//! Configuration parsing and CORS behavior of the app composition root.

use std::sync::Mutex;

use axum::body::Body;
use axum::http::{Request, StatusCode};
use tower::ServiceExt;

use tavolo_app::app;
use tavolo_app::config::Settings;
use tavolo_platform::oidc::OidcProviderConfig;

static ENV_LOCK: Mutex<()> = Mutex::new(());

const ENV_VARS: &[&str] = &[
    "DATABASE_URL",
    "DATABASE_ENGINE",
    "DATABASE_HOST",
    "DATABASE_PORT",
    "DATABASE_NAME",
    "DATABASE_USER",
    "DATABASE_PASSWORD",
    "DATABASE_OPTIONS",
    "APP_HOST",
    "APP_PORT",
    "REDIS_URL",
    "GAME_TTL_SECONDS",
    "STATIC_DIR",
    "HAND_ACK_TIMEOUT_SECONDS",
    "TURN_TIMEOUT_SECONDS",
    "DEADLINE_HEARTBEAT_MS",
    "LOGGING_CONFIG",
    "CORS_ALLOW_ORIGINS",
    "CORS_ALLOW_ORIGIN_REGEX",
    "CORS_ALLOW_METHODS",
    "CORS_ALLOW_HEADERS",
    "CORS_ALLOW_CREDENTIALS",
    "CORS_EXPOSE_HEADERS",
    "CORS_MAX_AGE",
    "OTEL_ENABLED",
    "OTEL_SERVICE_NAME",
    "OTEL_EXPORTER_OTLP_ENDPOINT",
    "OTEL_EXPORTER_OTLP_HEADERS",
    "OTEL_EXCLUDED_PATHS",
    "OTEL_METRIC_EXPORT_INTERVAL_MILLIS",
    "OTEL_METRICS_POLL_INTERVAL_SECONDS",
    "OIDC_ISSUER",
    "OIDC_CLIENT_ID",
    "OIDC_CLIENT_SECRET",
    "OIDC_REDIRECT_URI",
    "OIDC_POST_LOGIN_REDIRECT",
    "OIDC_POST_LOGOUT_REDIRECT",
];

fn clear_oidc_env() {
    for (name, _) in std::env::vars() {
        if name.starts_with("OIDC_") {
            std::env::remove_var(&name);
        }
    }
    for name in ENV_VARS {
        std::env::remove_var(name);
    }
}

fn with_env<T>(vars: &[(&str, &str)], f: impl FnOnce() -> T) -> T {
    let _guard = ENV_LOCK.lock().expect("env lock");
    clear_oidc_env();
    for (name, value) in vars {
        std::env::set_var(name, value);
    }
    let result = f();
    clear_oidc_env();
    result
}

#[test]
fn defaults_match_the_python_settings() {
    let settings = with_env(&[], Settings::from_env).expect("settings");
    assert_eq!(settings.app_host, "0.0.0.0");
    assert_eq!(settings.app_port, 8080);
    assert_eq!(settings.game_ttl_seconds, 86400);
    assert_eq!(settings.static_dir, "web/dist");
    assert_eq!(settings.oidc_providers.len(), 1);
    let provider = &settings.oidc_providers[0];
    assert_eq!(provider.provider, "default");
    assert_eq!(provider.issuer, "http://localhost:8180/tavolo");
    assert_eq!(provider.client_id, "tavolo");
    assert_eq!(
        provider.redirect_uri,
        "http://localhost:8080/auth/default/callback"
    );
    assert_eq!(
        settings.database_url,
        "postgres://tavolo:password@localhost/tavolo"
    );
    assert!(!settings.otel_enabled);
    assert_eq!(settings.otel_excluded_paths, vec!["/api/health"]);
}

