use axum::{
    Json,
    extract::{Extension, Request, State},
    http::{
        HeaderMap, StatusCode,
        header::{AUTHORIZATION, COOKIE},
    },
    middleware::Next,
    response::Response,
};
use platform_auth::{
    AccessTokenClaims, AuthProvider, BindingStatus, read_refresh_session_token, verify_access_token,
};
use serde_json::{Value, json};
use time::OffsetDateTime;
use tracing::warn;

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

const INTERNAL_AUTH_USER_ID_HEADER: &str = "x-genarrative-authenticated-user-id";
const INTERNAL_API_SECRET_HEADER: &str = "x-genarrative-internal-api-secret";

// 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,
}

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
    }
}

pub async fn require_bearer_auth(
    State(state): State<AppState>,
    mut request: Request,
    next: Next,
) -> Result<Response, AppError> {
    if allows_internal_forwarded_auth(request.uri().path())
        && let Some(claims) = try_build_internal_forwarded_claims(&state, request.headers())
    {
        request
            .extensions_mut()
            .insert(AuthenticatedAccessToken::new(claims));
        return Ok(next.run(request).await);
    }

    let bearer_token = extract_bearer_token(request.headers())?;
    let request_id = request
        .extensions()
        .get::<RequestContext>()
        .map(|context| context.request_id().to_string())
        .unwrap_or_else(|| "unknown".to_string());
    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)
        })?
        .ok_or_else(|| {
            warn!(
                %request_id,
                user_id = %claims.user_id(),
                "Bearer JWT 对应用户不存在"
            );
            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"));
    }

    request
        .extensions_mut()
        .insert(AuthenticatedAccessToken::new(claims));

    Ok(next.run(request).await)
}

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())
}

fn allows_internal_forwarded_auth(path: &str) -> bool {
    // Node 代理已经完成平台账号 JWT 校验，Rust 运行时只信任这些明确的内部转发路径。
    path.starts_with("/api/runtime/big-fish/")
        || path.starts_with("/api/runtime/chat/")
        || path.starts_with("/api/runtime/creative-agent/")
        || path.starts_with("/api/runtime/puzzle/")
}

fn try_build_internal_forwarded_claims(
    state: &AppState,
    headers: &HeaderMap,
) -> Option<AccessTokenClaims> {
    let expected_secret = state.config.internal_api_secret.as_ref()?.trim();
    if expected_secret.is_empty() {
        return None;
    }

    let provided_secret = headers
        .get(INTERNAL_API_SECRET_HEADER)
        .and_then(|value| value.to_str().ok())
        .map(str::trim)
        .filter(|value| !value.is_empty())?;
    if provided_secret != expected_secret {
        return None;
    }

    let user_id = headers
        .get(INTERNAL_AUTH_USER_ID_HEADER)
        .and_then(|value| value.to_str().ok())
        .map(str::trim)
        .filter(|value| !value.is_empty())?
        .to_string();

    // 这里的 claims 只服务于经 Node 已鉴权后的本地内部转发链路，避免在开发态复制整套账号仓储。
    AccessTokenClaims::from_input(
        platform_auth::AccessTokenClaimsInput {
            user_id: user_id.clone(),
            session_id: format!("internal-forwarded-{user_id}"),
            provider: AuthProvider::Password,
            roles: vec!["user".to_string()],
            token_version: 0,
            phone_verified: false,
            binding_status: BindingStatus::Active,
            display_name: None,
        },
        state.auth_jwt_config(),
        OffsetDateTime::now_utc(),
    )
    .ok()
}

#[cfg(test)]
mod tests {
    use super::{
        INTERNAL_API_SECRET_HEADER, INTERNAL_AUTH_USER_ID_HEADER, RefreshSessionToken,
        allows_internal_forwarded_auth, extract_bearer_token, try_build_internal_forwarded_claims,
    };
    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");
    }

    #[test]
    fn internal_forwarded_auth_allows_node_proxy_runtime_paths() {
        assert!(allows_internal_forwarded_auth(
            "/api/runtime/big-fish/sessions"
        ));
        assert!(allows_internal_forwarded_auth(
            "/api/runtime/chat/npc/turn/stream"
        ));
        assert!(allows_internal_forwarded_auth(
            "/api/runtime/creative-agent/sessions"
        ));
        assert!(allows_internal_forwarded_auth("/api/runtime/puzzle/works"));
        assert!(!allows_internal_forwarded_auth("/api/auth/me"));
    }

    #[test]
    fn internal_forwarded_claims_require_matching_secret() {
        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(
            INTERNAL_AUTH_USER_ID_HEADER,
            HeaderValue::from_static("user_forwarded_01"),
        );
        headers.insert(
            INTERNAL_API_SECRET_HEADER,
            HeaderValue::from_static("bridge-secret"),
        );

        let claims =
            try_build_internal_forwarded_claims(&state, &headers).expect("claims should resolve");

        assert_eq!(claims.user_id(), "user_forwarded_01");
        assert_eq!(claims.token_version(), 0);
    }
}