package tokens

import (
	"time"

	"github.com/mitchellh/mapstructure"
	"github.com/gophercloud/gophercloud"
)

// Endpoint represents a single API endpoint offered by a service.
// It matches either a public, internal or admin URL.
// If supported, it contains a region specifier, again if provided.
// The significance of the Region field will depend upon your provider.
type Endpoint struct {
	ID        string `mapstructure:"id"`
	Region    string `mapstructure:"region"`
	Interface string `mapstructure:"interface"`
	URL       string `mapstructure:"url"`
}

// CatalogEntry provides a type-safe interface to an Identity API V3 service catalog listing.
// Each class of service, such as cloud DNS or block storage services, could have multiple
// CatalogEntry representing it (one by interface type, e.g public, admin or internal).
//
// Note: when looking for the desired service, try, whenever possible, to key off the type field.
// Otherwise, you'll tie the representation of the service to a specific provider.
type CatalogEntry struct {

	// Service ID
	ID string `mapstructure:"id"`

	// Name will contain the provider-specified name for the service.
	Name string `mapstructure:"name"`

	// Type will contain a type string if OpenStack defines a type for the service.
	// Otherwise, for provider-specific services, the provider may assign their own type strings.
	Type string `mapstructure:"type"`

	// Endpoints will let the caller iterate over all the different endpoints that may exist for
	// the service.
	Endpoints []Endpoint `mapstructure:"endpoints"`
}

// ServiceCatalog provides a view into the service catalog from a previous, successful authentication.
type ServiceCatalog struct {
	Entries []CatalogEntry
}

// commonResult is the deferred result of a Create or a Get call.
type commonResult struct {
	gophercloud.Result
}

// Extract is a shortcut for ExtractToken.
// This function is deprecated and still present for backward compatibility.
func (r commonResult) Extract() (*Token, error) {
	return r.ExtractToken()
}

// ExtractToken interprets a commonResult as a Token.
func (r commonResult) ExtractToken() (*Token, error) {
	if r.Err != nil {
		return nil, r.Err
	}

	var response struct {
		Token struct {
			ExpiresAt string `mapstructure:"expires_at"`
		} `mapstructure:"token"`
	}

	var token Token

	// Parse the token itself from the stored headers.
	token.ID = r.Header.Get("X-Subject-Token")

	err := mapstructure.Decode(r.Body, &response)
	if err != nil {
		return nil, err
	}

	// Attempt to parse the timestamp.
	token.ExpiresAt, err = time.Parse(gophercloud.RFC3339Milli, response.Token.ExpiresAt)

	return &token, err
}

// ExtractServiceCatalog returns the ServiceCatalog that was generated along with the user's Token.
func (result CreateResult) ExtractServiceCatalog() (*ServiceCatalog, error) {
	if result.Err != nil {
		return nil, result.Err
	}

	var response struct {
		Token struct {
			Entries []CatalogEntry `mapstructure:"catalog"`
		} `mapstructure:"token"`
	}

	err := mapstructure.Decode(result.Body, &response)
	if err != nil {
		return nil, err
	}

	return &ServiceCatalog{Entries: response.Token.Entries}, nil
}

// CreateResult defers the interpretation of a created token.
// Use ExtractToken() to interpret it as a Token, or ExtractServiceCatalog() to interpret it as a service catalog.
type CreateResult struct {
	commonResult
}

// createErr quickly creates a CreateResult that reports an error.
func createErr(err error) CreateResult {
	return CreateResult{
		commonResult: commonResult{Result: gophercloud.Result{Err: err}},
	}
}

// GetResult is the deferred response from a Get call.
type GetResult struct {
	commonResult
}

// RevokeResult is the deferred response from a Revoke call.
type RevokeResult struct {
	commonResult
}

// Token is a string that grants a user access to a controlled set of services in an OpenStack provider.
// Each Token is valid for a set length of time.
type Token struct {
	// ID is the issued token.
	ID string

	// ExpiresAt is the timestamp at which this token will no longer be accepted.
	ExpiresAt time.Time
}