#[test]
fn indexed_oidc_providers_are_parsed_in_order() {
    let settings = with_env(
        &[
            ("OIDC_0_PROVIDER", "google"),
            ("OIDC_0_ISSUER", "https://accounts.google.com"),
            ("OIDC_0_CLIENT_ID", "gid"),
            ("OIDC_0_CLIENT_SECRET", "gsecret"),
            ("OIDC_1_PROVIDER", "github"),
            ("OIDC_1_ISSUER", "https://github.com/login/oauth"),
            ("OIDC_1_CLIENT_ID", "ghid"),
        ],
        Settings::from_env,
    )
    .expect("settings");
    assert_eq!(settings.oidc_providers.len(), 2);
    assert_eq!(settings.oidc_providers[0].provider, "google");
    assert_eq!(
        settings.oidc_providers[0].redirect_uri,
        "http://localhost:8080/auth/google/callback"
    );
    assert_eq!(
        settings.oidc_providers[0].client_secret.as_deref(),
        Some("gsecret")
    );
    assert_eq!(settings.oidc_providers[1].provider, "github");
    assert!(settings.oidc_providers[1].client_secret.is_none());
}

#[test]
fn invalid_oidc_configurations_are_rejected() {
    let error = with_env(
        &[
            ("OIDC_0_PROVIDER", "a"),
            ("OIDC_0_ISSUER", "https://x"),
            ("OIDC_0_CLIENT_ID", "x"),
            ("OIDC_2_PROVIDER", "b"),
            ("OIDC_2_ISSUER", "https://y"),
            ("OIDC_2_CLIENT_ID", "y"),
        ],
        Settings::from_env,
    )
    .expect_err("missing index must fail");
    assert!(error.contains("contiguous"), "{error}");

    let error = with_env(&[("OIDC_ISSUER", "https://legacy")], Settings::from_env)
        .expect_err("legacy variables must fail");
    assert!(error.contains("indexed per provider"), "{error}");

    let error = with_env(
        &[
            ("OIDC_0_PROVIDER", "bad name!"),
            ("OIDC_0_ISSUER", "https://x"),
            ("OIDC_0_CLIENT_ID", "x"),
        ],
        Settings::from_env,
    )
    .expect_err("invalid provider names must fail");
    assert!(error.contains("letters, digits"), "{error}");

    let error = with_env(
        &[
            ("OIDC_0_PROVIDER", "a"),
            ("OIDC_0_ISSUER", "https://x"),
            ("OIDC_0_CLIENT_ID", "x"),
            ("OIDC_0_WAT", "?"),
        ],
        Settings::from_env,
    )
    .expect_err("unknown variables must fail");
    assert!(
        error.contains("unknown OIDC environment variable"),
        "{error}"
    );
}

#[test]
fn database_dsn_quotes_credentials() {
    let settings = with_env(
        &[
            ("DATABASE_USER", "ta:v@lo"),
            ("DATABASE_PASSWORD", "p@ss word"),
            ("DATABASE_HOST", "db.example"),
            ("DATABASE_PORT", "5433"),
            ("DATABASE_NAME", "tavolo"),
            ("DATABASE_OPTIONS", "ssl=require"),
        ],
        Settings::from_env,
    )
    .expect("settings");
    assert_eq!(
        settings.database_url,
        "postgres://ta%3Av%40lo:p%40ss%20word@db.example:5433/tavolo?ssl=require"
    );
}

#[tokio::test]
async fn cors_is_disabled_without_configuration() {
    let settings = base_settings();
    let (platform, sessions) = app::in_memory_platform(&settings).expect("platform");
    let router = app::build_router(platform, sessions, &settings);
    let response = router
        .clone()
        .oneshot(
            Request::builder()
                .uri("/api/health")
                .header("origin", "https://cards.example")
                .body(Body::empty())
                .unwrap(),
        )
        .await
        .unwrap();
    assert_eq!(response.status(), StatusCode::OK);
    assert!(response
        .headers()
        .get("access-control-allow-origin")
        .is_none());
}

#[tokio::test]
async fn cors_allows_configured_origins_and_regexes() {
    let mut settings = base_settings();
    settings.cors_allow_origins = Some(vec!["https://cards.example".into()]);
    settings.cors_allow_origin_regex = Some(r"https://preview-[a-z0-9-]+\.example\.com".into());
    settings.cors_allow_methods = Some(vec!["GET".into(), "POST".into()]);
    settings.cors_max_age = 3600;
    let (platform, sessions) = app::in_memory_platform(&settings).expect("platform");
    let router = app::build_router(platform, sessions, &settings);

