use actix_web::{web, App, HttpResponse, HttpServer, Responder};
use redis::{Client, AsyncCommands};
use reqwest::Client as HTTPClient;
use serde::{Serialize, Deserialize};
use serde_json::Value;
use std::collections::HashMap;
use std::env;
use std::error::Error;
use futures::{StreamExt, FutureExt};
use tokio::sync::broadcast::{self, Receiver};

#[derive(Debug, Serialize, Deserialize)]
#[serde(rename_all = "snake_case")]
enum PayloadKind {
    NewMessage,
    NewFollower,
    NewShout,
    NewApproval,
    NewComment,
    NewRate
}

#[derive(Debug, Serialize, Deserialize)]
struct Payload {
    chat_id: Option<String>,
    shout_id: Option<i32>,
    author_id: Option<i32>,
    topic_id: Option<i32>,
    reaction_id: Option<i32>,
    community_id: Option<i32>,
    kind: PayloadKind,
    body: String,
}

async fn get_auth_id(token: &str) -> Result<i32, Box<dyn Error>> {
    let api_base = env::var("API_BASE")?;
    let gql = match api_base.contains("v2") {
        true => r#"mutation { getSession { user { id } } }"#, // v2
        _ => r#"query { sessiom { user { id } } }"# // authorizer
    };
    let client = HTTPClient::new();
    let response = client
        .post(api_base)
        .bearer_auth(token) // NOTE: auth token is here
        .body(gql)
        .send()
        .await?;
    let response_body: Value = response.json().await?;
    let id = response_body["data"]["getSession"]["user"]["id"]
        .as_i64()
        .ok_or("Failed to get user id by token")? as i32;
    Ok(id)
}

async fn sse_handler(
    token: web::Path<String>,
    rx: web::Data<Receiver<String>>,
    redis: web::Data<Client>,
) -> impl Responder {
    let author_id = match get_auth_id(&token).await {
        Ok(id) => id,
        Err(e) => {
            eprintln!("Не удалось проверить токен: {}", e);
            return HttpResponse::Unauthorized().finish();
        }
    };

    let mut con = redis.get_async_connection().await.unwrap();
    let _: () = con
        .sadd("authors-online", &author_id)
        .await
        .unwrap();

    let chats: Vec<String> = con
        .smembers(format!("chats_by_author/{}", author_id))
        .await
        .unwrap();

    let mut pubsub = con.into_pubsub();
    for chat_id in chats {
        pubsub.subscribe(format!("message:{}", chat_id)).await.unwrap();
    }

    let mut rx = rx.get_ref().subscribe();
    let server_event = rx.recv().await.unwrap();

    let _: () = con
        .srem("authors-online", &author_id)
        .await
        .unwrap();

    HttpResponse::Ok()
        .append_header(("content-type", "text/event-stream"))
        .streaming(server_event)
}

#[actix_web::main]
async fn main() -> std::io::Result<()> {
    let (tx, mut rx) = broadcast::channel(100);
    let redis_url = env::var("REDIS_URL").unwrap();
    let client = redis::Client::open(redis_url).unwrap();
    let _handle = tokio::spawn(async move {
        let mut conn = client.get_async_connection().await.unwrap();
        let mut pubsub = conn.into_pubsub();

        pubsub.subscribe("new_follower").await.unwrap();
        pubsub.subscribe("new_shout").await.unwrap();
        pubsub.subscribe("new_reaction").await.unwrap();

        while let Some(msg) = pubsub.on_message().next().await {
            let payload: HashMap<String, String> = msg.get_payload().unwrap();
            tx.send(serde_json::to_string(&payload).unwrap()).unwrap();
        }
    });

    HttpServer::new(move || {
        let rx = tx.subscribe();
        App::new()
            .app_data(web::Data::new(rx))
            .app_data(web::Data::new(client.clone()))
            .route("/aware/{token}", web::get().to(sse_handler))
    })
    .bind("127.0.0.1:8080")?
    .run()
    .await
}