//! State [`tower::Service`] response types.

use std::sync::Arc;

use zebra_chain::{
    block::{self, Block},
    transaction::Transaction,
    transparent,
};

// Allow *only* this unused import, so that rustdoc link resolution
// will work with inline links.
#[allow(unused_imports)]
use crate::Request;

#[derive(Clone, Debug, PartialEq, Eq)]
/// A response to a [`StateService`] [`Request`].
pub enum Response {
    /// Response to [`Request::CommitBlock`] indicating that a block was
    /// successfully committed to the state.
    Committed(block::Hash),

    /// Response to [`Request::Depth`] with the depth of the specified block.
    Depth(Option<u32>),

    /// Response to [`Request::Tip`] with the current best chain tip.
    Tip(Option<(block::Height, block::Hash)>),

    /// Response to [`Request::BlockLocator`] with a block locator object.
    BlockLocator(Vec<block::Hash>),

    /// Response to [`Request::Transaction`] with the specified transaction.
    Transaction(Option<Arc<Transaction>>),

    /// Response to [`Request::Block`] with the specified block.
    Block(Option<Arc<Block>>),

    /// The response to a `AwaitUtxo` request.
    Utxo(transparent::Utxo),

    /// The response to a `FindBlockHashes` request.
    BlockHashes(Vec<block::Hash>),

    /// The response to a `FindBlockHeaders` request.
    BlockHeaders(Vec<block::CountedHeader>),
}

#[derive(Clone, Debug, PartialEq, Eq)]
/// A response to a read-only [`ReadStateService`] [`ReadRequest`].
pub enum ReadResponse {
    /// Response to [`ReadRequest::Block`] with the specified block.
    Block(Option<Arc<Block>>),

    /// Response to [`ReadRequest::Transaction`] with the specified transaction.
    Transaction(Option<Arc<Transaction>>),
}