import { useState, useEffect, useRef } from 'react';
import { useRouter } from 'next/router';
import Layout from '../components/Layout';

export default function Profile() {
  const router = useRouter();
  const fileInputRef = useRef(null);
  
  // User state
  const [user, setUser] = useState(null);
  
  // UI state
  const [loading, setLoading] = useState(true);
  const [saving, setSaving] = useState(false);
  const [editMode, setEditMode] = useState(false);
  const [message, setMessage] = useState({ type: '', text: '' });
  const [stats, setStats] = useState({
    totalCards: 0,
    totalCollections: 0,
    totalDecks: 0,
    totalValue: 0
  });
  
  // Form state
  const [formData, setFormData] = useState({
    first_name: '',
    last_name: '',
    username: '',
    bio: '',
    favorite_games: []
  });

  useEffect(() => {
    loadUserProfile();
    loadUserStats();
  }, []);

  const loadUserProfile = async () => {
    try {
      const token = localStorage.getItem('auth_token');
      if (!token) {
        router.push('/login');
        return;
      }

      const response = await fetch('/api/user/profile', {
        headers: {
          'Authorization': `Bearer ${token}`
        }
      });

      if (response.ok) {
        const userData = await response.json();
        setUser(userData);
        setFormData({
          first_name: userData.first_name || '',
          last_name: userData.last_name || '',
          username: userData.username || '',
          bio: userData.bio || '',
          favorite_games: userData.favorite_games || []
        });
      } else if (response.status === 401) {
        router.push('/login');
      }
    } catch (error) {
      console.error('Error loading profile:', error);
      setMessage({ type: 'error', text: 'Failed to load profile' });
    } finally {
      setLoading(false);
    }
  };

  const loadUserStats = async () => {
    try {
      const token = localStorage.getItem('auth_token');
      if (!token) return;

      const response = await fetch('/api/user/stats', {
        headers: {
          'Authorization': `Bearer ${token}`
        }
      });

      if (response.ok) {
        const statsData = await response.json();
        setStats(statsData);
      }
    } catch (error) {
      console.error('Error loading stats:', error);
    }
  };

  const handleInputChange = (field, value) => {
    setFormData(prev => ({
      ...prev,
      [field]: value
    }));
  };

  const handleGameToggle = (game) => {
    setFormData(prev => ({
      ...prev,
      favorite_games: prev.favorite_games.includes(game)
        ? prev.favorite_games.filter(g => g !== game)
        : [...prev.favorite_games, game]
    }));
  };

  const handleSave = async () => {
    setSaving(true);
    setMessage({ type: '', text: '' });

    try {
      const token = localStorage.getItem('auth_token');
      const response = await fetch('/api/user/profile', {
        method: 'PUT',
        headers: {
          'Content-Type': 'application/json',
          'Authorization': `Bearer ${token}`
        },
        body: JSON.stringify(formData)
      });

      if (response.ok) {
        const updatedUser = await response.json();
        setUser(updatedUser);
        setEditMode(false);
        setMessage({ type: 'success', text: 'Profile updated successfully!' });
      } else {
        const error = await response.json();
        setMessage({ type: 'error', text: error.message || 'Failed to update profile' });
      }
    } catch (error) {
      console.error('Error updating profile:', error);
      setMessage({ type: 'error', text: 'Failed to update profile' });
    } finally {
      setSaving(false);
    }
  };

  const handleAvatarUpload = async (event) => {
    const file = event.target.files[0];
    if (!file) return;

