use std::env;

use matrix_sdk::{
    Client, Room, RoomState,
    config::SyncSettings,
    ruma::events::room::{
        member::{MembershipState, StrippedRoomMemberEvent},
        message::{
            AddMentions, ForwardThread, MessageType, OriginalSyncRoomMessageEvent,
            RoomMessageEventContent,
        },
    },
};

use crate::commands;

async fn on_room_message(event: OriginalSyncRoomMessageEvent, room: Room) {
    if room.state() != RoomState::Joined {
        return;
    }

    let MessageType::Text(text_content) = event.content.msgtype.to_owned() else {
        return;
    };

    let body = text_content.body.trim();
    if !body.starts_with('!') {
        return;
    }

    let mut parts = body.splitn(3, ' ');
    let command = parts.next().unwrap_or("");
    let arg = parts.next();

    let response = match command {
        "!roll" => commands::roll::run_core(arg),
        "!random" => commands::random::run_core(arg),
        "!about" => commands::about::run_core(),
        _ => return,
    };

    let reply = RoomMessageEventContent::text_plain(response).make_reply_to(
        &event.into_full_event(room.room_id().to_owned()),
        ForwardThread::No,
        AddMentions::Yes,
    );

    match room.send(reply).await {
        Ok(_) => (),
        Err(e) => {
            println!("Failed to send message: {e}");
        }
    }
}

async fn on_stripped_member(event: StrippedRoomMemberEvent, client: Client, room: Room) {
    let user_id = match client.user_id() {
        Some(u) => u,
        None => {
            println!("Irregular Matrix ID");
            return;
        }
    };

    if event.state_key != user_id {
        return;
    }

    if event.content.membership != MembershipState::Invite {
        return;
    }

    if let Err(e) = room.join().await {
        println!("Failed to join room: {e}");
    }
}

pub async fn run() {
    let homeserver =
        env::var("MATRIX_HOMESERVER").expect("Expected MATRIX_HOMESERVER in environment");
    let username = env::var("MATRIX_USERNAME").expect("Expected MATRIX_USERNAME in environment");
    let password = env::var("MATRIX_PASSWORD").expect("Expected MATRIX_PASSWORD in environment");

    let client = Client::builder()
        .homeserver_url(&homeserver)
        .build()
        .await
        .expect("Failed to build Matrix client");

    client
        .matrix_auth()
        .login_username(&username, &password)
        .initial_device_display_name("caitsith")
        .send()
        .await
        .expect("Failed to log in to Matrix");

    println!("Logged in to Matrix as {username}");

    let sync_response = client
        .sync_once(SyncSettings::default())
        .await
        .expect("Matrix initial sync error");

    client.add_event_handler(on_room_message);
    client.add_event_handler(on_stripped_member);

    client
        .sync(SyncSettings::default().token(sync_response.next_batch))
        .await
        .expect("Matrix sync error");
}