// Rocket generates a lot of warnings for handlers
// TODO: figure out why
#![allow(unreachable_patterns)]
use std::{error::Error, net::SocketAddr, sync::Arc, time::Duration};

use async_graphql::{extensions, http::GraphiQLSource, Schema};
use async_graphql_axum::{GraphQL, GraphQLSubscription};
//allows to extract the IP of connecting user
use axum::extract::connect_info::ConnectInfo;
use axum::{
    extract::{self, ws::WebSocketUpgrade, Query, State},
    http::{header, StatusCode},
    response::{self, IntoResponse, Response},
    routing::{any, get, post},
    Router,
};
use cacher::FilesystemCacher;
use clap::Parser;
use letterbox_notmuch::Notmuch;
#[cfg(feature = "tantivy")]
use letterbox_server::tantivy::TantivyConnection;
use letterbox_server::{
    graphql::{compute_catchup_ids, Attachment, MutationRoot, QueryRoot, SubscriptionRoot},
    nm::{attachment_bytes, cid_attachment_bytes, label_unprocessed},
    ws::ConnectionTracker,
};
use letterbox_shared::WebsocketMessage;
use serde::Deserialize;
use sqlx::postgres::PgPool;
use tokio::{net::TcpListener, sync::Mutex};
use tower_http::trace::{DefaultMakeSpan, TraceLayer};
use tracing::{error, info};

// Make our own error that wraps `ServerError`.
struct AppError(letterbox_server::ServerError);

// Tell axum how to convert `AppError` into a response.
impl IntoResponse for AppError {
    fn into_response(self) -> Response {
        (
            StatusCode::INTERNAL_SERVER_ERROR,
            format!("Something went wrong: {}", self.0),
        )
            .into_response()
    }
}
// This enables using `?` on functions that return `Result<_, letterbox_server::Error>` to turn them into
// `Result<_, AppError>`. That way you don't need to do that manually.
impl<E> From<E> for AppError
where
    E: Into<letterbox_server::ServerError>,
{
    fn from(err: E) -> Self {
        Self(err.into())
    }
}

fn inline_attachment_response(attachment: Attachment) -> impl IntoResponse {
    info!("attachment filename {:?}", attachment.filename);
    let mut hdr_map = headers::HeaderMap::new();
    if let Some(filename) = attachment.filename {
        hdr_map.insert(
            header::CONTENT_DISPOSITION,
            format!(r#"inline; filename="{}""#, filename)
                .parse()
                .unwrap(),
        );
    }
    if let Some(ct) = attachment.content_type {
        hdr_map.insert(header::CONTENT_TYPE, ct.parse().unwrap());
    }
    info!("hdr_map {hdr_map:?}");
    (hdr_map, attachment.bytes).into_response()
}

fn download_attachment_response(attachment: Attachment) -> impl IntoResponse {
    info!("attachment filename {:?}", attachment.filename);
    let mut hdr_map = headers::HeaderMap::new();
    if let Some(filename) = attachment.filename {
        hdr_map.insert(
            header::CONTENT_DISPOSITION,
            format!(r#"attachment; filename="{}""#, filename)
                .parse()
                .unwrap(),
        );
    }
    if let Some(ct) = attachment.content_type {
        hdr_map.insert(header::CONTENT_TYPE, ct.parse().unwrap());
    }
    info!("hdr_map {hdr_map:?}");
    (hdr_map, attachment.bytes).into_response()
}

#[axum_macros::debug_handler]
async fn view_attachment(
    State(AppState { nm, .. }): State<AppState>,
    extract::Path((id, idx, _)): extract::Path<(String, String, String)>,
) -> Result<impl IntoResponse, AppError> {
    let mid = if id.starts_with("id:") {
        id.to_string()
    } else {
        format!("id:{}", id)
    };
    info!("view attachment {mid} {idx}");
    let idx: Vec<_> = idx
        .split('.')
        .map(|s| s.parse().expect("not a usize"))
        .collect();
    let attachment = attachment_bytes(&nm, &mid, &idx)?;
    Ok(inline_attachment_response(attachment))
}

