ot-tools-io 0.6.1

/*
SPDX-License-Identifier: GPL-3.0-or-later
Copyright © 2024 Mike Robeson [dijksterhuis]
*/

//! Types and ser/de of `*.ot` binary data files.

use crate::markers::SlotMarkers;
use crate::projects::SlotAttributes;
use crate::settings::{LoopMode, TimeStretchMode, TrigQuantizationMode};
use crate::slices::{Slice, Slices};
use crate::traits::SwapBytes;
use crate::{
    HasChecksumField, HasFileVersionField, HasHeaderField, OctatrackFileIO, OtToolsIoError,
};
use ot_tools_io_derive::IntegrityChecks;
use serde::{Deserialize, Serialize};
use serde_big_array::BigArray;
use thiserror::Error;

#[cfg(test)]
mod test_utils {
    use super::{
        LoopConfig, LoopMode, SampleSettingsError, SampleSettingsFile, Slice, Slices,
        TimeStretchMode, TrigQuantizationMode, TrimConfig, DEFAULT_GAIN, DEFAULT_TEMPO,
        SAMPLES_FILE_VERSION, SAMPLES_HEADER,
    };

    pub(crate) fn create_mock_new(
        tempo: Option<u32>,
        gain: Option<u16>,
    ) -> Result<SampleSettingsFile, SampleSettingsError> {
        let trim_config = TrimConfig {
            start: 0,
            end: 0,
            length: 0,
        };

        let loop_config = LoopConfig {
            start: 0,
            length: 0,
            mode: LoopMode::default(),
        };

        let default_slice = Slice {
            trim_start: 0,
            trim_end: 0,
            loop_start: 0xFFFFFFFF,
        };

        let slices: [Slice; 64] = [default_slice; 64];

        let slice_conf = Slices { slices, count: 0 };

        SampleSettingsFile::new(
            &tempo.unwrap_or(DEFAULT_TEMPO),
            &TimeStretchMode::Off,
            &TrigQuantizationMode::PatternLength,
            &gain.unwrap_or(DEFAULT_GAIN),
            &trim_config,
            &loop_config,
            &slice_conf,
        )
    }

    pub(crate) fn mock_0_slice() -> SampleSettingsFile {
        SampleSettingsFile {
            header: SAMPLES_HEADER,
            datatype_version: SAMPLES_FILE_VERSION,
            unknown: 1,
            tempo: 2281,
            trim_len: 800,
            loop_len: 800,
            stretch: 2,
            loop_mode: 0,
            gain: 48,
            quantization: 255,
            trim_start: 0,
            trim_end: 890839,
            loop_start: 0,
            slices: Slices::default().slices,
            slices_len: 0,
            checksum: 998,
        }
    }
}

#[derive(Debug, Error)]
pub enum SampleSettingsError {
    #[error("invalid gain, must be u16 in range 0 <= x <= 96: {value}")]
    GainOutOfBounds { value: u32 },
    #[error("invalid tempo value, must be u32 in range 720 <= x <= 7200: {value}")]
    TempoOutOfBounds { value: u32 },
}

// in `hexdump -C` format:
// ```
// FORM....DPS1SMPA
// ......
// ```
/// Standard header bytes in a sample settings file
pub const SAMPLES_HEADER: [u8; 21] = [
    0x46, 0x4F, 0x52, 0x4D, 0x00, 0x00, 0x00, 0x00, 0x44, 0x50, 0x53, 0x31, 0x53, 0x4D, 0x50, 0x41,
    0x00, 0x00, 0x00, 0x00, 0x00,
];

/// Current/supported datatype version for a sample settings file
pub const SAMPLES_FILE_VERSION: u8 = 2;

pub const DEFAULT_TEMPO: u32 = 2880;
pub const DEFAULT_GAIN: u16 = 48;

