//! 飞牛音乐本地流代理（axum）。
//!
//! 原生 `/track/stream`、`/static/cover` 需要 `Cookie: music-token=<token>`，而
//! WebView 的 `<audio>/<img>` 无法设置 Cookie。本模块绑定 `127.0.0.1:<动态端口>`，
//! 转发请求时注入 Cookie 与可选的安全码头，前端直接用本地地址播放/显示，天然支持 Range/seek。

use std::collections::HashMap;
use std::sync::{Arc, Mutex};

use axum::{
    extract::{Query, State},
    http::{header, HeaderMap, StatusCode},
    response::{IntoResponse, Response},
    routing::get,
    Router,
};

use super::conn::normalize_base_url;

/// 由 Feiniu 运行期与代理 handler 共享的连接配置（登录更新、登出置空）。
#[derive(Clone, Default)]
pub struct ProxyCfg {
    pub base_url: String,
    pub token: String,
    pub access_code: String,
}

#[derive(Clone)]
pub struct ProxyShared {
    pub client: reqwest::Client,
    pub cfg: Arc<Mutex<ProxyCfg>>,
}

/// 启动本地流代理，绑定到 `127.0.0.1:0`（动态空闲端口），返回实际端口。
/// 代理以独立 tokio 任务常驻应用存活期；token 变化经共享 `ProxyCfg` 即时生效，无需重启。
pub async fn start(shared: ProxyShared) -> Result<u16, String> {
    let listener = tokio::net::TcpListener::bind("127.0.0.1:0")
        .await
        .map_err(|e| format!("绑定本地端口失败: {e}"))?;
    let port = listener
        .local_addr()
        .map_err(|e| e.to_string())?
        .port();
    let app = Router::new()
        .route("/feiniu/stream", get(proxy_stream))
        .route("/feiniu/cover", get(proxy_cover))
        .with_state(shared);
    tokio::spawn(async move {
        if let Err(e) = axum::serve(listener, app).await {
            crate::logger::log_error("music", &format!("飞牛流代理异常: {e}"));
        }
    });
    Ok(port)
}

async fn proxy_stream(
    State(s): State<ProxyShared>,
    Query(q): Query<HashMap<String, String>>,
    headers: HeaderMap,
) -> Response {
    let guid = q.get("guid").cloned().unwrap_or_default().trim().to_string();
    if guid.is_empty() {
        return (StatusCode::BAD_REQUEST, "missing guid").into_response();
    }
    forward(
        &s,
        "/music/api/v1/track/stream",
        vec![("guid".to_string(), guid)],
        &headers,
    )
    .await
}

async fn proxy_cover(
    State(s): State<ProxyShared>,
    Query(q): Query<HashMap<String, String>>,
    headers: HeaderMap,
) -> Response {
    let cover_id = q
        .get("coverId")
        .cloned()
        .unwrap_or_default()
        .trim()
        .to_string();
    if cover_id.is_empty() {
        return (StatusCode::BAD_REQUEST, "missing coverId").into_response();
    }
    let size = q.get("size").cloned().unwrap_or_else(|| "320".into());
    forward(
        &s,
        "/music/api/v1/static/cover",
        vec![
            ("coverId".to_string(), cover_id),
            ("size".to_string(), size),
        ],
        &headers,
    )
    .await
}

/// 统一转发：向 NAS 发起上游 GET，注入 Cookie/安全码，透传 Range 与响应头，流式回传 body。
async fn forward(
    s: &ProxyShared,
    path: &str,
    query: Vec<(String, String)>,
    headers: &HeaderMap,
) -> Response {
    let cfg = match s.cfg.lock() {
        Ok(g) => g.clone(),
        Err(e) => e.into_inner().clone(),
    };
    if cfg.base_url.is_empty() || cfg.token.is_empty() {
        return (StatusCode::UNAUTHORIZED, "飞牛音乐未登录").into_response();
    }

    let base = normalize_base_url(&cfg.base_url);
    let url = format!("{base}{path}");
    let qrefs: Vec<(&str, &str)> = query.iter().map(|(k, v)| (k.as_str(), v.as_str())).collect();

    let mut rb = s.client.get(&url).query(&qrefs);
    rb = rb.header("cookie", format!("music-token={}", cfg.token));
    if !cfg.access_code.is_empty() {
        use base64::Engine;
        rb = rb
            .header(
                "x-access-code",
                base64::engine::general_purpose::STANDARD.encode(cfg.access_code.as_bytes()),
            )
            .header("x-access-source", "app");
    }
    if let Some(range) = headers.get(header::RANGE) {
        rb = rb.header(header::RANGE, range.clone());
    }
    drop(cfg);

    let resp = match rb.send().await {
        Ok(r) => r,
        Err(e) => return (StatusCode::BAD_GATEWAY, format!("上游错误: {e}")).into_response(),
    };
    let status = resp.status();

    let ct = resp.headers().get(header::CONTENT_TYPE).cloned();
    let cl = resp.headers().get(header::CONTENT_LENGTH).cloned();
    let cr = resp.headers().get(header::CONTENT_RANGE).cloned();
    let ar = resp.headers().get(header::ACCEPT_RANGES).cloned();

    let body = axum::body::Body::from_stream(resp.bytes_stream());
    let mut out = Response::new(body);
    *out.status_mut() = status;
    let h = out.headers_mut();
    if let Some(v) = ct {
        h.insert(header::CONTENT_TYPE, v);
    }
    if let Some(v) = cl {
        h.insert(header::CONTENT_LENGTH, v);
    }
    if let Some(v) = cr {
        h.insert(header::CONTENT_RANGE, v);
    }
    if let Some(v) = ar {
        h.insert(header::ACCEPT_RANGES, v);
    }
    out
}