use std::{convert::Infallible, error::Error, sync::Arc, time::Duration};

use async_std::io::stdin;
use futures_timer::Delay;
use mammut::{
    apps::{AppBuilder, Scopes},
    Mastodon, Registration,
};
use rand::Rng;
use telegram_bot::{Api, ChatId, ChatRef, ToChatRef};

use crate::{
    publish::MastodonPublisher,
    selection::{telegram::get_chat_ref, SelectorExt, TelegramSelector},
};

use futures::{channel::mpsc::channel, sink::unfold, SinkExt, StreamExt, TryStreamExt};
use model::SampleModelExt;

mod config;
mod model;
mod publish;
mod selection;

const CONFIG_PATH: &str = "bot_config.json";

#[tokio::main]
async fn main() -> Result<(), Box<dyn Error>> {
    let mut cfg = match config::Config::from(CONFIG_PATH) {
        Ok(cfg) => Ok(cfg),
        Err(_) => {
            println!(
                "Failed reading config at [{}], writing default",
                CONFIG_PATH
            );
            config::Config::default().save(CONFIG_PATH)?;
            Err(anyhow::anyhow!("Invalid configuration"))
        }
    }?;

    let app = AppBuilder {
        client_name: "izzilis",
        redirect_uris: "urn:ietf:wg:oauth:2.0:oob",
        scopes: Scopes::Write,
        website: None,
    };

    let mut registration = Registration::new(cfg.fediverse_base_url.clone());
    registration.register(app)?;

    let mastodon = if let Some(data) = &cfg.fediverse_token {
        Mastodon::from_data(data.clone())
    } else {
        let url = registration.authorise()?;
        println!("{}", url);

        let mut buffer = String::new();
        stdin().read_line(&mut buffer).await?;

        let fedi = registration.create_access_token(buffer)?;

        cfg.fediverse_token = Some(fedi.data.clone());
        cfg.save(CONFIG_PATH)?;

        fedi
    };

    let publisher = MastodonPublisher::new(mastodon);

    let api = Arc::new(Api::new(cfg.bot_token.clone()));

    let chat = get_chat_ref(
        api.clone(),
        if ChatId::new(0) == cfg.chat_ref {
            None
        } else {
            Some(cfg.chat_ref.clone().to_chat_ref())
        },
    )
    .await
    .expect("could not get chat ref");

    let chat_ref = chat.lock().await.clone();

    if let ChatRef::Id(id) = chat_ref {
        cfg.chat_ref = id;
        cfg.save(CONFIG_PATH)?;
    }

    let (sender, receiver) = channel(cfg.post_buffer as usize);

    let cfg_clone = cfg.clone();

    let mut model = TelegramSelector::new(
        api,
        chat,
        Box::pin(unfold((), move |_, chat_ref| {
            let mut cfg_clone = cfg_clone.clone();
            async move {
                if let ChatRef::Id(id) = &chat_ref {
                    cfg_clone.chat_ref = id.clone();
                    let _ = cfg_clone.save(CONFIG_PATH);
                }
                Ok::<_, Infallible>(())
            }
        })),
    )
    .filter(
        model::GPTSampleModel::new(
            cfg.python_path.clone(),
            cfg.gpt_code_path.clone(),
            vec![
                "generate_unconditional_samples.py".to_string(),
                "--model_name".to_string(),
                cfg.model_name.clone(),
                "--temperature".to_string(),
                cfg.temperature.clone(),
                "--top_k".to_string(),
                cfg.top_k.clone(),
                "--nsamples".to_string(),
                "1".to_string(),
            ],
        )
        .into_stream()
        .try_filter(|message| {
            let not_empty = !message.is_empty();
            async move { not_empty }
        }),
    )
    .map_err(|e| Box::new(e) as Box<dyn Error>);

    tokio::spawn(async move {
        sender
            .sink_map_err(|e| Box::new(e) as Box<dyn Error>)
            .send_all(&mut model)
            .await
            .expect("Broken buffer");
    });

    publisher
        .sink_map_err(|e| Box::new(e) as Box<dyn Error>)
        .send_all(
            &mut receiver
                .then(|item| {
                    let interval_seconds = cfg.interval_seconds.clone();
                    Box::pin(async move {
                        Delay::new(Duration::from_secs(
                            rand::thread_rng()
                                .gen_range(interval_seconds.min..=interval_seconds.max),
                        ))
                        .await;
                        item
                    })
                })
                .map(Ok),
        )
        .await?;

    return Ok(());
}