import { hash } from 'bcryptjs';
import { prisma } from '@/services/database';

export interface RegisterInput {
  email: string;
  password: string;
  name?: string;
}

export interface AuthResult {
  success: boolean;
  error?: string;
  user?: {
    id: string;
    email: string;
    name: string | null;
  };
}

export async function registerUser(input: RegisterInput): Promise<AuthResult> {
  const { email, password, name } = input;

  // Check if user already exists
  const existingUser = await prisma.user.findUnique({
    where: { email },
  });

  if (existingUser) {
    return {
      success: false,
      error: 'Un compte existe déjà avec cet email',
    };
  }

  // Hash password
  const hashedPassword = await hash(password, 12);

  // Create user
  const user = await prisma.user.create({
    data: {
      email,
      password: hashedPassword,
      name: name || null,
    },
  });

  return {
    success: true,
    user: {
      id: user.id,
      email: user.email,
      name: user.name,
    },
  };
}

export async function getUserByEmail(email: string) {
  return prisma.user.findUnique({
    where: { email },
  });
}

export async function getUserById(id: string) {
  return prisma.user.findUnique({
    where: { id },
  });
}

export interface UpdateProfileInput {
  name?: string;
  email?: string;
}

export async function updateUserProfile(
  userId: string,
  input: UpdateProfileInput
): Promise<AuthResult> {
  const { name, email } = input;

  // If changing email, check it's not already taken
  if (email) {
    const existingUser = await prisma.user.findFirst({
      where: {
        email,
        NOT: { id: userId },
      },
    });

    if (existingUser) {
      return {
        success: false,
        error: 'Cet email est déjà utilisé par un autre compte',
      };
    }
  }

  const user = await prisma.user.update({
    where: { id: userId },
    data: {
      ...(name !== undefined && { name: name || null }),
      ...(email && { email }),
    },
  });

  return {
    success: true,
    user: {
      id: user.id,
      email: user.email,
      name: user.name,
    },
  };
}

export async function updateUserPassword(
  userId: string,
  currentPassword: string,
  newPassword: string
): Promise<{ success: boolean; error?: string }> {
  const { compare } = await import('bcryptjs');

  const user = await prisma.user.findUnique({
    where: { id: userId },
  });

  if (!user) {
    return { success: false, error: 'Utilisateur non trouvé' };
  }

  // Verify current password
  const isValid = await compare(currentPassword, user.password);
  if (!isValid) {
    return { success: false, error: 'Mot de passe actuel incorrect' };
  }

  // Hash new password
  const hashedPassword = await hash(newPassword, 12);

  await prisma.user.update({
    where: { id: userId },
    data: { password: hashedPassword },
  });

  return { success: true };
}

export interface UserStats {
  sessions: number;
  motivatorSessions: number;
  sharedSessions: number;
  sharedMotivatorSessions: number;
}

export interface UserWithStats {
  id: string;
  email: string;
  name: string | null;
  createdAt: Date;
  updatedAt: Date;
  _count: UserStats;
}

export async function getAllUsersWithStats(): Promise<UserWithStats[]> {
  const users = await prisma.user.findMany({
    select: {
      id: true,
      email: true,
      name: true,
      createdAt: true,
      updatedAt: true,
      _count: {
        select: {
          sessions: true,
          sharedSessions: true,
        },
      },
    },
    orderBy: { createdAt: 'desc' },
  });

  // Get motivator sessions count separately (Prisma doesn't have these in User model _count directly)
  const usersWithMotivators = await Promise.all(
    users.map(async (user) => {
      const motivatorCount = await prisma.movingMotivatorsSession.count({
        where: { userId: user.id },
      });
      const sharedMotivatorCount = await prisma.mMSessionShare.count({
        where: { userId: user.id },
      });

      return {
        ...user,
        _count: {
          ...user._count,
          motivatorSessions: motivatorCount,
          sharedMotivatorSessions: sharedMotivatorCount,
        },
      };
    })
  );

  return usersWithMotivators;
}