Seed provenance + inventory: source links and seed lots (#50) (#64)

Co-authored-by: Steve Dudenhoeffer <[email protected]>

internal/domain/domain.go

@@ -109,6 +109,14 @@ const (
 	OpCreate = "create"
 	OpUpdate = "update"
 	OpDelete = "delete"
+
+	// Units a seed lot's quantity can be counted in (mirrors the schema CHECK).
+	UnitSeeds   = "seeds"
+	UnitGrams   = "grams"
+	UnitOunces  = "ounces"
+	UnitPackets = "packets"
+	UnitBulbs   = "bulbs"
+	UnitPlants  = "plants"
 )
 
 // ChangeSet groups the revisions produced by one logical operation — the unit of
@@ -280,6 +288,11 @@ type GardenObject struct {
 }
 
 // Plant is a catalog entry. OwnerID nil means a read-only seeded built-in.
+//
+// SourceURL/Vendor are provenance for the variety itself — the page you'd go
+// back to in order to buy it again. What you actually bought, and how much is
+// left, lives in SeedLot instead: the same variety may come from two vendors in
+// two years, and a single pair of columns here would collapse that.
 type Plant struct {
 	ID             int64   `json:"id"`
 	OwnerID        *int64  `json:"ownerId,omitempty"` // nil = built-in
@@ -289,12 +302,44 @@ type Plant struct {
 	Color          string  `json:"color"`
 	Icon           string  `json:"icon"`
 	DaysToMaturity *int    `json:"daysToMaturity,omitempty"`
+	SourceURL      string  `json:"sourceUrl"`
+	Vendor         string  `json:"vendor"`
 	Notes          string  `json:"notes"`
 	Version        int64   `json:"version"`
 	CreatedAt      string  `json:"createdAt"`
 	UpdatedAt      string  `json:"updatedAt"`
 }
 
+// SeedLot is one purchase: a specific packet of a specific variety, from a
+// specific vendor, in a specific year. Owned by the buyer even when it points at
+// a built-in plant, and never shared along with a garden.
+type SeedLot struct {
+	ID             int64    `json:"id"`
+	OwnerID        int64    `json:"ownerId"`
+	PlantID        int64    `json:"plantId"`
+	Vendor         string   `json:"vendor"`
+	SourceURL      string   `json:"sourceUrl"`
+	SKU            string   `json:"sku"`
+	LotCode        string   `json:"lotCode"`
+	PurchasedAt    *string  `json:"purchasedAt,omitempty"`
+	PackedForYear  *int     `json:"packedForYear,omitempty"`
+	Quantity       float64  `json:"quantity"`
+	Unit           string   `json:"unit"`
+	CostCents      *int     `json:"costCents,omitempty"`
+	GerminationPct *float64 `json:"germinationPct,omitempty"`
+	Notes          string   `json:"notes"`
+	Version        int64    `json:"version"`
+	CreatedAt      string   `json:"createdAt"`
+	UpdatedAt      string   `json:"updatedAt"`
+
+	// Used is the summed effective count of active plantings attributed to this
+	// lot, and Remaining is Quantity - Used. Both are computed by the service and
+	// never stored: a stored running total drifts the moment anything edits a
+	// planting behind its back, and can't be audited afterwards.
+	Used      float64 `json:"used"`
+	Remaining float64 `json:"remaining"`
+}
+
 // Planting ("plop") is a circular patch of one plant, positioned in its parent
 // object's local frame. Count nil means it is derived from area / spacing².
 type Planting struct {
@@ -308,9 +353,13 @@ type Planting struct {
 	Label     *string `json:"label,omitempty"`
 	PlantedAt *string `json:"plantedAt,omitempty"`
 	RemovedAt *string `json:"removedAt,omitempty"`
-	Version   int64   `json:"version"`
-	CreatedAt string  `json:"createdAt"`
-	UpdatedAt string  `json:"updatedAt"`
+	// SeedLotID attributes this planting to a purchase, so a lot can report what
+	// is left. Nullable: most plantings never name a lot, and retiring a lot sets
+	// this back to NULL rather than destroying planting history.
+	SeedLotID *int64 `json:"seedLotId,omitempty"`
+	Version   int64  `json:"version"`
+	CreatedAt string `json:"createdAt"`
+	UpdatedAt string `json:"updatedAt"`
 
 	// DerivedCount is the plant count implied by the plop's area and the plant's
 	// mature spacing: max(1, round(π·r² / spacing²)). It is computed by the