/// Struct to create a valid Octatrack `.ot` file a.k.a. a sample settings file.
/// General metadata for the sample's configuration on the OT
/// and the slice array with pointer positions for the sliced WAV.
///
/// NOTE: On the naming for this -- the Octatrack manual specifically refers to
/// > SAVE SAMPLE SETTINGS will save the trim, slice and attribute settings in a
/// > separate file and link it to the sample currently being edited.
/// > -- page 87.
///
/// So ... this is the SETTINGS file.
#[derive(Serialize, Deserialize, PartialEq, Debug, Clone, Hash, IntegrityChecks)]
pub struct SampleSettingsFile {
    /// Header
    pub header: [u8; 21],

    /// Datatype's version ID//
    pub datatype_version: u8,

    /// Unknown data -- can sometimes be 1, usually 0.
    pub unknown: u8,

    /// Tempo is always the machine UI's BPM multiplied by 24
    pub tempo: u32,

    /// Number of bars for the sample trim length marker.
    /// By default, trim length should be equal to trim end,
    /// and probably loop length too for drum hit sample chains.
    pub trim_len: u32,

    /// Number of bars for the sample loop length marker.
    /// By default, loop length should be equal to trim length for sample chains.
    pub loop_len: u32,

    /// Default time-stretch algorithm applied to the sample.
    /// See the [`TimeStretchMode`] enum for suitable choices.
    pub stretch: u32,

    /// Default loop mode applied to the sample.
    /// See the [`LoopMode`] enum for suitable choices.
    pub loop_mode: u32,

    /// Gain of the sample.
    /// -24.0 db <= x <= +24 db range in the machine's UI, with increments of 0.5 db changes.
    /// 0 <= x <= 96 range in binary data file.
    pub gain: u16,

    /// Default trig quantization mode applied to the sample.
    /// See the [`TrigQuantizationMode`] enum for suitable choices.
    pub quantization: u8,

    /// Where the trim start marker is placed for the sample, measured in bars.
    /// Default is 0 (start of sample).
    pub trim_start: u32,

    /// Where the trim end marker is placed for the sample.
    /// When the sample is being played in normal mode (i.e. not using slices),
    /// the Octatrack will not play samples past this point.
    /// By default, trim length should be equal to trim end,
    /// and probably loop length too for drum hit sample chains.
    pub trim_end: u32,

    /// Start position for any loops. Default should be the same as trim start.
    /// Measured in bars.
    /// A note from the Octatrack manual on loop point/start behaviour:
    /// > If a loop point is set, the sample will play from the start point to the
    /// > end point, then loop from the loop point to the end point
    pub loop_start: u32,

    /// 64 length array containing `Slice`s.
    /// See the `Slice` struct for more details.
    /// Any empty slice positions should have zero-valued struct fields.
    #[serde(with = "BigArray")]
    pub slices: [Slice; 64],

    /// Number of usable `Slice`s in this sample.
    /// Used by the Octatrack to ignore zero-valued `Slice`s in the `slices` array when loading the sample.
    pub slices_len: u32,

    /// Checksum value for the struct.
    /// This must be calculated **after** the struct is created on little-endian systems
    /// (requires byte swapping all struct fields to get the correct checksum value).
    pub checksum: u16,
}

