Reapply "feat(loyalty): EnakPoint & EnakCoin" (#32)

This reverts commit 4e24f9bbb0.

internal/models/wallet_trace.go

@@ -0,0 +1,46 @@
+package models
+
+import (
+	"time"
+
+	"github.com/google/uuid"
+)
+
+// AdminWalletTrace is GET /marketing/wallet-transactions/:id/trace
+// (docs/prd-point-coin.md F7, §8.1): the lots a ledger row took from or created, and
+// where each of them came from, lot by lot, back to the lot that first brought the
+// balance into a wallet. It follows balance across transfers, exchanges and refunds.
+type AdminWalletTrace struct {
+	Transaction AdminWalletTraceRow `json:"transaction"`
+	// One per lot the row took from (a debit) or created (a credit).
+	Lots []AdminWalletTraceLot `json:"lots"`
+}
+
+// AdminWalletTraceLot is how much of a row went through one lot, and that lot's chain.
+type AdminWalletTraceLot struct {
+	Amount int64 `json:"amount"`
+	// The lot itself first, then the lot it was carried over from, and so on. The
+	// last step is the lot an EARN, ADJUSTMENT or MIGRATION created.
+	Chain []AdminWalletTraceStep `json:"chain"`
+}
+
+// AdminWalletTraceStep is one lot on a chain and the row that created it.
+type AdminWalletTraceStep struct {
+	Lot    AdminWalletLot      `json:"lot"`
+	Source AdminWalletTraceRow `json:"source"`
+}
+
+// AdminWalletTraceRow is a ledger row as a trace shows it, with the real name of the
+// customer it belongs to.
+type AdminWalletTraceRow struct {
+	ID            uuid.UUID           `json:"id"`
+	Customer      AdminWalletNamedRef `json:"customer"`
+	Currency      string              `json:"currency"`
+	Type          string              `json:"type"`
+	Amount        int64               `json:"amount"`
+	Description   string              `json:"description"`
+	ReferenceType string              `json:"reference_type"`
+	ReferenceID   uuid.UUID           `json:"reference_id"`
+	OutletID      *uuid.UUID          `json:"outlet_id,omitempty"`
+	CreatedAt     time.Time           `json:"created_at"`
+}