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

use anyhow::anyhow;
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::mpsc::unbounded_channel();
    let websocket_task =tokio::spawn( async move {
    client.handle_websocket_stream(Vav::new(db),shutdown_recv).await});
    match tokio::signal::ctrl_c().await {
        Ok(()) => {},
        Err(err) => {
            eprintln!("Unable to listen for shutdown signal: {}", err);
            // we also shut down in case of error
        },
    }
    shutdown_send.send(())?;
    websocket_task.await??;
    }
    Ok(())
}