//! The operations a commit claims it applied.

use crate::cid::Cid;
use crate::error::OpKind;
use crate::key::Key;

/// One record operation from a firehose commit, as inversion needs it.
///
/// Every variant carries the previous value, because sync 1.1 requires
/// producers to send it: without it an operation cannot be inverted at all.
#[derive(Debug, Clone, PartialEq, Eq)]
pub enum Op {
    /// A record appeared at `key` holding `cid`.
    Create { key: Key, cid: Cid },
    /// The record at `key` changed from `prev` to `cid`.
    Update { key: Key, cid: Cid, prev: Cid },
    /// The record at `key`, which held `prev`, went away.
    Delete { key: Key, prev: Cid },
}

impl Op {
    pub fn key(&self) -> &Key {
        match self {
            Op::Create { key, .. } | Op::Update { key, .. } | Op::Delete { key, .. } => key,
        }
    }

    pub fn kind(&self) -> OpKind {
        match self {
            Op::Create { .. } => OpKind::Create,
            Op::Update { .. } => OpKind::Update,
            Op::Delete { .. } => OpKind::Delete,
        }
    }
}