import { createHash } from "node:crypto";
import { ULTRAPI_VERSION } from "../config/defaults.js";
import { estimateCredits } from "../models/price-catalog.js";
import type { PriceCatalog, UltraConfig } from "../types.js";

/** Identity, provenance, and redaction helpers the controller stamps onto what it records. */

export function providerFailureStatus(error: string): number | undefined {
  if (/(rate.?limit|too many requests|\b429\b|overloaded)/i.test(error)) return 429;
  if (/(?:\b5\d\d\b|internal server|service unavailable|bad gateway|gateway timeout)/i.test(error)) return 500;
  return undefined;
}

export function redactLedgerValue<T>(value: T, redactions: readonly string[]): T {
  if (typeof value === "string") return redactions.reduce((text, raw) => raw ? text.replaceAll(raw, "<REDACTED>") : text, value) as T;
  if (Array.isArray(value)) return value.map((entry) => redactLedgerValue(entry, redactions)) as T;
  if (value && typeof value === "object") return Object.fromEntries(Object.entries(value).map(([key, entry]) => [key, redactLedgerValue(entry, redactions)])) as T;
  return value;
}

export function configFingerprint(config: UltraConfig): string {
  const { changeReason: _changeReason, createdAt: _createdAt, ...stable } = config as UltraConfig & { changeReason?: unknown; createdAt?: unknown };
  return createHash("sha256").update(JSON.stringify(stable)).digest("hex");
}

export function requestProvenance(config: UltraConfig, availableModels: readonly string[], priceCatalog: PriceCatalog) {
  return {
    configHash: configFingerprint(config),
    modelCatalogHash: createHash("sha256").update(JSON.stringify(availableModels)).digest("hex"),
    priceCatalogVersion: priceCatalog.version,
    piVersion: config.compatibility.piVersion,
    piAgentsVersion: config.compatibility.piAgentsVersion,
    ultraPiVersion: ULTRAPI_VERSION,
  };
}

export function expectedModelSavings(catalog: PriceCatalog, expensiveModel: string, cheapModel: string): number {
  if (!catalog.models[expensiveModel] || !catalog.models[cheapModel]) return 0;
  const expensive = estimateCredits(catalog, expensiveModel, 8_000, 0, 800);
  const cheap = estimateCredits(catalog, cheapModel, 8_000, 0, 800);
  return expensive > 0 ? Math.max(0, (expensive - cheap) / expensive) : 0;
}

export function sameJsonValue(left: unknown, right: unknown): boolean {
  if (left === right) return true;
  if (!left || !right || typeof left !== "object" || typeof right !== "object") return false;
  if (Array.isArray(left) || Array.isArray(right)) {
    return Array.isArray(left) && Array.isArray(right) && left.length === right.length && left.every((value, index) => sameJsonValue(value, right[index]));
  }
  const leftRecord = left as Record<string, unknown>;
  const rightRecord = right as Record<string, unknown>;
  const leftKeys = Object.keys(leftRecord);
  const rightKeys = Object.keys(rightRecord);
  return leftKeys.length === rightKeys.length && leftKeys.every((key) => Object.hasOwn(rightRecord, key) && sameJsonValue(leftRecord[key], rightRecord[key]));
}