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

This reverts commit 4e24f9bbb0.

internal/entities/campaign.go

@@ -12,10 +12,31 @@ type CampaignType string
 const (
 	CampaignTypeReward CampaignType = "REWARD"
 	CampaignTypePoints CampaignType = "POINTS"
-	CampaignTypeTokens CampaignType = "TOKENS"
+	CampaignTypeCoins  CampaignType = "COINS"
 	CampaignTypeMixed  CampaignType = "MIXED"
 )
 
+// legacyCampaignTokens is what COINS was called before tokens became EnakCoin
+// (docs/prd-point-coin.md §10). Requests may still send it; it is stored as COINS.
+const legacyCampaignTokens = "TOKENS"
+
+// NormalizeCampaignType maps the legacy TOKENS to COINS and leaves anything else as is.
+func NormalizeCampaignType(t string) CampaignType {
+	if t == legacyCampaignTokens {
+		return CampaignTypeCoins
+	}
+	return CampaignType(t)
+}
+
+// NormalizeCampaignRewardType maps the legacy TOKENS to COINS and leaves anything
+// else as is.
+func NormalizeCampaignRewardType(t string) CampaignRewardType {
+	if t == legacyCampaignTokens {
+		return CampaignRewardTypeCoins
+	}
+	return CampaignRewardType(t)
+}
+
 type RuleType string
 
 const (
@@ -31,7 +52,7 @@ type CampaignRewardType string
 
 const (
 	CampaignRewardTypePoints CampaignRewardType = "POINTS"
-	CampaignRewardTypeTokens CampaignRewardType = "TOKENS"
+	CampaignRewardTypeCoins  CampaignRewardType = "COINS"
 	CampaignRewardTypeReward CampaignRewardType = "REWARD"
 )