interface ViewPaddings {
  top: number;
  bottom: number;
  left: number;
  right: number;
}

interface LayoutInfo {
  breakpoint: string;
  screenWidth: number;
  screenHeight: number;
  isMobile: boolean;
  isTablet: boolean;
  isDesktop: boolean;
}

interface PlatformInfo {
  os: string;
  version: string;
}

interface LocaleInfo {
  languageCode: string;
  isRTL: boolean;
}

interface InitialConfig {
  paddings: ViewPaddings;
  viewInsets: ViewPaddings;
  safeArea: ViewPaddings;
  keyboardHeight: number;
  layout: LayoutInfo | null;
  platform: PlatformInfo | null;
  locale: LocaleInfo | null;
}

type EdgeSource =
  | {
      top?: number;
      bottom?: number;
      left?: number;
      right?: number;
    }
  | null
  | undefined;

function num(value: unknown): number {
  return typeof value === "number" && Number.isFinite(value) ? value : 0;
}

function safeParse(value: string): unknown {
  try {
    return JSON.parse(value);
  } catch {
    return null;
  }
}

function getEventData(event: unknown): Record<string, unknown> | null {
  if (!event || typeof event !== "object") return null;

  const envelope = event as Record<string, unknown>;
  const rawData = envelope.data ?? envelope.payload;

  if (!rawData || typeof rawData !== "object") return null;
  return rawData as Record<string, unknown>;
}

function readEdges(source: EdgeSource): ViewPaddings {
  return {
    top: num(source?.top),
    bottom: num(source?.bottom),
    left: num(source?.left),
    right: num(source?.right),
  };
}

/**
 * مقادیر safe-area در `initial_config` (فیلد safeArea) از فلاتر در واحد منطقی
 * (CSS px / dp) می‌آیند و مستقیماً برای CSS درست‌اند. اما مسیر قدیمی
 * `get_view_paddings` مقادیر را در پیکسل فیزیکی (× devicePixelRatio) می‌فرستد؛
 * این تابع آن‌ها را به px منطقی برمی‌گرداند تا با CSS هم‌خوان شوند.
 */
function toLogical(edges: ViewPaddings): ViewPaddings {
  const ratio =
    typeof window !== "undefined" && window.devicePixelRatio > 0
      ? window.devicePixelRatio
      : 1;

  return {
    top: edges.top / ratio,
    bottom: edges.bottom / ratio,
    left: edges.left / ratio,
    right: edges.right / ratio,
  };
}

class ViewPaddingsBridge {
  private paddings: ViewPaddings = { top: 0, bottom: 0, left: 0, right: 0 };
  private config: InitialConfig = {
    paddings: { top: 0, bottom: 0, left: 0, right: 0 },
    viewInsets: { top: 0, bottom: 0, left: 0, right: 0 },
    safeArea: { top: 0, bottom: 0, left: 0, right: 0 },
    keyboardHeight: 0,
    layout: null,
    platform: null,
    locale: null,
  };
  private listeners: Array<(paddings: ViewPaddings) => void> = [];
  private configListeners: Array<(config: InitialConfig) => void> = [];
  private hasInitialConfig = false;

  constructor() {
    if (typeof window !== "undefined" && window.__HABIB_BOOTSTRAP__) {
      this.applyInitialConfig(window.__HABIB_BOOTSTRAP__);
      this.hasInitialConfig = true;
    }
    this.init();
  }

  private init() {
    if (typeof window === "undefined") return;

    this.setupFlutterListener();
    this.setupConfigEventListener();
  }

  // مسیر جایگزین: برخی نسخه‌های اپ به‌جای onFlutterResponse، کانفیگ را با
  // CustomEvent('flutterConfig') یا postMessage می‌فرستند (طبق سند پل).
  // payload در این مسیر همان بدنه‌ی initial_config است (بدون پوشش action/data).
  private setupConfigEventListener() {
    const handle = (raw: unknown) => {
      if (!raw || typeof raw !== "object") return;
      const envelope = raw as Record<string, any>;
      const data = (envelope.payload ?? envelope.data ?? envelope) as Record<
        string,
        any
      >;
      if (this.hasInitialConfig) {
        if (data.locale) this.applyLocale(data.locale);
        return;
      }
      if (data.safeArea || data.viewInsets) {
        this.applyInitialConfig(data);
        this.hasInitialConfig = true;
      } else if (data.locale) {
        this.applyLocale(data.locale);
      }
    };

    window.addEventListener("flutterConfig", (event) => {
      handle((event as CustomEvent).detail);
    });

    window.addEventListener("message", (event) => {
      const data =
        typeof event.data === "string" ? safeParse(event.data) : event.data;
      handle(data);
    });
  }

  private setupFlutterListener() {
    const win = window as Window & {
      addFlutterResponseListener?: (
        listener: (event: any) => void,
      ) => () => void;
    };

    const attach = () => {
      if (typeof win.addFlutterResponseListener !== "function") return false;

      win.addFlutterResponseListener((event) => {
        if (!event || event.success === false) return;

        // Flutter clients use both `data` and `payload` for bridge responses.
        // In particular, the uppercase INITIAL_CONFIG protocol uses `payload`.
        // Keep the locale in that response so the route can be localized as soon
        // as the WebView opens.
        const data = getEventData(event);
        if (!data) return;

        switch (event.action) {
          case "initial_config":
          case "INITIAL_CONFIG":
            this.applyInitialConfig(data);
            this.hasInitialConfig = true;
            return;

          case "locale_changed":
          case "language_changed":
          case "LOCALE_CHANGED":
          case "LANGUAGE_CHANGED": {
            this.applyLocale(data?.locale ?? data);
            return;
          }

