import { Injectable, Logger } from '@nestjs/common';
import * as bcrypt from 'bcrypt';
import { LoginPayload, RegisteredUser, User } from 'src/interface/interface';


@Injectable()
export class UsersService {
    private logger: Logger = new Logger(`UsersService`)
    private users: RegisteredUser[] = [];
    private idCounter = 1;

    public async createUser(user: User): Promise<RegisteredUser> {
        return new Promise(async (resolve, reject) => {
            const existing = this.users.find(u => u.email === user.email);
            if (existing) {
                reject('User already exists');
            } else {
                const hashedPassword = await bcrypt.hash(user.password, 10);
                const newUser: RegisteredUser = {
                    id: (this.idCounter++).toString(),
                    name: user.name,
                    email: user.email,
                    password: hashedPassword,
                };
                this.users.push(newUser);
                this.logger.log(`Current users count: ${this.users.length}`)
                resolve(newUser)
            }
        })
    }

    public async findByEmail(email: string): Promise<RegisteredUser | undefined> {
        return this.users.find(user => user.email === email);
    }

    public async validateUser(login: LoginPayload): Promise<Omit<RegisteredUser, 'password'>> {
        return new Promise((resolve, reject) => {
            this.findByEmail(login.email)
                .then(user => {
                    if (!user) return reject('No such user');

                    // console.log('Comparing passwords...');
                    // console.log('Login.password:', login.password, typeof login.password);
                    // console.log('User.password:', user.password, typeof user.password);

                    if (typeof login.password !== 'string' || typeof user.password !== 'string') {
                        return reject('Password and hash must be strings');
                    }

                    bcrypt.compare(login.password, user.password, (err, isMatch) => {
                        if (err) return reject(err);
                        if (!isMatch) return reject(`Password doesn't match`);

                        const { password, ...safeUser } = user;
                        resolve(safeUser);
                    });
                })
                .catch(err => reject(err));
        });
    }

    public async findById(id: string): Promise<RegisteredUser | undefined> {
        return this.users.find(user => user.id === id);
    }

    public getAllUsers(): Omit<RegisteredUser, 'password'>[] {
        return this.users.map(({ password, ...rest }) => rest);
    }

    public async updateUser(updatedUser: RegisteredUser): Promise<void> {
        const index = this.users.findIndex(user => user.id === updatedUser.id);

        if (index === -1) {
            throw new Error(`User with ID ${updatedUser.id} not found`);
        }

        this.users[index] = updatedUser;
        this.logger.log(`User ${updatedUser.id} updated successfully`);
    }

}