//! Alignment record data field tag.

use std::{borrow::Borrow, fmt};

use bstr::ByteSlice;

/// An alignment record data field tag.
#[derive(Clone, Copy, Eq, Hash, Ord, PartialEq, PartialOrd)]
pub struct Tag([u8; 2]);

impl Tag {
    /// The smallest template-independent mapping quality in the template (`AM`).
    pub const MIN_MAPPING_QUALITY: Self = Self::new(b'A', b'M');

    /// Alignment score generated by aligner (`AS`).
    pub const ALIGNMENT_SCORE: Self = Self::new(b'A', b'S');

    /// Barcode sequence identifying the sample (`BC`).
    pub const SAMPLE_BARCODE_SEQUENCE: Self = Self::new(b'B', b'C');

    /// Offset to base alignment quality (BAQ) (`BQ`).
    pub const BASE_ALIGNMENT_QUALITY_OFFSETS: Self = Self::new(b'B', b'Q');

    /// Phred quality of the unique molecular barcode bases in the `OX` tag (`BZ`).
    pub const ORIGINAL_UMI_QUALITY_SCORES: Self = Self::new(b'O', b'X');

    /// Cell identifier (`CB`).
    pub const CELL_BARCODE_ID: Self = Self::new(b'C', b'B');

    /// Reference name of the next hit (`CC`).
    pub const NEXT_HIT_REFERENCE_SEQUENCE_NAME: Self = Self::new(b'C', b'C');

    /// BAM only: `CIGAR` in BAM's binary encoding if (and only if) it consists of > 65535 operators
    /// (`CG`).
    pub const CIGAR: Self = Self::new(b'C', b'G');

    /// Edit distance between the color sequence and the color reference (see also `NM`) (`CM`).
    pub const COLOR_EDIT_DISTANCE: Self = Self::new(b'C', b'M');

    /// Free-text comments (`CO`).
    pub const COMMENT: Self = Self::new(b'C', b'O');

    /// Leftmost coordinate of the next hit (`CP`).
    pub const NEXT_HIT_POSITION: Self = Self::new(b'C', b'P');

    /// Color read base qualities (`CQ`).
    pub const COLOR_QUALITY_SCORES: Self = Self::new(b'C', b'Q');

    /// Cellular barcode sequence bases (uncorrected) (`CR`).
    pub const CELL_BARCODE_SEQUENCE: Self = Self::new(b'C', b'R');

    /// Color read sequence (`CS`).
    pub const COLOR_SEQUENCE: Self = Self::new(b'C', b'S');

    /// Complete read annotation tag, used for consensus annotation dummy features (`CT`).
    pub const COMPLETE_READ_ANNOTATIONS: Self = Self::new(b'C', b'T');

    /// Phred quality of the cellular barcode sequence in the `CR` tag (`CY`).
    pub const CELL_BARCODE_QUALITY_SCORES: Self = Self::new(b'C', b'Y');

    /// The 2nd most likely base calls (`E2`).
    pub const NEXT_HIT_SEQUENCE: Self = Self::new(b'E', b'2');

    /// The index of segment in the template (`FI`).
    pub const SEGMENT_INDEX: Self = Self::new(b'F', b'I');

    /// Segment suffix (`FS`).
    pub const SEGMENT_SUFFIX: Self = Self::new(b'F', b'S');

    /// Flow signal intensities (`FZ`).
    pub const ALTERNATIVE_SEQUENCE: Self = Self::new(b'F', b'Z');

    /// Reserved for backwards compatibility reasons (`GC`).
    pub const RESERVED_GC: Self = Self::new(b'G', b'C');

    /// Reserved for backwards compatibility reasons (`GQ`).
    pub const RESERVED_GQ: Self = Self::new(b'G', b'Q');

    /// Reserved for backwards compatibility reasons (`GS`).
    pub const RESERVED_GS: Self = Self::new(b'G', b'S');

    /// Number of perfect hits (`H0`).
    pub const PERFECT_HIT_COUNT: Self = Self::new(b'H', b'0');

    /// Number of 1-difference hits (see also `NM`) (`H1`).
    pub const ONE_DIFFERENCE_HIT_COUNT: Self = Self::new(b'H', b'1');

    /// Number of 2-difference hits (`H2`).
    pub const TWO_DIFFERENCE_HIT_COUNT: Self = Self::new(b'H', b'2');

    /// Query hit index (`HI`).
    pub const HIT_INDEX: Self = Self::new(b'H', b'I');

    /// Query hit total count (`IH`).
    pub const TOTAL_HIT_COUNT: Self = Self::new(b'I', b'H');

    /// Library (`LB`).
    pub const LIBRARY: Self = Self::new(b'L', b'B');

    /// CIGAR string for mate/next segment (`MC`).
    pub const MATE_CIGAR: Self = Self::new(b'M', b'C');

    /// String encoding mismatched and deleted reference bases (`MD`).
    pub const MISMATCHED_POSITIONS: Self = Self::new(b'M', b'D');

    /// Reserved for backwards compatibility reasons (`MF`).
    pub const RESERVED_MF: Self = Self::new(b'M', b'F');

    /// Molecular identifier (`MI`).
    ///
    /// A string that uniquely identifies the molecule from which the record was derived.
    pub const UMI_ID: Self = Self::new(b'M', b'I');

    /// Base modification probabilities (`ML`).
    pub const BASE_MODIFICATION_PROBABILITIES: Self = Self::new(b'M', b'L');

    /// Base modifications / methylation (`MM`).
    pub const BASE_MODIFICATIONS: Self = Self::new(b'M', b'M');

