/**
 * 前端请求封装。
 * - 游客会话走 cookie（credentials: include），会话失效由服务端重建
 * - 浏览器无法改写 User-Agent；X-Real-IP 由服务端反代上游时注入
 * - 直连上游时若需自定义头，请走本站 Go 代理接口
 */
(function (global) {
    var DEFAULT_TIMEOUT_MS = 30000;

    function buildQuery(params) {
        if (!params) return "";
        var pairs = [];
        Object.keys(params).forEach(function (key) {
            var value = params[key];
            if (value == null) return;
            pairs.push(encodeURIComponent(key) + "=" + encodeURIComponent(String(value)));
        });
        return pairs.length ? "?" + pairs.join("&") : "";
    }

    /**
     * @param {string} url
     * @param {{
     *   method?: string,
     *   data?: any,
     *   params?: Record<string, any>,
     *   headers?: Record<string, string>,
     *   timeout?: number,
     * }} [options]
     */
    function request(url, options) {
        options = options || {};
        var method = String(options.method || "GET").toUpperCase();
        var headers = Object.assign(
            { Accept: "application/json" },
            options.headers || {}
        );
        var finalUrl = url + buildQuery(options.params);
        var body;
        var controller = typeof AbortController !== "undefined" ? new AbortController() : null;
        var timer;

        if (options.data != null && method !== "GET" && method !== "HEAD") {
            if (typeof FormData !== "undefined" && options.data instanceof FormData) {
                body = options.data;
            } else {
                headers["Content-Type"] = headers["Content-Type"] || "application/json";
                body =
                    headers["Content-Type"].indexOf("application/json") >= 0
                        ? JSON.stringify(options.data)
                        : options.data;
            }
        }

        var fetchOpts = {
            method: method,
            headers: headers,
            credentials: "include",
            signal: controller ? controller.signal : undefined,
        };
        if (body != null) fetchOpts.body = body;

        var timeoutMs =
            typeof options.timeout === "number" ? options.timeout : DEFAULT_TIMEOUT_MS;
        if (controller && timeoutMs > 0) {
            timer = setTimeout(function () {
                controller.abort();
            }, timeoutMs);
        }

        return fetch(finalUrl, fetchOpts)
            .then(function (res) {
                var contentType = res.headers.get("content-type") || "";
                var parse = contentType.indexOf("application/json") >= 0
                    ? res.json()
                    : res.text();
                return parse.then(function (data) {
                    if (!res.ok) {
                        var err = new Error(
                            (data && data.msg) || (data && data.message) || res.statusText || "request failed"
                        );
                        err.status = res.status;
                        err.code = data && data.code;
                        err.data = data;
                        throw err;
                    }
                    return data;
                });
            })
            .finally(function () {
                if (timer) clearTimeout(timer);
            });
    }

    global.HttpRequest = {
        request: request,
        get: function (url, options) {
            return request(url, Object.assign({}, options, { method: "GET" }));
        },
        post: function (url, data, options) {
            return request(url, Object.assign({}, options, { method: "POST", data: data }));
        },
    };
})(typeof window !== "undefined" ? window : this);