"use client";

import { createContext, useContext, useState, useEffect, useCallback, type ReactNode } from "react";

interface User {
  id: string;
  email: string;
  name: string;
  isPremium: boolean;
  isPro: boolean;
  flhBalance: number;
  dailyMsgCount: number;
  preferredName?: string;
  coachPersona?: string;
  madhab?: string;
  coachingGoals?: string;
  createdAt?: string;
  trialEndsAt?: string;
}

interface StreakData {
  currentStreak: number;
  longestStreak: number;
  lastClaimDate: string | null;
  canClaim: boolean;
  streakFreeze: number;
  todayReward: number;
}

interface XpData {
  level: number;
  xp: number;
  xpToNext: number;
  totalXp: number;
}

interface AuthContextType {
  user: User | null;
  token: string | null;
  loading: boolean;
  login: (email: string, password: string) => Promise<void>;
  register: (email: string, name: string, password: string) => Promise<void>;
  oauthLogin: (provider: string) => Promise<void>;
  logout: () => void;
  refreshUser: () => Promise<void>;
  streak: StreakData | null;
  xp: XpData | null;
  refreshStreak: () => Promise<void>;
  refreshXp: () => Promise<void>;
}

const AuthContext = createContext<AuthContextType | undefined>(undefined);

export function AuthProvider({ children }: { children: ReactNode }) {
  const [user, setUser] = useState<User | null>(null);
  const [token, setToken] = useState<string | null>(null);
  const [loading, setLoading] = useState(true);
  const [streak, setStreak] = useState<StreakData | null>(null);
  const [xp, setXp] = useState<XpData | null>(null);

  useEffect(() => {
    const stored = localStorage.getItem("flh_token");
    if (stored) {
      setToken(stored);
      fetchUser(stored);
    } else {
      setLoading(false);
    }

    // Listen for token changes (e.g., from OAuth popup)
    const handleStorage = (e: StorageEvent) => {
      if (e.key === "flh_token" && e.newValue) {
        setToken(e.newValue);
        fetchUser(e.newValue);
      }
    };
    window.addEventListener("storage", handleStorage);
    return () => window.removeEventListener("storage", handleStorage);
  }, []);

  const fetchUser = async (t: string) => {
    try {
      const res = await fetch("/mobile/api/auth/me", {
        headers: { Authorization: `Bearer ${t}` },
      });
      if (res.ok) {
        const data = await res.json();
        setUser(data.user);
      } else {
        localStorage.removeItem("flh_token");
        setToken(null);
      }
    } catch {
      // ignore
    } finally {
      setLoading(false);
    }
  };

  const login = useCallback(async (email: string, password: string) => {
    const res = await fetch("/mobile/api/auth/login", {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({ email, password }),
    });
    if (!res.ok) {
      const err = await res.json();
      throw new Error(err.error || "Login failed");
    }
    const data = await res.json();
    localStorage.setItem("flh_token", data.token);
    setToken(data.token);
    setUser(data.user);
  }, []);

  const register = useCallback(async (email: string, name: string, password: string) => {
    const res = await fetch("/mobile/api/auth/register", {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({ email, name, password }),
    });
    if (!res.ok) {
      const err = await res.json();
      throw new Error(err.error || "Registration failed");
    }
    const data = await res.json();
    localStorage.setItem("flh_token", data.token);
    setToken(data.token);
    setUser(data.user);
  }, []);

  const oauthLogin = useCallback(async (provider: string) => {
    // Open a popup window for OAuth
    const width = 600;
    const height = 700;
    const left = window.screenX + (window.innerWidth - width) / 2;
    const top = window.screenY + (window.innerHeight - height) / 2;

    const popup = window.open(
      `/mobile/api/auth/${provider}`,
      `oauth-${provider}`,
      `width=${width},height=${height},left=${left},top=${top},popup=1`
    );

    if (!popup) {
      // Popup blocked — fall back to direct navigation
      window.location.href = `/mobile/api/auth/${provider}`;
    }
    // The popup will close itself after successful auth via the callback page
  }, []);

  const logout = useCallback(() => {
    localStorage.removeItem("flh_token");
    setToken(null);
    setUser(null);
    setStreak(null);
    setXp(null);
  }, []);

  const refreshUser = useCallback(async () => {
    if (!token) return;
    await fetchUser(token);
  }, [token]);

  const refreshStreak = useCallback(async () => {
    if (!token) return;
    try {
      const res = await fetch("/mobile/api/gamification/streak", {
        headers: { Authorization: `Bearer ${token}` },
      });
      if (res.ok) {
        const data = await res.json();
        setStreak(data);
      }
    } catch {
      // ignore
    }
  }, [token]);

  const refreshXp = useCallback(async () => {
    if (!token) return;
    try {
      const res = await fetch("/mobile/api/gamification/xp", {
        headers: { Authorization: `Bearer ${token}` },
      });
      if (res.ok) {
        const data = await res.json();
        setXp(data);
      }
    } catch {
      // ignore
    }
  }, [token]);

  // Fetch streak and XP when token becomes available
  useEffect(() => {
    if (token && user) {
      refreshStreak();
      refreshXp();
    }
  }, [token, user, refreshStreak, refreshXp]);

  return (
    <AuthContext.Provider value={{ user, token, loading, login, register, oauthLogin, logout, refreshUser, streak, xp, refreshStreak, refreshXp }}>
      {children}
    </AuthContext.Provider>
  );
}

export function useAuth() {
  const ctx = useContext(AuthContext);
  if (!ctx) throw new Error("useAuth must be used within AuthProvider");
  return ctx;
}