package routers

import (
	"errors"

	"github.com/rackspace/gophercloud"
	"github.com/rackspace/gophercloud/pagination"
)

// ListOpts allows the filtering and sorting of paginated collections through
// the API. Filtering is achieved by passing in struct field values that map to
// the floating IP attributes you want to see returned. SortKey allows you to
// sort by a particular network attribute. SortDir sets the direction, and is
// either `asc' or `desc'. Marker and Limit are used for pagination.
type ListOpts struct {
	ID           string `q:"id"`
	Name         string `q:"name"`
	AdminStateUp *bool  `q:"admin_state_up"`
	Distributed  *bool  `q:"distributed"`
	Status       string `q:"status"`
	TenantID     string `q:"tenant_id"`
	Limit        int    `q:"limit"`
	Marker       string `q:"marker"`
	SortKey      string `q:"sort_key"`
	SortDir      string `q:"sort_dir"`
}

// List returns a Pager which allows you to iterate over a collection of
// routers. It accepts a ListOpts struct, which allows you to filter and sort
// the returned collection for greater efficiency.
//
// Default policy settings return only those routers that are owned by the
// tenant who submits the request, unless an admin user submits the request.
func List(c *gophercloud.ServiceClient, opts ListOpts) pagination.Pager {
	q, err := gophercloud.BuildQueryString(&opts)
	if err != nil {
		return pagination.Pager{Err: err}
	}
	u := rootURL(c) + q.String()
	return pagination.NewPager(c, u, func(r pagination.PageResult) pagination.Page {
		return RouterPage{pagination.LinkedPageBase{PageResult: r}}
	})
}

// CreateOptsBuilder is the interface options structs have to satisfy in order
// to be used in the main Create operation in this package. Since many
// extensions decorate or modify the common logic, it is useful for them to
// satisfy a basic interface in order for them to be used.
type CreateOptsBuilder interface {
	ToRouterCreateMap() (map[string]interface{}, error)
}

// CreateOpts contains all the values needed to create a new router. There are
// no required values.
type CreateOpts struct {
	Name         string
	AdminStateUp *bool
	Distributed  *bool
	TenantID     string
	GatewayInfo  *GatewayInfo
}

// ToRouterCreateMap casts a CreateOpts struct to a map.
func (opts CreateOpts) ToRouterCreateMap() (map[string]interface{}, error) {
	r := make(map[string]interface{})

	if gophercloud.MaybeString(opts.Name) != nil {
		r["name"] = opts.Name
	}

	if opts.AdminStateUp != nil {
		r["admin_state_up"] = opts.AdminStateUp
	}

	if opts.Distributed != nil {
		r["distributed"] = opts.Distributed
	}

	if gophercloud.MaybeString(opts.TenantID) != nil {
		r["tenant_id"] = opts.TenantID
	}

	if opts.GatewayInfo != nil {
		r["external_gateway_info"] = opts.GatewayInfo
	}

	return map[string]interface{}{"router": r}, nil
}

// Create accepts a CreateOpts struct and uses the values to create a new
// logical router. When it is created, the router does not have an internal
// interface - it is not associated to any subnet.
//
// You can optionally specify an external gateway for a router using the
// GatewayInfo struct. The external gateway for the router must be plugged into
// an external network (it is external if its `router:external' field is set to
// true).
func Create(c *gophercloud.ServiceClient, opts CreateOptsBuilder) CreateResult {
	var res CreateResult

	reqBody, err := opts.ToRouterCreateMap()
	if err != nil {
		res.Err = err
		return res
	}

	_, res.Err = c.Post(rootURL(c), reqBody, &res.Body, nil)
	return res
}

// Get retrieves a particular router based on its unique ID.
func Get(c *gophercloud.ServiceClient, id string) GetResult {
	var res GetResult
	_, res.Err = c.Get(resourceURL(c, id), &res.Body, nil)
	return res
}

// UpdateOpts contains the values used when updating a router.
type UpdateOpts struct {
	Name         string
	AdminStateUp *bool
	Distributed  *bool
	GatewayInfo  *GatewayInfo
	Routes       []Route
}

