"use client";

import { PhoneNumberUtil } from "google-libphonenumber";
import { resolveCountryName } from "@/data/countries";

export type UserGeoRegion = {
  ip?: string;
  city?: string;
  country?: string;
  countryCode?: string; // e.g. "IR", "US", "GB"
  phoneCode?: string; // e.g. "+98", "+1", "+44"
};

const phoneUtil = PhoneNumberUtil.getInstance();

const STORAGE_KEY = "user_geo_region";
const PHONE_STORAGE_KEY = "geoIPPhoneCode";

let cachedRegion: UserGeoRegion | null = null;
let geoRegionPromise: Promise<UserGeoRegion> | null = null;
const listeners = new Set<(region: UserGeoRegion) => void>();

export function resetUserGeoRegionForTesting() {
  cachedRegion = null;
  geoRegionPromise = null;
  listeners.clear();
}

export function subscribeToUserGeoRegion(
  fn: (region: UserGeoRegion) => void,
): () => void {
  listeners.add(fn);
  return () => {
    listeners.delete(fn);
  };
}

export function getStoredUserGeoRegion(): UserGeoRegion | null {
  if (cachedRegion) return cachedRegion;
  if (typeof window !== "undefined") {
    try {
      const stored = localStorage.getItem(STORAGE_KEY);
      if (stored) {
        const parsed = JSON.parse(stored) as UserGeoRegion;
        if (
          parsed &&
          (parsed.country ||
            parsed.phoneCode ||
            parsed.city ||
            parsed.countryCode)
        ) {
          cachedRegion = parsed;
          return parsed;
        }
      }
    } catch {}
  }
  return null;
}

export function setStoredUserGeoRegion(region: UserGeoRegion) {
  const current =
    cachedRegion ||
    (typeof window !== "undefined" ? getStoredUserGeoRegion() : null);
  const merged: UserGeoRegion = {
    ...(current || {}),
    ...region,
  };
  cachedRegion = merged;
  if (typeof window !== "undefined") {
    try {
      localStorage.setItem(STORAGE_KEY, JSON.stringify(merged));
      if (merged.phoneCode) {
        localStorage.setItem(PHONE_STORAGE_KEY, merged.phoneCode);
      }
    } catch {}
  }
  listeners.forEach((fn) => {
    fn(merged);
  });
}

function resolvePhoneCodeFromCountryCode(isoCode?: string): string | undefined {
  if (!isoCode) return undefined;
  try {
    const callingCode = phoneUtil.getCountryCodeForRegion(
      isoCode.toUpperCase(),
    );
    if (callingCode) {
      return `+${callingCode}`;
    }
  } catch {}
  return undefined;
}

function getFallbackGeoRegion(): UserGeoRegion {
  const existing = getStoredUserGeoRegion();
  if (
    existing &&
    (existing.country ||
      existing.phoneCode ||
      existing.countryCode ||
      existing.city)
  ) {
    console.log(
      "[GEO_BRIDGE_LOG] 📦 Preserving existing stored user geo region:",
      JSON.stringify(existing),
    );
    return existing;
  }

  console.log("[GEO_BRIDGE_LOG] ⚠️ Using default fallback region (+44)...");
  const defaultRegion: UserGeoRegion = {
    phoneCode: "+44",
  };
  setStoredUserGeoRegion(defaultRegion);
  return defaultRegion;
}

/**
 * Fetch geo region strictly via Flutter bridge action protocol ('get_location').
 * No direct backend HTTP requests are made.
 */
function fetchFlutterBridgeGeoRegion(): Promise<UserGeoRegion> {
  return new Promise<UserGeoRegion>((resolve) => {
    let resolved = false;
    let unsubscribe: (() => void) | undefined;
    let timer: ReturnType<typeof setTimeout> | null = null;

    const finish = (region: UserGeoRegion) => {
      if (resolved) return;
      resolved = true;
      if (timer) {
        clearTimeout(timer);
        timer = null;
      }
      if (unsubscribe) {
        try {
          unsubscribe();
        } catch {}
        unsubscribe = undefined;
      }
      resolve(region);
    };

    console.log(
      "[GEO_BRIDGE_LOG] 🌉 Registering Flutter response listener for get_location...",
    );