    /// Length of sequence at the time `MM` and `ML` were produced (`MN`).
    pub const BASE_MODIFICATION_SEQUENCE_LENGTH: Self = Self::new(b'M', b'N');

    /// Mapping quality of the mate/next segment (`MQ`).
    pub const MATE_MAPPING_QUALITY: Self = Self::new(b'M', b'Q');

    /// Number of reported alignments that contain the query in the current record (`NH`).
    pub const ALIGNMENT_HIT_COUNT: Self = Self::new(b'N', b'H');

    /// Edit distance to the reference (`NM`).
    pub const EDIT_DISTANCE: Self = Self::new(b'N', b'M');

    /// Original alignment (`OA`).
    pub const ORIGINAL_ALIGNMENT: Self = Self::new(b'O', b'A');

    /// Original CIGAR (deprecated; use `OA` instead) (`OC`).
    pub const ORIGINAL_CIGAR: Self = Self::new(b'O', b'C');

    /// Original mapping position (deprecated; use `OA` instead) (`OP`).
    pub const ORIGINAL_POSITION: Self = Self::new(b'O', b'P');

    /// Original base quality (`OQ`).
    pub const ORIGINAL_QUALITY_SCORES: Self = Self::new(b'O', b'Q');

    /// Original unique molecular barcode bases (`OX`).
    pub const ORIGINAL_UMI_BARCODE_SEQUENCE: Self = Self::new(b'O', b'X');

    /// Program (`PG`).
    pub const PROGRAM: Self = Self::new(b'P', b'G');

    /// Phred likelihood of the template (`PQ`).
    pub const TEMPLATE_LIKELIHOOD: Self = Self::new(b'P', b'Q');

    /// Read annotations for parse of the padded read sequence (`PT`).
    pub const PADDED_READ_ANNOTATIONS: Self = Self::new(b'P', b'T');

    /// Platform unit (`PU`).
    pub const PLATFORM_UNIT: Self = Self::new(b'P', b'U');

    /// Phred quality of the mate/next segment sequence in the `R2` tag (`Q2`).
    pub const MATE_QUALITY_SCORES: Self = Self::new(b'Q', b'2');

    /// Phred quality of the sample barcode sequence in the `BC` tag (`QT`).
    pub const SAMPLE_BARCODE_QUALITY_SCORES: Self = Self::new(b'Q', b'T');

    /// Quality score of the unique molecular identifier in the `RX` tag (`QX`).
    pub const UMI_QUALITY_SCORES: Self = Self::new(b'Q', b'X');

    /// Sequence of the mate/next segment in the template (`R2`).
    pub const MATE_SEQUENCE: Self = Self::new(b'R', b'2');

    /// Read group (`RG`).
    pub const READ_GROUP: Self = Self::new(b'R', b'G');

    /// Reserved for backwards compatibility reasons (`RT`).
    pub const RESERVED_RT: Self = Self::new(b'R', b'T');

    /// Sequence bases of the (possibly corrected) unique molecular identifier (`RX`).
    pub const UMI_SEQUENCE: Self = Self::new(b'R', b'X');

    /// Reserved for backwards compatibility reasons (`S2`).
    pub const RESERVED_S2: Self = Self::new(b'S', b'2');

    /// Other canonical alignments in a chimeric alignment (`SA`).
    pub const OTHER_ALIGNMENTS: Self = Self::new(b'S', b'A');

    /// Template-independent mapping quality (`SM`).
    pub const TEMPLATE_MAPPING_QUALITY: Self = Self::new(b'S', b'M');

    /// Reserved for backwards compatibility reasons (`SQ`).
    pub const RESERVED_SQ: Self = Self::new(b'S', b'Q');

    /// The number of segments in the template (`TC`).
    pub const SEGMENT_COUNT: Self = Self::new(b'T', b'C');

    /// Transcript strand (`TS`).
    pub const TRANSCRIPT_STRAND: Self = Self::new(b'T', b'S');

    /// Phred probability of the 2nd call being wrong conditional on the best being wrong (`U2`).
    pub const NEXT_HIT_QUALITY_SCORES: Self = Self::new(b'U', b'2');

    /// Phred likelihood of the segment, conditional on the mapping being correct (`UQ`).
    pub const SEGMENT_LIKELIHOOD: Self = Self::new(b'U', b'Q');

    /// Creates a tag.
    ///
    /// # Examples
    ///
    /// ```
    /// use noodles_sam::alignment::record::data::field::Tag;
    /// let tag = Tag::new(b'x', b'n');
    /// ```
    pub const fn new(a: u8, b: u8) -> Self {
        Self([a, b])
    }
}

impl fmt::Debug for Tag {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_tuple("Tag")
            .field(&self.as_ref().as_bstr())
            .finish()
    }
}

impl AsRef<[u8; 2]> for Tag {
    fn as_ref(&self) -> &[u8; 2] {
        &self.0
    }
}

impl Borrow<[u8; 2]> for Tag {
    fn borrow(&self) -> &[u8; 2] {
        self.as_ref()
    }
}

impl From<[u8; 2]> for Tag {
    fn from(buf: [u8; 2]) -> Self {
        Self(buf)
    }
}

impl PartialEq<[u8; 2]> for Tag {
    fn eq(&self, other: &[u8; 2]) -> bool {
        self.as_ref().eq(other)
    }
}

impl From<Tag> for [u8; 2] {
    fn from(tag: Tag) -> Self {
        tag.0
    }
}

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

    #[test]
    fn test_fmt_debug() {
        assert_eq!(format!("{:?}", Tag::ALIGNMENT_HIT_COUNT), r#"Tag("NH")"#);
    }
}