use err::Error;
use futures_util::{Stream, StreamExt};
use items::{RangeCompletableItem, Sitemty, StreamItem};
use items_0::collect_c::Collectable;
use netpod::{log::*, BinnedRange, NanoRange};
use std::fmt;
use std::time::{Duration, Instant};
use tracing::Instrument;

#[allow(unused)]
macro_rules! trace2 {
    (D$($arg:tt)*) => ();
    ($($arg:tt)*) => (eprintln!($($arg)*));
}

#[allow(unused)]
macro_rules! trace3 {
    (D$($arg:tt)*) => ();
    ($($arg:tt)*) => (eprintln!($($arg)*));
}

#[allow(unused)]
macro_rules! trace4 {
    (D$($arg:tt)*) => ();
    ($($arg:tt)*) => (eprintln!($($arg)*));
}

async fn collect_in_span<T, S>(
    stream: S,
    deadline: Instant,
    events_max: u64,
    range: Option<NanoRange>,
    binrange: Option<BinnedRange>,
) -> Result<Box<dyn items_0::collect_c::Collected>, Error>
where
    S: Stream<Item = Sitemty<T>> + Unpin,
    T: Collectable + items_0::WithLen + fmt::Debug,
{
    let mut collector: Option<Box<dyn items_0::collect_c::Collector>> = None;
    let mut stream = stream;
    let deadline = deadline.into();
    let mut range_complete = false;
    let mut timed_out = false;
    let mut total_duration = Duration::ZERO;
    loop {
        let item = match tokio::time::timeout_at(deadline, stream.next()).await {
            Ok(Some(k)) => k,
            Ok(None) => break,
            Err(_e) => {
                warn!("collect_in_span time out");
                timed_out = true;
                if let Some(coll) = collector.as_mut() {
                    coll.set_timed_out();
                } else {
                    warn!("Timeout but no collector yet");
                }
                break;
            }
        };
        trace!("collect_in_span see item {item:?}");
        match item {
            Ok(item) => match item {
                StreamItem::DataItem(item) => match item {
                    RangeCompletableItem::RangeComplete => {
                        range_complete = true;
                        if let Some(coll) = collector.as_mut() {
                            coll.set_range_complete();
                        } else {
                            warn!("Received RangeComplete but no collector yet");
                        }
                    }
                    RangeCompletableItem::Data(mut item) => {
                        debug!("collect_in_span sees len {}", item.len());
                        if collector.is_none() {
                            let c = item.new_collector();
                            collector = Some(c);
                        }
                        let coll = collector.as_mut().unwrap();
                        coll.ingest(&mut item);
                        if coll.len() as u64 >= events_max {
                            warn!("Reached events_max {} abort", events_max);
                            break;
                        }
                    }
                },
                StreamItem::Log(item) => {
                    trace!("Log {:?}", item);
                }
                StreamItem::Stats(item) => {
                    trace!("Stats {:?}", item);
                    use items::StatsItem;
                    use netpod::DiskStats;
                    match item {
                        // TODO factor and simplify the stats collection:
                        StatsItem::EventDataReadStats(_) => {}
                        StatsItem::RangeFilterStats(_) => {}
                        StatsItem::DiskStats(item) => match item {
                            DiskStats::OpenStats(k) => {
                                total_duration += k.duration;
                            }
                            DiskStats::SeekStats(k) => {
                                total_duration += k.duration;
                            }
                            DiskStats::ReadStats(k) => {
                                total_duration += k.duration;
                            }
                            DiskStats::ReadExactStats(k) => {
                                total_duration += k.duration;
                            }
                        },
                    }
                }
            },
            Err(e) => {
                // TODO  Need to use some flags to get good enough error message for remote user.
                return Err(e);
            }
        }
    }
    let _ = range_complete;
    let _ = timed_out;
    let res = collector
        .ok_or_else(|| Error::with_msg_no_trace(format!("no result because no collector was created")))?
        .result(range, binrange)?;
    debug!("Total duration: {:?}", total_duration);
    Ok(res)
}

pub async fn collect<T, S>(
    stream: S,
    deadline: Instant,
    events_max: u64,
    range: Option<NanoRange>,
    binrange: Option<BinnedRange>,
) -> Result<Box<dyn items_0::collect_c::Collected>, Error>
where
    S: Stream<Item = Sitemty<T>> + Unpin,
    T: Collectable + items_0::WithLen + fmt::Debug,
{
    let span = tracing::span!(tracing::Level::TRACE, "collect");
    collect_in_span(stream, deadline, events_max, range, binrange)
        .instrument(span)
        .await
}