use axum::{
    Json,
    extract::{Extension, Request, State},
    http::{
        HeaderMap, StatusCode,
        header::{AUTHORIZATION, COOKIE},
    },
    middleware::Next,
    response::Response,
};
use platform_auth::{AccessTokenClaims, read_refresh_session_token, verify_access_token};
#[cfg(any())]
use platform_auth::{
    RUNTIME_GUEST_SCOPE_PUBLIC_PLAY, RuntimeGuestTokenClaims, RuntimeGuestTokenClaimsInput,
    sign_runtime_guest_token, verify_runtime_guest_token,
};
use serde_json::{Value, json};
#[cfg(any())]
use shared_contracts::auth::RuntimeGuestTokenResponse;
#[cfg(any())]
use shared_kernel::{format_rfc3339, new_uuid_simple_string};
use time::OffsetDateTime;
use tracing::warn;

use crate::{
    api_response::json_success_body, http_error::AppError, request_context::RequestContext,
    state::AppState,
};

// 统一把已校验的 claims 写入 request extensions，避免后续 handler 再次重复解析 Bearer token。
#[derive(Clone, Debug)]
pub struct AuthenticatedAccessToken {
    claims: AccessTokenClaims,
}

#[derive(Clone, Debug)]
pub struct RefreshSessionToken {
    token: String,
}

#[derive(Clone, Debug)]
#[cfg(any())]
pub enum RuntimePrincipal {
    User(AuthenticatedAccessToken),
    Guest(RuntimeGuestTokenClaims),
}

#[derive(Clone, Copy, Debug, Eq, PartialEq)]
#[cfg(any())]
pub enum RuntimePrincipalKind {
    User,
    Guest,
}

impl AuthenticatedAccessToken {
    pub fn new(claims: AccessTokenClaims) -> Self {
        Self { claims }
    }

    pub fn claims(&self) -> &AccessTokenClaims {
        &self.claims
    }
}

impl RefreshSessionToken {
    pub fn new(token: String) -> Self {
        Self { token }
    }

    pub fn token(&self) -> &str {
        &self.token
    }
}

#[cfg(any())]
impl RuntimePrincipal {
    pub fn subject(&self) -> &str {
        match self {
            Self::User(authenticated) => authenticated.claims().user_id(),
            Self::Guest(claims) => claims.subject(),
        }
    }

    pub fn kind(&self) -> RuntimePrincipalKind {
        match self {
            Self::User(_) => RuntimePrincipalKind::User,
            Self::Guest(_) => RuntimePrincipalKind::Guest,
        }
    }
}

#[cfg(any())]
impl RuntimePrincipalKind {
    pub fn as_str(self) -> &'static str {
        match self {
            Self::User => "user",
            Self::Guest => "guest",
        }
    }
}

#[cfg(any())]
pub async fn issue_runtime_guest_token(
    State(state): State<AppState>,
    Extension(request_context): Extension<RequestContext>,
) -> Result<Json<Value>, AppError> {
    let issued_at = OffsetDateTime::now_utc();
    let claims = RuntimeGuestTokenClaims::from_input(
        RuntimeGuestTokenClaimsInput {
            subject: format!("guest-runtime-{}", new_uuid_simple_string()),
            scope: RUNTIME_GUEST_SCOPE_PUBLIC_PLAY.to_string(),
        },
        state.auth_jwt_config(),
        issued_at,
    )
    .map_err(|error| {
        AppError::from_status(StatusCode::INTERNAL_SERVER_ERROR).with_message(error.to_string())
    })?;
    let token = sign_runtime_guest_token(&claims, state.auth_jwt_config()).map_err(|error| {
        AppError::from_status(StatusCode::INTERNAL_SERVER_ERROR).with_message(error.to_string())
    })?;
    let expires_at = OffsetDateTime::from_unix_timestamp(claims.expires_at_unix() as i64)
        .ok()
        .and_then(|value| format_rfc3339(value).ok())
        .unwrap_or_else(|| "1970-01-01T00:00:00Z".to_string());

    Ok(json_success_body(
        Some(&request_context),
        RuntimeGuestTokenResponse {
            token,
            expires_at,
            subject: claims.subject().to_string(),
            scope: claims.scope().to_string(),
        },
    ))
}

pub async fn require_bearer_auth(
    State(state): State<AppState>,
    mut request: Request,
    next: Next,
) -> Result<Response, AppError> {
    let headers = request.headers().clone();
    let request_id = request_id_from_request(&request);
    let Some(authenticated) = authenticate_request(&state, headers, request_id).await? else {
        return Err(AppError::from_status(StatusCode::UNAUTHORIZED));
    };
    request.extensions_mut().insert(authenticated.clone());

    let mut response = next.run(request).await;
    response.extensions_mut().insert(authenticated);

