use super::DiceBot;
use crate::db::sqlite::Database;
use crate::db::Rooms;
use crate::error::BotError;
use log::{debug, error, info, warn};
use matrix_sdk::ruma::events::room::member::RoomMemberEventContent;
use matrix_sdk::ruma::events::{StrippedStateEvent, SyncMessageLikeEvent};
use matrix_sdk::{Client, DisplayName};
use matrix_sdk::{self, room::Room, ruma::events::room::message::RoomMessageEventContent};
use std::ops::Sub;
use std::time::{Duration, SystemTime};
use std::time::UNIX_EPOCH;

/// Check if a message is recent enough to actually process. If the
/// message is within "oldest_message_age" seconds, this function
/// returns true. If it's older than that, it returns false and logs a
/// debug message.
fn check_message_age(
    event: &SyncMessageLikeEvent<RoomMessageEventContent>,
    oldest_message_age: u64,
) -> bool {
    let sending_time = event
        .origin_server_ts()
        .to_system_time()
        .unwrap_or(UNIX_EPOCH);

    let oldest_timestamp = SystemTime::now().sub(Duration::from_secs(oldest_message_age));

    if sending_time > oldest_timestamp {
        true
    } else {
        let age = match oldest_timestamp.duration_since(sending_time) {
            Ok(n) => format!("{} seconds too old", n.as_secs()),
            Err(_) => "before the UNIX epoch".to_owned(),
        };

        debug!("Ignoring message because it is {}: {:?}", age, event);
        false
    }
}

/// Determine whether or not to process a received message. This check
/// is necessary in addition to the event processing check because we
/// may receive message events when entering a room for the first
/// time, and we don't want to respond to things before the bot was in
/// the channel, but we do want to respond to things that were sent if
/// the bot left and rejoined quickly.
async fn should_process_message<'a>(
    bot: &DiceBot,
    event: &SyncMessageLikeEvent<RoomMessageEventContent>,
) -> Result<(String, String), BotError> {
    //Ignore messages that are older than configured duration.
    if !check_message_age(event, bot.config.oldest_message_age()) {
        let state_check = bot.state.read().unwrap();
        if !((*state_check).logged_skipped_old_messages()) {
            drop(state_check);
            let mut state = bot.state.write().unwrap();
            (*state).skipped_old_messages();
        }

        return Err(BotError::ShouldNotProcessError);
    }

    let msg_body: String = event
        .as_original()
        .map(|e| e.content.body())
        .map(str::to_string)
        .unwrap_or_else(|| String::new());

    let sender_username: String = format!("@{}:{}", event.sender().localpart(), event.sender().server_name());

    Ok((msg_body, sender_username))
}

async fn should_process_event(db: &Database, room_id: &str, event_id: &str) -> bool {
    db.should_process(room_id, event_id)
        .await
        .unwrap_or_else(|e| {
            error!(
                "Database error when checking if we should process an event: {}",
                e.to_string()
            );
            false
        })
}

pub(super) async fn on_stripped_state_member(
    event: StrippedStateEvent<RoomMemberEventContent>,
    client: Client,
    room: Room,
) {
    let room = match room {
        Room::Invited(invited_room) => invited_room,
        _ => return,
    };

    if room.own_user_id().as_str() != event.state_key {
        return;
    }

    info!(
        "Autojoining room {}",
        room.display_name().await.ok().unwrap_or_else(|| DisplayName::Named("[error]".to_string()))
    );

    if let Err(e) = client.join_room_by_id(&room.room_id()).await {
        warn!("Could not join room: {}", e.to_string())
    }
}

pub(super) async fn on_room_message(
    event: SyncMessageLikeEvent<RoomMessageEventContent>,
    room: Room,
    bot: DiceBot,
) {
    let room = match room {
        Room::Joined(joined_room) => joined_room,
        _ => return,
    };

    let room_id = room.room_id().as_str();
    if !should_process_event(&bot.db, room_id, event.event_id().as_str()).await {
        return;
    }

    let (msg_body, sender_username) =
        if let Ok((msg_body, sender_username)) = should_process_message(&bot, &event).await {
            (msg_body, sender_username)
        } else {
            return;
        };

    let results = bot
        .execute_commands(&room, &sender_username, &msg_body)
        .await;

    bot.handle_results(&room, &sender_username, event.event_id().to_owned(), results)
        .await;
}