    // Validate file type and size
    if (!file.type.startsWith('image/')) {
      setMessage({ type: 'error', text: 'Please select an image file' });
      return;
    }

    if (file.size > 5 * 1024 * 1024) { // 5MB limit
      setMessage({ type: 'error', text: 'Image must be less than 5MB' });
      return;
    }

    const formData = new FormData();
    formData.append('avatar', file);

    try {
      setSaving(true);
      const token = localStorage.getItem('auth_token');
      const response = await fetch('/api/user/avatar', {
        method: 'POST',
        headers: {
          'Authorization': `Bearer ${token}`
        },
        body: formData
      });

      if (response.ok) {
        const result = await response.json();
        setUser(prev => ({ ...prev, avatar_url: result.avatar_url }));
        setMessage({ type: 'success', text: 'Avatar updated successfully!' });
      } else {
        const error = await response.json();
        setMessage({ type: 'error', text: error.message || 'Failed to upload avatar' });
      }
    } catch (error) {
      console.error('Error uploading avatar:', error);
      setMessage({ type: 'error', text: 'Failed to upload avatar' });
    } finally {
      setSaving(false);
    }
  };

  const generateAvatar = async () => {
    try {
      setSaving(true);
      const token = localStorage.getItem('auth_token');
      const response = await fetch('/api/user/avatar/generate', {
        method: 'POST',
        headers: {
          'Authorization': `Bearer ${token}`
        }
      });

      if (response.ok) {
        const result = await response.json();
        setUser(prev => ({ ...prev, avatar_url: result.avatar_url }));
        setMessage({ type: 'success', text: 'Avatar generated successfully!' });
      } else {
        const error = await response.json();
        setMessage({ type: 'error', text: error.message || 'Failed to generate avatar' });
      }
    } catch (error) {
      console.error('Error generating avatar:', error);
      setMessage({ type: 'error', text: 'Failed to generate avatar' });
    } finally {
      setSaving(false);
    }
  };

  const formatCurrency = (amount) => {
    return new Intl.NumberFormat('en-US', {
      style: 'currency',
      currency: 'USD'
    }).format(amount);
  };

  const formatDate = (dateString) => {
    return new Date(dateString).toLocaleDateString('en-US', {
      year: 'numeric',
      month: 'long',
      day: 'numeric'
    });
  };

  const getDisplayName = () => {
    if (!user) return '';
    if (user.first_name || user.last_name) {
      return `${user.first_name} ${user.last_name}`.trim();
    }
    return user.username || user.email;
  };

  const getInitials = () => {
    if (!user) return '';
    if (user.first_name || user.last_name) {
      return `${user.first_name?.charAt(0) || ''}${user.last_name?.charAt(0) || ''}`.toUpperCase();
    }
    return user.email?.charAt(0).toUpperCase() || 'U';
  };

  const gameOptions = [
    { value: 'MTG', label: 'Magic: The Gathering', color: 'purple', icon: '🔮' },
    { value: 'Pokemon', label: 'Pokemon', color: 'blue', icon: '⚡' },
    { value: 'Lorcana', label: 'Disney Lorcana', color: 'pink', icon: '✨' }
  ];

  if (loading) {
    return (
      <Layout user={user}>
        <div className="flex items-center justify-center min-h-screen">
          <div className="animate-spin rounded-full h-32 w-32 border-b-2" style={{ borderColor: 'var(--accent-ember)' }}></div>
        </div>
      </Layout>
    );
  }

  return (
    <Layout user={user}>
      <div className="max-w-4xl mx-auto p-6">
        {/* Header */}
        <div className="mb-8">
          <h1 className="text-3xl font-bold mb-2" style={{ color: 'var(--text-primary)' }}>
            Profile
          </h1>
          <p className="text-lg" style={{ color: 'var(--text-secondary)' }}>
            Manage your account information and preferences
          </p>
        </div>

        {/* Message */}
        {message.text && (
          <div className={`mb-6 p-4 rounded-xl ${
            message.type === 'success' 
              ? 'bg-green-50 dark:bg-green-900/20 text-green-800 dark:text-green-200 border border-green-200 dark:border-green-800'
              : 'bg-red-50 dark:bg-red-900/20 text-red-800 dark:text-red-200 border border-red-200 dark:border-red-800'
          }`}>
            {message.text}
          </div>
        )}

