weatherfeeder/model/alert.go

// FILE: model/alert.go
package model

import "time"

// WeatherAlertRun is a snapshot of *active* alerts for a location as-of a point in time.
//
// This mirrors WeatherForecastRun's "one issued snapshot -> many contained items" shape:
//
//   - A single run may contain zero, one, or many alerts.
//   - Runs are intended to be immutable snapshots (“provider asserted X at AsOf”).
//
// Normalizers should prefer to set AsOf from a provider-supplied “updated/generated” timestamp.
// If unavailable, AsOf may be set to the poll/emit time as a fallback.
type WeatherAlertRun struct {
	// Optional location metadata (provider-dependent).
	LocationID   string `json:"locationId,omitempty"`
	LocationName string `json:"locationName,omitempty"`

	// AsOf is when the provider asserted this alert snapshot is current (required).
	AsOf time.Time `json:"asOf"`

	// Optional spatial context.
	Latitude  *float64 `json:"latitude,omitempty"`
	Longitude *float64 `json:"longitude,omitempty"`

	// Active alerts contained in this snapshot (order is provider-dependent).
	Alerts []WeatherAlert `json:"alerts"`
}

// WeatherAlert is the canonical representation of a single alert.
//
// This is intentionally a “useful subset” of rich provider payloads.
// Normalizers may populate ProviderExtras for structured provider-specific fields
// that don’t cleanly fit the canonical shape.
type WeatherAlert struct {
	// Provider-stable identifier (often a URL/URI).
	ID string `json:"id"`

	// Classification / headline fields.
	Event    string `json:"event,omitempty"`
	Headline string `json:"headline,omitempty"`

	Severity  string `json:"severity,omitempty"`  // e.g. Extreme/Severe/Moderate/Minor/Unknown
	Urgency   string `json:"urgency,omitempty"`   // provider-defined urgency value
	Certainty string `json:"certainty,omitempty"` // e.g. Observed/Likely/Possible/Unlikely/Unknown

	Status      string `json:"status,omitempty"`      // e.g. Actual/Exercise/Test/System/Unknown
	MessageType string `json:"messageType,omitempty"` // e.g. Alert/Update/Cancel
	Category    string `json:"category,omitempty"`    // e.g. Met/Geo/Safety/Rescue/Fire/Health/Env/Transport/Infra/CBRNE/Other
	Response    string `json:"response,omitempty"`    // e.g. Shelter/Evacuate/Prepare/Execute/Avoid/Monitor/Assess/AllClear/None

	// Narrative.
	Description string `json:"description,omitempty"`
	Instruction string `json:"instruction,omitempty"`

	// Timing (all optional; provider-dependent).
	// Onset and Ends describe the alert period. Expires is provider expiration metadata.
	Sent      *time.Time `json:"sent,omitempty"`
	Effective *time.Time `json:"effective,omitempty"`
	Onset     *time.Time `json:"onset,omitempty"`
	Ends      *time.Time `json:"ends,omitempty"`
	Expires   *time.Time `json:"expires,omitempty"`

	// Scope / affected area.
	AreaDescription string `json:"areaDescription,omitempty"` // often a provider string

	// Provenance.
	SenderName string `json:"senderName,omitempty"`

	References []AlertReference `json:"references,omitempty"`
}

// AlertReference is a reference to a related alert (updates, replacements, etc.).
type AlertReference struct {
	ID         string     `json:"id,omitempty"`         // provider reference ID/URI
	Identifier string     `json:"identifier,omitempty"` // provider identifier string, if distinct
	Sender     string     `json:"sender,omitempty"`
	Sent       *time.Time `json:"sent,omitempty"`
}