#![allow(clippy::or_fun_call, clippy::expect_fun_call, dead_code)]

use std::{
    collections::BTreeMap,
    convert::TryFrom,
    sync::{Arc, Once},
    time::UNIX_EPOCH,
};

use ruma::{
    events::{
        room::{
            join_rules::JoinRule,
            member::{MemberEventContent, MembershipState},
        },
        EventType,
    },
    identifiers::{EventId, RoomId, RoomVersionId, UserId},
};
use serde_json::{json, Value as JsonValue};
use state_res::{Error, Result, StateEvent, StateMap, StateResolution, StateStore};
use tracing_subscriber as tracer;

pub static LOGGER: Once = Once::new();

static mut SERVER_TIMESTAMP: i32 = 0;

pub fn do_check(
    events: &[Arc<StateEvent>],
    edges: Vec<Vec<EventId>>,
    expected_state_ids: Vec<EventId>,
) {
    // to activate logging use `RUST_LOG=debug cargo t`
    let _ = LOGGER.call_once(|| {
        tracer::fmt()
            .with_env_filter(tracer::EnvFilter::from_default_env())
            .init()
    });

    let mut store = TestStore(
        INITIAL_EVENTS()
            .values()
            .chain(events)
            .map(|ev| (ev.event_id(), ev.clone()))
            .collect(),
    );

    // This will be lexi_topo_sorted for resolution
    let mut graph = BTreeMap::new();
    // this is the same as in `resolve` event_id -> StateEvent
    let mut fake_event_map = BTreeMap::new();

    // create the DB of events that led up to this point
    // TODO maybe clean up some of these clones it is just tests but...
    for ev in INITIAL_EVENTS().values().chain(events) {
        graph.insert(ev.event_id().clone(), vec![]);
        fake_event_map.insert(ev.event_id().clone(), ev.clone());
    }

    for pair in INITIAL_EDGES().windows(2) {
        if let [a, b] = &pair {
            graph.entry(a.clone()).or_insert(vec![]).push(b.clone());
        }
    }

    for edge_list in edges {
        for pair in edge_list.windows(2) {
            if let [a, b] = &pair {
                graph.entry(a.clone()).or_insert(vec![]).push(b.clone());
            }
        }
    }

    // event_id -> StateEvent
    let mut event_map: BTreeMap<EventId, Arc<StateEvent>> = BTreeMap::new();
    // event_id -> StateMap<EventId>
    let mut state_at_event: BTreeMap<EventId, StateMap<EventId>> = BTreeMap::new();

    // resolve the current state and add it to the state_at_event map then continue
    // on in "time"
    for node in
        StateResolution::lexicographical_topological_sort(&graph, |id| (0, UNIX_EPOCH, id.clone()))
    {
        let fake_event = fake_event_map.get(&node).unwrap();
        let event_id = fake_event.event_id();

        let prev_events = graph.get(&node).unwrap();

        let state_before: StateMap<EventId> = if prev_events.is_empty() {
            BTreeMap::new()
        } else if prev_events.len() == 1 {
            state_at_event.get(&prev_events[0]).unwrap().clone()
        } else {
            let state_sets = prev_events
                .iter()
                .filter_map(|k| state_at_event.get(k))
                .cloned()
                .collect::<Vec<_>>();

            tracing::info!(
                "{:#?}",
                state_sets
                    .iter()
                    .map(|map| map
                        .iter()
                        .map(|((ty, key), id)| format!("(({}{:?}), {})", ty, key, id))
                        .collect::<Vec<_>>())
                    .collect::<Vec<_>>()
            );

            let resolved = StateResolution::resolve(
                &room_id(),
                &RoomVersionId::Version6,
                &state_sets,
                Some(event_map.clone()),
                &store,
            );
            match resolved {
                Ok(state) => state,
                Err(e) => panic!("resolution for {} failed: {}", node, e),
            }
        };

        let mut state_after = state_before.clone();

        // if fake_event.state_key().is_some() {
        let ty = fake_event.kind().clone();
        // we know there is a state_key unwrap OK
        let key = fake_event.state_key().clone();
        state_after.insert((ty, key), event_id.clone());
        // }

        let auth_types = state_res::auth_types_for_event(
            fake_event.kind(),
            fake_event.sender(),
            Some(fake_event.state_key()),
            fake_event.content().clone(),
        );

        let mut auth_events = vec![];
        for key in auth_types {
            if state_before.contains_key(&key) {
                auth_events.push(state_before[&key].clone())
            }
        }

        // TODO The event is just remade, adding the auth_events and prev_events here
        // the `to_pdu_event` was split into `init` and the fn below, could be better
        let e = fake_event;
        let ev_id = e.event_id();
        let event = to_pdu_event(
            &e.event_id().to_string(),
            e.sender().clone(),
            e.kind(),
            Some(e.state_key()).as_deref(),
            e.content().clone(),
            &auth_events,
            prev_events,
        );

