package repository

import (
	"bytes"
	"context"
	"errors"
	"log/slog"

	"github.com/gofrs/uuid/v5"
	"github.com/jackc/pgx/v5"
	"github.com/jackc/pgx/v5/pgxpool"
)

var (
	ErrNotFound error = errors.New("user cannot be found")
)

type UserRow struct {
	Id             uuid.UUID
	Email          string
	HashedPassword []byte
	Salt           []byte
}

func (u UserRow) Equal(user UserRow) bool {
	return u.Id == user.Id && u.Email == user.Email && bytes.Equal(u.HashedPassword, user.HashedPassword) && bytes.Equal(u.Salt, user.Salt)
}

type UserRepository struct {
	logger *slog.Logger
	db     *pgxpool.Pool
}

func NewUserRepository(logger *slog.Logger, db *pgxpool.Pool) *UserRepository {
	return &UserRepository{
		logger: logger,
		db:     db,
	}
}

func (r *UserRepository) GetById(ctx context.Context, id uuid.UUID) (UserRow, error) {
	user := UserRow{}

	err := r.db.QueryRow(ctx, "SELECT * FROM users WHERE id = $1;", id).Scan(&user.Id, &user.Email, &user.HashedPassword, &user.Salt)

	if err != nil {
		if err == pgx.ErrNoRows {
			return user, ErrNotFound
		}

		r.logger.ErrorContext(ctx, err.Error())
		return user, err
	}

	return user, nil
}

func (r *UserRepository) GetByEmail(ctx context.Context, email string) (UserRow, error) {
	user := UserRow{}

	err := r.db.QueryRow(ctx, "SELECT * FROM users WHERE email = $1;", email).Scan(&user.Id, &user.Email, &user.HashedPassword, &user.Salt)

	if err != nil {
		if err == pgx.ErrNoRows {
			return user, ErrNotFound
		}

		r.logger.ErrorContext(ctx, err.Error())
		return user, err
	}

	return user, nil
}

func (r *UserRepository) Create(ctx context.Context, user UserRow) (UserRow, error) {
	var result pgx.Row
	if user.Id.IsNil() {
		result = r.db.QueryRow(ctx, "INSERT INTO users (email, hashed_password, salt) VALUES ($1, $2, $3) RETURNING id;", user.Email, user.HashedPassword, user.Salt)

		err := result.Scan(&user.Id)

		if err != nil {
			r.logger.ErrorContext(ctx, err.Error())
			return UserRow{}, err
		}
	} else {
		_, err := r.db.Exec(ctx, "INSERT INTO users (id, email, hashed_password, salt) VALUES ($1, $2, $3, $4);", user.Id, user.Email, user.HashedPassword, user.Salt)

		if err != nil {
			r.logger.ErrorContext(ctx, err.Error())
			return UserRow{}, err
		}
	}

	return user, nil
}

func (r *UserRepository) Update(ctx context.Context, user UserRow) error {
	result, err := r.db.Exec(ctx, "UPDATE users SET email = $1, hashed_password = $2, salt = $3 WHERE id = $4;", user.Email, user.HashedPassword, user.Salt, user.Id)

	if err != nil {
		r.logger.ErrorContext(ctx, err.Error())
		return err
	}

	rowsAffected := result.RowsAffected()

	if rowsAffected == 0 {
		return ErrNotFound
	}

	return nil
}

func (r *UserRepository) Delete(ctx context.Context, id uuid.UUID) error {
	result, err := r.db.Exec(ctx, "DELETE FROM users WHERE id = $1;", id)

	if err != nil {
		r.logger.ErrorContext(ctx, err.Error())
		return err
	}

	rowsAffected := result.RowsAffected()

	if rowsAffected == 0 {
		return ErrNotFound
	}

	return nil
}