impl SampleSettingsFile {
    /// Create a new `SampleSettingsFile`
    ///
    /// Values like `tempo` and `gain` need to be normalized to relevant OT
    /// bounds before using this method.
    /// ```rust
    /// # use std::array::from_fn;
    /// # use ot_tools_io::samples::{SampleSettingsFile, TrimConfig, LoopConfig};
    /// # use ot_tools_io::settings::{
    /// #    TrigQuantizationMode,
    /// #    LoopMode,
    /// #    TimeStretchMode,
    /// # };
    /// # use ot_tools_io::slices::{Slices, Slice};
    /// # let slice_arr: [Slice; 64] = from_fn(|_| Slice::default());
    /// # let slices: Slices = Slices { slices: slice_arr, count: 0 };
    /// let x = SampleSettingsFile::new(
    ///     &2880,
    ///     // ...
    ///     # &TimeStretchMode::default(),
    ///     # &TrigQuantizationMode::default(),
    ///     &48,
    ///     // ...
    ///     # &TrimConfig { start: 0, end: 100, length: 25 },
    ///     # &LoopConfig { start: 0, length: 100, mode: LoopMode::Off },
    ///     # &slices,
    /// ).unwrap();
    /// assert_eq!(x.tempo, 2880);
    /// assert_eq!(x.gain, 48);
    /// ```
    pub fn new(
        tempo: &u32,
        stretch: &TimeStretchMode,
        quantization: &TrigQuantizationMode,
        gain: &u16,
        trim_config: &TrimConfig,
        loop_config: &LoopConfig,
        slices: &Slices,
    ) -> Result<Self, SampleSettingsError> {
        #[allow(clippy::manual_range_contains)]
        if tempo < &720 || tempo > &7200 {
            return Err(SampleSettingsError::TempoOutOfBounds { value: *tempo });
        }

        #[allow(clippy::manual_range_contains)]
        if gain < &0 || gain > &96 {
            return Err(SampleSettingsError::GainOutOfBounds {
                value: *gain as u32,
            });
        }

        Ok(Self {
            header: SAMPLES_HEADER,
            datatype_version: SAMPLES_FILE_VERSION,
            unknown: 0,
            gain: *gain,
            stretch: (*stretch).into(),
            tempo: *tempo,
            quantization: (*quantization).into(),
            trim_start: trim_config.start,
            trim_end: trim_config.end,
            trim_len: trim_config.length, // bin lengths are multiplied by 100?
            loop_start: loop_config.start,
            loop_len: loop_config.length, // bin lengths are multiplied by 100?
            loop_mode: loop_config.mode.into(),
            slices: slices.slices,
            slices_len: slices.count,
            checksum: 0,
        })
    }
}

#[cfg(test)]
mod new {
    use super::test_utils::create_mock_new;
    use crate::OtToolsIoError;
    #[test]
    fn invalid_oob_temp() -> Result<(), OtToolsIoError> {
        assert_eq!(
            create_mock_new(Some(7201), None).unwrap_err().to_string(),
            "invalid tempo value, must be u32 in range 720 <= x <= 7200: 7201".to_string(),
        );
        Ok(())
    }

    #[test]
    fn invalid_oob_gain() -> Result<(), OtToolsIoError> {
        assert_eq!(
            create_mock_new(None, Some(97)).unwrap_err().to_string(),
            "invalid gain, must be u16 in range 0 <= x <= 96: 97".to_string(),
        );
        Ok(())
    }
}

impl SwapBytes for SampleSettingsFile {
    fn swap_bytes(self) -> Self {
        let mut bswapped_slices: [Slice; 64] = self.slices;

        for (i, slice) in self.slices.iter().enumerate() {
            bswapped_slices[i] = slice.swap_bytes();
        }

        Self {
            header: SAMPLES_HEADER,
            datatype_version: SAMPLES_FILE_VERSION,
            unknown: self.unknown,
            tempo: self.tempo.swap_bytes(),
            trim_len: self.trim_len.swap_bytes(),
            loop_len: self.loop_len.swap_bytes(),
            stretch: self.stretch.swap_bytes(),
            loop_mode: self.loop_mode.swap_bytes(),
            gain: self.gain.swap_bytes(),
            quantization: self.quantization.swap_bytes(),
            trim_start: self.trim_start.swap_bytes(),
            trim_end: self.trim_end.swap_bytes(),
            loop_start: self.loop_start.swap_bytes(),
            slices: bswapped_slices,
            slices_len: self.slices_len.swap_bytes(),
            checksum: self.checksum.swap_bytes(),
        }
    }
}

impl OctatrackFileIO for SampleSettingsFile {
    /// Encodes struct data to binary representation, after some pre-processing.
    ///
    /// Before serializing, will:
    /// 1. modify tempo and gain values to machine ranges
    /// 2. swaps bytes of values (when current system is little-endian)
    /// 3. generate checksum value
    fn encode(&self) -> Result<Vec<u8>, OtToolsIoError> {
        let mut chkd = self.clone();
        chkd.checksum = self.calculate_checksum()?;

        let encoded = if cfg!(target_endian = "little") {
            bincode::serialize(&chkd.swap_bytes())?
        } else {
            bincode::serialize(&chkd)?
        };
        Ok(encoded)
    }

