import "server-only";

import { z } from "zod";

const featurePricingSchema = z.object({
  feature_key: z.string(),
  model_tier: z.enum(["standard", "premium", "internal"]),
  credit_cost: z.number().int().positive(),
  version: z.number().int().positive(),
});

type PricingClient = {
  rpc(rpcName: string, args: Record<string, unknown>): PromiseLike<{
    data: unknown;
    error: { message: string } | null;
  }>;
};

export class FeaturePricingError extends Error {
  readonly code: string;

  constructor(code: string) {
    super(`Feature pricing failed: ${code}`);
    this.name = "FeaturePricingError";
    this.code = code;
  }
}

export type FeaturePricing = z.infer<typeof featurePricingSchema>;

export async function resolveFeaturePricing(
  accounting: PricingClient,
  featureKey: FeaturePricing["feature_key"],
  modelId: string,
): Promise<FeaturePricing> {
  try {
    const { data, error } = await accounting.rpc("resolve_feature_pricing", {
      p_feature_key: featureKey,
      p_model_id: modelId,
    });
    const row = Array.isArray(data) ? data[0] : data;
    const parsed = featurePricingSchema.safeParse(row);
    if (error) throw new FeaturePricingError(error.message);
    if (!parsed.success) throw new FeaturePricingError("feature_pricing_invalid_response");
    return parsed.data;
  } catch (error) {
    if (error instanceof FeaturePricingError) throw error;
    throw new FeaturePricingError(error instanceof Error ? error.message : "feature_pricing_unavailable");
  }
}