ducky/subscriptions

     1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/subscription.go	Thu Jun 11 23:15:01 2015 -0400
     1.3 @@ -0,0 +1,149 @@
     1.4 +package subscriptions
     1.5 +
     1.6 +import (
     1.7 +	"errors"
     1.8 +	"time"
     1.9 +
    1.10 +	"code.secondbit.org/uuid.hg"
    1.11 +)
    1.12 +
    1.13 +const (
    1.14 +	// MonthlyPeriod represents a period of once a month.
    1.15 +	MonthlyPeriod period = "monthly"
    1.16 +)
    1.17 +
    1.18 +var (
    1.19 +	// ErrSubscriptionAlreadyExists is returned when a Subscription
    1.20 +	// with an identical ID already exists in the subscriptionStore.
    1.21 +	ErrSubscriptionAlreadyExists = errors.New("Subscription already exists")
    1.22 +	// ErrSubscriptionNotFound is returned when a single Subscription
    1.23 +	// is acted upon or requested, but cannot be found.
    1.24 +	ErrSubscriptionNotFound = errors.New("Subscription not found")
    1.25 +	// ErrStripeCustomerAlreadyExists is returned when a Subscription
    1.26 +	// is created or updates its StripeCustomer property, but that
    1.27 +	// StripeCustomer is already associated with another Subscription.
    1.28 +	ErrStripeCustomerAlreadyExists = errors.New("Stripe customer already assigned to another Subscription")
    1.29 +	// ErrSubscriptionChangeEmpty is returned when a SubscriptionChange
    1.30 +	// is empty but is passed to subscriptionStore.UpdateSubscription
    1.31 +	// anyways.
    1.32 +	ErrSubscriptionChangeEmpty = errors.New("SubscriptionChange is empty")
    1.33 +	// ErrNoSubscriptionID is returned when one or more Subscription IDs
    1.34 +	// are required, but none are provided.
    1.35 +	ErrNoSubscriptionID = errors.New("no Subscription ID provided")
    1.36 +)
    1.37 +
    1.38 +type period string
    1.39 +
    1.40 +// Subscription represents the state of a user's payments. It holds
    1.41 +// metadata about the last time a user was charged, how much a user
    1.42 +// should be charged, how to charge a user and how much to charge
    1.43 +// the user.
    1.44 +type Subscription struct {
    1.45 +	ID             uuid.ID
    1.46 +	UserID         uuid.ID
    1.47 +	StripeCustomer string
    1.48 +	Amount         int
    1.49 +	Period         period
    1.50 +	Created        time.Time
    1.51 +	BeginCharging  time.Time
    1.52 +	LastCharged    time.Time
    1.53 +	LastNotified   time.Time
    1.54 +	InLockout      bool
    1.55 +}
    1.56 +
    1.57 +// SubscriptionChange represents desired changes to a Subscription
    1.58 +// object. A nil value means that property should remain unchanged.
    1.59 +type SubscriptionChange struct {
    1.60 +	StripeCustomer *string
    1.61 +	Amount         *int
    1.62 +	Period         *period
    1.63 +	BeginCharging  *time.Time
    1.64 +	LastCharged    *time.Time
    1.65 +	LastNotified   *time.Time
    1.66 +	InLockout      *bool
    1.67 +}
    1.68 +
    1.69 +// IsEmpty returns true if the SubscriptionChange doesn't request
    1.70 +// a change to any property of the Subscription.
    1.71 +func (change SubscriptionChange) IsEmpty() bool {
    1.72 +	if change.StripeCustomer != nil {
    1.73 +		return false
    1.74 +	}
    1.75 +	if change.Amount != nil {
    1.76 +		return false
    1.77 +	}
    1.78 +	if change.Period != nil {
    1.79 +		return false
    1.80 +	}
    1.81 +	if change.BeginCharging != nil {
    1.82 +		return false
    1.83 +	}
    1.84 +	if change.LastCharged != nil {
    1.85 +		return false
    1.86 +	}
    1.87 +	if change.LastNotified != nil {
    1.88 +		return false
    1.89 +	}
    1.90 +	if change.InLockout != nil {
    1.91 +		return false
    1.92 +	}
    1.93 +	return true
    1.94 +}
    1.95 +
    1.96 +// ApplyChange updates a Subscription based on the changes requested
    1.97 +// by a SubscriptionChange.
    1.98 +func (s *Subscription) ApplyChange(change SubscriptionChange) {
    1.99 +	if change.StripeCustomer != nil {
   1.100 +		s.StripeCustomer = *change.StripeCustomer
   1.101 +	}
   1.102 +	if change.Amount != nil {
   1.103 +		s.Amount = *change.Amount
   1.104 +	}
   1.105 +	if change.Period != nil {
   1.106 +		s.Period = *change.Period
   1.107 +	}
   1.108 +	if change.BeginCharging != nil {
   1.109 +		s.BeginCharging = *change.BeginCharging
   1.110 +	}
   1.111 +	if change.LastCharged != nil {
   1.112 +		s.LastCharged = *change.LastCharged
   1.113 +	}
   1.114 +	if change.LastNotified != nil {
   1.115 +		s.LastNotified = *change.LastNotified
   1.116 +	}
   1.117 +	if change.InLockout != nil {
   1.118 +		s.InLockout = *change.InLockout
   1.119 +	}
   1.120 +}
   1.121 +
   1.122 +// ByLastChargeDate allows us to sort a []Subscription by the LastCharged
   1.123 +// property, with the lowest LastCharged date first.
   1.124 +type ByLastChargeDate []Subscription
   1.125 +
   1.126 +// Len returns the length the SubscriptionsByLastChargeDate. It fulfills
   1.127 +// the sort.Interface interface.
   1.128 +func (s ByLastChargeDate) Len() int {
   1.129 +	return len(s)
   1.130 +}
   1.131 +
   1.132 +// Swap puts the item in position i in position j, and the item in position
   1.133 +// j in position i. It fulfills the sort.Interface interface.
   1.134 +func (s ByLastChargeDate) Swap(i, j int) {
   1.135 +	s[i], s[j] = s[j], s[i]
   1.136 +}
   1.137 +
   1.138 +// Less returns true if the item in position i should be sorted before the
   1.139 +// item in position j.
   1.140 +func (s ByLastChargeDate) Less(i, j int) bool {
   1.141 +	return s[i].LastCharged.Before(s[j].LastCharged)
   1.142 +}
   1.143 +
   1.144 +type subscriptionStore interface {
   1.145 +	reset() error
   1.146 +	createSubscription(sub Subscription) error
   1.147 +	updateSubscription(id uuid.ID, change SubscriptionChange) error
   1.148 +	deleteSubscription(id uuid.ID) error
   1.149 +	listSubscriptionsLastChargedBefore(time.Time) ([]Subscription, error)
   1.150 +	getSubscriptions(ids []uuid.ID) (map[string]Subscription, error)
   1.151 +	getSubscriptionByUser(id uuid.ID) (Subscription, error)
   1.152 +}