        // This can be used to sort of test this function
        // match StateResolution::apply_event(
        //     &room_id(),
        //     &RoomVersionId::Version6,
        //     Arc::clone(&event),
        //     &state_after,
        //     Some(event_map.clone()),
        //     &store,
        // ) {
        //     Ok(res) => {
        //         println!(
        //             "res contains: {} passed: {} for {}\n{:?}",
        //             state_after
        //                 .get(&(event.kind(), event.state_key()))
        //                 .map(|id| id == &ev_id)
        //                 .unwrap_or_default(),
        //             res,
        //             event.event_id().as_str(),
        //             event
        //                 .prev_event_ids()
        //                 .iter()
        //                 .map(|id| id.to_string())
        //                 .collect::<Vec<_>>()
        //         );
        //     }
        //     Err(e) => panic!("resolution for {} failed: {}", node, e),
        // }

        // we have to update our store, an actual user of this lib would
        // be giving us state from a DB.
        store.0.insert(ev_id.clone(), event.clone());

        state_at_event.insert(node, state_after);
        event_map.insert(event_id.clone(), Arc::clone(store.0.get(&ev_id).unwrap()));
    }

    let mut expected_state = StateMap::new();
    for node in expected_state_ids {
        let ev = event_map.get(&node).expect(&format!(
            "{} not found in {:?}",
            node.to_string(),
            event_map
                .keys()
                .map(ToString::to_string)
                .collect::<Vec<_>>(),
        ));

        let key = (ev.kind(), ev.state_key());

        expected_state.insert(key, node);
    }

    let start_state = state_at_event.get(&event_id("$START:foo")).unwrap();

    let end_state = state_at_event
        .get(&event_id("$END:foo"))
        .unwrap()
        .iter()
        .filter(|(k, v)| expected_state.contains_key(k) || start_state.get(k) != Some(*v))
        .map(|(k, v)| (k.clone(), v.clone()))
        .collect::<StateMap<EventId>>();

    assert_eq!(expected_state, end_state);
}

pub struct TestStore(pub BTreeMap<EventId, Arc<StateEvent>>);

#[allow(unused)]
impl StateStore for TestStore {
    fn get_event(&self, room_id: &RoomId, event_id: &EventId) -> Result<Arc<StateEvent>> {
        self.0
            .get(event_id)
            .map(Arc::clone)
            .ok_or_else(|| Error::NotFound(format!("{} not found", event_id.to_string())))
    }
}

pub fn event_id(id: &str) -> EventId {
    if id.contains('$') {
        return EventId::try_from(id).unwrap();
    }
    EventId::try_from(format!("${}:foo", id)).unwrap()
}

pub fn alice() -> UserId {
    UserId::try_from("@alice:foo").unwrap()
}
pub fn bob() -> UserId {
    UserId::try_from("@bob:foo").unwrap()
}
pub fn charlie() -> UserId {
    UserId::try_from("@charlie:foo").unwrap()
}
pub fn ella() -> UserId {
    UserId::try_from("@ella:foo").unwrap()
}
pub fn zara() -> UserId {
    UserId::try_from("@zara:foo").unwrap()
}

pub fn room_id() -> RoomId {
    RoomId::try_from("!test:foo").unwrap()
}

pub fn member_content_ban() -> JsonValue {
    serde_json::to_value(MemberEventContent {
        membership: MembershipState::Ban,
        displayname: None,
        avatar_url: None,
        is_direct: None,
        third_party_invite: None,
    })
    .unwrap()
}

pub fn member_content_join() -> JsonValue {
    serde_json::to_value(MemberEventContent {
        membership: MembershipState::Join,
        displayname: None,
        avatar_url: None,
        is_direct: None,
        third_party_invite: None,
    })
    .unwrap()
}

pub fn to_init_pdu_event(
    id: &str,
    sender: UserId,
    ev_type: EventType,
    state_key: Option<&str>,
    content: JsonValue,
) -> Arc<StateEvent> {
    let ts = unsafe {
        let ts = SERVER_TIMESTAMP;
        // increment the "origin_server_ts" value
        SERVER_TIMESTAMP += 1;
        ts
    };
    let id = if id.contains('$') {
        id.to_string()
    } else {
        format!("${}:foo", id)
    };

