package users

import (
	"github.com/gophercloud/gophercloud"
	db "github.com/gophercloud/gophercloud/openstack/db/v1/databases"
	"github.com/gophercloud/gophercloud/pagination"
)

// CreateOptsBuilder is the top-level interface for creating JSON maps.
type CreateOptsBuilder interface {
	ToUserCreateMap() (map[string]interface{}, error)
}

// CreateOpts is the struct responsible for configuring a new user; often in the
// context of an instance.
type CreateOpts struct {
	// Specifies a name for the user. Valid names can be composed
	// of the following characters: letters (either case); numbers; these
	// characters '@', '?', '#', ' ' but NEVER beginning a name string; '_' is
	// permitted anywhere. Prohibited characters that are forbidden include:
	// single quotes, double quotes, back quotes, semicolons, commas, backslashes,
	// and forward slashes. Spaces at the front or end of a user name are also
	// not permitted.
	Name string `json:"name" required:"true"`
	// Specifies a password for the user.
	Password string `json:"password" required:"true"`
	// An array of databases that this user will connect to. The
	// "name" field is the only requirement for each option.
	Databases db.BatchCreateOpts `json:"databases,omitempty"`
	// Specifies the host from which a user is allowed to connect to
	// the database. Possible values are a string containing an IPv4 address or
	// "%" to allow connecting from any host. Optional; the default is "%".
	Host string `json:"host,omitempty"`
}

// ToMap is a convenience function for creating sub-maps for individual users.
func (opts CreateOpts) ToMap() (map[string]interface{}, error) {
	if opts.Name == "root" {
		err := gophercloud.ErrInvalidInput{}
		err.Argument = "users.CreateOpts.Name"
		err.Value = "root"
		err.Info = "root is a reserved user name and cannot be used"
		return nil, err
	}
	return gophercloud.BuildRequestBody(opts, "")
}

// BatchCreateOpts allows multiple users to be created at once.
type BatchCreateOpts []CreateOpts

// ToUserCreateMap will generate a JSON map.
func (opts BatchCreateOpts) ToUserCreateMap() (map[string]interface{}, error) {
	users := make([]map[string]interface{}, len(opts))
	for i, opt := range opts {
		user, err := opt.ToMap()
		if err != nil {
			return nil, err
		}
		users[i] = user
	}
	return map[string]interface{}{"users": users}, nil
}

// Create asynchronously provisions a new user for the specified database
// instance based on the configuration defined in CreateOpts. If databases are
// assigned for a particular user, the user will be granted all privileges
// for those specified databases. "root" is a reserved name and cannot be used.
func Create(client *gophercloud.ServiceClient, instanceID string, opts CreateOptsBuilder) CreateResult {
	var r CreateResult
	b, err := opts.ToUserCreateMap()
	if err != nil {
		r.Err = err
		return r
	}
	_, r.Err = client.Post(baseURL(client, instanceID), &b, nil, nil)
	return r
}

// List will list all the users associated with a specified database instance,
// along with their associated databases. This operation will not return any
// system users or administrators for a database.
func List(client *gophercloud.ServiceClient, instanceID string) pagination.Pager {
	return pagination.NewPager(client, baseURL(client, instanceID), func(r pagination.PageResult) pagination.Page {
		return UserPage{pagination.LinkedPageBase{PageResult: r}}
	})
}

// Delete will permanently delete a user from a specified database instance.
func Delete(client *gophercloud.ServiceClient, instanceID, userName string) DeleteResult {
	var r DeleteResult
	_, r.Err = client.Delete(userURL(client, instanceID, userName), nil)
	return r
}