          // به‌روزرسانی فضای امن هنگام چرخش/تغییر notch (px منطقی).
          case "safe_area_changed":
            this.applySafeArea(readEdges(data));
            return;

          // ارتفاع کیبورد به‌صورت زنده (px منطقی).
          case "keyboard_changed": {
            const height = num(data.height);
            this.config = { ...this.config, keyboardHeight: height };
            this.applyKeyboard(height);
            this.notifyConfigListeners();
            return;
          }

          // سازگاری عقب‌رو: پاسخ ساده‌ی get_view_paddings (px فیزیکی، فقط لبه‌ها).
          // اگر initial_config رسیده باشد، آن مرجع است و این نادیده گرفته می‌شود.
          case "get_view_paddings":
            if (this.hasInitialConfig) return;
            this.applyEdges(toLogical(readEdges(data)));
            return;

          default:
            return;
        }
      });

      return true;
    };

    if (!attach()) {
      const interval = setInterval(() => {
        if (attach()) clearInterval(interval);
      }, 50);
    }
  }

  private applyInitialConfig(data: any) {
    const viewInsets = readEdges(data?.viewInsets);
    const safeArea = readEdges(data?.safeArea);
    // فیلد safeArea از فلاتر در px منطقی است و واحد درست برای CSS؛ همین مبنا
    // برای --safe-* است. (فیلد viewInsets در این payload در px فیزیکی و عملاً
    // تکرار همان viewPadding است، پس در محاسبه‌ی فضای امن استفاده نمی‌شود.)
    const paddings = safeArea;

    this.config = {
      paddings,
      viewInsets,
      safeArea,
      keyboardHeight: 0,
      layout: data?.layout
        ? {
            breakpoint: String(data.layout.breakpoint ?? ""),
            screenWidth: num(data.layout.screenWidth),
            screenHeight: num(data.layout.screenHeight),
            isMobile: Boolean(data.layout.isMobile),
            isTablet: Boolean(data.layout.isTablet),
            isDesktop: Boolean(data.layout.isDesktop),
          }
        : null,
      platform: data?.platform
        ? {
            os: String(data.platform.os ?? ""),
            version: String(data.platform.version ?? ""),
          }
        : null,
      locale: data?.locale
        ? {
            languageCode: String(data.locale.languageCode ?? ""),
            isRTL: Boolean(data.locale.isRTL ?? data.locale.isRtl),
          }
        : null,
    };

    this.applyEdges(paddings);
    this.applyKeyboard(0);
    this.notifyConfigListeners();
  }

  private applySafeArea(safeArea: ViewPaddings) {
    this.config = {
      ...this.config,
      safeArea,
      paddings: safeArea,
    };
    this.applyEdges(safeArea);
    this.notifyConfigListeners();
  }

  private applyLocale(locale: any) {
    if (!locale) return;

    this.config = {
      ...this.config,
      locale: {
        languageCode: String(locale.languageCode ?? locale.language_code ?? ""),
        isRTL: Boolean(locale.isRTL ?? locale.isRtl ?? locale.is_rtl),
      },
    };
    this.notifyConfigListeners();
  }

  private applyEdges(paddings: ViewPaddings) {
    this.paddings = paddings;
    this.applyPaddings();
    this.notifyListeners();
  }

  private applyPaddings() {
    if (typeof document === "undefined") return;

    const root = document.documentElement.style;
    root.setProperty("--safe-top", `${this.paddings.top}px`);
    root.setProperty("--safe-bottom", `${this.paddings.bottom}px`);
    root.setProperty("--safe-left", `${this.paddings.left}px`);
    root.setProperty("--safe-right", `${this.paddings.right}px`);
  }

  private applyKeyboard(height: number) {
    if (typeof document === "undefined") return;
    document.documentElement.style.setProperty("--kb-height", `${height}px`);
  }

  private notifyListeners() {
    this.listeners.forEach((listener) => {
      listener(this.paddings);
    });
  }

  private notifyConfigListeners() {
    this.configListeners.forEach((listener) => {
      listener(this.getConfig());
    });
  }

  public getPaddings(): ViewPaddings {
    return { ...this.paddings };
  }

  public getConfig(): InitialConfig {
    return {
      ...this.config,
      paddings: { ...this.config.paddings },
      viewInsets: { ...this.config.viewInsets },
      safeArea: { ...this.config.safeArea },
    };
  }

  public subscribe(listener: (paddings: ViewPaddings) => void): () => void {
    this.listeners.push(listener);
    return () => {
      const index = this.listeners.indexOf(listener);
      if (index >= 0) this.listeners.splice(index, 1);
    };
  }

  public subscribeConfig(
    listener: (config: InitialConfig) => void,
  ): () => void {
    this.configListeners.push(listener);
    return () => {
      const index = this.configListeners.indexOf(listener);
      if (index >= 0) this.configListeners.splice(index, 1);
    };
  }
}

export type {
  ViewPaddings,
  InitialConfig,
  LayoutInfo,
  PlatformInfo,
  LocaleInfo,
};
export const viewPaddingsBridge = new ViewPaddingsBridge();