use std::future;

use axum::extract::{Json, State};
use futures::stream::StreamExt as _;

use super::post;
use crate::{
    channel::app,
    name::Name,
    test::fixtures::{self, future::Expect as _},
};

#[tokio::test]
async fn new_channel() {
    // Set up the environment

    let app = fixtures::scratch_app().await;
    let creator = fixtures::identity::create(&app, &fixtures::now()).await;
    let resume_point = fixtures::boot::resume_point(&app).await;

    // Call the endpoint

    let name = fixtures::channel::propose();
    let request = post::Request { name: name.clone() };
    let post::Response(response) =
        post::handler(State(app.clone()), creator, fixtures::now(), Json(request))
            .await
            .expect("creating a channel in an empty app succeeds");

    // Verify the structure of the response

    assert_eq!(name, response.name);

    // Verify the semantics

    let snapshot = app.boot().snapshot().await.expect("boot always succeeds");
    assert!(snapshot.channels.iter().any(|channel| channel == &response));

    let channel = app
        .channels()
        .get(&response.id)
        .await
        .expect("the newly-created channel exists");
    assert_eq!(response, channel);

    let mut events = app
        .events()
        .subscribe(resume_point)
        .await
        .expect("subscribing never fails")
        .filter_map(fixtures::event::channel)
        .filter_map(fixtures::event::channel::created)
        .filter(|event| future::ready(event.channel == response));

    let event = events.next().expect_some("creation event published").await;

    assert_eq!(event.channel, response);
}

#[tokio::test]
async fn duplicate_name() {
    // Set up the environment

    let app = fixtures::scratch_app().await;
    let creator = fixtures::identity::create(&app, &fixtures::now()).await;
    let channel = fixtures::channel::create(&app, &fixtures::now()).await;

    // Call the endpoint

    let request = post::Request {
        name: channel.name.clone(),
    };
    let post::Error(error) =
        post::handler(State(app.clone()), creator, fixtures::now(), Json(request))
            .await
            .expect_err("duplicate channel name should fail the request");

    // Verify the structure of the response

    assert!(matches!(
        error,
        app::CreateError::DuplicateName(name) if channel.name == name
    ));
}

#[tokio::test]
async fn conflicting_canonical_name() {
    // Set up the environment

    let app = fixtures::scratch_app().await;
    let creator = fixtures::identity::create(&app, &fixtures::now()).await;

    let existing_name = Name::from("rijksmuseum");
    app.channels()
        .create(&existing_name, &fixtures::now())
        .await
        .expect("creating a channel in an empty environment succeeds");

    let conflicting_name = Name::from("r\u{0133}ksmuseum");

    // Call the endpoint

    let request = post::Request {
        name: conflicting_name.clone(),
    };
    let post::Error(error) =
        post::handler(State(app.clone()), creator, fixtures::now(), Json(request))
            .await
            .expect_err("duplicate channel name should fail the request");

    // Verify the structure of the response

    assert!(matches!(
        error,
        app::CreateError::DuplicateName(name) if conflicting_name == name
    ));
}

#[tokio::test]
async fn invalid_name() {
    // Set up the environment

    let app = fixtures::scratch_app().await;
    let creator = fixtures::identity::create(&app, &fixtures::now()).await;

    // Call the endpoint

    let name = fixtures::channel::propose_invalid_name();
    let request = post::Request { name: name.clone() };
    let post::Error(error) =
        post::handler(State(app.clone()), creator, fixtures::now(), Json(request))
            .await
            .expect_err("invalid channel name should fail the request");

    // Verify the structure of the response

    assert!(matches!(
        error,
        app::CreateError::InvalidName(error_name) if name == error_name
    ));
}

#[tokio::test]
async fn name_reusable_after_delete() {
    // Set up the environment

    let app = fixtures::scratch_app().await;
    let creator = fixtures::identity::create(&app, &fixtures::now()).await;
    let name = fixtures::channel::propose();

    // Call the endpoint (first time)

    let request = post::Request { name: name.clone() };
    let post::Response(response) = post::handler(
        State(app.clone()),
        creator.clone(),
        fixtures::now(),
        Json(request),
    )
    .await
    .expect("new channel in an empty app");

    // Delete the channel

    app.channels()
        .delete(&response.id, &fixtures::now())
        .await
        .expect("deleting a newly-created channel succeeds");

    // Call the endpoint (second time)

    let request = post::Request { name: name.clone() };
    let post::Response(response) =
        post::handler(State(app.clone()), creator, fixtures::now(), Json(request))
            .await
            .expect("creation succeeds after original channel deleted");

    // Verify the structure of the response

    assert_eq!(name, response.name);

    // Verify the semantics

    let channel = app
        .channels()
        .get(&response.id)
        .await
        .expect("the newly-created channel exists");
    assert_eq!(response, channel);
}

#[tokio::test]
async fn name_reusable_after_expiry() {
    // Set up the environment

    let app = fixtures::scratch_app().await;
    let creator = fixtures::identity::create(&app, &fixtures::ancient()).await;
    let name = fixtures::channel::propose();

    // Call the endpoint (first time)

    let request = post::Request { name: name.clone() };
    let post::Response(_) = post::handler(
        State(app.clone()),
        creator.clone(),
        fixtures::ancient(),
        Json(request),
    )
    .await
    .expect("new channel in an empty app");

    // Delete the channel

    app.channels()
        .expire(&fixtures::now())
        .await
        .expect("expiry always succeeds");

    // Call the endpoint (second time)

    let request = post::Request { name: name.clone() };
    let post::Response(response) =
        post::handler(State(app.clone()), creator, fixtures::now(), Json(request))
            .await
            .expect("creation succeeds after original channel expired");

    // Verify the structure of the response

    assert_eq!(name, response.name);

    // Verify the semantics

    let channel = app
        .channels()
        .get(&response.id)
        .await
        .expect("the newly-created channel exists");
    assert_eq!(response, channel);
}