    /// Decode raw bytes of a `.ot` data file into a new struct,
    /// swap byte values if system is little-endian then do some minor
    /// post-processing to get user-friendly settings values.
    fn decode(bytes: &[u8]) -> Result<Self, OtToolsIoError> {
        let decoded: Self = bincode::deserialize(bytes)?;
        let mut bswapd = decoded.clone();

        // swapping bytes is one required when running on little-endian systems
        if cfg!(target_endian = "little") {
            bswapd = decoded.swap_bytes();
        }

        Ok(bswapd)
    }
}

#[cfg(test)]
mod decode {
    use crate::read_bin_file;
    use crate::samples::test_utils::mock_0_slice;
    use crate::test_utils::get_samples_dirpath;
    use crate::{OctatrackFileIO, OtToolsIoError, SampleSettingsFile};
    #[test]
    fn valid() -> Result<(), OtToolsIoError> {
        let path = get_samples_dirpath().join("checksum").join("0slices.ot");
        let bytes = read_bin_file(&path)?;
        let s = SampleSettingsFile::decode(&bytes)?;
        assert_eq!(s, mock_0_slice());
        Ok(())
    }
}

#[cfg(test)]
mod encode {
    use crate::read_bin_file;
    use crate::samples::test_utils::mock_0_slice;
    use crate::test_utils::get_samples_dirpath;
    use crate::{OctatrackFileIO, OtToolsIoError};
    #[test]
    fn valid() -> Result<(), OtToolsIoError> {
        let path = get_samples_dirpath().join("checksum").join("0slices.ot");
        let bytes = read_bin_file(&path)?;
        let b = mock_0_slice().encode()?;
        assert_eq!(b, bytes);
        Ok(())
    }
}

impl HasChecksumField for SampleSettingsFile {
    // tests for this are in the main tests directory -- `samples_settings_files.rs`
    fn calculate_checksum(&self) -> Result<u16, OtToolsIoError> {
        let bytes = bincode::serialize(&self)?;

        // skip header and checksum byte values
        let checksum_bytes = &bytes[16..bytes.len() - 2];

        let chk: u32 = checksum_bytes
            .iter()
            .map(|x| *x as u32)
            .sum::<u32>()
            .rem_euclid(u16::MAX as u32 + 1);

        Ok(chk as u16)
    }

    fn check_checksum(&self) -> Result<bool, OtToolsIoError> {
        Ok(self.checksum == self.calculate_checksum()?)
    }
}

#[cfg(test)]
mod checksum_field {
    use super::test_utils::create_mock_new;
    use crate::{HasChecksumField, OtToolsIoError};
    #[test]
    fn valid() -> Result<(), OtToolsIoError> {
        let mut x = create_mock_new(None, None)?;
        x.checksum = x.calculate_checksum()?;
        assert!(x.check_checksum()?);
        Ok(())
    }

    #[test]
    fn invalid() -> Result<(), OtToolsIoError> {
        let mut x = create_mock_new(None, None)?;
        x.checksum = x.calculate_checksum()?;
        x.checksum = 0;
        assert!(!x.check_checksum()?);
        Ok(())
    }

    mod files {
        use crate::test_utils::get_samples_dirpath;
        use crate::{HasChecksumField, OctatrackFileIO, OtToolsIoError, SampleSettingsFile};

        fn helper(test_name: String) -> Result<(u16, u16), OtToolsIoError> {
            let mut src_path = get_samples_dirpath().join("checksum").join(&test_name);
            src_path.set_extension("ot");

            let valid = SampleSettingsFile::from_data_file(&src_path)?;
            let mut x = valid.clone();
            x.checksum = 0;

