use std::collections::*;
use std::path::PathBuf;
use std::sync::Arc;

use tokio::io::{AsyncRead, AsyncReadExt};
use tokio::sync::mpsc;

use futures::prelude::*;

//use ruma_client::Client;
//use ruma_client_api::r0::message as rumamessage;
//use ruma_events::{self, room::message::*};

use matrix_sdk::events::{
    room::message::{MessageEventContent, TextMessageEventContent},
    AnyMessageEventContent,
};
use matrix_sdk::identifiers::RoomId;
use matrix_sdk::uuid::Uuid;

use crate::config::*;

#[derive(Debug)]
pub enum Error {
    BadUrl,
    UnknownRoom(RoomId),
    Matrix(matrix_sdk::Error),
}

pub struct Message {
    dest_room: RoomId,
    text: String,
    delay_secs: u32,
}

pub type MatrixClient = matrix_sdk::Client;

impl Message {
    pub fn new(dest_room: RoomId, msg: String) -> Self {
        Self::new_delay(dest_room, msg, 0)
    }

    pub fn new_delay(dest_room: RoomId, text: String, delay_secs: u32) -> Self {
        Self {
            dest_room,
            text,
            delay_secs,
        }
    }
}

pub async fn create_and_auth_client(acct: Account) -> Result<Arc<MatrixClient>, Error> {
    let hs_url = url::Url::parse(&acct.homeserver).map_err(|_| Error::BadUrl)?;

    let cc = matrix_sdk::ClientConfig::new()
        .user_agent("mtxspooler")
        .unwrap();
    let c = matrix_sdk::Client::new_with_config(hs_url, cc).map_err(Error::Matrix)?;

    // Now log in.
    match acct.auth {
        Auth::UsernamePass(un, pw) => {
            let didref = acct.device_id.as_deref();
            c.login(&un, &pw, didref, didref)
                .map_err(Error::Matrix)
                .await?;
        }
    }

    Ok(Arc::new(c))
}

pub async fn submit_messages(cli: Arc<MatrixClient>, mut recv: mpsc::Receiver<Message>) {
    while let Some(msg) = recv.recv().await {
        if let Err(e) = do_submit_msg(&msg, &cli).await {
            panic!("[client] error handling message submission: {:?}", e);
        }
    }
}

async fn do_submit_msg(msg: &Message, cli: &Arc<MatrixClient>) -> Result<(), Error> {
    let jroom = get_room_try_join(cli, &msg.dest_room).await?;

    let mec = MessageEventContent::text_plain(&msg.text);
    let ec = AnyMessageEventContent::RoomMessage(mec);
    jroom.send(ec, None).map_err(Error::Matrix).await?;

    Ok(())
}

pub async fn get_room_try_join(
    cli: &Arc<MatrixClient>,
    rid: &RoomId,
) -> Result<matrix_sdk::room::Joined, Error> {
    use matrix_sdk::room::*;
    match cli
        .get_room(rid)
        .ok_or_else(|| Error::UnknownRoom(rid.clone()))?
    {
        Room::Joined(j) => Ok(j),
        Room::Invited(i) => {
            i.accept_invitation().map_err(Error::Matrix).await?;
            Ok(cli.get_joined_room(rid).expect("client: get invited room"))
        }
        Room::Left(l) => {
            l.join().map_err(Error::Matrix).await?;
            Ok(cli.get_joined_room(rid).expect("client: get room joined"))
        }
    }
}

fn gen_device_id(un: &str, pw: &str) -> String {
    use sha2::Digest;
    let mut hasher = sha2::Sha256::new();
    hasher.update(un.as_bytes());
    hasher.update("\0");
    hasher.update(pw.as_bytes());
    hasher.update("\0_mtxspooler_salt");
    let h: [u8; 32] = hasher.finalize().into();
    hex::encode(h)
}