declare const wx: any;

/** A terminal gate for this process. Only a real package restart clears it. */
export default class ClientUpdate {
    private static initialized = false;
    private static manager: any = null;
    private static state: "checking" | "downloading" | "ready" | "unavailable" = "checking";
    private static rejection: any = null;
    private static dialogOpen = false;
    private static waitTimer: any = null;
    private static previewPanel: HTMLElement = null;

    static get blocked(): boolean { return this.rejection !== null; }
    static get blockedResponse(): any { return this.rejection; }

    static initialize(simulateInPreview = false): void {
        if (this.initialized) return;
        this.initialized = true;
        if (typeof wx !== "undefined" && typeof wx.getUpdateManager === "function") {
            try {
                this.manager = wx.getUpdateManager();
                this.manager.onCheckForUpdate(result => {
                    if (this.state === "ready") return;
                    this.state = result.hasUpdate ? "downloading" : "unavailable";
                    if (this.blocked) this.showPrompt();
                });
                this.manager.onUpdateReady(() => {
                    this.state = "ready";
                    if (this.blocked) this.showPrompt();
                });
                this.manager.onUpdateFailed(() => {
                    this.state = "unavailable";
                    if (this.blocked) this.showPrompt();
                });
            } catch (_) { this.state = "unavailable"; }
        } else {
            this.state = "unavailable";
        }
        // Local UI simulation only. Never changes the reported version or bypasses the server gate.
        if (typeof CC_PREVIEW !== "undefined" && CC_PREVIEW && simulateInPreview) {
            this.handleResponse({ code: 0, errorCode: "CLIENT_UPDATE_REQUIRED", msg: "强更流程预览", data: null });
        }
    }

    /** Also converts late successful responses to the same error after another request blocks us. */
    static handleResponse(response: any): any {
        if (!this.blocked && response?.errorCode === "CLIENT_UPDATE_REQUIRED") {
            this.initialize();
            this.rejection = response;
            this.freezeGame();
            this.showPrompt();
        }
        return this.rejection || response;
    }

    /** GameManager calls this before its normal foreground resume. */
    static onShow(): boolean {
        if (!this.blocked) return false;
        this.freezeGame();
        this.showPrompt();
        return true;
    }

    private static freezeGame(): void {
        cc.fx.GameConfig.GM_INFO.gameState = false;
        const scene = cc.director.getScene();
        if (scene) scene.pauseSystemEvents(true);
        cc.audioEngine.pauseAll();
        cc.game.pause();
    }

    private static clearWait(): void {
        if (this.waitTimer !== null) clearTimeout(this.waitTimer);
        this.waitTimer = null;
    }

    private static showPrompt(): void {
        if (typeof wx === "undefined" || typeof wx.showModal !== "function") {
            this.showPreviewPanel();
            return;
        }
        if (this.state === "checking" || this.state === "downloading") {
            if (this.dialogOpen) return;
            wx.showLoading({ title: "正在准备更新", mask: true });
            if (this.waitTimer === null) {
                this.waitTimer = setTimeout(() => {
                    this.waitTimer = null;
                    if (this.state !== "ready") {
                        this.state = "unavailable";
                        this.showPrompt();
                    }
                }, 30000);
            }
            return;
        }
        this.clearWait();
        if (this.dialogOpen) return;
        wx.hideLoading();
        const promptState = this.state;
        const ready = promptState === "ready";
        this.dialogOpen = true;
        wx.showModal({
            title: "游戏需要更新",
            content: ready ? "新版本已准备好，请重启更新。更新后将自动登录。"
                : "当前版本已无法继续游戏，暂未取得可用的新版本。请退出后重新进入；仍有问题请稍后再试。",
            showCancel: false,
            confirmText: ready ? "重启更新" : "退出游戏",
            success: result => {
                if (!result.confirm || this.state !== promptState) return;
                if (ready) {
                    try { this.manager.applyUpdate(); }
                    catch (_) { this.state = "unavailable"; }
                } else if (typeof wx.exitMiniProgram === "function") {
                    wx.exitMiniProgram({ fail: () => {
                        wx.showToast({ title: "请手动退出后重新进入", icon: "none", duration: 3000 });
                    } });
                }
            },
            complete: () => {
                this.dialogOpen = false;
                if (this.state !== promptState) {
                    setTimeout(() => this.showPrompt(), 0);
                } else {
                    // Keep a visible mask even if the platform refuses to exit/restart or dismisses the modal.
                    wx.showLoading({ title: ready ? "请重启游戏" : "请重新进入游戏", mask: true });
                }
            },
        });
    }

    private static showPreviewPanel(): void {
        if (this.previewPanel || typeof document === "undefined" || !document.body) return;
        const panel = document.createElement("div");
        panel.style.cssText = "position:fixed;inset:0;z-index:2147483647;background:#182036;color:#fff;display:flex;flex-direction:column;align-items:center;justify-content:center;text-align:center;padding:24px;font:18px sans-serif";
        const title = document.createElement("h2");
        title.textContent = "游戏需要更新";
        const message = document.createElement("p");
        message.textContent = "请加载兼容的新版本后刷新页面。更新后将自动登录。";
        const button = document.createElement("button");
        button.textContent = "刷新页面";
        button.style.cssText = "padding:12px 28px;margin-top:20px;font:18px sans-serif;cursor:pointer";
        button.onclick = () => window.location.reload();
        panel.appendChild(title);
        panel.appendChild(message);
        panel.appendChild(button);
        document.body.appendChild(panel);
        this.previewPanel = panel;
    }
}