            Ok((x.calculate_checksum()?, valid.checksum))
        }

        #[test]
        fn zero_slices_trig_quant_one_step() -> Result<(), OtToolsIoError> {
            let (test, valid) = helper("0slices-tq1step".to_string())?;
            assert_eq!(test, valid);
            Ok(())
        }

        #[test]
        fn zero_slices() -> Result<(), OtToolsIoError> {
            let (test, valid) = helper("0slices".to_string())?;
            assert_eq!(test, valid);
            Ok(())
        }

        #[test]
        fn one_slice() -> Result<(), OtToolsIoError> {
            let (test, valid) = helper("1slices".to_string())?;
            assert_eq!(test, valid);
            Ok(())
        }

        #[test]
        fn two_slices() -> Result<(), OtToolsIoError> {
            let (test, valid) = helper("2slices".to_string())?;
            assert_eq!(test, valid);
            Ok(())
        }

        #[test]
        fn four_slices() -> Result<(), OtToolsIoError> {
            let (test, valid) = helper("4slices".to_string())?;
            assert_eq!(test, valid);
            Ok(())
        }

        #[test]
        fn eight_slices() -> Result<(), OtToolsIoError> {
            let (test, valid) = helper("8slices".to_string())?;
            assert_eq!(test, valid);
            Ok(())
        }

        #[test]
        fn sixteen_slices() -> Result<(), OtToolsIoError> {
            let (test, valid) = helper("16slices".to_string())?;
            assert_eq!(test, valid);
            Ok(())
        }

        #[test]
        fn thirty_two_slices() -> Result<(), OtToolsIoError> {
            let (test, valid) = helper("32slices".to_string())?;
            assert_eq!(test, valid);
            Ok(())
        }

        #[test]
        fn forty_eight_slices() -> Result<(), OtToolsIoError> {
            let (test, valid) = helper("48slices".to_string())?;
            assert_eq!(test, valid);
            Ok(())
        }

        #[test]
        fn sixty_two_slices() -> Result<(), OtToolsIoError> {
            let (test, valid) = helper("62slices".to_string())?;
            assert_eq!(test, valid);
            Ok(())
        }

        #[test]
        fn sixty_three_slices() -> Result<(), OtToolsIoError> {
            let (test, valid) = helper("63slices".to_string())?;
            assert_eq!(test, valid);
            Ok(())
        }

        #[test]
        fn sixty_four_slices_correct() -> Result<(), OtToolsIoError> {
            let (test, valid) = helper("64slices".to_string())?;
            assert_eq!(test, valid);
            Ok(())
        }
    }
}

impl HasHeaderField for SampleSettingsFile {
    fn check_header(&self) -> Result<bool, OtToolsIoError> {
        Ok(self.header == SAMPLES_HEADER)
    }
}

#[cfg(test)]
mod header_field {
    use super::test_utils::create_mock_new;
    use crate::{HasHeaderField, OtToolsIoError};
    #[test]
    fn valid() -> Result<(), OtToolsIoError> {
        assert!(create_mock_new(None, None)?.check_header()?);
        Ok(())
    }

    #[test]
    fn invalid() -> Result<(), OtToolsIoError> {
        let mut mutated = create_mock_new(None, None)?;
        mutated.header[0] = 0x00;
        mutated.header[20] = 111;
        assert!(!mutated.check_header()?);
        Ok(())
    }
}

impl HasFileVersionField for SampleSettingsFile {
    fn check_file_version(&self) -> Result<bool, OtToolsIoError> {
        Ok(self.datatype_version == SAMPLES_FILE_VERSION)
    }
}

