoms:          Vec<&'static str>,
                    outputs:        Vec<&'static str>,
                    input_help:     Vec<&'static str>,
                    output_help:    Vec<&'static str>,
                }

                impl $variant {
                    #[allow(unused_mut)]
                    pub fn new() -> Self {
                        let mut input_help = vec![$(crate::dsp::$variant::$para,)*];
                        $(input_help.push(crate::dsp::$variant::$atom);)*

                        Self {
                            inputs:  vec![$(stringify!($para),)*],
                            atoms:   vec![$(stringify!($atom),)*],
                            outputs: vec![$(stringify!($out),)*],

                            input_help,
                            output_help: vec![$(crate::dsp::$variant::$out,)*],
                        }
                    }

                    pub fn in_name(&self, in_idx: usize) -> Option<&'static str> {
                        if let Some(s) = self.inputs.get(in_idx) {
                            Some(*s)
                        } else {
                            Some(*(self.atoms.get(in_idx)?))
                        }
                    }

                    pub fn at_name(&self, in_idx: usize) -> Option<&'static str> {
                        Some(*(self.atoms.get(in_idx)?))
                    }

                    pub fn out_name(&self, out_idx: usize) -> Option<&'static str> {
                        Some(*(self.outputs.get(out_idx)?))
                    }

                    pub fn in_help(&self, in_idx: usize) -> Option<&'static str> {
                        Some(*self.input_help.get(in_idx)?)
                    }

                    pub fn out_help(&self, out_idx: usize) -> Option<&'static str> {
                        Some(*(self.output_help.get(out_idx)?))
                    }

                    pub fn norm(&self, in_idx: usize, x: f32) -> f32 {
                        match in_idx {
                            $($in_idx => crate::dsp::norm_v::$variant::$para(x),)+
                            _         => 0.0,
                        }
                    }

                    pub fn denorm(&self, in_idx: usize, x: f32) -> f32 {
                        match in_idx {
                            $($in_idx => crate::dsp::denorm_v::$variant::$para(x),)+
                            _         => 0.0,
                        }
                    }

                    pub fn out_count(&self) -> usize { self.outputs.len() }
                    pub fn in_count(&self)  -> usize { self.inputs.len() }
                    pub fn at_count(&self)  -> usize { self.atoms.len() }
                }
            )+
        }

        impl NodeInfo {
            pub fn from(s: &str) -> Self {
                match s {
                    stringify!($s1)    => NodeInfo::$v1,
                    $(stringify!($str) =>
                        NodeInfo::$variant(
                            (NodeId::$variant(0),
                             crate::dsp::ni::$variant::new()))),+,
                    _                  => NodeInfo::Nop,
                }
            }

            pub fn in_name(&self, idx: usize) -> Option<&'static str> {
                match self {
                    NodeInfo::$v1                 => None,
                    $(NodeInfo::$variant((_, ni)) => ni.in_name(idx)),+
                }
            }

            pub fn out_name(&self, idx: usize) -> Option<&'static str> {
                match self {
                    NodeInfo::$v1                 => None,
                    $(NodeInfo::$variant((_, ni)) => ni.out_name(idx)),+
                }
            }

            pub fn in_help(&self, idx: usize) -> Option<&'static str> {
                match self {
                    NodeInfo::$v1                 => None,
                    $(NodeInfo::$variant((_, ni)) => ni.in_help(idx)),+
                }
            }

            pub fn out_help(&self, idx: usize) -> Option<&'static str> {
                match self {
                    NodeInfo::$v1                 => None,
                    $(NodeInfo::$variant((_, ni)) => ni.out_help(idx)),+
                }
            }

            pub fn to_id(&self) -> NodeId {
                match self {
                    NodeInfo::$v1                 => NodeId::$v1,
                    $(NodeInfo::$variant((id, _)) => *id),+
                }
            }

            pub fn at_count(&self) -> usize {
                match self {
                    NodeInfo::$v1           => 0,
                    $(NodeInfo::$variant(n) => n.1.at_count()),+
                }
            }

            pub fn in_count(&self) -> usize {
                match self {
                    NodeInfo::$v1           => 0,
                    $(NodeInfo::$variant(n) => n.1.in_count()),+
                }
            }

