mod mattermost;
use std::path::Path;

use anyhow::anyhow;
use tokio::signal::unix;
use tokio::{self};
use tracing::{debug, warn};

struct Vav {
    db_connection: Option<sqlite::ConnectionWithFullMutex>,
}
impl Vav {
    fn new<T: AsRef<Path>>(path: Option<T>) -> Self {
        let ret = Self {
            db_connection: path
                .and_then(|path| sqlite::Connection::open_with_full_mutex(path).ok()),
        };
        if let Some(connection) = &ret.db_connection {
            let create_table_res = connection.execute(
                "CREATE TABLE keyval (key text NOT NULL PRIMARY KEY, value text NOT NULL)",
            );
            if let Err(err) = create_table_res {
                warn!("Error while creating db {err}");
            }
        }
        ret
    }
}
const INSERT_STATEMENT: &str = "INSERT INTO keyval (key,value) VALUES (?,?)";
const SELECT_ONE: &str = "SELECT key,value FROM keyval where key=?";
const SELECT_ALL: &str = "SELECT key,value FROM keyval";
#[async_trait::async_trait]
impl mattermost::Handler for Vav {
    async fn handle(
        &self,
        update: mattermost::model::WebsocketUpdate,
        client: &mattermost::Client,
    ) -> Result<(), anyhow::Error> {
        debug!("as json: {update:?}");

        let posted = match update.update {
            mattermost::model::Update::Posted(posted) => posted,
            _ => return Ok(()),
        };
        let message = &posted.post.message;
        if !message.starts_with('!') {
            return Ok(());
        }
        let message = message.strip_prefix('!').unwrap();
        let (message, rest) = message.split_once(' ').unwrap_or((message, ""));
        match message {
            "store" => {
                let message = rest;
                let (name, value) = message
                    .split_once(' ')
                    .ok_or(anyhow::anyhow!("missing value in command store"))?;
                if let Some(connection) = &self.db_connection {
                    let mut statement = connection.prepare(INSERT_STATEMENT)?;
                    statement.bind((1, name))?;
                    statement.bind((2, value))?;
                    if let Err(err) = statement.next() {
                        warn!("Error while writing to db {err}");
                    }
                }
            }
            "lookup" => {
                let name = rest;
                let response = if let Some(connection) = &self.db_connection {
                    let mut statement = connection.prepare(SELECT_ONE)?;
                    statement.bind((1, name))?;
                    match statement.next() {
                        Ok(sqlite::State::Done) => "no entry under that name".to_owned(),
                        Ok(sqlite::State::Row) => statement.read::<String, _>(1)?,
                        Err(err) => {
                            warn!("Error while writing to db {err}");
                            return Err(err.into());
                        }
                    }
                } else {
                    "uggh, no db".to_owned()
                };
                client.reply_to(posted.post, response).await?;
            }
            "list" => {
                let response = if let Some(connection) = &self.db_connection {
                    let mut statement = connection.prepare(SELECT_ALL)?;
                    let mut res = vec!["Stored keys:".to_owned()];
                    while let Ok(result) = statement.next() {
                        if result == sqlite::State::Done {
                            break;
                        }
                        res.push(statement.read::<String, _>(0)?)
                    }
                    res.join("\n")
                } else {
                    "uggh, no db".to_owned()
                };
                client.reply_to(posted.post, response).await?;
            }
            _ => return Err(anyhow!("Unrecognized command {message}")),
        }
        Ok(())
    }
}

#[tokio::main(worker_threads = 2)]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    tracing_subscriber::fmt::init();
    let login = std::env::var("USER_MAIL")?;
    let password = std::env::var("USER_PASSWORD")?;
    let db = std::env::var("SQLITE_PATH").ok();
    let auth = mattermost::AuthData { login, password };
    let mut client = mattermost::Client::new(auth, "https://mattermost.continuum.ii.uni.wroc.pl");
    client.update_bearer_token().await?;
    {
        let (shutdown_send, shutdown_recv) = tokio::sync::oneshot::channel();
        let (on_task_finish_send, on_task_finish_recv) = tokio::sync::oneshot::channel();
        let websocket_task = tokio::spawn(async move {
            let result = client
                .handle_websocket_stream(Vav::new(db), shutdown_recv)
                .await;
            on_task_finish_send.send(result).unwrap();
        });
        {
            let mut sigterm = unix::signal(unix::SignalKind::terminate())?;
            let mut sigint = unix::signal(unix::SignalKind::interrupt())?;
            let mut sigquit = unix::signal(unix::SignalKind::quit())?;
            tokio::select! {
                _ = sigterm.recv() => {},
                _ = sigint.recv() => {},
                _ = sigquit.recv() => {},
                task_result = on_task_finish_recv => {
                    warn!("Task closed with result {:?}",task_result);
                },
            };
        }
        _ = shutdown_send.send(());
        websocket_task.await?;
    }
    Ok(())
}