    // Allowed origin: echoed. Disallowed origin: no header, request still runs.
    let response = router
        .clone()
        .oneshot(
            Request::builder()
                .uri("/api/health")
                .header("origin", "https://cards.example")
                .body(Body::empty())
                .unwrap(),
        )
        .await
        .unwrap();
    assert_eq!(
        response.headers()["access-control-allow-origin"],
        "https://cards.example"
    );
    let response = router
        .clone()
        .oneshot(
            Request::builder()
                .uri("/api/health")
                .header("origin", "https://preview-abc.example.com")
                .body(Body::empty())
                .unwrap(),
        )
        .await
        .unwrap();
    assert_eq!(
        response.headers()["access-control-allow-origin"],
        "https://preview-abc.example.com"
    );
    let response = router
        .clone()
        .oneshot(
            Request::builder()
                .uri("/api/health")
                .header("origin", "https://mallory.example")
                .body(Body::empty())
                .unwrap(),
        )
        .await
        .unwrap();
    assert_eq!(response.status(), StatusCode::OK);
    assert!(response
        .headers()
        .get("access-control-allow-origin")
        .is_none());

    // Preflight.
    let response = router
        .clone()
        .oneshot(
            Request::builder()
                .method("OPTIONS")
                .uri("/api/health")
                .header("origin", "https://cards.example")
                .header("access-control-request-method", "POST")
                .body(Body::empty())
                .unwrap(),
        )
        .await
        .unwrap();
    assert_eq!(response.status(), StatusCode::OK);
    let methods = response.headers()["access-control-allow-methods"]
        .to_str()
        .unwrap()
        .to_string();
    assert!(methods.contains("POST"), "{methods}");
    assert_eq!(response.headers()["access-control-max-age"], "3600");

    let response = router
        .clone()
        .oneshot(
            Request::builder()
                .method("OPTIONS")
                .uri("/api/health")
                .header("origin", "https://mallory.example")
                .header("access-control-request-method", "GET")
                .body(Body::empty())
                .unwrap(),
        )
        .await
        .unwrap();
    assert_eq!(response.status(), StatusCode::BAD_REQUEST);
}

#[tokio::test]
async fn cors_credentials_echo_the_origin_for_wildcards() {
    let mut settings = base_settings();
    settings.cors_allow_origins = Some(vec!["*".into()]);
    settings.cors_allow_credentials = true;
    let (platform, sessions) = app::in_memory_platform(&settings).expect("platform");
    let router = app::build_router(platform, sessions, &settings);
    let response = router
        .clone()
        .oneshot(
            Request::builder()
                .uri("/api/health")
                .header("origin", "https://cards.example")
                .body(Body::empty())
                .unwrap(),
        )
        .await
        .unwrap();
    assert_eq!(
        response.headers()["access-control-allow-origin"],
        "https://cards.example"
    );
    assert_eq!(
        response.headers()["access-control-allow-credentials"],
        "true"
    );
}

fn base_settings() -> Settings {
    Settings {
        database_url: "postgres://unused".into(),
        oidc_providers: vec![OidcProviderConfig {
            provider: "default".into(),
            issuer: "http://localhost:8180/tavolo".into(),
            client_id: "tavolo".into(),
            client_secret: None,
            redirect_uri: "http://localhost:8080/auth/default/callback".into(),
            post_login_redirect: "/".into(),
            post_logout_redirect: "/".into(),
        }],
        app_host: "127.0.0.1".into(),
        app_port: 0,
        redis_url: None,
        game_ttl_seconds: 86400,
        static_dir: "/nonexistent-web-dist".into(),
        hand_ack_timeout_seconds: 30,
        turn_timeout_seconds: 30,
        deadline_heartbeat_ms: 50,
        logging_config: None,
        cors_allow_origins: None,
        cors_allow_origin_regex: None,
        cors_allow_methods: None,
        cors_allow_headers: None,
        cors_allow_credentials: false,
        cors_expose_headers: None,
        cors_max_age: 600,
        otel_enabled: false,
        otel_service_name: "tavolo".into(),
        otel_exporter_endpoint: None,
        otel_exporter_headers: None,
        otel_excluded_paths: vec!["/api/health".into()],
        otel_metric_export_interval_millis: 60000,
        otel_metrics_poll_interval_seconds: 15,
    }
}