extern crate gqlmapi_rs;
use gqlmapi_rs::MAPIGraphQL;

use std::{
    io::{self, Read},
    string::FromUtf8Error,
    sync::mpsc::{self, RecvError},
};

#[derive(Debug)]
enum Error {
    Io(io::Error),
    Utf8(FromUtf8Error),
    GraphQL(String),
    Channel(RecvError),
    Lock,
}

fn main() -> Result<(), Error> {
    println!("Type/paste a query here (finish by pressing Ctrl+Z on an empty line):");
    let mut buf = Vec::new();
    io::stdin().read_to_end(&mut buf).map_err(Error::Io)?;
    let query = String::from_utf8(buf).map_err(Error::Utf8)?;
    let results = execute_query(query)?;
    println!("Results: {}", results);
    Ok(())
}

fn execute_query(query: String) -> Result<String, Error> {
    let gqlmapi = MAPIGraphQL::new(true);
    let query = gqlmapi.parse_query(&query).map_err(Error::GraphQL)?;
    let (tx_next, rx_next) = mpsc::channel();
    let (tx_complete, rx_complete) = mpsc::channel();
    let subscription = gqlmapi.subscribe(query.clone(), "", "");
    let mut locked_subscription = subscription.lock().map_err(|_| Error::Lock)?;
    locked_subscription
        .listen(tx_next, tx_complete)
        .map_err(Error::GraphQL)?;
    let results = rx_next.recv().map_err(Error::Channel)?;
    rx_complete.recv().map_err(Error::Channel)?;

    Ok(results)
}