package database

import "gorm.io/gorm"

// DeliveryStatus represents the status of a delivery
type DeliveryStatus string

// Delivery status values.
const (
	DeliveryStatusPending   DeliveryStatus = "pending"
	DeliveryStatusDelivered DeliveryStatus = "delivered"
	DeliveryStatusFailed    DeliveryStatus = "failed"
	DeliveryStatusRetrying  DeliveryStatus = "retrying"
)

// Terminal reports whether a delivery in this status has finished, so
// the delivery engine will make no further attempt of its own.
//
// It is what decides which deliveries the event log offers to replay:
// a pending or retrying delivery is still the engine's, and replaying
// one would race it.
func (s DeliveryStatus) Terminal() bool {
	switch s {
	case DeliveryStatusDelivered, DeliveryStatusFailed:
		return true
	case DeliveryStatusPending, DeliveryStatusRetrying:
		return false
	default:
		return false
	}
}

// Delivery represents a delivery attempt for an event to a target
//
//nolint:lll // a struct tag cannot wrap
type Delivery struct {
	BaseModel

	EventID  string         `gorm:"type:uuid;not null;index:idx_deliveries_event_id,priority:1"       json:"eventId"`
	TargetID string         `gorm:"type:uuid;not null"                                                json:"targetId"`
	Status   DeliveryStatus `gorm:"not null;default:'pending';index:idx_deliveries_status,priority:1" json:"status"`

	// DeletedAt repeats the BaseModel field only to be the second column
	// of the event_id and status indexes, for the reason DeliveryResult
	// gives.
	DeletedAt gorm.DeletedAt `gorm:"index:idx_deliveries_event_id,priority:2;index:idx_deliveries_status,priority:2" json:"deletedAt,omitzero"`

	// Relations
	Event           Event            `json:"event,omitzero"`
	Target          Target           `json:"target,omitzero"`
	DeliveryResults []DeliveryResult `json:"deliveryResults,omitempty"`
}