declare const wx: any;

export type ServerTarget = "production" | "test";

/** Fixed for the lifetime of the JS process. A saved choice only affects the next launch. */
export default class ServerEnvironment {
    private static readonly preferenceKey = "matchmaster:nextServer:v1";
    private static active: ServerTarget = null;
    private static switchAllowed = false;

    static current(): ServerTarget {
        if (this.active !== null) return this.active;
        try {
            const version = typeof wx !== "undefined" && wx.getAccountInfoSync?.().miniProgram?.envVersion;
            this.switchAllowed = version === "develop" || version === "trial";
        } catch (_) { this.switchAllowed = false; }
        this.active = this.switchAllowed ? this.readChoice() || "test" : "production";
        return this.active;
    }

    static canSwitch(): boolean {
        this.current();
        return this.switchAllowed;
    }

    static next(): ServerTarget {
        return this.canSwitch() ? this.readChoice() || "test" : "production";
    }

    static saveNext(target: ServerTarget): void {
        if (!this.canSwitch() || (target !== "production" && target !== "test")) {
            throw new Error("当前版本不允许切换服务器");
        }
        cc.sys.localStorage.setItem(this.preferenceKey, target);
        if (cc.sys.localStorage.getItem(this.preferenceKey) !== target) {
            throw new Error("服务器选择保存失败，请重试");
        }
    }

    private static readChoice(): ServerTarget {
        try {
            const value = cc.sys.localStorage.getItem(this.preferenceKey);
            return value === "production" || value === "test" ? value : null;
        } catch (_) { return null; }
    }

    static storageKey(key: string): string {
        // Device preferences and the existing standalone web preview retain their keys.
        if (key === "music" || typeof wx === "undefined") return key;
        // Unscoped legacy data remains on disk as a backup, never uploaded to an unknown server.
        return "matchmaster:server:v1:" + this.current() + ":" + key;
    }
}