        <div className="grid grid-cols-1 lg:grid-cols-3 gap-8">
          {/* Profile Card */}
          <div className="lg:col-span-1">
            <div className="card p-6 text-center">
              {/* Avatar */}
              <div className="mb-6">
                <div className="relative inline-block">
                  {user?.avatar_url ? (
                    <img
                      src={user.avatar_url}
                      alt="Profile"
                      className="w-32 h-32 rounded-full object-cover mx-auto border-4"
                      style={{ borderColor: 'var(--accent-ember)' }}
                    />
                  ) : (
                    <div
                      className="w-32 h-32 rounded-full flex items-center justify-center mx-auto text-4xl font-bold text-white border-4"
                      style={{ 
                        backgroundColor: 'var(--accent-ember)',
                        borderColor: 'var(--accent-flame)'
                      }}
                    >
                      {getInitials()}
                    </div>
                  )}
                  
                  {/* Avatar Upload Button */}
                  <button
                    onClick={() => fileInputRef.current?.click()}
                    disabled={saving}
                    className="absolute bottom-0 right-0 p-2 rounded-full shadow-lg transition-all duration-200 hover:scale-110"
                    style={{ backgroundColor: 'var(--accent-flame)', color: 'white' }}
                    title="Upload new avatar"
                  >
                    <svg className="w-4 h-4" fill="none" stroke="currentColor" viewBox="0 0 24 24">
                      <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M3 9a2 2 0 012-2h.93a2 2 0 001.664-.89l.812-1.22A2 2 0 0110.07 4h3.86a2 2 0 011.664.89l.812 1.22A2 2 0 0018.07 7H19a2 2 0 012 2v9a2 2 0 01-2 2H5a2 2 0 01-2-2V9z" />
                      <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M15 13a3 3 0 11-6 0 3 3 0 016 0z" />
                    </svg>
                  </button>
                  
                  <input
                    ref={fileInputRef}
                    type="file"
                    accept="image/*"
                    onChange={handleAvatarUpload}
                    className="hidden"
                  />
                </div>
                
                {/* Generate Avatar Button */}
                <button
                  onClick={generateAvatar}
                  disabled={saving}
                  className="mt-4 px-4 py-2 rounded-xl font-medium transition-all duration-200 hover:shadow-md"
                  style={{ 
                    backgroundColor: 'var(--bg-tertiary)', 
                    color: 'var(--text-primary)',
                    border: '1px solid var(--border)'
                  }}
                >
                  Generate Avatar
                </button>
              </div>

              {/* Basic Info */}
              <div className="mb-6">
                <h2 className="text-2xl font-bold mb-1" style={{ color: 'var(--text-primary)' }}>
                  {getDisplayName()}
                </h2>
                {user?.username && (
                  <p className="text-lg mb-2" style={{ color: 'var(--text-secondary)' }}>
                    @{user.username}
                  </p>
                )}
                <p className="text-sm" style={{ color: 'var(--text-secondary)' }}>
                  {user?.email}
                </p>
                <div className="flex items-center justify-center mt-2">
                  <span 
                    className="px-3 py-1 text-xs rounded-full font-medium"
                    style={{ 
                      backgroundColor: user?.role === 'admin' ? 'var(--accent-ember)' : 'var(--accent-gold)',
                      color: 'white'
                    }}
                  >
                    {user?.role?.toUpperCase()}
                  </span>
                </div>
              </div>

              {/* Bio */}
              {user?.bio && (
                <div className="mb-6">
                  <p className="text-sm leading-relaxed" style={{ color: 'var(--text-secondary)' }}>
                    {user.bio}
                  </p>
                </div>
              )}

              {/* Member Since */}
              {user?.created_at && (
                <div className="text-center">
                  <p className="text-sm" style={{ color: 'var(--text-secondary)' }}>
                    Member since {formatDate(user.created_at)}
                  </p>
                </div>
              )}
            </div>

