// ---------------------------------------------------------------------------
// AuthContext — pre-built auth provider wired to AnyDB users collection
// ---------------------------------------------------------------------------
// PRE-INSTALLED in every AUTO_DB React project with auth: true.
// CodeWriterAgent just wraps App in <AuthProvider> and uses:
//   import { useAuth } from "@/contexts/AuthContext"
//   const { user, login, signup, logout, loading } = useAuth()
//
// Interface already knows:
//   - users collection has: email (unique), name, avatar_url, plan, role, created_at
//   - login: findOne by email + password hash
//   - signup: insertOne with default plan='free'
//   - session: localStorage token with user object
// ---------------------------------------------------------------------------

import React, { createContext, useContext, useState, useEffect, useCallback } from "react";
import anydb from "@/lib/anydb";
// Toast helper — uses window alert as fallback if useToast not available
const notify = (title: string, desc?: string) => {
  try {
    // Try to dispatch a custom event that a Toaster component can pick up
    window.dispatchEvent(new CustomEvent('app-toast', { detail: { title, description: desc } }));
  } catch {
    console.log(`[Auth] ${title}: ${desc || ''}`);
  }
};

interface User {
  _id: string;
  email: string;
  name: string;
  avatar_url?: string;
  plan?: string;
  role?: string;
  created_at?: string;
}

interface AuthContextType {
  user: User | null;
  loading: boolean;
  error: string | null;
  login: (email: string, password: string) => Promise<boolean>;
  signup: (name: string, email: string, password: string) => Promise<boolean>;
  logout: () => void;
  updateProfile: (updates: Partial<User>) => Promise<boolean>;
  isAuthenticated: boolean;
}

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

const AUTH_KEY = "anydb_auth_user";

export function AuthProvider({ children }: { children: React.ReactNode }) {
  const [user, setUser] = useState<User | null>(null);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);
  const toast = (opts: { title: string; description?: string; variant?: string }) => notify(opts.title, opts.description);

  // Restore session from localStorage on mount
  useEffect(() => {
    try {
      const stored = localStorage.getItem(AUTH_KEY);
      if (stored) {
        setUser(JSON.parse(stored));
      }
    } catch {
      localStorage.removeItem(AUTH_KEY);
    }
    setLoading(false);
  }, []);

  const login = useCallback(async (email: string, password: string): Promise<boolean> => {
    setLoading(true);
    setError(null);
    try {
      const col = await anydb.collection("users");
      const result = await col.find({ email: email.toLowerCase() }, { limit: 1 });
      const found = result.data?.[0];

      if (!found) {
        setError("No account found with that email");
        toast({ title: "Login failed", description: "No account found with that email", variant: "destructive" });
        return false;
      }

      // Simple password check (in production, use bcrypt on server)
      if (found.password_hash !== password && found.password !== password) {
        setError("Incorrect password");
        toast({ title: "Login failed", description: "Incorrect password", variant: "destructive" });
        return false;
      }

      const { password_hash, password: _pw, ...safeUser } = found;
      setUser(safeUser);
      localStorage.setItem(AUTH_KEY, JSON.stringify(safeUser));
      toast({ title: "Welcome back!", description: `Signed in as ${safeUser.name || safeUser.email}` });
      return true;
    } catch (err: any) {
      setError(err.message || "Login failed");
      toast({ title: "Error", description: "Something went wrong. Please try again.", variant: "destructive" });
      return false;
    } finally {
      setLoading(false);
    }
  }, [toast]);

  const signup = useCallback(async (name: string, email: string, password: string): Promise<boolean> => {
    setLoading(true);
    setError(null);
    try {
      const col = await anydb.collection("users");

      // Check if email already exists
      const existing = await col.find({ email: email.toLowerCase() }, { limit: 1 });
      if (existing.data?.length > 0) {
        setError("An account with that email already exists");
        toast({ title: "Signup failed", description: "An account with that email already exists", variant: "destructive" });
        return false;
      }

      // Create user
      const newUser = await col.insertOne({
        name,
        email: email.toLowerCase(),
        password_hash: password, // In production: hash with bcrypt on server
        plan: "free",
        role: "user",
        avatar_url: "",
        created_at: new Date().toISOString(),
      });

      const safeUser: User = {
        _id: newUser._id || newUser.insertedId,
        name,
        email: email.toLowerCase(),
        plan: "free",
        role: "user",
        created_at: new Date().toISOString(),
      };

      setUser(safeUser);
      localStorage.setItem(AUTH_KEY, JSON.stringify(safeUser));
      toast({ title: "Account created!", description: `Welcome, ${name}!` });
      return true;
    } catch (err: any) {
      setError(err.message || "Signup failed");
      toast({ title: "Error", description: "Could not create account. Please try again.", variant: "destructive" });
      return false;
    } finally {
      setLoading(false);
    }
  }, [toast]);

  const logout = useCallback(() => {
    setUser(null);
    localStorage.removeItem(AUTH_KEY);
    toast({ title: "Signed out", description: "You have been signed out." });
  }, [toast]);

  const updateProfile = useCallback(async (updates: Partial<User>): Promise<boolean> => {
    if (!user?._id) return false;
    try {
      const col = await anydb.collection("users");
      await col.updateOne({ _id: user._id }, updates);
      const updatedUser = { ...user, ...updates };
      setUser(updatedUser);
      localStorage.setItem(AUTH_KEY, JSON.stringify(updatedUser));
      toast({ title: "Profile updated" });
      return true;
    } catch (err: any) {
      toast({ title: "Error", description: "Could not update profile", variant: "destructive" });
      return false;
    }
  }, [user, toast]);

  return (
    <AuthContext.Provider value={{
      user,
      loading,
      error,
      login,
      signup,
      logout,
      updateProfile,
      isAuthenticated: !!user,
    }}>
      {children}
    </AuthContext.Provider>
  );
}

/**
 * Use auth state and actions.
 *
 * Usage:
 *   const { user, login, signup, logout, isAuthenticated, loading } = useAuth()
 *   if (!isAuthenticated) return <Navigate to="/login" />
 *   await login(email, password)
 *   await signup(name, email, password)
 *   logout()
 */
export function useAuth(): AuthContextType {
  const context = useContext(AuthContext);
  if (!context) {
    throw new Error("useAuth must be used within an AuthProvider");
  }
  return context;
}

/**
 * Protected route wrapper. Redirects to /login if not authenticated.
 *
 * Usage in App.tsx:
 *   <Route path="/dashboard" element={<ProtectedRoute><Dashboard /></ProtectedRoute>} />
 */
export function ProtectedRoute({ children }: { children: React.ReactNode }) {
  const { isAuthenticated, loading } = useAuth();

  if (loading) {
    return (
      <div className="min-h-screen flex items-center justify-center">
        <div className="animate-spin rounded-full h-8 w-8 border-b-2 border-primary" />
      </div>
    );
  }

  if (!isAuthenticated) {
    // Redirect to login
    window.location.href = "/login";
    return null;
  }

  return <>{children}</>;
}