use super::Event;
use crate::{
    client::Client, events::trade::cancel_trade_for, metrics::PlayerMetrics,
    persistence::character_updater::CharacterUpdater, presence::Presence, state_ext::StateExt,
    BattleModeBuffer, Server,
};
use common::{
    comp,
    comp::{group, pet::is_tameable},
    uid::{Uid, UidAllocator},
};
use common_base::span;
use common_net::msg::{PlayerListUpdate, PresenceKind, ServerGeneral};
use common_state::State;
use specs::{saveload::MarkerAllocator, Builder, Entity as EcsEntity, Join, WorldExt};
use tracing::{debug, error, trace, warn, Instrument};

pub fn handle_exit_ingame(server: &mut Server, entity: EcsEntity) {
    span!(_guard, "handle_exit_ingame");
    let state = server.state_mut();

    // Sync the player's character data to the database. This must be done before
    // removing any components from the entity
    let entity = persist_entity(state, entity);

    // Create new entity with just `Client`, `Uid`, `Player`, and `...Stream`
    // components Easier than checking and removing all other known components
    // Note: If other `ServerEvent`s are referring to this entity they will be
    // disrupted

    let maybe_admin = state.ecs().write_storage::<comp::Admin>().remove(entity);
    let maybe_group = state
        .ecs()
        .write_storage::<group::Group>()
        .get(entity)
        .cloned();

    if let Some((client, uid, player)) = (|| {
        let ecs = state.ecs();
        Some((
            ecs.write_storage::<Client>().remove(entity)?,
            ecs.write_storage::<Uid>().remove(entity)?,
            ecs.write_storage::<comp::Player>().remove(entity)?,
        ))
    })() {
        // Tell client its request was successful
        client.send_fallible(ServerGeneral::ExitInGameSuccess);

        let entity_builder = state.ecs_mut().create_entity().with(client).with(player);

        // Preserve group component if present
        let entity_builder = match maybe_group {
            Some(group) => entity_builder.with(group),
            None => entity_builder,
        };

        // Preserve admin component if present
        let entity_builder = match maybe_admin {
            Some(admin) => entity_builder.with(admin),
            None => entity_builder,
        };

        // Ensure UidAllocator maps this uid to the new entity
        let uid = entity_builder
            .world
            .write_resource::<UidAllocator>()
            .allocate(entity_builder.entity, Some(uid.into()));
        let new_entity = entity_builder.with(uid).build();
        if let Some(group) = maybe_group {
            let mut group_manager = state.ecs().write_resource::<group::GroupManager>();
            if group_manager
                .group_info(group)
                .map(|info| info.leader == entity)
                .unwrap_or(false)
            {
                group_manager.assign_leader(
                    new_entity,
                    &state.ecs().read_storage(),
                    &state.ecs().entities(),
                    &state.ecs().read_storage(),
                    &state.ecs().read_storage(),
                    // Nothing actually changing since Uid is transferred
                    |_, _| {},
                );
            }
        }
    }
    // Erase group component to avoid group restructure when deleting the entity
    state.ecs().write_storage::<group::Group>().remove(entity);

    // Delete old entity
    if let Err(e) = state.delete_entity_recorded(entity) {
        error!(
            ?e,
            ?entity,
            "Failed to delete entity when removing character"
        );
    }
}

fn get_reason_str(reason: &comp::DisconnectReason) -> &str {
    match reason {
        comp::DisconnectReason::Timeout => "timeout",
        comp::DisconnectReason::NetworkError => "network_error",
        comp::DisconnectReason::NewerLogin => "newer_login",
        comp::DisconnectReason::Kicked => "kicked",
        comp::DisconnectReason::ClientRequested => "client_requested",
    }
}

pub fn handle_client_disconnect(
    server: &mut Server,
    mut entity: EcsEntity,
    reason: comp::DisconnectReason,
    skip_persistence: bool,
) -> Event {
    span!(_guard, "handle_client_disconnect");
    cancel_trade_for(server, entity);
    if let Some(client) = server
        .state()
        .ecs()
        .write_storage::<Client>()
        .get_mut(entity)
    {
        // NOTE: There are not and likely will not be a way to safeguard against
        // receiving multiple `ServerEvent::ClientDisconnect` messages in a tick
        // intended for the same player, so the `None` case here is *not* a bug
        // and we should not log it as a potential issue.
        server
            .state()
            .ecs()
            .read_resource::<PlayerMetrics>()
            .clients_disconnected
            .with_label_values(&[get_reason_str(&reason)])
            .inc();

