use serde::{Deserialize, Serialize};
use zerocopy::{AsBytes, FromBytes};

/// Represent an internally generated document unique identifier.
///
/// It is used to inform the database the document you want to deserialize.
/// Helpful for custom ranking.
#[derive(
    Debug,
    Copy,
    Clone,
    Eq,
    PartialEq,
    PartialOrd,
    Ord,
    Hash,
    Serialize,
    Deserialize,
    AsBytes,
    FromBytes,
)]
#[repr(C)]
pub struct DocumentId(pub u64);

/// This structure represent the position of a word
/// in a document and its attributes.
///
/// This is stored in the map, generated at index time,
/// extracted and interpreted at search time.
#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, AsBytes, FromBytes)]
#[repr(C)]
pub struct DocIndex {
    /// The document identifier where the word was found.
    pub document_id: DocumentId,

    /// The attribute in the document where the word was found
    /// along with the index in it.
    pub attribute: u16,
    pub word_index: u16,

    /// The position in bytes where the word was found
    /// along with the length of it.
    ///
    /// It informs on the original word area in the text indexed
    /// without needing to run the tokenizer again.
    pub char_index: u16,
    pub char_length: u16,
}

/// This structure represent a matching word with informations
/// on the location of the word in the document.
///
/// The order of the field is important because it defines
/// the way these structures are ordered between themselves.
#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct Highlight {
    /// The attribute in the document where the word was found
    /// along with the index in it.
    pub attribute: u16,

    /// The position in bytes where the word was found.
    ///
    /// It informs on the original word area in the text indexed
    /// without needing to run the tokenizer again.
    pub char_index: u16,

    /// The length in bytes of the found word.
    ///
    /// It informs on the original word area in the text indexed
    /// without needing to run the tokenizer again.
    pub char_length: u16,
}