use crate::client_api_connection::*;
use crate::settings::Settings;
use crate::ui::*;
use crate::veilid_client_capnp::*;
use async_std::prelude::FutureExt;
use log::*;
use std::cell::*;
use std::net::SocketAddr;
use std::rc::Rc;
use std::time::{Duration, SystemTime};
use veilid_core::xx::{Eventual, EventualCommon};

#[derive(PartialEq, Clone)]
pub enum ConnectionState {
    Disconnected,
    Connected(SocketAddr, SystemTime),
    Retrying(SocketAddr, SystemTime),
}
impl ConnectionState {
    pub fn is_disconnected(&self) -> bool {
        matches!(*self, Self::Disconnected)
    }
    pub fn is_connected(&self) -> bool {
        matches!(*self, Self::Connected(_, _))
    }
    pub fn is_retrying(&self) -> bool {
        matches!(*self, Self::Retrying(_, _))
    }
}

struct CommandProcessorInner {
    ui: UI,
    capi: Option<ClientApiConnection>,
    reconnect: bool,
    finished: bool,
    autoconnect: bool,
    autoreconnect: bool,
    server_addr: Option<SocketAddr>,
    connection_waker: Eventual,
}

type Handle<T> = Rc<RefCell<T>>;

#[derive(Clone)]
pub struct CommandProcessor {
    inner: Handle<CommandProcessorInner>,
}

impl CommandProcessor {
    pub fn new(ui: UI, settings: &Settings) -> Self {
        Self {
            inner: Rc::new(RefCell::new(CommandProcessorInner {
                ui,
                capi: None,
                reconnect: settings.autoreconnect,
                finished: false,
                autoconnect: settings.autoconnect,
                autoreconnect: settings.autoreconnect,
                server_addr: None,
                connection_waker: Eventual::new(),
            })),
        }
    }
    pub fn set_client_api_connection(&mut self, capi: ClientApiConnection) {
        self.inner.borrow_mut().capi = Some(capi);
    }
    fn inner(&self) -> Ref<CommandProcessorInner> {
        self.inner.borrow()
    }
    fn inner_mut(&self) -> RefMut<CommandProcessorInner> {
        self.inner.borrow_mut()
    }
    fn ui(&self) -> UI {
        self.inner.borrow().ui.clone()
    }
    fn capi(&self) -> ClientApiConnection {
        self.inner.borrow().capi.as_ref().unwrap().clone()
    }

    fn word_split(line: &str) -> (String, Option<String>) {
        let trimmed = line.trim();
        if let Some(p) = trimmed.find(char::is_whitespace) {
            let first = trimmed[0..p].to_owned();
            let rest = trimmed[p..].trim_start().to_owned();
            (first, Some(rest))
        } else {
            (trimmed.to_owned(), None)
        }
    }

    pub fn cmd_help(&self, _rest: Option<String>, callback: UICallback) -> Result<(), String> {
        trace!("CommandProcessor::cmd_help");
        self.ui().add_node_event(
            r#"Commands:
exit/quit           - exit the client
disconnect          - disconnect the client from the Veilid node 
shutdown            - shut the server down
attach              - attach the server to the Veilid network
detach              - detach the server from the Veilid network
debug               - send a debugging command to the Veilid server
"#,
        );
        let ui = self.ui();
        ui.send_callback(callback);
        Ok(())
    }

    pub fn cmd_exit(&self, callback: UICallback) -> Result<(), String> {
        trace!("CommandProcessor::cmd_exit");
        let ui = self.ui();
        ui.send_callback(callback);
        ui.quit();
        Ok(())
    }

    pub fn cmd_shutdown(&self, callback: UICallback) -> Result<(), String> {
        trace!("CommandProcessor::cmd_shutdown");
        let mut capi = self.capi();
        let ui = self.ui();
        async_std::task::spawn_local(async move {
            if let Err(e) = capi.server_shutdown().await {
                error!("Server command 'shutdown' failed to execute: {}", e);
            }
            ui.send_callback(callback);
        });
        Ok(())
    }

    pub fn cmd_attach(&self, callback: UICallback) -> Result<(), String> {
        trace!("CommandProcessor::cmd_attach");
        let mut capi = self.capi();
        let ui = self.ui();
        async_std::task::spawn_local(async move {
            if let Err(e) = capi.server_attach().await {
                error!("Server command 'attach' failed to execute: {}", e);
            }
            ui.send_callback(callback);
        });
        Ok(())
    }

    pub fn cmd_detach(&self, callback: UICallback) -> Result<(), String> {
        trace!("CommandProcessor::cmd_detach");
        let mut capi = self.capi();
        let ui = self.ui();
        async_std::task::spawn_local(async move {
            if let Err(e) = capi.server_detach().await {
                error!("Server command 'detach' failed to execute: {}", e);
            }
            ui.send_callback(callback);
        });
        Ok(())
    }

    pub fn cmd_disconnect(&self, callback: UICallback) -> Result<(), String> {
        trace!("CommandProcessor::cmd_disconnect");
        let mut capi = self.capi();
        let ui = self.ui();
        async_std::task::spawn_local(async move {
            capi.disconnect().await;
            ui.send_callback(callback);
        });
        Ok(())
    }