#[cfg(test)]
mod file_version_field {
    use super::test_utils::create_mock_new;
    use crate::{HasFileVersionField, OtToolsIoError};
    #[test]
    fn valid() -> Result<(), OtToolsIoError> {
        assert!(create_mock_new(None, None)?.check_file_version()?);
        Ok(())
    }

    #[test]
    fn invalid() -> Result<(), OtToolsIoError> {
        let mut mutated = create_mock_new(None, None)?;
        mutated.datatype_version = 0;
        assert!(!mutated.check_file_version()?);
        Ok(())
    }
}

/// Helper function to avoid infinite recursion for the `From<(&SlotAttributes, &SlotMarkers)>` trait
/// implementation for `SampleSettingsFile`
// this
pub(crate) fn from_slot_tuple(attrs: SlotAttributes, markers: SlotMarkers) -> SampleSettingsFile {
    SampleSettingsFile {
        header: SAMPLES_HEADER,
        datatype_version: SAMPLES_FILE_VERSION,
        unknown: 0,
        tempo: attrs.bpm as u32,
        // TODO: bar len -- markers.trim_end - markers.trim_offset
        trim_len: 0,
        // TODO: bar len -- markers.trim_end - markers.loop_point
        loop_len: 0,
        stretch: attrs.timestrech_mode.into(),
        loop_mode: attrs.loop_mode.into(),
        gain: attrs.gain as u16,
        quantization: attrs.trig_quantization_mode.into(),
        trim_start: markers.trim_offset,
        trim_end: markers.trim_end,
        loop_start: markers.loop_point,
        slices: markers.slices,
        slices_len: markers.slice_count,
        checksum: 0,
    }
}

impl From<(SlotAttributes, SlotMarkers)> for SampleSettingsFile {
    fn from(value: (SlotAttributes, SlotMarkers)) -> Self {
        let (attrs, markers) = value;
        from_slot_tuple(attrs, markers)
    }
}

impl From<(&SlotAttributes, &SlotMarkers)> for SampleSettingsFile {
    fn from(value: (&SlotAttributes, &SlotMarkers)) -> Self {
        let (attrs, markers) = value;
        from_slot_tuple(attrs.clone(), markers.clone())
    }
}

#[cfg(test)]
mod sample_settings_from {
    use crate::projects::SlotsAttributes;
    use crate::samples::from_slot_tuple;
    use crate::MarkersFile;
    use crate::OtToolsIoError;
    use crate::SampleSettingsFile;
    #[test]
    fn from_slot_tuple_valid() -> Result<(), OtToolsIoError> {
        let slots = SlotsAttributes::default();
        let slot = slots
            .flex_slots
            .iter()
            .find(|x| x.is_some())
            .unwrap()
            .clone();
        let markers = MarkersFile::default().flex_slots[0].clone();
        from_slot_tuple(slot.unwrap(), markers);
        Ok(())
    }

    #[test]
    fn from_owned_valid() -> Result<(), OtToolsIoError> {
        let slots = SlotsAttributes::default();
        let slot = slots
            .flex_slots
            .iter()
            .find(|x| x.is_some())
            .unwrap()
            .clone();
        let markers = MarkersFile::default().flex_slots[0].clone();
        let _ = SampleSettingsFile::from((slot.unwrap(), markers));
        Ok(())
    }

    #[test]
    fn from_borrowed_valid() -> Result<(), OtToolsIoError> {
        let slots = SlotsAttributes::default();
        let slot = slots
            .flex_slots
            .iter()
            .find(|x| x.is_some())
            .unwrap()
            .clone();
        let markers = MarkersFile::default().flex_slots[0].clone();
        let _ = SampleSettingsFile::from((&slot.unwrap(), &markers));
        Ok(())
    }
}