            pub fn out_count(&self) -> usize {
                match self {
                    NodeInfo::$v1           => 0,
                    $(NodeInfo::$variant(n) => n.1.out_count()),+
                }
            }
        }
    }
}

macro_rules! make_node_enum {
    ($s1: ident => $v1: ident,
        $($str: ident => $variant: ident
            UIType:: $gui_type: ident
            UICategory:: $ui_cat: ident
            $(($in_idx: literal $para: ident
               $n_fun: ident $d_fun: ident
               $min: expr, $max: expr, $def: expr))*
            $({$in_at_idx: literal $at_idx: literal $atom: ident
               $at_fun: ident ($at_init: expr)
               $amin: literal $amax: literal})*
            $([$out_idx: literal $out: ident])*
            ,)+
    ) => {
        /// Represents the actually by the DSP thread ([crate::NodeExecutor])
        /// executed [Node]. You don't construct this directly, but let the
        /// [crate::NodeConfigurator] or more abstract types like
        /// [crate::Matrix] do this for you. See also [NodeId] for a way to
        /// refer to these.
        ///
        /// The method [Node::process] is called by [crate::NodeExecutor]
        /// and comes with the overhead of a big `match` statement.
        ///
        /// This is the only point of primitive polymorphism inside
        /// the DSP graph. Dynamic polymorphism via the trait object
        /// is not done, as I hope the `match` dispatch is a slight bit faster
        /// because it's more static.
        ///
        /// The size of a [Node] is also limited and protected by a test
        /// in the test suite. The size should not be needlessly increased
        /// by implementations, in the hope to achieve better
        /// cache locality. All allocated [Node]s are held in a big
        /// continuous vector inside the [crate::NodeExecutor].
        ///
        /// The function [node_factory] is responsible for actually creating
        /// the [Node].
        #[derive(Debug, Clone)]
        pub enum Node {
            /// An empty node that does nothing. It's a placeholder
            /// for non allocated nodes.
            $v1,
            $($variant { node: $variant },)+
        }

        impl Node {
            /// Returns the [NodeId] that can be used to refer to this node.
            /// The node does not store it's instance index, so you have to
            /// provide it. If the instance is of no meaning for the
            /// use case pass 0 to `instance`.
            pub fn to_id(&self, instance: usize) -> NodeId {
                match self {
                    Node::$v1               => NodeId::$v1,
                    $(Node::$variant { .. } => NodeId::$variant(instance as u8)),+
                }
            }

            /// Resets any state of this [Node], such as
            /// any internal state variables or counters or whatever.
            /// The [Node] should just behave as if it was freshly returned
            /// from [node_factory].
            pub fn reset(&mut self) {
                match self {
                    Node::$v1           => {},
                    $(Node::$variant { node } => {
                        node.reset();
                    }),+
                }
            }

            /// Sets the current sample rate this [Node] should operate at.
            pub fn set_sample_rate(&mut self, sample_rate: f32) {
                match self {
                    Node::$v1           => {},
                    $(Node::$variant { node } => {
                        node.set_sample_rate(sample_rate);
                    }),+
                }
            }

        }
    }
}

node_list!{make_node_info_enum}
node_list!{make_node_enum}

pub fn node_factory(node_id: NodeId) -> Option<(Node, NodeInfo)> {
    macro_rules! make_node_factory_match {
        ($s1: expr => $v1: ident,
            $($str: ident => $variant: ident
                UIType:: $gui_type: ident
                UICategory:: $ui_cat: ident
                $(($in_idx: literal $para: ident
                   $n_fun: ident $d_fun: ident
                   $min: expr, $max: expr, $def: expr))*
                $({$in_at_idx: literal $at_idx: literal $atom: ident
                   $at_fun: ident ($at_init: expr)
                   $amin: literal $amax: literal})*
                $([$out_idx: literal $out: ident])*
            ,)+
        ) => {
            match node_id {
                $(NodeId::$variant(_) => Some((
                    Node::$variant { node: $variant::new() },
                    NodeInfo::from_node_id(node_id),
                )),)+
                _ => None,
            }
        }
    }

