/// Possible downstream states during request multiplexing
#[derive(Debug, Clone, Copy)]
pub(crate) enum DownstreamStateMachine {
    /// more request (body) to read
    Reading,
    /// no more data to read
    ReadingFinished,
    /// downstream is already errored or closed
    Errored,
}

#[allow(clippy::wrong_self_convention)]
impl DownstreamStateMachine {
    pub fn new(finished: bool) -> Self {
        if finished {
            Self::ReadingFinished
        } else {
            Self::Reading
        }
    }

    // Can call read() to read more data or wait on closing
    pub fn can_poll(&self) -> bool {
        !matches!(self, Self::Errored)
    }

    pub fn is_reading(&self) -> bool {
        matches!(self, Self::Reading)
    }

    pub fn is_done(&self) -> bool {
        !matches!(self, Self::Reading)
    }

    pub fn is_errored(&self) -> bool {
        matches!(self, Self::Errored)
    }

    /// Move the state machine to Finished state if `set` is true
    pub fn maybe_finished(&mut self, set: bool) {
        if set {
            *self = Self::ReadingFinished
        }
    }

    pub fn to_errored(&mut self) {
        *self = Self::Errored
    }
}

/// Possible upstream states during request multiplexing
#[derive(Debug, Clone, Copy)]
pub(crate) struct ResponseStateMachine {
    upstream_response_done: bool,
    cached_response_done: bool,
}

impl ResponseStateMachine {
    pub fn new() -> Self {
        ResponseStateMachine {
            upstream_response_done: false,
            cached_response_done: true, // no cached response by default
        }
    }

    pub fn is_done(&self) -> bool {
        self.upstream_response_done && self.cached_response_done
    }

    pub fn upstream_done(&self) -> bool {
        self.upstream_response_done
    }

    pub fn cached_done(&self) -> bool {
        self.cached_response_done
    }

    pub fn enable_cached_response(&mut self) {
        self.cached_response_done = false;
    }

    pub fn maybe_set_upstream_done(&mut self, done: bool) {
        if done {
            self.upstream_response_done = true;
        }
    }

    pub fn maybe_set_cache_done(&mut self, done: bool) {
        if done {
            self.cached_response_done = true;
        }
    }
}