    let json = if let Some(state_key) = state_key {
        json!({
            "auth_events": [],
            "prev_events": [],
            "event_id": id,
            "sender": sender,
            "type": ev_type,
            "state_key": state_key,
            "content": content,
            "origin_server_ts": ts,
            "room_id": room_id(),
            "origin": "foo",
            "depth": 0,
            "hashes": { "sha256": "hello" },
            "signatures": {},
        })
    } else {
        json!({
            "auth_events": [],
            "prev_events": [],
            "event_id": id,
            "sender": sender,
            "type": ev_type,
            "content": content,
            "origin_server_ts": ts,
            "room_id": room_id(),
            "origin": "foo",
            "depth": 0,
            "hashes": { "sha256": "hello" },
            "signatures": {},
        })
    };
    Arc::new(serde_json::from_value(json).unwrap())
}

pub fn to_pdu_event<S>(
    id: &str,
    sender: UserId,
    ev_type: EventType,
    state_key: Option<&str>,
    content: JsonValue,
    auth_events: &[S],
    prev_events: &[S],
) -> Arc<StateEvent>
where
    S: AsRef<str>,
{
    let ts = unsafe {
        let ts = SERVER_TIMESTAMP;
        // increment the "origin_server_ts" value
        SERVER_TIMESTAMP += 1;
        ts
    };
    let id = if id.contains('$') {
        id.to_string()
    } else {
        format!("${}:foo", id)
    };
    let auth_events = auth_events
        .iter()
        .map(AsRef::as_ref)
        .map(event_id)
        .collect::<Vec<_>>();
    let prev_events = prev_events
        .iter()
        .map(AsRef::as_ref)
        .map(event_id)
        .collect::<Vec<_>>();

    let json = if let Some(state_key) = state_key {
        json!({
            "auth_events": auth_events,
            "prev_events": prev_events,
            "event_id": id,
            "sender": sender,
            "type": ev_type,
            "state_key": state_key,
            "content": content,
            "origin_server_ts": ts,
            "room_id": room_id(),
            "origin": "foo",
            "depth": 0,
            "hashes": { "sha256": "hello" },
            "signatures": {},
        })
    } else {
        json!({
            "auth_events": auth_events,
            "prev_events": prev_events,
            "event_id": id,
            "sender": sender,
            "type": ev_type,
            "content": content,
            "origin_server_ts": ts,
            "room_id": room_id(),
            "origin": "foo",
            "depth": 0,
            "hashes": { "sha256": "hello" },
            "signatures": {},
        })
    };
    Arc::new(serde_json::from_value(json).unwrap())
}

// all graphs start with these input events
#[allow(non_snake_case)]
pub fn INITIAL_EVENTS() -> BTreeMap<EventId, Arc<StateEvent>> {
    // this is always called so we can init the logger here
    let _ = LOGGER.call_once(|| {
        tracer::fmt()
            .with_env_filter(tracer::EnvFilter::from_default_env())
            .init()
    });

    vec![
        to_pdu_event::<EventId>(
            "CREATE",
            alice(),
            EventType::RoomCreate,
            Some(""),
            json!({ "creator": alice() }),
            &[],
            &[],
        ),
        to_pdu_event(
            "IMA",
            alice(),
            EventType::RoomMember,
            Some(alice().to_string().as_str()),
            member_content_join(),
            &["CREATE"],
            &["CREATE"],
        ),
        to_pdu_event(
            "IPOWER",
            alice(),
            EventType::RoomPowerLevels,
            Some(""),
            json!({"users": {alice().to_string(): 100}}),
            &["CREATE", "IMA"],
            &["IMA"],
        ),
        to_pdu_event(
            "IJR",
            alice(),
            EventType::RoomJoinRules,
            Some(""),
            json!({ "join_rule": JoinRule::Public }),
            &["CREATE", "IMA", "IPOWER"],
            &["IPOWER"],
        ),
        to_pdu_event(
            "IMB",
            bob(),
            EventType::RoomMember,
            Some(bob().to_string().as_str()),
            member_content_join(),
            &["CREATE", "IJR", "IPOWER"],
            &["IJR"],
        ),
        to_pdu_event(
            "IMC",
            charlie(),
            EventType::RoomMember,
            Some(charlie().to_string().as_str()),
            member_content_join(),
            &["CREATE", "IJR", "IPOWER"],
            &["IMB"],
        ),
        to_pdu_event::<EventId>(
            "START",
            charlie(),
            EventType::RoomTopic,
            Some(""),
            json!({}),
            &[],
            &[],
        ),
        to_pdu_event::<EventId>(
            "END",
            charlie(),
            EventType::RoomTopic,
            Some(""),
            json!({}),
            &[],
            &[],
        ),
    ]
    .into_iter()
    .map(|ev| (ev.event_id(), ev))
    .collect()
}

#[allow(non_snake_case)]
pub fn INITIAL_EDGES() -> Vec<EventId> {
    vec!["START", "IMC", "IMB", "IJR", "IPOWER", "IMA", "CREATE"]
        .into_iter()
        .map(event_id)
        .collect::<Vec<_>>()
}