    Ok(response)
}

#[cfg(any())]
pub async fn require_runtime_principal_auth(
    State(state): State<AppState>,
    mut request: Request,
    next: Next,
) -> Result<Response, AppError> {
    let headers = request.headers().clone();
    let request_id = request_id_from_request(&request);
    let Some(principal) = authenticate_runtime_principal(&state, headers, request_id).await? else {
        return Err(AppError::from_status(StatusCode::UNAUTHORIZED));
    };
    request.extensions_mut().insert(principal.clone());

    let mut response = next.run(request).await;
    response.extensions_mut().insert(principal);

    Ok(response)
}

#[cfg(any())]
async fn authenticate_runtime_principal(
    state: &AppState,
    headers: HeaderMap,
    request_id: String,
) -> Result<Option<RuntimePrincipal>, AppError> {
    if !headers.contains_key(AUTHORIZATION) {
        return Ok(None);
    }

    match authenticate_request(state, headers.clone(), request_id.clone()).await {
        Ok(Some(authenticated)) => Ok(Some(RuntimePrincipal::User(authenticated))),
        Ok(None) => Ok(None),
        Err(_) => {
            let bearer_token = extract_bearer_token(&headers)?;
            let claims = verify_runtime_guest_token(&bearer_token, state.auth_jwt_config())
                .map_err(|error| {
                    warn!(
                        %request_id,
                        error = %error,
                        "runtime guest JWT 校验失败"
                    );
                    AppError::from_status(StatusCode::UNAUTHORIZED)
                })?;
            if claims.scope() != RUNTIME_GUEST_SCOPE_PUBLIC_PLAY {
                warn!(
                    %request_id,
                    scope = %claims.scope(),
                    "runtime guest JWT scope 非法"
                );
                return Err(AppError::from_status(StatusCode::UNAUTHORIZED));
            }
            Ok(Some(RuntimePrincipal::Guest(claims)))
        }
    }
}

pub async fn optional_access_token_from_headers(
    state: &AppState,
    _path: String,
    headers: HeaderMap,
    request_id: String,
) -> Result<Option<AuthenticatedAccessToken>, AppError> {
    authenticate_request(state, headers, request_id).await
}

async fn authenticate_request(
    state: &AppState,
    headers: HeaderMap,
    request_id: String,
) -> Result<Option<AuthenticatedAccessToken>, AppError> {
    if !headers.contains_key(AUTHORIZATION) {
        return Ok(None);
    }

    let bearer_token = extract_bearer_token(&headers)?;
    let claims = verify_access_token(&bearer_token, state.auth_jwt_config()).map_err(|error| {
        warn!(
            %request_id,
            error = %error,
            "Bearer JWT 校验失败"
        );
        AppError::from_status(StatusCode::UNAUTHORIZED)
    })?;
    let current_user = state
        .auth_user_service()
        .get_user_by_id(claims.user_id())
        .map_err(|error| {
            warn!(
                %request_id,
                error = %error,
                "Bearer JWT 用户快照读取失败"
            );
            AppError::from_status(StatusCode::INTERNAL_SERVER_ERROR)
        })?;
    let Some(current_user) = current_user else {
        warn!(
            %request_id,
            user_id = %claims.user_id(),
            "Bearer JWT 对应用户不存在"
        );
        return Err(AppError::from_status(StatusCode::UNAUTHORIZED));
    };
    if current_user.token_version != claims.token_version() {
        warn!(
            %request_id,
            user_id = %claims.user_id(),
            token_version = claims.token_version(),
            current_token_version = current_user.token_version,
            "Bearer JWT 版本已失效"
        );
        return Err(AppError::from_status(StatusCode::UNAUTHORIZED)
            .with_message("当前登录态已失效，请重新登录"));
    }

    let session_is_active = state
        .refresh_session_service()
        .is_session_active_for_user(
            claims.user_id(),
            claims.session_id(),
            OffsetDateTime::now_utc(),
        )
        .map_err(|error| {
            warn!(
                %request_id,
                user_id = %claims.user_id(),
                session_id = %claims.session_id(),
                error = %error,
                "Bearer JWT refresh session 状态读取失败"
            );
            AppError::from_status(StatusCode::INTERNAL_SERVER_ERROR)
        })?;
    if !session_is_active {
        warn!(
            %request_id,
            user_id = %claims.user_id(),
            session_id = %claims.session_id(),
            "Bearer JWT 对应 refresh session 已失效"
        );
        return Err(AppError::from_status(StatusCode::UNAUTHORIZED)
            .with_message("当前登录态已失效，请重新登录"));
    }

