use learn_axum::configuration::{get_configuration, DatabaseSettings};
use learn_axum::telemetry::{get_subscriber, init_subscriber};
use once_cell::sync::Lazy;
use sqlx::{Connection, Executor, PgConnection, PgPool};
use tokio::net::TcpListener;
use uuid::Uuid;

/// Ensure that the `tracing` stack is only initialised once using `once_cell`
static TRACING: Lazy<()> = Lazy::new(|| {
    let default_filter_level = "info".to_string();
    let subscriber_name = "test".to_string();
    // We cannot assign the output of `get_subscriber` to a variable based on the
    // value TEST_LOG` because the sink is part of the type returned by
    // `get_subscriber`, therefore they are not the same type. We could work around
    // it, but this is the most straight-forward way of moving forward.
    if std::env::var("TEST_LOG").is_ok() {
        let subscriber = get_subscriber(subscriber_name, default_filter_level, std::io::stdout);
        init_subscriber(subscriber);
    } else {
        let subscriber = get_subscriber(subscriber_name, default_filter_level, std::io::sink);
        init_subscriber(subscriber);
    };
});

pub struct TestApp {
    pub address: String,
    pub db_pool: PgPool,
}

#[tokio::test]
async fn health_check_works() {
    // Arrange
    let TestApp { address, .. } = spawn_app().await;

    // Act
    let client = reqwest::Client::new();
    let response = client
        .get(format!("{address}/health_check"))
        .send()
        .await
        .expect("Failed to execute request.");

    // Assert
    assert!(response.status().is_success());
    assert_eq!(Some(0), response.content_length());
}

#[tokio::test]
async fn subscribe_returns_a_422_when_data_is_missing() {
    // Arrange
    let TestApp { address, .. } = spawn_app().await;
    let client = reqwest::Client::new();
    let test_cases = vec![
        ("name=le%20guin", "missing the email"),
        ("email=ursula_le_guin%40gmail.com", "missing the name"),
        ("", "missing both name and email"),
    ];

    for (invalid_body, error_message) in test_cases {
        // Act
        let response = client
            .post(&format!("{address}/subscriptions"))
            .header("Content-Type", "application/x-www-form-urlencoded")
            .body(invalid_body)
            .send()
            .await
            .expect("Failed to execute request.");

        // Assert
        assert_eq!(
            422,
            response.status().as_u16(),
            "The API did not fail with 422 when the payload was {}.",
            error_message
        );
    }
}

#[tokio::test]
async fn subscribe_returns_a_200_for_valid_form_data() {
    // Arrange
    let app = spawn_app().await;
    let client = reqwest::Client::new();

    // Act
    let body = "name=le%20guin&email=ursula_le_guin%40gmail.com";
    let response = client
        .post(&format!("{}/subscriptions", &app.address))
        .header("Content-Type", "application/x-www-form-urlencoded")
        .body(body)
        .send()
        .await
        .expect("Failed to execute request.");

    // Assert
    assert_eq!(200, response.status().as_u16());

    let saved = sqlx::query!("SELECT email, name FROM subscriptions",)
        .fetch_one(&app.db_pool)
        .await
        .expect("Failed to fetch saved subscription.");

    assert_eq!(saved.email, "ursula_le_guin@gmail.com");
    assert_eq!(saved.name, "le guin");
}

#[tokio::test]
async fn subscribe_returns_a_400_when_fields_are_present_but_invalid() {
    // Arrange
    let app = spawn_app().await;
    let client = reqwest::Client::new();
    let test_cases = vec![
        ("name=&email=ursula_le_guin%40gmail.com", "empty name"),
        ("name=Ursula&email=", "empty email"),
        ("name=Ursula&email=definitely-not-an-email", "invalid email"),
    ];

    for (body, description) in test_cases {
        // Act
        let response = client
            .post(&format!("{}/subscriptions", &app.address))
            .header("Content-Type", "application/x-www-form-urlencoded")
            .body(body)
            .send()
            .await
            .expect("Failed to execute request.");

        // Assert
        assert_eq!(
            400,
            response.status().as_u16(),
            "The API did not return a 200 OK when the payload was {}.",
            description
        );
    }
}

async fn spawn_app() -> TestApp {
    // The first time `initialize` is invoked the code in `TRACING` is executed.
    // All other invocations will instead skip execution.
    Lazy::force(&TRACING);

    let listener = TcpListener::bind("127.0.0.1:0").await.unwrap();
    let address = format!("http://{}", listener.local_addr().unwrap());

    let mut configuration = get_configuration().expect("Failed to read configuration.");
    configuration.database.name = Uuid::new_v4().to_string();
    let connection_pool = configure_database(&configuration.database).await;

    let service = learn_axum::startup::app(connection_pool.clone());
    tokio::spawn(async move {
        axum::serve(listener, service).await.unwrap();
    });
    TestApp {
        address,
        db_pool: connection_pool,
    }
}

pub async fn configure_database(config: &DatabaseSettings) -> PgPool {
    // Create database
    let mut connection = PgConnection::connect_with(&config.without_db())
        .await
        .expect("Failed to connect to Postgres");
    connection
        .execute(format!(r#"CREATE DATABASE "{}";"#, config.name).as_str())
        .await
        .expect("Failed to create database.");

    // Migrate database
    let connection_pool = PgPool::connect_with(config.with_db())
        .await
        .expect("Failed to connect to Postgres.");
    sqlx::migrate!("./migrations")
        .run(&connection_pool)
        .await
        .expect("Failed to migrate the database");

    connection_pool
}