import { CONFIG } from "./config.js";
import { loadSession, saveSession, clearSession } from "./storage.js";

function urlJoin(base, path) {
    if (!base) return path;
    return base.replace(/\/+$/, "") + "/" + path.replace(/^\/+/, "");
}

async function parseResponse(res) {
    const ct = (res.headers.get("content-type") || "").toLowerCase();
    if (ct.includes("application/json")) return await res.json();
    const text = await res.text();
    // иногда сервер шлёт json как text/plain
    try { return JSON.parse(text); } catch { return text; }
}

export async function renewTokens() {
    const s = loadSession();
    if (!s) throw new Error("NO_SESSION");

    // /renew/ ждёт user_id и live_token в headers :contentReference[oaicite:1]{index=1}
    const res = await fetch(urlJoin(CONFIG.API_BASE_URL, CONFIG.ENDPOINTS.renew), {
        method: "GET",
        headers: {
            "user_id": String(s.user_id),
                            "live_token": String(s.live_token)
        }
    });

    if (res.status === CONFIG.AUTH_ERROR_STATUS) {
        clearSession();
        throw new Error("RENEW_DENIED");
    }

    if (!res.ok) {
        const body = await parseResponse(res);
        throw new Error(typeof body === "string" ? body : "RENEW_FAILED");
    }

    const data = await parseResponse(res);
    if (!data?.short_token || !data?.live_token) {
        throw new Error("BAD_RENEW_RESPONSE");
    }

    const next = { ...s, short_token: data.short_token, live_token: data.live_token };
    saveSession(next);
    return next;
}

export async function apiFetch(path, {
    method = "GET",
    headers = {},
    body = null,
    auth = true
} = {}) {
    const s = loadSession();

    const reqHeaders = { ...headers };
    if (auth) {
        if (!s?.short_token) throw new Error("NO_AUTH");
        // Все защищённые ручки проверяют short_token в headers :contentReference[oaicite:2]{index=2}
        reqHeaders["short_token"] = String(s.short_token);
    }

    const doRequest = async () => {
        const res = await fetch(urlJoin(CONFIG.API_BASE_URL, path), {
            method,
            headers: {
                ...reqHeaders,
                ...(body ? { "content-type": "application/json" } : {})
            },
            body: body ? JSON.stringify(body) : null
        });
        return res;
    };

    let res = await doRequest();

    // Авто-обновление токенов при 426 :contentReference[oaicite:3]{index=3}
    if (auth && res.status === CONFIG.AUTH_ERROR_STATUS) {
        await renewTokens();
        // обновим заголовок short_token и повторим один раз
        const s2 = loadSession();
        reqHeaders["short_token"] = String(s2.short_token);
        res = await doRequest();
    }

    const payload = await parseResponse(res);
    if (!res.ok) {
        const err = new Error("API_ERROR");
        err.status = res.status;
        err.payload = payload;
        throw err;
    }

    return payload;
}