feat: add billing and usage domain cores

backend/internal/postgres/billing.go

@@ -0,0 +1,68 @@
+package postgres
+
+import (
+	"context"
+	"database/sql"
+	"encoding/json"
+	"fmt"
+
+	"git.nianxx.cn/wangxuming/NianAIGC/backend/internal/billing"
+)
+
+const ListBillingPriceRulesSQL = `SELECT id, provider, capability, req_key, unit, standard_unit_price_fen, markup_multiplier, enabled, conditions, quantity_source, priority, parameter_dimensions
+FROM public.billing_price_rules
+WHERE ($1::boolean OR enabled = true)
+ORDER BY provider, capability, id`
+
+type BillingWalletPoster struct{ database *Database }
+
+func NewBillingWalletPoster(database *Database) BillingWalletPoster {
+	return BillingWalletPoster{database: database}
+}
+func (poster BillingWalletPoster) PostWalletEntry(ctx context.Context, p billing.WalletPostParams) (billing.WalletPosting, error) {
+	metadata, err := json.Marshal(p.Metadata)
+	if err != nil {
+		return billing.WalletPosting{}, fmt.Errorf("encode wallet metadata: %w", err)
+	}
+	row, err := poster.database.PostWalletEntry(ctx, WalletEntryParams{LedgerID: p.LedgerID, OrganizationID: p.OrganizationID, AccountID: p.AccountID, JobID: p.JobID, Kind: p.Kind, DeltaFen: p.DeltaFen, Currency: p.Currency, IdempotencyKey: p.IdempotencyKey, Description: p.Description, Metadata: metadata})
+	if err != nil {
+		return billing.WalletPosting{}, err
+	}
+	return billing.WalletPosting{LedgerID: row.LedgerID, BalanceAfterFen: row.BalanceAfterFen, BalanceFen: row.BalanceFen, TotalRechargedFen: row.TotalRechargedFen, TotalChargedFen: row.TotalChargedFen, CreatedAt: row.CreatedAt, UpdatedAt: row.UpdatedAt, DeltaFen: row.DeltaFen}, nil
+}
+
+func (db *Database) ListBillingPriceRules(ctx context.Context, includeDisabled bool) ([]billing.PriceRule, error) {
+	if db.config.Backend != BackendPostgres || db.querier == nil {
+		return nil, fmt.Errorf("PostgreSQL is unavailable when ZHINIAN_DATA_BACKEND=%s", db.config.Backend)
+	}
+	rows, err := db.querier.Query(ctx, ListBillingPriceRulesSQL, includeDisabled)
+	if err != nil {
+		return nil, fmt.Errorf("list billing price rules: %w", err)
+	}
+	defer rows.Close()
+	var out []billing.PriceRule
+	for rows.Next() {
+		var rule billing.PriceRule
+		var req, quantity sql.NullString
+		var conditions, dimensions json.RawMessage
+		if err := rows.Scan(&rule.ID, &rule.Provider, &rule.Capability, &req, &rule.Unit, &rule.StandardUnitPriceFen, &rule.MarkupMultiplier, &rule.Enabled, &conditions, &quantity, &rule.Priority, &dimensions); err != nil {
+			return nil, fmt.Errorf("scan billing price rule: %w", err)
+		}
+		rule.ReqKey = req.String
+		rule.QuantitySource = billing.QuantitySource(quantity.String)
+		if len(conditions) > 0 {
+			if err := json.Unmarshal(conditions, &rule.Conditions); err != nil {
+				return nil, fmt.Errorf("decode billing conditions: %w", err)
+			}
+		}
+		if len(dimensions) > 0 {
+			if err := json.Unmarshal(dimensions, &rule.Dimensions); err != nil {
+				return nil, fmt.Errorf("decode billing dimensions: %w", err)
+			}
+		}
+		out = append(out, rule)
+	}
+	return out, rows.Err()
+}
+
+var _ billing.WalletPoster = BillingWalletPoster{}