const bcrypt = require('bcryptjs');
const jwt = require('jsonwebtoken');
const User = require('../models/userModel');
const {
  sendWelcomeEmail,
  sendPasswordChangeConfirmationEmail,
} = require('../utils/emailService');

// Helper function to create JWT
const signToken = (id) => {
  return jwt.sign({ id }, process.env.JWT_SECRET, {
    expiresIn: process.env.JWT_EXPIRES_IN,
  });
};

// SIGNUP
exports.signup = async (req, res) => {
  try {
    const { name, email, phone, password } = req.body;

    const existingUser = await User.findOne({ email });
    if (existingUser) {
      return res.status(400).json({ message: 'Email already registered' });
    }

    // Check if phone number already exists
    const existingPhone = await User.findOne({ phone });
    if (existingPhone) {
      return res
        .status(400)
        .json({ message: 'Phone number already registered' });
    }

    // Create user - the pre-save hook in userModel will hash the password
    const newUser = await User.create({
      name,
      email,
      phone,
      password, // Will be hashed by pre-save hook
    });

    const token = signToken(newUser._id);

    // Send welcome email (non-blocking - don't wait for it)
    sendWelcomeEmail(newUser).catch(() => { });

    res.status(201).json({
      status: 'success',
      token,
      user: {
        id: newUser._id,
        name: newUser.name,
        email: newUser.email,
        phone: newUser.phone,
        role: newUser.role,
      },
    });
  } catch (err) {
    res.status(500).json({ message: 'Signup failed', error: err.message });
  }
};

// LOGIN
exports.login = async (req, res) => {
  try {
    const { email, password } = req.body;

    // 1) Check if email and password exist
    if (!email || !password) {
      return res
        .status(400)
        .json({ message: 'Please provide email and password' });
    }

    // 2) Check if user exists && password is correct
    const user = await User.findOne({ email })
      .select('+password')
      .populate('provider');
    if (!user) {
      return res.status(401).json({ message: 'Invalid email or password' });
    }

    const isMatch = await bcrypt.compare(password, user.password);
    if (!isMatch) {
      return res.status(401).json({ message: 'Invalid email or password' });
    }

    // 3) Check if user account is active
    if (!user.isActive) {
      return res.status(403).json({
        message: 'Your account has been deactivated. Please contact support.',
      });
    }

    // 4) Check if vendor's provider is active
    if (user.role === 'vendor' && user.provider) {
      if (!user.provider.isActive) {
        return res.status(403).json({
          message:
            'Your vendor account has been deactivated. Please contact support.',
        });
      }
    }

    // 3) If everything ok, send token
    const token = signToken(user._id);

    res.status(200).json({
      status: 'success',
      token,
      user: {
        id: user._id,
        name: user.name,
        email: user.email,
        phone: user.phone,
        role: user.role,
        permissions: user.permissions || [],
        provider: user.role === 'vendor' ? user.provider : undefined,
      },
    });
  } catch (err) {
    res.status(500).json({ message: 'Login failed', error: err.message });
  }
};

// ADMIN PORTAL LOGIN - Only for admin, employee, and vendor roles
exports.adminLogin = async (req, res) => {
  try {
    const { email, password } = req.body;

    // 1) Check if email and password exist
    if (!email || !password) {
      return res
        .status(400)
        .json({ message: 'Please provide email and password' });
    }

    // 2) Check if user exists && password is correct
    const user = await User.findOne({ email })
      .select('+password')
      .populate('provider');
    if (!user) {
      return res.status(401).json({ message: 'Invalid email or password' });
    }

    const isMatch = await bcrypt.compare(password, user.password);
    if (!isMatch) {
      return res.status(401).json({ message: 'Invalid email or password' });
    }

    // 3) Check if user has admin portal access (admin, employee, or vendor)
    const allowedRoles = ['admin', 'employee', 'vendor'];
    if (!allowedRoles.includes(user.role)) {
      return res.status(403).json({
        message:
          'Access denied. This portal is only for administrators, employees, and vendors.',
      });
    }

    // 4) Check if user account is active
    if (!user.isActive) {
      return res.status(403).json({
        message: 'Your account has been deactivated. Please contact support.',
      });
    }

    // 5) Check if vendor's provider is active
    if (user.role === 'vendor' && user.provider) {
      if (!user.provider.isActive) {
        return res.status(403).json({
          message:
            'Your vendor account has been deactivated. Please contact support.',
        });
      }
    }

