<?php

namespace App\Http\Controllers\Auth;

use App\Http\Controllers\Controller;
use App\Models\SocialAccount;
use App\Models\User;
use Illuminate\Http\RedirectResponse;
use Illuminate\Support\Facades\Auth;
use Illuminate\Support\Str;
use Laravel\Socialite\Facades\Socialite;

class SocialiteController extends Controller
{
    /**
     * Suggest a username based on social profile.
     */
    protected function suggestUsername($socialUser): string
    {
        return Str::slug(
            $socialUser->getNickname() ?? explode('@', $socialUser->getEmail())[0],
            '_'
        );
    }

    /**
     * Get enabled providers from config.
     */
    protected function getEnabledProviders(): array
    {
        return collect(config('auth-ui.providers', []))
            ->filter(fn ($provider) => $provider['enabled'] ?? false)
            ->keys()
            ->all();
    }

    /**
     * Redirect the user to the provider authentication page.
     */
    public function redirect(string $provider): RedirectResponse
    {
        if (! in_array($provider, $this->getEnabledProviders())) {
            abort(404, 'Provider not enabled');
        }

        return Socialite::driver($provider)->redirect();
    }

    /**
     * Obtain the user information from provider.
     */
    public function callback(string $provider): RedirectResponse
    {
        if (! in_array($provider, $this->getEnabledProviders())) {
            abort(404, 'Provider not enabled');
        }

        try {
            $socialUser = Socialite::driver($provider)->user();
        } catch (\Exception $e) {
            return redirect()->route('login')->withErrors([
                'email' => 'Unable to authenticate with '.$provider.'. Please try again.',
            ]);
        }

        // First, check if this provider account is already linked to a user
        $socialAccount = SocialAccount::where('provider', $provider)
            ->where('provider_id', $socialUser->getId())
            ->first();

        if ($socialAccount) {
            Auth::login($socialAccount->user, remember: true);
            request()->session()->regenerate();

            return redirect()->intended(config('auth-ui.redirects.login', '/'));
        }

        // Check if a user with this email already exists
        $existingUser = User::where('email', $socialUser->getEmail())->first();

        if ($existingUser) {
            if (! $existingUser->hasVerifiedEmail()) {
                return redirect()->route('login')->withErrors([
                    'email' => 'An account with this email already exists. Please verify your email first, then link your social account.',
                ]);
            }

            $existingUser->socialAccounts()->create([
                'provider' => $provider,
                'provider_id' => $socialUser->getId(),
            ]);

            Auth::login($existingUser, remember: true);
            request()->session()->regenerate();

            return redirect()->intended(config('auth-ui.redirects.login', '/'));
        }

        // New user — check if registration is enabled
        if (! config('auth-ui.features.registration')) {
            return redirect()->route('login')->withErrors([
                'email' => 'Registration is disabled. Please contact an administrator.',
            ]);
        }

        $name = $socialUser->getName() ?? $socialUser->getNickname() ?? 'User';
        $nameParts = explode(' ', $name, 2);
        $suggestedUsername = $this->suggestUsername($socialUser);

        // Check if username is already taken
        if (User::whereRaw('LOWER(username) = ?', [strtolower($suggestedUsername)])->exists()) {
            session()->put('socialite_user', [
                'email' => $socialUser->getEmail(),
                'first_name' => $nameParts[0],
                'last_name' => $nameParts[1] ?? '',
                'suggested_username' => $suggestedUsername,
                'provider' => $provider,
                'provider_id' => $socialUser->getId(),
            ]);

            return redirect()->route('auth.complete-profile');
        }

        $user = User::create([
            'username' => $suggestedUsername,
            'first_name' => $nameParts[0],
            'last_name' => $nameParts[1] ?? '',
            'email' => $socialUser->getEmail(),
        ]);

        $user->forceFill(['email_verified_at' => now()])->save();

        $user->socialAccounts()->create([
            'provider' => $provider,
            'provider_id' => $socialUser->getId(),
        ]);

        Auth::login($user, remember: true);
        request()->session()->regenerate();

        return redirect()->intended(config('auth-ui.redirects.login', '/'));
    }
}