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};
use serde_json::{Value, json};
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,
}

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> {
    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)
    })?;

    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())
}

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