    // 6) If everything ok, send token
    const token = signToken(user._id);

    res.status(200).json({
      status: 'success',
      token,
      user: {
        id: user._id,
        name: user.name,
        email: user.email,
        phone: user.phone,
        role: user.role,
        permissions: user.permissions || [],
        provider: user.role === 'vendor' ? user.provider : undefined,
      },
    });
  } catch (err) {
    res.status(500).json({ message: 'Admin login failed', error: err.message });
  }
};

exports.getMe = async (req, res) => {
  try {
    const user = await User.findById(req.user.id).populate('provider');
    if (!user) {
      return res.status(404).json({ message: 'User not found' });
    }

    res.status(200).json({
      status: 'success',
      user: {
        id: user._id,
        name: user.name,
        email: user.email,
        phone: user.phone,
        role: user.role,
        permissions: user.permissions || [],
        provider: user.role === 'vendor' ? user.provider : undefined,
      },
    });
  } catch (err) {
    res
      .status(500)
      .json({ message: 'Failed to get user details', error: err.message });
  }
};

exports.protect = async (req, res, next) => {
  try {
    let token;

    // 1) Check if token exists in headers
    if (
      req.headers.authorization &&
      req.headers.authorization.startsWith('Bearer')
    ) {
      token = req.headers.authorization.split(' ')[1];
    }

    if (!token) {
      return res.status(401).json({ message: 'You are not logged in!' });
    }

    // 2) Verify token
    const decoded = jwt.verify(token, process.env.JWT_SECRET);

    // 3) Check if user still exists
    const currentUser = await User.findById(decoded.id);
    if (!currentUser) {
      return res.status(401).json({ message: 'User no longer exists.' });
    }

    // 4) Check if user is active
    if (!currentUser.isActive) {
      return res.status(403).json({
        message: 'Your account has been deactivated. Please contact support.',
      });
    }

    // 5) Grant access
    req.user = currentUser;
    next();
  } catch (err) {
    res
      .status(401)
      .json({ message: 'Invalid or expired token', error: err.message });
  }
};

// Optional authentication - sets req.user if token is valid, but doesn't fail if no token
exports.optionalAuth = async (req, res, next) => {
  try {
    let token;

    // 1) Check if token exists in headers
    if (
      req.headers.authorization &&
      req.headers.authorization.startsWith('Bearer')
    ) {
      token = req.headers.authorization.split(' ')[1];
    }

    // If no token, just continue without setting req.user
    if (!token) {
      return next();
    }

    // 2) Verify token
    const decoded = jwt.verify(token, process.env.JWT_SECRET);

    // 3) Check if user still exists
    const currentUser = await User.findById(decoded.id);
    if (currentUser) {
      req.user = currentUser;
    }

    next();
  } catch (err) {
    // If token is invalid, just continue without setting req.user
    next();
  }
};

exports.logout = (req, res) => {
  res
    .status(200)
    .json({ status: 'success', message: 'Logged out successfully' });
};

exports.deleteAccount = async (req, res) => {
  try {
    const { currentPassword } = req.body;

    // 1) Check if password is provided
    if (!currentPassword) {
      return res
        .status(400)
        .json({ message: 'Password is required to delete account' });
    }

    // 2) Get user with password
    const user = await User.findById(req.user._id).select('+password');

    // 3) Verify password
    const isMatch = await bcrypt.compare(currentPassword, user.password);
    if (!isMatch) {
      return res.status(401).json({ message: 'Incorrect password' });
    }

    // 4) Delete the account
    await User.findByIdAndDelete(req.user._id);

    res.status(200).json({
      status: 'success',
      message: 'Account deleted successfully',
    });
  } catch (err) {
    res
      .status(500)
      .json({ message: 'Failed to delete account', error: err.message });
  }
};

exports.updateMe = async (req, res) => {
  try {
    const { name, email, phone, city, currentPassword } = req.body;

    // 1) لازم يكتب الباسورد القديمة
    if (!currentPassword) {
      return res
        .status(400)
        .json({ message: 'You must enter your current password' });
    }

    // 2) نجيب المستخدم ونقارن الباسورد
    const user = await User.findById(req.user._id).select('+password');

    const isMatch = await bcrypt.compare(currentPassword, user.password);
    if (!isMatch) {
      return res.status(401).json({ message: 'Current password is incorrect' });
    }