// Update allows routers to be updated. You can update the name, administrative
// state, and the external gateway. For more information about how to set the
// external gateway for a router, see Create. This operation does not enable
// the update of router interfaces. To do this, use the AddInterface and
// RemoveInterface functions.
func Update(c *gophercloud.ServiceClient, id string, opts UpdateOpts) UpdateResult {
	type router struct {
		Name         *string      `json:"name,omitempty"`
		AdminStateUp *bool        `json:"admin_state_up,omitempty"`
		Distributed  *bool        `json:"distributed,omitempty"`
		GatewayInfo  *GatewayInfo `json:"external_gateway_info,omitempty"`
		Routes       []Route      `json:"routes"`
	}

	type request struct {
		Router router `json:"router"`
	}

	reqBody := request{Router: router{
		Name:         gophercloud.MaybeString(opts.Name),
		AdminStateUp: opts.AdminStateUp,
		Distributed:  opts.Distributed,
	}}

	if opts.GatewayInfo != nil {
		reqBody.Router.GatewayInfo = opts.GatewayInfo
	}

	if opts.Routes != nil {
		reqBody.Router.Routes = opts.Routes
	}

	// Send request to API
	var res UpdateResult
	_, res.Err = c.Put(resourceURL(c, id), reqBody, &res.Body, &gophercloud.RequestOpts{
		OkCodes: []int{200},
	})

	return res
}

// Delete will permanently delete a particular router based on its unique ID.
func Delete(c *gophercloud.ServiceClient, id string) DeleteResult {
	var res DeleteResult
	_, res.Err = c.Delete(resourceURL(c, id), nil)
	return res
}

var errInvalidInterfaceOpts = errors.New("When adding a router interface you must provide either a subnet ID or a port ID")

// InterfaceOpts allow you to work with operations that either add or remote
// an internal interface from a router.
type InterfaceOpts struct {
	SubnetID string
	PortID   string
}

// AddInterface attaches a subnet to an internal router interface. You must
// specify either a SubnetID or PortID in the request body. If you specify both,
// the operation will fail and an error will be returned.
//
// If you specify a SubnetID, the gateway IP address for that particular subnet
// is used to create the router interface. Alternatively, if you specify a
// PortID, the IP address associated with the port is used to create the router
// interface.
//
// If you reference a port that is associated with multiple IP addresses, or
// if the port is associated with zero IP addresses, the operation will fail and
// a 400 Bad Request error will be returned.
//
// If you reference a port already in use, the operation will fail and a 409
// Conflict error will be returned.
//
// The PortID that is returned after using Extract() on the result of this
// operation can either be the same PortID passed in or, on the other hand, the
// identifier of a new port created by this operation. After the operation
// completes, the device ID of the port is set to the router ID, and the
// device owner attribute is set to `network:router_interface'.
func AddInterface(c *gophercloud.ServiceClient, id string, opts InterfaceOpts) InterfaceResult {
	var res InterfaceResult

	// Validate
	if (opts.SubnetID == "" && opts.PortID == "") || (opts.SubnetID != "" && opts.PortID != "") {
		res.Err = errInvalidInterfaceOpts
		return res
	}

	type request struct {
		SubnetID string `json:"subnet_id,omitempty"`
		PortID   string `json:"port_id,omitempty"`
	}

	body := request{SubnetID: opts.SubnetID, PortID: opts.PortID}

	_, res.Err = c.Put(addInterfaceURL(c, id), body, &res.Body, &gophercloud.RequestOpts{
		OkCodes: []int{200},
	})

	return res
}

// RemoveInterface removes an internal router interface, which detaches a
// subnet from the router. You must specify either a SubnetID or PortID, since
// these values are used to identify the router interface to remove.
//
// Unlike AddInterface, you can also specify both a SubnetID and PortID. If you
// choose to specify both, the subnet ID must correspond to the subnet ID of
// the first IP address on the port specified by the port ID. Otherwise, the
// operation will fail and return a 409 Conflict error.
//
// If the router, subnet or port which are referenced do not exist or are not
// visible to you, the operation will fail and a 404 Not Found error will be
// returned. After this operation completes, the port connecting the router
// with the subnet is removed from the subnet for the network.
func RemoveInterface(c *gophercloud.ServiceClient, id string, opts InterfaceOpts) InterfaceResult {
	var res InterfaceResult

	type request struct {
		SubnetID string `json:"subnet_id,omitempty"`
		PortID   string `json:"port_id,omitempty"`
	}

	body := request{SubnetID: opts.SubnetID, PortID: opts.PortID}

	_, res.Err = c.Put(removeInterfaceURL(c, id), body, &res.Body, &gophercloud.RequestOpts{
		OkCodes: []int{200},
	})

	return res
}