            {/* Stats Card */}
            <div className="card p-6 mt-6">
              <h3 className="text-lg font-semibold mb-4" style={{ color: 'var(--text-primary)' }}>
                Collection Stats
              </h3>
              <div className="space-y-4">
                <div className="flex justify-between items-center">
                  <span style={{ color: 'var(--text-secondary)' }}>Total Cards</span>
                  <span className="font-semibold" style={{ color: 'var(--text-primary)' }}>
                    {stats.totalCards.toLocaleString()}
                  </span>
                </div>
                <div className="flex justify-between items-center">
                  <span style={{ color: 'var(--text-secondary)' }}>Collections</span>
                  <span className="font-semibold" style={{ color: 'var(--text-primary)' }}>
                    {stats.totalCollections}
                  </span>
                </div>
                <div className="flex justify-between items-center">
                  <span style={{ color: 'var(--text-secondary)' }}>Decks</span>
                  <span className="font-semibold" style={{ color: 'var(--text-primary)' }}>
                    {stats.totalDecks}
                  </span>
                </div>
                <div className="flex justify-between items-center pt-2 border-t" style={{ borderColor: 'var(--border)' }}>
                  <span style={{ color: 'var(--text-secondary)' }}>Total Value</span>
                  <span className="font-bold text-lg" style={{ color: 'var(--accent-ember)' }}>
                    {formatCurrency(stats.totalValue)}
                  </span>
                </div>
              </div>
            </div>
          </div>

          {/* Profile Form */}
          <div className="lg:col-span-2">
            <div className="card p-6">
              <div className="flex justify-between items-center mb-6">
                <h3 className="text-xl font-semibold" style={{ color: 'var(--text-primary)' }}>
                  Profile Information
                </h3>
                <button
                  onClick={() => editMode ? handleSave() : setEditMode(true)}
                  disabled={saving}
                  className="px-4 py-2 rounded-xl font-medium transition-all duration-200 hover:shadow-md"
                  style={{ 
                    backgroundColor: editMode ? 'var(--accent-ember)' : 'var(--bg-tertiary)',
                    color: editMode ? 'white' : 'var(--text-primary)',
                    border: `1px solid ${editMode ? 'var(--accent-ember)' : 'var(--border)'}`
                  }}
                >
                  {saving ? 'Saving...' : editMode ? 'Save Changes' : 'Edit Profile'}
                </button>
              </div>

              <div className="space-y-6">
                {/* Name Fields */}
                <div className="grid grid-cols-1 md:grid-cols-2 gap-4">
                  <div>
                    <label className="block text-sm font-medium mb-2" style={{ color: 'var(--text-primary)' }}>
                      First Name
                    </label>
                    {editMode ? (
                      <input
                        type="text"
                        value={formData.first_name}
                        onChange={(e) => handleInputChange('first_name', e.target.value)}
                        className="input-field w-full"
                        placeholder="Enter your first name"
                      />
                    ) : (
                      <p className="py-2 text-sm" style={{ color: 'var(--text-secondary)' }}>
                        {user?.first_name || 'Not set'}
                      </p>
                    )}
                  </div>
                  <div>
                    <label className="block text-sm font-medium mb-2" style={{ color: 'var(--text-primary)' }}>
                      Last Name
                    </label>
                    {editMode ? (
                      <input
                        type="text"
                        value={formData.last_name}
                        onChange={(e) => handleInputChange('last_name', e.target.value)}
                        className="input-field w-full"
                        placeholder="Enter your last name"
                      />
                    ) : (
                      <p className="py-2 text-sm" style={{ color: 'var(--text-secondary)' }}>
                        {user?.last_name || 'Not set'}
                      </p>
                    )}
                  </div>
                </div>

                {/* Username */}
                <div>
                  <label className="block text-sm font-medium mb-2" style={{ color: 'var(--text-primary)' }}>
                    Username
                  </label>
                  {editMode ? (
                    <input
                      type="text"
                      value={formData.username}
                      onChange={(e) => handleInputChange('username', e.target.value)}
                      className="input-field w-full"
                      placeholder="Choose a unique username"
                    />
                  ) : (
                    <p className="py-2 text-sm" style={{ color: 'var(--text-secondary)' }}>
                      {user?.username || 'Not set'}
                    </p>
                  )}
                </div>