async fn download_attachment(
    State(AppState { nm, .. }): State<AppState>,
    extract::Path((id, idx, _)): extract::Path<(String, String, String)>,
) -> Result<impl IntoResponse, AppError> {
    let mid = if id.starts_with("id:") {
        id.to_string()
    } else {
        format!("id:{}", id)
    };
    info!("download attachment {mid} {idx}");
    let idx: Vec<_> = idx
        .split('.')
        .map(|s| s.parse().expect("not a usize"))
        .collect();
    let attachment = attachment_bytes(&nm, &mid, &idx)?;
    Ok(download_attachment_response(attachment))
}

async fn view_cid(
    State(AppState { nm, .. }): State<AppState>,
    extract::Path((id, cid)): extract::Path<(String, String)>,
) -> Result<impl IntoResponse, AppError> {
    let mid = if id.starts_with("id:") {
        id.to_string()
    } else {
        format!("id:{}", id)
    };
    info!("view cid attachment {mid} {cid}");
    let attachment = cid_attachment_bytes(&nm, &mid, &cid)?;
    Ok(inline_attachment_response(attachment))
}

// TODO make this work with gitea message ids like `wathiede/letterbox/pulls/91@git.z.xinu.tv`
async fn view_original(
    State(AppState { nm, .. }): State<AppState>,
    extract::Path(id): extract::Path<String>,
) -> Result<impl IntoResponse, AppError> {
    info!("view_original {id}");
    let bytes = nm.show_original(&id)?;
    let s = String::from_utf8_lossy(&bytes).to_string();
    Ok(s.into_response())
}

async fn graphiql() -> impl IntoResponse {
    response::Html(
        GraphiQLSource::build()
            .endpoint("/api/graphql/")
            .subscription_endpoint("/api/graphql/ws")
            .finish(),
    )
}

async fn start_ws(
    ws: WebSocketUpgrade,
    ConnectInfo(addr): ConnectInfo<SocketAddr>,
    State(AppState {
        connection_tracker, ..
    }): State<AppState>,
) -> impl IntoResponse {
    info!("intiating websocket connection for {addr}");
    ws.on_upgrade(async move |socket| connection_tracker.lock().await.add_peer(socket, addr).await)
}

#[derive(Debug, Deserialize)]
struct NotificationParams {
    delay_ms: Option<u64>,
    num_unprocessed: Option<usize>,
}

async fn send_refresh_websocket_handler(
    State(AppState {
        nm,
        pool,
        connection_tracker,
        ..
    }): State<AppState>,
    params: Query<NotificationParams>,
) -> impl IntoResponse {
    info!("send_refresh_websocket_handler params {params:?}");
    if let Some(delay_ms) = params.delay_ms {
        let delay = Duration::from_millis(delay_ms);
        info!("sleeping {delay:?}");
        tokio::time::sleep(delay).await;
    }
    let limit = match params.num_unprocessed {
        Some(0) => None,
        Some(limit) => Some(limit),
        None => Some(10),
    };

    let mut ids = None;
    match label_unprocessed(&nm, &pool, false, limit, "tag:unprocessed").await {
        Ok(i) => ids = Some(i),
        Err(err) => error!("Failed to label_unprocessed: {err:?}"),
    };
    connection_tracker
        .lock()
        .await
        .send_message_all(WebsocketMessage::RefreshMessages)
        .await;
    if let Some(ids) = ids {
        format!("{ids:?}")
    } else {
        "refresh triggered".to_string()
    }
}

