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extern crate serde_json;
#[macro_use]
extern crate serde_derive;
extern crate rand;
extern crate websocket;

use std::error::Error;
use std::fmt;
use std::net::TcpStream;

use serde_json as json;
use websocket as ws;

mod uuid;
mod value;

pub use self::value::Value;

pub struct ClientBuilder<'a> {
    builder: ws::ClientBuilder<'a>,
}

impl<'a> ClientBuilder<'a> {
    pub fn new(addr: &str) -> Result<Self, Box<Error>> {
        let builder = ws::ClientBuilder::new(addr)?;
        Ok(ClientBuilder { builder })
    }

    pub fn connect(&mut self) -> Result<Client, Box<Error>> {
        let conn = self.builder.connect_insecure()?;
        Ok(Client { conn })
    }
}

pub struct Client {
    conn: ws::sync::Client<TcpStream>,
}

impl Client {
    const SET: &'static str = "set";
    const GET: &'static str = "get";
    const SUB: &'static str = "subscribe";

    pub fn get(&mut self, path: String) -> Result<Value, Box<Error>> {
        let res = self.req(Request {
            action: Self::GET,
            request_id: uuid::gen(),
            path,
            value: None,
        })?;

        // None is a valid value
        Value::from_json(res.value.unwrap_or(json::Value::Null))
    }

    pub fn set(&mut self, path: String, value: Value) -> Result<(), Box<Error>> {
        self.req(Request {
            action: Self::SET,
            request_id: uuid::gen(),
            path,
            value: Some(From::from(value)),
        })?;
        Ok(())
    }

    pub fn sub<F: Fn(Value)>(&mut self, path: String, handler: F) -> Result<(), Box<Error>> {
        let res = self.req(Request {
            action: Self::SUB,
            request_id: uuid::gen(),
            path,
            value: None,
        })?;

        let sid = res.subscription_id.expect("subscription_id is missing");
        loop {
            let res = self.rx()?;
            if *res.subscription_id.as_ref().unwrap() != sid {
                return Err(From::from("sid mismatch"));
            }
            handler(Value::from_json(res.value.unwrap_or(json::Value::Null))?);
        }
    }

    fn req(&mut self, req: Request) -> Result<Response, Box<Error>> {
        let msg = ws::OwnedMessage::Text(json::to_string(&req).unwrap());
        self.conn.send_message(&msg)?;

        let res = self.rx()?;
        if *res.request_id.as_ref().unwrap() != req.request_id {
            return Err(From::from("rid mismatch"));
        }
        Ok(res)
    }

    fn rx(&mut self) -> Result<Response, Box<Error>> {
        match self.conn.recv_message()? {
            ws::OwnedMessage::Text(s) => {
                let res: Response = json::from_str(s.as_str()).unwrap();
                if let Some(err) = res.error {
                    return Err(From::from(err));
                }
                Ok(res)
            }
            _ => panic!("unknown message type"),
        }
    }
}

impl Drop for Client {
    fn drop(&mut self) {
        if let Err(err) = self.conn.send_message(&ws::OwnedMessage::Close(Some(
            ws::CloseData::new(
                1000, // normal closure
                String::from("adios"),
            ),
        ))) {
            eprintln!("disconnect message error: {}", err);
        }
        if let Err(err) = self.conn.shutdown() {
            eprintln!("shutdown error: {}", err)
        }
    }
}

#[derive(Serialize, Debug)]
#[serde(rename_all = "camelCase")]
struct Request {
    action: &'static str,
    path: String,
    request_id: String,
    value: Option<json::Value>,
    // filters: ?
}

#[derive(Deserialize, Debug)]
#[serde(rename_all = "camelCase")]
struct Response {
    action: String,
    path: Option<String>,
    value: Option<json::Value>,
    request_id: Option<String>,
    timestamp: Option<f64>,
    subscription_id: Option<String>,
    error: Option<ResponseError>,
}

#[derive(Deserialize, Debug)]
#[serde(rename_all = "camelCase")]
struct ResponseError {
    number: f64,
    reason: Option<String>,
    message: Option<String>,
}

impl fmt::Display for ResponseError {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(
            f,
            "{} {} {}",
            self.number,
            self.reason.as_ref().unwrap_or(&String::from("unknown")),
            self.message.as_ref().unwrap_or(&String::from("unknown"))
        )
    }
}

impl Error for ResponseError {
    fn description(&self) -> &str {
        "ResponseError"
    }
}