        if let Some(participant) = client.participant.take() {
            let pid = participant.remote_pid();
            server.runtime.spawn(
                async {
                    let now = std::time::Instant::now();
                    debug!("Start handle disconnect of client");
                    if let Err(e) = participant.disconnect().await {
                        debug!(
                            ?e,
                            "Error when disconnecting client, maybe the pipe already broke"
                        );
                    };
                    trace!("finished disconnect");
                    let elapsed = now.elapsed();
                    if elapsed.as_millis() > 100 {
                        warn!(?elapsed, "disconnecting took quite long");
                    } else {
                        debug!(?elapsed, "disconnecting took");
                    }
                }
                .instrument(tracing::debug_span!(
                    "client_disconnect",
                    ?pid,
                    ?entity,
                    ?reason,
                )),
            );
        }
    }

    let state = server.state_mut();

    // Tell other clients to remove from player list
    // And send a disconnected message
    if let (Some(uid), Some(_)) = (
        state.read_storage::<Uid>().get(entity),
        state.read_storage::<comp::Player>().get(entity),
    ) {
        state.notify_players(ServerGeneral::server_msg(comp::ChatType::Offline(*uid), ""));

        state.notify_players(ServerGeneral::PlayerListUpdate(PlayerListUpdate::Remove(
            *uid,
        )));
    }

    // Sync the player's character data to the database
    if !skip_persistence {
        entity = persist_entity(state, entity);
    }

    // Delete client entity
    if let Err(e) = server.state.delete_entity_recorded(entity) {
        error!(?e, ?entity, "Failed to delete disconnected client");
    }

    Event::ClientDisconnected { entity }
}

// When a player logs out, their data is queued for persistence in the next tick
// of the persistence batch update. The player will be
// temporarily unable to log in during this period to avoid
// the race condition of their login fetching their old data
// and overwriting the data saved here.
fn persist_entity(state: &mut State, entity: EcsEntity) -> EcsEntity {
    if let (
        Some(presence),
        Some(skill_set),
        Some(inventory),
        Some(player_uid),
        Some(player_info),
        mut character_updater,
        mut battlemode_buffer,
    ) = (
        state.read_storage::<Presence>().get(entity),
        state.read_storage::<comp::SkillSet>().get(entity),
        state.read_storage::<comp::Inventory>().get(entity),
        state.read_storage::<Uid>().get(entity),
        state.read_storage::<comp::Player>().get(entity),
        state.ecs().fetch_mut::<CharacterUpdater>(),
        state.ecs().fetch_mut::<BattleModeBuffer>(),
    ) {
        match presence.kind {
            PresenceKind::Character(char_id) => {
                let waypoint = state
                    .ecs()
                    .read_storage::<common::comp::Waypoint>()
                    .get(entity)
                    .cloned();
                // Store last battle mode change
                if let Some(change) = player_info.last_battlemode_change {
                    let mode = player_info.battle_mode;
                    let save = (mode, change);
                    battlemode_buffer.push(char_id, save);
                }

                // Get player's pets
                let alignments = state.ecs().read_storage::<comp::Alignment>();
                let bodies = state.ecs().read_storage::<comp::Body>();
                let stats = state.ecs().read_storage::<comp::Stats>();
                let pets = state.ecs().read_storage::<comp::Pet>();
                let pets = (&alignments, &bodies, &stats, &pets)
                    .join()
                    .filter_map(|(alignment, body, stats, pet)| match alignment {
                        // Don't try to persist non-tameable pets (likely spawned
                        // using /spawn) since there isn't any code to handle
                        // persisting them
                        common::comp::Alignment::Owned(ref pet_owner)
                            if pet_owner == player_uid && is_tameable(body) =>
                        {
                            Some(((*pet).clone(), *body, stats.clone()))
                        },
                        _ => None,
                    })
                    .collect();

                character_updater.add_pending_logout_update(
                    char_id,
                    (skill_set.clone(), inventory.clone(), pets, waypoint),
                );
            },
            PresenceKind::Spectator => { /* Do nothing, spectators do not need persisting */ },
        };
    }

    entity
}