                {/* Bio */}
                <div>
                  <label className="block text-sm font-medium mb-2" style={{ color: 'var(--text-primary)' }}>
                    Bio
                  </label>
                  {editMode ? (
                    <textarea
                      value={formData.bio}
                      onChange={(e) => handleInputChange('bio', e.target.value)}
                      className="input-field w-full h-24 resize-none"
                      placeholder="Tell us about yourself..."
                      maxLength={500}
                    />
                  ) : (
                    <p className="py-2 text-sm leading-relaxed" style={{ color: 'var(--text-secondary)' }}>
                      {user?.bio || 'No bio set'}
                    </p>
                  )}
                </div>

                {/* Favorite Games */}
                <div>
                  <label className="block text-sm font-medium mb-3" style={{ color: 'var(--text-primary)' }}>
                    Favorite Games
                  </label>
                  <div className="flex flex-wrap gap-3">
                    {gameOptions.map(game => (
                      <button
                        key={game.value}
                        onClick={() => editMode && handleGameToggle(game.value)}
                        disabled={!editMode}
                        className={`px-4 py-2 rounded-xl font-medium transition-all duration-200 flex items-center gap-2 ${
                          editMode ? 'cursor-pointer hover:shadow-md' : 'cursor-default'
                        } ${
                          (editMode ? formData.favorite_games : user?.favorite_games)?.includes(game.value)
                            ? 'shadow-lg'
                            : 'hover:shadow-md'
                        }`}
                        style={{
                          backgroundColor: (editMode ? formData.favorite_games : user?.favorite_games)?.includes(game.value) 
                            ? 'var(--accent-ember)' 
                            : 'var(--bg-tertiary)',
                          color: (editMode ? formData.favorite_games : user?.favorite_games)?.includes(game.value) 
                            ? 'white' 
                            : 'var(--text-primary)',
                          border: `1px solid ${
                            (editMode ? formData.favorite_games : user?.favorite_games)?.includes(game.value) 
                              ? 'var(--accent-ember)' 
                              : 'var(--border)'
                          }`
                        }}
                      >
                        <span>{game.icon}</span>
                        {game.label}
                      </button>
                    ))}
                  </div>
                </div>

                {/* Email (Read-only) */}
                <div>
                  <label className="block text-sm font-medium mb-2" style={{ color: 'var(--text-primary)' }}>
                    Email Address
                  </label>
                  <div className="flex items-center gap-3">
                    <p className="py-2 text-sm" style={{ color: 'var(--text-secondary)' }}>
                      {user?.email}
                    </p>
                    <span className="px-2 py-1 text-xs rounded-full bg-green-100 dark:bg-green-900/20 text-green-800 dark:text-green-200">
                      Verified
                    </span>
                  </div>
                  <p className="text-xs mt-1" style={{ color: 'var(--text-secondary)' }}>
                    To change your email, please contact support
                  </p>
                </div>

                {/* Cancel Button (only in edit mode) */}
                {editMode && (
                  <div className="flex justify-end pt-4">
                    <button
                      onClick={() => {
                        setEditMode(false);
                        setFormData({
                          first_name: user?.first_name || '',
                          last_name: user?.last_name || '',
                          username: user?.username || '',
                          bio: user?.bio || '',
                          favorite_games: user?.favorite_games || []
                        });
                        setMessage({ type: '', text: '' });
                      }}
                      className="px-4 py-2 rounded-xl font-medium transition-all duration-200 hover:shadow-md"
                      style={{ 
                        backgroundColor: 'var(--bg-tertiary)', 
                        color: 'var(--text-secondary)',
                        border: '1px solid var(--border)'
                      }}
                    >
                      Cancel
                    </button>
                  </div>
                )}
              </div>
            </div>
          </div>
        </div>
      </div>
    </Layout>
  );
}