package repository

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

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

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

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

type Users interface {
	GetByName(ctx context.Context, name string) (entity.UserEntity, error)
	Create(ctx context.Context, name, password, sessionTOken, scope string) (int64, error)
	Update(ctx context.Context, id int, entity entity.UserEntity) error
	UpdatePassword(ctx context.Context, name, password string) error
	CheckUserHash(ctx context.Context, name, password string) error
	UpdateScopes(ctx context.Context, name, scope string) error
	UpdateSessionToken(ctx context.Context, name, sessionToken string) (int64, 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(ctx context.Context, name string) (entity.UserEntity, error) {
	builder := sqlbuilder.NewSelectBuilder()
	builder.Select("*").From("users").Where(
		builder.E("Name", name),
	)
	query, args := builder.Build()

	rows, err := ur.connection.QueryContext(ctx, query, args...)
	if err != nil {
		return entity.UserEntity{}, err
	}

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

	return data[0], nil
}

func (ur userRepository) Create(ctx context.Context, name, password, sessionToken, 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", "DeletedAt", "Scopes", "SessionToken")
	queryBuilder.Values(name, string(hash), dt, dt, time.Time{}, scope, sessionToken)
	query, args := queryBuilder.Build()

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

	return 1, nil
}

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

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

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

func (ur userRepository) UpdateSessionToken(ctx context.Context, name, sessionToken string) (int64, error) {
	_, err := ur.GetByName(ctx, name)
	if err != nil {
		return 0, err
	}

	q := sqlbuilder.NewUpdateBuilder()
	q.Update(usersTableName)
	q.Set(
		q.Equal("SessionToken", sessionToken),
	)
	q.Where(
		q.Equal("Name", name),
	)

	query, args := q.Build()
	rowsUpdates, err := ur.connection.ExecContext(ctx, query, args...)
	if err != nil {
		return 0, err
	}

	return rowsUpdates.RowsAffected()
}

// 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(ctx context.Context, name, password string) error {
	record, err := ur.GetByName(ctx, 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(ctx context.Context, 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.ExecContext(ctx, query, args...)
	if err != nil {
		return err
	}
	return nil
}

func (ur userRepository) processRows(rows *sql.Rows) []entity.UserEntity {
	items := []entity.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
		var sessionToken string
		err := rows.Scan(&id, &createdAt, &updatedAt, &deletedAt, &username, &hash, &scopes, &sessionToken)
		if err != nil {
			fmt.Println(err)
		}

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

		items = append(items, item)
	}

	return items
}