package repository

import (
	"database/sql"
	"errors"
	"fmt"
	"time"

	"git.jamestombleson.com/jtom38/newsbot-api/internal/domain"

	"github.com/huandu/go-sqlbuilder"
	"golang.org/x/crypto/bcrypt"
)

const (
	TableName       string = "users"
	ErrUserNotFound string = "requested user was not found"
)

type Users interface {
	GetByName(name string) (domain.UserEntity, error)
	Create(name, password, scope string) (int64, error)
	Update(id int, entity domain.UserEntity) error
	UpdatePassword(name, password string) error
	CheckUserHash(name, password string) error
	UpdateScopes(name, scope string) error
}

// Creates a new instance of UserRepository with the bound sql
func NewUserRepository(conn *sql.DB) userRepository {
	return userRepository{
		connection: conn,
	}
}

type userRepository struct {
	connection *sql.DB
}

func (ur userRepository) GetByName(name string) (domain.UserEntity, error) {
	builder := sqlbuilder.NewSelectBuilder()
	builder.Select("*").From("users").Where(
		builder.E("Name", name),
	)
	query, args := builder.Build()

	rows, err := ur.connection.Query(query, args...)
	if err != nil {
		return domain.UserEntity{}, err
	}

	data := ur.processRows(rows)
	if len(data) == 0 {
		return domain.UserEntity{}, errors.New(ErrUserNotFound)
	}

	return data[0], nil
}

func (ur userRepository) Create(name, password, scope string) (int64, error) {
	passwordBytes := []byte(password)
	hash, err := bcrypt.GenerateFromPassword(passwordBytes, bcrypt.DefaultCost)
	if err != nil {
		return 0, err
	}

	dt := time.Now()
	queryBuilder := sqlbuilder.NewInsertBuilder()
	queryBuilder.InsertInto("users")
	queryBuilder.Cols("Name", "Hash", "UpdatedAt", "CreatedAt", "Scopes")
	queryBuilder.Values(name, string(hash), dt, dt, scope)
	query, args := queryBuilder.Build()

	_, err = ur.connection.Exec(query, args...)
	if err != nil {
		return 0, err
	}

	return 1, nil
}

func (ur userRepository) Update(id int, entity domain.UserEntity) error {
	return errors.New("not implemented")
}

func (ur userRepository) UpdatePassword(name, password string) error {
	_, err := ur.GetByName(name)
	if err != nil {
		return nil
	}

	queryBuilder := sqlbuilder.NewUpdateBuilder()
	queryBuilder.Update(TableName)
	//queryBuilder.Set
	return nil
}

// If the hash matches what we have in the database, an error will not be returned.
// If the user does not exist or the hash does not match, an error will be returned
func (ur userRepository) CheckUserHash(name, password string) error {
	record, err := ur.GetByName(name)
	if err != nil {
		return err
	}

	err = bcrypt.CompareHashAndPassword([]byte(record.Hash), []byte(password))
	if err != nil {
		return err
	}

	return nil
}

func (ur userRepository) UpdateScopes(name, scope string) error {
	builder := sqlbuilder.NewUpdateBuilder()
	builder.Update("users")
	builder.Set(
		builder.Assign("Scopes", scope),
	)
	builder.Where(
		builder.Equal("Name", name),
	)
	query, args := builder.Build()

	_, err := ur.connection.Exec(query, args...)
	if err != nil {
		return err
	}
	return nil
}

func (ur userRepository) processRows(rows *sql.Rows) []domain.UserEntity {
	items := []domain.UserEntity{}

	for rows.Next() {
		var id int64
		var username string
		var hash string
		var createdAt time.Time
		var updatedAt time.Time
		var deletedAt sql.NullTime
		var scopes string
		err := rows.Scan(&id, &createdAt, &updatedAt, &deletedAt, &username, &hash, &scopes)
		if err != nil {
			fmt.Println(err)
		}

		item := domain.UserEntity{
			ID:        id,
			UpdatedAt: updatedAt,
			Username:  username,
			Hash:      hash,
			Scopes:    scopes,
			CreatedAt: createdAt,
		}
		if deletedAt.Valid {
			item.DeletedAt = deletedAt.Time
		}

		items = append(items, item)
	}

	return items
}