use once_cell::sync::Lazy;
use sqlx::{postgres::PgPoolOptions, query, Connection, Executor, PgConnection, Pool, Postgres};
use uuid::Uuid;
use std:: net::TcpListener;
use zero2prod::{configuration::{get_configuration, DatabaseSettings}, telemetry::{get_subscriber, init_subscriber}};

pub struct TestApp {
	pub address: String,
	pub connection_pool: Pool<Postgres>,
}

static TRACING: Lazy<()> = Lazy::new(|| {
	let default_filter_level = "info".to_string();
	let subscriber_name = "test".to_string();

	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);
	}
});

async fn spawn_app() -> TestApp {
	Lazy::force(&TRACING);

    let listener = TcpListener::bind("127.0.0.1:0").expect("Failed to bind random port");
    let port = listener.local_addr().unwrap().port();
    let address = format!("http://127.0.0.1:{}", port);

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

    let server = zero2prod::startup::run(listener, connection_pool.clone()).expect("Failed to bind address");
    let _ = tokio::spawn(server);

	TestApp {
		address,
		connection_pool,
	}
}

pub async fn configure_database(config: &DatabaseSettings) -> Pool<Postgres> {
	let mut connection = PgConnection::connect_with(&config.without_db())
		.await
		.expect("Failed to connect to Postgres.");

		connection.execute(format!(r#"CREATE DATABASE "{}";"#, config.database_name).as_str())
		.await
		.expect("Failed to create database.");

	let connection_pool = PgPoolOptions::new()
		.max_connections(10)
		.connect_with(config.with_db())
		.await
		.expect("Failed to connect to Postgres.");

	sqlx::migrate!("./migrations")
		.run(&connection_pool)
		.await
		.expect("Failed to run migrations.");

	connection_pool
}

#[tokio::test]
async fn health_check_works() {
    let app = spawn_app().await;
    let health_check_endpoint = format!("{}/health_check", app.address);
    let client = reqwest::Client::new();
    let response = client
        .get(health_check_endpoint)
        .send()
        .await
        .expect("Failed to execute request.");

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

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

    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_eq!(200, response.status().as_u16());

	let saved = query!("SELECT email, name FROM subscriptions",)
		.fetch_one(&app.connection_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_data_is_missing() {
    let app = 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 {
        let response = client
            .post(&format!("{}/subscriptions", &app.address))
            .header("Content-Type", "application/x-www-form-urlencoded")
            .body(invalid_body)
            .send()
            .await
            .expect("Failed to execute request.");

        assert_eq!(
            400,
            response.status().as_u16(),
            "The API did not fail with 400 Bad Request when the payload was {}.",
            error_message
        );
    }
}

#[tokio::test]
async fn subscribe_returns_a_400_when_fields_are_present_but_invalid() {
	let app = spawn_app().await;
	let client = reqwest::Client::new();
	let test_cases = vec![
		("name=&email=ursula_le_guin%40gmail.com", "name is empty"),
		("name=le%20guin&email=", "email is empty"),
		("name=&email=", "name and email are empty"),
		("name=Ursula&email=definitely-not-an-email", "invalid email"),
	];

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

		assert_eq!(
			400,
			response.status().as_u16(),
			"The API did not return a 400 Bad Request when the payload was {}.",
			error_message
		);
	}
}