    node_list!{make_node_factory_match}
}

impl Node {
    /// This function is the heart of any DSP.
    /// It dispatches this call to the corresponding [Node] implementation.
    ///
    /// You don't want to call this directly, but let [crate::NodeConfigurator] and
    /// [crate::NodeExecutor] do their magic for you.
    ///
    /// The slices get passed a [ProcBuf] which is a super _unsafe_
    /// buffer, that requires special care and invariants to work safely.
    ///
    /// Arguments:
    /// * `ctx`: The [NodeAudioContext] usually provides global context information
    /// such as access to the actual buffers of the audio driver or access to
    /// MIDI events.
    /// * `atoms`: The [SAtom] settings the user can set in the UI or via
    /// other means. These are usually non interpolated/smoothed settings.
    /// * `params`: The smoothed input parameters as set by the user (eg. in the UI).
    /// There is usually no reason to use these, because any parameter can be
    /// overridden by assigning an output port to the corresponding input.
    /// This is provided for the rare case that you still want to use the
    /// value the user set in the interface, and not the input CV signal.
    /// * `inputs`: For each `params` parameter there is a input port.
    /// This slice will contain either a buffer from `params` or some output
    /// buffer from some other (previously executed) [Node]s output.
    /// * `outputs`: The output buffers this node will write it's signal/CV
    /// results to.
    /// * `led`: Contains the feedback [LedPhaseVals], which are used
    /// to communicate the current value (set once per `process()` call, usually at the end)
    /// of the most important internal signal. Usually stuff like the output
    /// value of an oscillator, envelope or the current sequencer output
    /// value. It also provides a second value, a so called _phase_
    /// which is usually used by graphical frontends to determine
    /// the phase of the oscillator, envelope or the sequencer to
    /// display some kind of position indicator.
    #[inline]
    pub fn process<T: NodeAudioContext>(
        &mut self, ctx: &mut T, ectx: &mut NodeExecContext,
        atoms: &[SAtom], params: &[ProcBuf],
        inputs: &[ProcBuf], outputs: &mut [ProcBuf],
        led: LedPhaseVals)
    {
        macro_rules! make_node_process {
            ($s1: ident => $v1: ident,
                $($str: ident => $variant: ident
                    UIType:: $gui_type: ident
                    UICategory:: $ui_cat: ident
                    $(($in_idx: literal $para: ident
                       $n_fun: ident $d_fun: ident
                       $min: expr, $max: expr, $def: expr))*
                    $({$in_at_idx: literal $at_idx: literal $atom: ident
                       $at_fun: ident ($at_init: expr)
                       $amin: literal $amax: literal})*
                    $([$out_idx: literal $out: ident])*
                ,)+
            ) => {
                match self {
                    Node::$v1 => {},
                    $(Node::$variant { node } =>
                        node.process(ctx, ectx, atoms, params,
                                     inputs, outputs, led),)+
                }
            }
        }

        node_list!{make_node_process}
    }
}


#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn check_node_size_staying_small() {
        assert_eq!(std::mem::size_of::<Node>(),     48);
        assert_eq!(std::mem::size_of::<NodeId>(),   2);
        assert_eq!(std::mem::size_of::<ParamId>(),  24);
    }

    #[test]
    fn check_pitch() {
        assert_eq!(d_pit!(-0.2).round() as i32, 110_i32);
        assert_eq!((n_pit!(110.0) * 100.0).round() as i32, -20_i32);
        assert_eq!(d_pit!(0.0).round() as i32, 440_i32);
        assert_eq!((n_pit!(440.0) * 100.0).round() as i32, 0_i32);
        assert_eq!(d_pit!(0.3).round() as i32, 3520_i32);
        assert_eq!((n_pit!(3520.0) * 100.0).round() as i32, 30_i32);

        for i in 1..999 {
            let x = (((i as f32) / 1000.0) - 0.5) * 2.0;
            let r = d_pit!(x);
            println!("x={:8.5} => {:8.5}", x, r);
            assert_eq!(
                (n_pit!(r) * 10000.0).round() as i32,
                (x * 10000.0).round() as i32);
        }
    }
}