    // 3) نعمل update للبيانات
    user.name = name || user.name;
    user.email = email || user.email;
    user.phone = phone || user.phone;
    user.city = city || user.city;

    await user.save();

    res.status(200).json({
      status: 'success',
      user: {
        id: user._id,
        name: user.name,
        email: user.email,
        phone: user.phone,
        city: user.city,
      },
    });
  } catch (err) {
    res.status(500).json({
      status: 'fail',
      message: 'Update failed',
      error: err.message,
    });
  }
};

exports.changePassword = async (req, res) => {
  try {
    const { currentPassword, newPassword, confirmNewPassword } = req.body;

    // 1) Check all fields exist
    if (!currentPassword || !newPassword || !confirmNewPassword) {
      return res.status(400).json({ message: 'All fields are required' });
    }

    // 2) Check new passwords match
    if (newPassword !== confirmNewPassword) {
      return res.status(400).json({ message: 'New passwords do not match' });
    }

    // 3) Get current user with password
    const user = await User.findById(req.user._id).select('+password');

    // 4) Check currentPassword is correct
    const isMatch = await bcrypt.compare(currentPassword, user.password);
    if (!isMatch) {
      return res.status(401).json({ message: 'Current password is incorrect' });
    }

    // 5) Set new password (will be hashed by pre-save hook)
    user.password = newPassword;

    // 6) Save user
    await user.save();

    // 7) Send password change confirmation email
    sendPasswordChangeConfirmationEmail(user).catch((err) =>
      console.error(
        'Failed to send password change confirmation email:',
        err.message,
      ),
    );

    res.status(200).json({
      status: 'success',
      message: 'Password updated successfully',
    });
  } catch (err) {
    res
      .status(500)
      .json({ message: 'Failed to update password', error: err.message });
  }
};

// FORGOT PASSWORD - sends reset token to email
exports.forgotPassword = async (req, res) => {
  try {
    const { email } = req.body;

    if (!email) {
      return res
        .status(400)
        .json({ message: 'Please provide an email address' });
    }

    const user = await User.findOne({ email });
    if (!user) {
      return res
        .status(404)
        .json({ message: 'No user found with that email address' });
    }

    const resetToken = user.createPasswordResetToken();
    await user.save({ validateBeforeSave: false });

    const { sendPasswordResetEmail } = require('../utils/emailService');

    try {
      await sendPasswordResetEmail(user, resetToken);

      res.status(200).json({
        status: 'success',
        message: 'Password reset link sent to email',
      });
    } catch (err) {
      user.passwordResetToken = undefined;
      user.passwordResetExpires = undefined;
      await user.save({ validateBeforeSave: false });

      return res.status(500).json({
        message: 'Failed to send password reset email. Please try again later.',
        error: err.message,
      });
    }
  } catch (err) {
    res.status(500).json({
      message: 'Failed to process forgot password request',
      error: err.message,
    });
  }
};

// RESET PASSWORD - validates token and sets new password
exports.resetPassword = async (req, res) => {
  try {
    const crypto = require('crypto');
    const { password, confirmPassword } = req.body;
    const { token } = req.params;

    if (!password || !confirmPassword) {
      return res
        .status(400)
        .json({ message: 'Please provide password and confirm password' });
    }

    if (password !== confirmPassword) {
      return res.status(400).json({ message: 'Passwords do not match' });
    }

    if (password.length < 6) {
      return res
        .status(400)
        .json({ message: 'Password must be at least 6 characters' });
    }

    const hashedToken = crypto.createHash('sha256').update(token).digest('hex');

    const user = await User.findOne({
      passwordResetToken: hashedToken,
      passwordResetExpires: { $gt: Date.now() },
    });

    if (!user) {
      return res.status(400).json({
        message:
          'Invalid or expired reset token. Please request a new password reset.',
      });
    }

    user.password = password;
    user.passwordResetToken = undefined;
    user.passwordResetExpires = undefined;
    await user.save();

    const jwtToken = signToken(user._id);

    res.status(200).json({
      status: 'success',
      message: 'Password reset successful',
      token: jwtToken,
    });
  } catch (err) {
    res.status(500).json({
      message: 'Failed to reset password',
      error: err.message,
    });
  }
};