    // 1) Register a listener with window.addFlutterResponseListener
    if (
      typeof window !== "undefined" &&
      typeof window.addFlutterResponseListener === "function"
    ) {
      unsubscribe = window.addFlutterResponseListener(
        (event: FlutterResponseEvent) => {
          if (!event) return;
          const action = event.action?.toLowerCase();
          // 2) Listens for event.action === "get_location"
          if (action === "get_location") {
            console.log(
              "[GEO_BRIDGE_LOG] 📥 Flutter get_location response received:",
              JSON.stringify(event),
            );

            const data = (event.data || (event as any).payload) as
              | {
                  ip?: string;
                  country?: string;
                  country_code?: string;
                  city?: string;
                }
              | undefined;

            if (
              event.success &&
              data &&
              (data.country || data.country_code || data.city || data.ip)
            ) {
              const rawCountry = data.country || data.country_code || "";
              const isoCode =
                data.country_code ||
                (rawCountry && rawCountry.trim().length === 2
                  ? rawCountry.trim().toUpperCase()
                  : undefined);
              const phoneCode = resolvePhoneCodeFromCountryCode(isoCode);
              const countryName =
                resolveCountryName(data.country || isoCode, "en") ||
                data.country;
              const countryFa =
                resolveCountryName(data.country || isoCode, "fa") ||
                countryName;

              console.log(
                `[GEO_BRIDGE_LOG] 🌍 Resolved from Flutter bridge: FA=${countryFa} | EN=${countryName} | Code=${isoCode} | City=${data.city || "None"} | IP=${data.ip || "None"} | Phone=${phoneCode || "+44"}`,
              );

              const region: UserGeoRegion = {
                ip: data.ip,
                city: data.city,
                country: countryName,
                countryCode: isoCode,
                phoneCode: phoneCode || "+44",
              };
              setStoredUserGeoRegion(region);
              finish(region);
            } else {
              console.warn(
                "[GEO_BRIDGE_LOG] ⚠️ Flutter get_location unsuccessful or empty, falling back to local cached default",
              );
              finish(getFallbackGeoRegion());
            }
          }
        },
      );
    }

    // 3) Posts message: window.HabibApp.postMessage(JSON.stringify({ action: "get_location" }))
    try {
      if (typeof window !== "undefined" && window.HabibApp?.postMessage) {
        console.log(
          "[GEO_BRIDGE_LOG] 📤 Posting { action: 'get_location' } to window.HabibApp...",
        );
        window.HabibApp.postMessage(JSON.stringify({ action: "get_location" }));
      } else if (
        typeof window !== "undefined" &&
        typeof (window as any).sendToFlutter === "function"
      ) {
        console.log(
          "[GEO_BRIDGE_LOG] 📤 Sending get_location via sendToFlutter...",
        );
        (window as any).sendToFlutter("get_location");
      }
    } catch (e) {
      console.error(
        "[GEO_BRIDGE_LOG] ❌ Failed to post get_location message:",
        e,
      );
    }

    // 4) Has a timeout fallback of 4000ms: if no response from Flutter, fallback to cached / default region (no HTTP)
    timer = setTimeout(() => {
      if (!resolved) {
        console.warn(
          "[GEO_BRIDGE_LOG] ⏱️ Flutter bridge get_location timed out after 4000ms, using fallback region...",
        );
        finish(getFallbackGeoRegion());
      }
    }, 4000);
  });
}

/**
 * Get user geo region.
 * Uses Flutter bridge action ('get_location') exclusively for location detection.
 * Never performs direct HTTP requests.
 */
export function getUserGeoRegion(force = false): Promise<UserGeoRegion> {
  // If !force: Check cachedRegion or getStoredUserGeoRegion(). If present and has location, return it immediately.
  if (!force) {
    const existing = cachedRegion || getStoredUserGeoRegion();
    if (
      existing &&
      (existing.country || existing.countryCode || existing.city)
    ) {
      console.log(
        "[GEO_BRIDGE_LOG] 📦 Returning cached/stored user geo region:",
        JSON.stringify(existing),
      );
      return Promise.resolve(existing);
    }
  } else {
    cachedRegion = null;
    geoRegionPromise = null;
  }

  if (geoRegionPromise) {
    return geoRegionPromise;
  }

  // Check if running inside Flutter Webview: typeof window !== "undefined" && window.HabibApp?.postMessage
  const isFlutter =
    typeof window !== "undefined" &&
    (Boolean(window.HabibApp?.postMessage) ||
      typeof (window as any).sendToFlutter === "function");

  if (isFlutter) {
    console.log(
      "[GEO_BRIDGE_LOG] 📱 Inside Flutter WebView detected, requesting location via Flutter bridge action 'get_location'",
    );
    geoRegionPromise = fetchFlutterBridgeGeoRegion().finally(() => {
      geoRegionPromise = null;
    });
  } else {
    console.log(
      "[GEO_BRIDGE_LOG] 🌐 Standard browser / non-Flutter environment: resolving from cached storage or default fallback (no HTTP calls)",
    );
    const fallback = getFallbackGeoRegion();
    geoRegionPromise = Promise.resolve(fallback);
  }

  return geoRegionPromise;
}