    pub fn cmd_debug(&self, rest: Option<String>, callback: UICallback) -> Result<(), String> {
        trace!("CommandProcessor::cmd_debug");
        let mut capi = self.capi();
        let ui = self.ui();
        async_std::task::spawn_local(async move {
            match capi.server_debug(rest.unwrap_or_default()).await {
                Ok(output) => ui.display_string_dialog("Debug Output", output, callback),
                Err(e) => {
                    error!("Server command 'debug' failed to execute: {}", e);
                    ui.send_callback(callback);
                }
            }
        });
        Ok(())
    }

    pub fn run_command(&self, command_line: &str, callback: UICallback) -> Result<(), String> {
        //
        let (cmd, rest) = Self::word_split(command_line);
        match cmd.as_str() {
            "help" => self.cmd_help(rest, callback),
            "exit" => self.cmd_exit(callback),
            "quit" => self.cmd_exit(callback),
            "disconnect" => self.cmd_disconnect(callback),
            "shutdown" => self.cmd_shutdown(callback),
            "attach" => self.cmd_attach(callback),
            "detach" => self.cmd_detach(callback),
            "debug" => self.cmd_debug(rest, callback),
            _ => {
                let ui = self.ui();
                ui.send_callback(callback);
                Err(format!("Invalid command: {}", cmd))
            }
        }
    }

    pub async fn connection_manager(&mut self) {
        // Connect until we're done
        while !self.inner_mut().finished {
            // Wait for connection request
            if !self.inner().autoconnect {
                let waker = self.inner_mut().connection_waker.instance_clone(());
                waker.await;
            } else {
                self.inner_mut().autoconnect = false;
            }
            self.inner_mut().connection_waker.reset();
            // Loop while we want to keep the connection
            let mut first = true;
            while self.inner().reconnect {
                let server_addr_opt = self.inner_mut().server_addr;
                let server_addr = match server_addr_opt {
                    None => break,
                    Some(addr) => addr,
                };
                if first {
                    info!("Connecting to server at {}", server_addr);
                    self.set_connection_state(ConnectionState::Retrying(
                        server_addr,
                        SystemTime::now(),
                    ));
                } else {
                    debug!("Retrying connection to {}", server_addr);
                }
                let mut capi = self.capi();
                let res = capi.connect(server_addr).await;
                if res.is_ok() {
                    info!(
                        "Connection to server at {} terminated normally",
                        server_addr
                    );
                    break;
                }
                if !self.inner().autoreconnect {
                    info!("Connection to server lost.");
                    break;
                }

                self.set_connection_state(ConnectionState::Retrying(
                    server_addr,
                    SystemTime::now(),
                ));

                debug!("Connection lost, retrying in 2 seconds");
                {
                    let waker = self.inner_mut().connection_waker.instance_clone(());
                    waker
                        .race(async_std::task::sleep(Duration::from_millis(2000)))
                        .await;
                }
                self.inner_mut().connection_waker.reset();
                first = false;
            }
            info!("Disconnected.");
            self.set_connection_state(ConnectionState::Disconnected);
            self.inner_mut().reconnect = true;
        }
    }

    // called by ui
    ////////////////////////////////////////////
    pub fn set_server_address(&mut self, server_addr: Option<SocketAddr>) {
        self.inner_mut().server_addr = server_addr;
    }
    pub fn get_server_address(&self) -> Option<SocketAddr> {
        self.inner().server_addr
    }
    // called by client_api_connection
    // calls into ui
    ////////////////////////////////////////////
    pub fn set_attachment_state(&mut self, state: AttachmentState) {
        self.inner_mut().ui.set_attachment_state(state);
    }

    // called by client_api_connection
    // calls into ui
    ////////////////////////////////////////////
    pub fn set_connection_state(&mut self, state: ConnectionState) {
        self.inner_mut().ui.set_connection_state(state);
    }
    // called by ui
    ////////////////////////////////////////////
    pub fn start_connection(&mut self) {
        self.inner_mut().reconnect = true;
        self.inner_mut().connection_waker.resolve();
    }
    // pub fn stop_connection(&mut self) {
    //     self.inner_mut().reconnect = false;
    //     let mut capi = self.capi().clone();
    //     async_std::task::spawn_local(async move {
    //         capi.disconnect().await;
    //     });
    // }
    pub fn cancel_reconnect(&mut self) {
        self.inner_mut().reconnect = false;
        self.inner_mut().connection_waker.resolve();
    }
    pub fn quit(&mut self) {
        self.inner_mut().finished = true;
        self.inner_mut().reconnect = false;
        self.inner_mut().connection_waker.resolve();
    }

    // called by ui
    // calls into client_api_connection
    ////////////////////////////////////////////
    pub fn attach(&mut self) {
        trace!("CommandProcessor::attach");
        let mut capi = self.capi();

        async_std::task::spawn_local(async move {
            if let Err(e) = capi.server_attach().await {
                error!("Server command 'attach' failed to execute: {}", e);
            }
        });
    }

    pub fn detach(&mut self) {
        trace!("CommandProcessor::detach");
        let mut capi = self.capi();

        async_std::task::spawn_local(async move {
            if let Err(e) = capi.server_detach().await {
                error!("Server command 'detach' failed to execute: {}", e);
            }
        });
    }
}