async fn watch_new(
    nm: Notmuch,
    pool: PgPool,
    conn_tracker: Arc<Mutex<ConnectionTracker>>,
    poll_time: Duration,
) -> Result<(), async_graphql::Error> {
    async fn watch_new_iteration(
        nm: &Notmuch,
        pool: &PgPool,
        conn_tracker: Arc<Mutex<ConnectionTracker>>,
        old_ids: &[String],
    ) -> Result<Vec<String>, async_graphql::Error> {
        let ids = compute_catchup_ids(&nm, &pool, "is:unread").await?;
        info!("old_ids: {} ids: {}", old_ids.len(), ids.len());
        if old_ids != ids {
            label_unprocessed(&nm, &pool, false, Some(100), "tag:unprocessed").await?;
            conn_tracker
                .lock()
                .await
                .send_message_all(WebsocketMessage::RefreshMessages)
                .await
        }
        Ok(ids)
    }
    let mut old_ids = Vec::new();
    loop {
        old_ids = match watch_new_iteration(&nm, &pool, conn_tracker.clone(), &old_ids).await {
            Ok(old_ids) => old_ids,
            Err(err) => {
                error!("watch_new_iteration failed: {err:?}");
                continue;
            }
        };
        tokio::time::sleep(poll_time).await;
    }
}

#[derive(Clone)]
struct AppState {
    nm: Notmuch,
    pool: PgPool,
    connection_tracker: Arc<Mutex<ConnectionTracker>>,
}

#[derive(Parser)]
#[command(version, about, long_about = None)]
struct Cli {
    #[arg(short, long, default_value = "0.0.0.0:9345")]
    addr: SocketAddr,
    newsreader_database_url: String,
    newsreader_tantivy_db_path: String,
    slurp_cache_path: String,
}

#[tokio::main]
async fn main() -> Result<(), Box<dyn Error>> {
    let cli = Cli::parse();
    let _guard = xtracing::init(env!("CARGO_BIN_NAME"))?;
    build_info::build_info!(fn bi);
    info!("Build Info: {}", letterbox_shared::build_version(bi));
    if !std::fs::exists(&cli.slurp_cache_path)? {
        info!("Creating slurp cache @ '{}'", &cli.slurp_cache_path);
        std::fs::create_dir_all(&cli.slurp_cache_path)?;
    }
    let pool = PgPool::connect(&cli.newsreader_database_url).await?;
    let nm = Notmuch::default();
    sqlx::migrate!("./migrations").run(&pool).await?;
    #[cfg(feature = "tantivy")]
    let tantivy_conn = TantivyConnection::new(&cli.newsreader_tantivy_db_path)?;

    let cacher = FilesystemCacher::new(&cli.slurp_cache_path)?;
    let schema = Schema::build(QueryRoot, MutationRoot, SubscriptionRoot)
        .data(nm.clone())
        .data(cacher)
        .data(pool.clone());

    let schema = schema.extension(extensions::Logger).finish();

    let connection_tracker = Arc::new(Mutex::new(ConnectionTracker::default()));
    let ct = Arc::clone(&connection_tracker);
    let poll_time = Duration::from_secs(60);
    let _h = tokio::spawn(watch_new(nm.clone(), pool.clone(), ct, poll_time));

    let api_routes = Router::new()
        .route(
            "/download/attachment/{id}/{idx}/{*rest}",
            get(download_attachment),
        )
        .route("/view/attachment/{id}/{idx}/{*rest}", get(view_attachment))
        .route("/original/{id}", get(view_original))
        .route("/cid/{id}/{cid}", get(view_cid))
        .route("/ws", any(start_ws))
        .route_service("/graphql/ws", GraphQLSubscription::new(schema.clone()))
        .route(
            "/graphql/",
            get(graphiql).post_service(GraphQL::new(schema.clone())),
        );

    let notification_routes = Router::new()
        .route("/mail", post(send_refresh_websocket_handler))
        .route("/news", post(send_refresh_websocket_handler));
    let app = Router::new()
        .nest("/api", api_routes)
        .nest("/notification", notification_routes)
        .with_state(AppState {
            nm,
            pool,
            connection_tracker,
        })
        .layer(
            TraceLayer::new_for_http()
                .make_span_with(DefaultMakeSpan::default().include_headers(true)),
        );

    let listener = TcpListener::bind(cli.addr).await.unwrap();
    tracing::info!("listening on {}", listener.local_addr().unwrap());
    axum::serve(
        listener,
        app.into_make_service_with_connect_info::<SocketAddr>(),
    )
    .await
    .unwrap();
    Ok(())
}