/// A helper struct for the OT Sample's Trim settings

#[derive(PartialEq, Debug, Clone, Copy)]
pub struct TrimConfig {
    /// Start of full audio sample (n samples)
    pub start: u32,
    /// End of full audio sample (n samples)
    pub end: u32,
    /// Length of audio sample to play before stopping/looping playback
    /// NOTE: This is measured in number of bars.
    pub length: u32,
}

impl From<SampleSettingsFile> for TrimConfig {
    fn from(decoded: SampleSettingsFile) -> Self {
        Self {
            start: decoded.trim_start,
            end: decoded.trim_end,
            length: decoded.trim_len,
        }
    }
}

impl From<&SampleSettingsFile> for TrimConfig {
    fn from(decoded: &SampleSettingsFile) -> Self {
        Self::from(decoded.clone())
    }
}

impl From<SlotMarkers> for TrimConfig {
    fn from(value: SlotMarkers) -> Self {
        Self {
            start: value.trim_offset,
            end: value.trim_end,
            length: value.trim_end - value.trim_offset,
        }
    }
}

impl From<&SlotMarkers> for TrimConfig {
    fn from(value: &SlotMarkers) -> Self {
        Self::from(value.clone())
    }
}

#[cfg(test)]
mod trim_config_from {
    mod sample_settings {
        use crate::samples::test_utils::create_mock_new;
        use crate::samples::TrimConfig;
        use crate::OtToolsIoError;
        #[test]
        fn owned() -> Result<(), OtToolsIoError> {
            let s = create_mock_new(None, None)?;
            assert_eq!(
                TrimConfig::from(s),
                TrimConfig {
                    start: 0,
                    end: 0,
                    length: 0,
                }
            );
            Ok(())
        }
        #[test]
        fn borrowed() -> Result<(), OtToolsIoError> {
            let s = create_mock_new(None, None)?;
            assert_eq!(
                TrimConfig::from(&s),
                TrimConfig {
                    start: 0,
                    end: 0,
                    length: 0,
                }
            );
            Ok(())
        }
    }

    mod slot_markers {
        use crate::samples::TrimConfig;
        use crate::MarkersFile;
        use crate::OtToolsIoError;
        #[test]
        fn owned() -> Result<(), OtToolsIoError> {
            let markers = MarkersFile::default().flex_slots[0].clone();
            assert_eq!(
                TrimConfig::from(markers),
                TrimConfig {
                    start: 0,
                    end: 0,
                    length: 0,
                }
            );
            Ok(())
        }
        #[test]
        fn borrowed() -> Result<(), OtToolsIoError> {
            let markers = MarkersFile::default().flex_slots[0].clone();
            assert_eq!(
                TrimConfig::from(&markers),
                TrimConfig {
                    start: 0,
                    end: 0,
                    length: 0,
                }
            );
            Ok(())
        }
    }
}

/// A helper struct for the OT Sample's Loop settings

#[derive(PartialEq, Debug, Clone, Copy)]
pub struct LoopConfig {
    /// Loop start position for the audio sample (n samples).
    pub start: u32,

    /// Length of the loop for the audio sample (n samples).
    pub length: u32,

    /// Type of looping mode.
    pub mode: LoopMode,
}

impl LoopConfig {
    pub fn new(start: u32, length: u32, mode: LoopMode) -> Self {
        Self {
            start,
            length,
            mode,
        }
    }
}

#[cfg(test)]
mod loop_config_new {

    use crate::samples::{LoopConfig, LoopMode};

    #[test]
    fn test_new_sample_loop_config_loop_off() {
        assert_eq!(
            LoopConfig::new(0, 10, LoopMode::Off),
            LoopConfig {
                start: 0,
                length: 10,
                mode: LoopMode::Off
            }
        );
    }

    #[test]
    fn test_new_sample_loop_config_umin_start_umax_length() {
        assert_eq!(
            LoopConfig::new(u32::MIN, u32::MAX, LoopMode::Off),
            LoopConfig {
                start: u32::MIN,
                length: u32::MAX,
                mode: LoopMode::Off
            }
        );
    }

