export const STORAGE_BUDGET_SCHEMA_VERSION = 1 as const;

export interface StorageBudgetBreakdown {
  schemaVersion: typeof STORAGE_BUDGET_SCHEMA_VERSION;
  projectId: string;
  projectBytes: number;
  snapshotBytes: number;
  lodBytes: number;
  mediaBytes: number;
  vdbBytes: number;
  totalBytes: number;
}

export function createStorageBudget(projectId: string, values: Partial<Omit<StorageBudgetBreakdown, "schemaVersion" | "projectId" | "totalBytes">> = {}): StorageBudgetBreakdown {
  const fields = ["projectBytes", "snapshotBytes", "lodBytes", "mediaBytes", "vdbBytes"] as const;
  const normalized = Object.fromEntries(fields.map((field) => {
    const value = values[field] ?? 0;
    if (!Number.isSafeInteger(value) || value < 0) throw new Error(`STORAGE_BUDGET_INVALID: ${field}`);
    return [field, value];
  })) as Pick<StorageBudgetBreakdown, typeof fields[number]>;
  const totalBytes = fields.reduce((total, field) => {
    const next = total + normalized[field];
    if (!Number.isSafeInteger(next)) throw new Error("STORAGE_BUDGET_INVALID: totalBytes");
    return next;
  }, 0);
  return { schemaVersion: STORAGE_BUDGET_SCHEMA_VERSION, projectId, ...normalized, totalBytes };
}

export function formatStorageBytes(bytes: number): string {
  if (!Number.isSafeInteger(bytes) || bytes < 0) throw new Error("STORAGE_BUDGET_INVALID: bytes");
  if (bytes < 1024) return `${bytes} B`;
  const units = ["KiB", "MiB", "GiB", "TiB"];
  let value = bytes;
  for (const unit of units) {
    value /= 1024;
    if (value < 1024 || unit === units[units.length - 1]) return `${value.toFixed(value >= 10 ? 0 : 1)} ${unit}`;
  }
  return `${bytes} B`;
}