    Ok(Some(AuthenticatedAccessToken::new(claims)))
}

fn request_id_from_request(request: &Request) -> String {
    request
        .extensions()
        .get::<RequestContext>()
        .map(|context| context.request_id().to_string())
        .unwrap_or_else(|| "unknown".to_string())
}

pub async fn inspect_auth_claims(
    Extension(request_context): Extension<RequestContext>,
    Extension(authenticated): Extension<AuthenticatedAccessToken>,
) -> Json<Value> {
    json_success_body(
        Some(&request_context),
        json!({
            "claims": authenticated.claims(),
        }),
    )
}

pub async fn attach_refresh_session_token(
    State(state): State<AppState>,
    mut request: Request,
    next: Next,
) -> Response {
    if let Some(token) = request
        .headers()
        .get(COOKIE)
        .and_then(|value| value.to_str().ok())
        .and_then(|cookie_header| {
            read_refresh_session_token(cookie_header, state.refresh_cookie_config())
        })
    {
        request
            .extensions_mut()
            .insert(RefreshSessionToken::new(token));
    }

    next.run(request).await
}

pub async fn inspect_refresh_session_cookie(
    State(state): State<AppState>,
    Extension(request_context): Extension<RequestContext>,
    request: Request,
) -> Json<Value> {
    let maybe_token = request.extensions().get::<RefreshSessionToken>();

    json_success_body(
        Some(&request_context),
        json!({
            "cookieName": state.refresh_cookie_config().cookie_name(),
            "present": maybe_token.is_some(),
            "tokenLength": maybe_token.map(|token| token.token().len()),
        }),
    )
}

fn extract_bearer_token(headers: &HeaderMap) -> Result<String, AppError> {
    let authorization = headers
        .get(AUTHORIZATION)
        .and_then(|value| value.to_str().ok())
        .map(str::trim)
        .ok_or_else(|| AppError::from_status(StatusCode::UNAUTHORIZED))?;

    let token = authorization
        .strip_prefix("Bearer ")
        .or_else(|| authorization.strip_prefix("bearer "))
        .map(str::trim)
        .filter(|token| !token.is_empty())
        .ok_or_else(|| AppError::from_status(StatusCode::UNAUTHORIZED))?;

    Ok(token.to_string())
}

#[cfg(test)]
mod tests {
    use super::{RefreshSessionToken, extract_bearer_token, optional_access_token_from_headers};
    use crate::{config::AppConfig, state::AppState};
    use axum::{
        http::{HeaderMap, HeaderValue, StatusCode, header::AUTHORIZATION},
        response::IntoResponse,
    };

    #[test]
    fn extract_bearer_token_accepts_standard_header() {
        let mut headers = HeaderMap::new();
        headers.insert(
            AUTHORIZATION,
            HeaderValue::from_static("Bearer token-value"),
        );

        let token = extract_bearer_token(&headers).expect("bearer token should be extracted");

        assert_eq!(token, "token-value");
    }

    #[test]
    fn extract_bearer_token_rejects_missing_scheme() {
        let mut headers = HeaderMap::new();
        headers.insert(AUTHORIZATION, HeaderValue::from_static("Basic abc"));

        let error = extract_bearer_token(&headers).expect_err("basic auth should be rejected");

        assert_eq!(error.into_response().status(), StatusCode::UNAUTHORIZED);
    }

    #[test]
    fn refresh_session_token_retains_original_value() {
        let token = RefreshSessionToken::new("refresh-token-01".to_string());

        assert_eq!(token.token(), "refresh-token-01");
    }

    #[tokio::test]
    async fn internal_forwarding_headers_do_not_authenticate_without_bearer_token() {
        let mut config = AppConfig::default();
        config.internal_api_secret = Some("bridge-secret".to_string());
        let state = AppState::new(config).expect("state should build");
        let mut headers = HeaderMap::new();
        headers.insert(
            "x-genarrative-authenticated-user-id",
            HeaderValue::from_static("user_forwarded_01"),
        );
        headers.insert(
            "x-genarrative-internal-api-secret",
            HeaderValue::from_static("bridge-secret"),
        );

        let authenticated = optional_access_token_from_headers(
            &state,
            "/api/runtime/puzzle/works".to_string(),
            headers,
            "req-retired-internal-forward".to_string(),
        )
        .await
        .expect("forwarding headers should be ignored");

        assert!(authenticated.is_none());
    }
}