    #[test]
    fn test_new_sample_loop_config_loop_normal() {
        assert_eq!(
            LoopConfig::new(0, 10, LoopMode::Normal),
            LoopConfig {
                start: 0,
                length: 10,
                mode: LoopMode::Normal
            }
        );
    }

    #[test]
    fn test_new_sample_loop_config_loop_pingpong() {
        assert_eq!(
            LoopConfig::new(0, 10, LoopMode::PingPong),
            LoopConfig {
                start: 0,
                length: 10,
                mode: LoopMode::PingPong
            }
        );
    }
}

impl From<SampleSettingsFile> for LoopConfig {
    fn from(decoded: SampleSettingsFile) -> Self {
        Self::new(
            decoded.loop_start,
            decoded.loop_len,
            LoopMode::try_from(&(decoded.loop_mode as u8)).unwrap_or(LoopMode::default()),
        )
    }
}

impl From<&SampleSettingsFile> for LoopConfig {
    fn from(decoded: &SampleSettingsFile) -> Self {
        Self::from(decoded.clone())
    }
}

#[cfg(test)]
mod loop_config_from {
    use super::{
        test_utils::create_mock_new, LoopConfig, LoopMode, OtToolsIoError, SampleSettingsFile,
        Slices, DEFAULT_GAIN, DEFAULT_TEMPO, SAMPLES_FILE_VERSION, SAMPLES_HEADER,
    };

    #[test]
    fn owned() -> Result<(), OtToolsIoError> {
        let s = create_mock_new(None, None)?;
        assert_eq!(
            LoopConfig::from(s),
            LoopConfig {
                start: 0,
                length: 0,
                mode: LoopMode::default(),
            }
        );
        Ok(())
    }
    #[test]
    fn borrowed() -> Result<(), OtToolsIoError> {
        let s = create_mock_new(None, None)?;
        assert_eq!(
            LoopConfig::from(&s),
            LoopConfig {
                start: 0,
                length: 0,
                mode: LoopMode::default(),
            }
        );
        Ok(())
    }

    fn mock_for_loop_conf(
        loop_start: u32,
        loop_len: u32,
        loop_mode: LoopMode,
    ) -> SampleSettingsFile {
        SampleSettingsFile {
            loop_len,
            loop_start,
            loop_mode: loop_mode.into(),
            header: SAMPLES_HEADER,
            datatype_version: SAMPLES_FILE_VERSION,
            tempo: DEFAULT_TEMPO,
            unknown: 0,
            trim_len: 0,
            stretch: 0,
            gain: DEFAULT_GAIN,
            quantization: 0,
            trim_start: 0,
            trim_end: 0,
            slices: Slices::default().slices,
            slices_len: 0,
            checksum: 0,
        }
    }

    #[test]
    fn test_umin_start_umax_len() {
        assert_eq!(
            LoopConfig::from(mock_for_loop_conf(u32::MIN, u32::MAX, LoopMode::Off)),
            LoopConfig {
                start: u32::MIN,
                length: u32::MAX,
                mode: LoopMode::Off
            }
        );
    }

    #[test]
    fn test_loop_off() {
        assert_eq!(
            LoopConfig::from(mock_for_loop_conf(0, 10, LoopMode::Off)),
            LoopConfig {
                start: 0,
                length: 10,
                mode: LoopMode::Off
            }
        );
    }

    #[test]
    fn test_loop_normal() {
        assert_eq!(
            LoopConfig::from(mock_for_loop_conf(0, 10, LoopMode::Normal)),
            LoopConfig {
                start: 0,
                length: 10,
                mode: LoopMode::Normal
            }
        );
    }

    #[test]
    fn test_loop_pingpong() {
        assert_eq!(
            LoopConfig::from(mock_for_loop_conf(0, 10, LoopMode::PingPong)),
            LoopConfig {
                start: 0,
                length: 10,
                mode: LoopMode::PingPong
            }
        );
    }
}