#![allow(dead_code)] // not nearly finished

use std::array;

use crate::file::err;

#[derive(Debug, Default)]
pub enum NewNoteAction {
    #[default]
    Cut = 0,
    Continue = 1,
    NoteOff = 2,
    NoteFade = 3,
}

impl TryFrom<u8> for NewNoteAction {
    type Error = u8;

    fn try_from(value: u8) -> Result<Self, Self::Error> {
        match value {
            0 => Ok(Self::Cut),
            1 => Ok(Self::Continue),
            2 => Ok(Self::NoteOff),
            3 => Ok(Self::NoteFade),
            _ => Err(value),
        }
    }
}

#[derive(Debug, Default)]
pub enum DuplicateCheckType {
    #[default]
    Off = 0,
    Note = 1,
    Sample = 2,
    Instrument = 3,
}

impl TryFrom<u8> for DuplicateCheckType {
    type Error = ();

    fn try_from(value: u8) -> Result<Self, Self::Error> {
        match value {
            0 => Ok(Self::Off),
            1 => Ok(Self::Note),
            2 => Ok(Self::Sample),
            3 => Ok(Self::Instrument),
            _ => Err(()),
        }
    }
}

#[derive(Debug, Default)]
pub enum DuplicateCheckAction {
    #[default]
    Cut = 0,
    NoteOff = 1,
    NoteFade = 2,
}

impl TryFrom<u8> for DuplicateCheckAction {
    type Error = ();

    fn try_from(value: u8) -> Result<Self, Self::Error> {
        match value {
            0 => Ok(Self::Cut),
            1 => Ok(Self::NoteOff),
            2 => Ok(Self::NoteFade),
            _ => Err(()),
        }
    }
}

#[derive(Debug)]
pub struct ImpulseInstrument {
    pub dos_file_name: [u8; 12],
    pub new_note_action: NewNoteAction,
    pub duplicate_check_type: DuplicateCheckType,
    pub duplicate_check_action: DuplicateCheckAction,
    pub fade_out: u16,
    pub pitch_pan_seperation: i8,
    pub pitch_pan_center: u8,
    pub global_volume: u8,
    pub default_pan: Option<u8>,
    pub random_volume: u8,
    pub random_pan: u8,
    pub created_with: u16,
    pub number_of_samples: u8,
    pub name: String,
    pub initial_filter_cutoff: u8,
    pub initial_filter_resonance: u8,
    pub midi_channel: u8,
    pub midi_program: u8,
    pub midi_bank: u16,
    pub note_sample_table: [(u8, u8); 120],
    pub volume_envelope: ImpulseEnvelope,
    pub pan_envelope: ImpulseEnvelope,
    pub pitch_envelope: ImpulseEnvelope,
}

impl ImpulseInstrument {
    const SIZE: usize = 554;

    pub fn parse(buf: &[u8; Self::SIZE]) -> Result<Self, err::LoadErr> {
        if !buf.starts_with(b"IMPI") {
            return Err(err::LoadErr::Invalid);
        }

        // unwrap is okay as the slice length is const
        let dos_file_name: [u8; 12] = buf[0x04..=0x0F].try_into().unwrap();

        if buf[10] != 0 {
            return Err(err::LoadErr::Invalid);
        }
        // let new_note_action = match NewNoteAction::try_from(buf[0x11]) {
        //     Ok(nna) => nna,
        //     Err(_) => {
        //         // defect_handler(LoadDefect::OutOfBoundsValue);
        //         NewNoteAction::default()
        //     }
        // };
        let new_note_action = NewNoteAction::try_from(buf[0x11]).unwrap_or_default();
        // let duplicate_check_type = match DuplicateCheckType::try_from(buf[0x12]) {
        //     Ok(dct) => dct,
        //     Err(_) => {
        //         // defect_handler(LoadDefect::OutOfBoundsValue);
        //         DuplicateCheckType::default()
        //     }
        // };
        let duplicate_check_type = DuplicateCheckType::try_from(buf[0x12]).unwrap_or_default();
        // let duplicate_check_action = match DuplicateCheckAction::try_from(buf[0x13]) {
        //     Ok(dca) => dca,
        //     Err(_) => {
        //         // defect_handler(LoadDefect::OutOfBoundsValue);
        //         DuplicateCheckAction::default()
        //     }
        // };
        let duplicate_check_action = DuplicateCheckAction::try_from(buf[0x13]).unwrap_or_default();
        let fade_out = u16::from_le_bytes([buf[0x14], buf[0x15]]);
        let pitch_pan_seperation = {
            let tmp = i8::from_le_bytes([buf[0x16]]);
            if !(-32..=32).contains(&tmp) {
                // defect_handler(LoadDefect::OutOfBoundsValue);
                0
            } else {
                tmp
            }
        };
        let pitch_pan_center = if buf[0x17] <= 119 {
            buf[0x17]
        } else {
            // defect_handler(LoadDefect::OutOfBoundsValue);
            59
        };
        let global_volume = if buf[0x18] <= 128 {
            buf[0x18]
        } else {
            // defect_handler(LoadDefect::OutOfBoundsValue);
            64
        };

        let default_pan = if buf[0x19] == 128 {
            None
        } else if buf[0x19] > 64 {
            // defect_handler(LoadDefect::OutOfBoundsValue);
            Some(32)
        } else {
            Some(buf[0x19])
        };

        let random_volume = buf[0x1A];
        assert!(random_volume <= 100);
        let random_pan = buf[0x1B];
        assert!(random_pan <= 100);
        let created_with = u16::from_le_bytes([buf[0x1C], buf[0x1D]]);
        let number_of_samples = buf[0x1E];

        let name = String::from_utf8(
            buf[0x20..=0x39]
                .split(|b| *b == 0)
                .next()
                .unwrap()
                .to_owned(),
        )
        .unwrap();

        let initial_filter_cutoff = buf[0x3A];
        let initial_filter_resonance = buf[0x3B];
        let midi_channel = buf[0x3C];
        let midi_program = buf[0x3D];
        let midi_bank = u16::from_le_bytes([buf[0x3E], buf[0x3F]]);
        let note_sample_table: [(u8, u8); 120] = buf[0x030..0x130]
            .chunks_exact(2)
            .map(|chunk| (chunk[0], chunk[1]))
            .collect::<Vec<(u8, u8)>>()
            .try_into()
            .unwrap();

        let volume_envelope = ImpulseEnvelope::load(
            &buf[0x130..0x130 + ImpulseEnvelope::SIZE]
                .try_into()
                .unwrap(),
        );
        let pan_envelope = ImpulseEnvelope::load(
            &buf[0x182..0x182 + ImpulseEnvelope::SIZE]
                .try_into()
                .unwrap(),
        );
        let pitch_envelope = ImpulseEnvelope::load(
            &buf[0x1D4..0x1D4 + ImpulseEnvelope::SIZE]
                .try_into()
                .unwrap(),
        );

        Ok(Self {
            dos_file_name,
            new_note_action,
            duplicate_check_type,
            duplicate_check_action,
            fade_out,
            pitch_pan_seperation,
            pitch_pan_center,
            global_volume,
            default_pan,
            random_volume,
            random_pan,
            created_with,
            number_of_samples,
            name,
            initial_filter_cutoff,
            initial_filter_resonance,
            midi_channel,
            midi_program,
            midi_bank,
            note_sample_table,
            volume_envelope,
            pan_envelope,
            pitch_envelope,
        })
    }
}

/// flags and node values are interpreted differently depending on the type of envelope.
/// doesn't affect loading
#[derive(Debug)]
pub struct ImpulseEnvelope {
    flags: u8,
    num_node_points: u8,
    loop_start: u8,
    loop_end: u8,
    sustain_loop_start: u8,
    sustain_loop_end: u8,
    nodes: [(u8, u16); 25],
}

impl ImpulseEnvelope {
    const SIZE: usize = 81; // = 0x51

    fn load(buf: &[u8; Self::SIZE]) -> Self {
        let flags = buf[0];
        let num_node_points = buf[1];
        let loop_start = buf[2];
        let loop_end = buf[3];
        let sustain_loop_start = buf[4];
        let sustain_loop_end = buf[5];

        let nodes = array::from_fn(|idx| {
            let chunk = 6 + idx * 3;
            (
                buf[chunk],
                u16::from_le_bytes([buf[chunk + 1], buf[chunk + 2]]),
            )
        });

        Self {
            flags,
            num_node_points,
            loop_start,
            loop_end,
            sustain_loop_start,
            sustain_loop_end,
            nodes,
        }
    }
}