/**
 * Search-box.ai
 * Author: Simon-Pierre Boucher
 * Contact: contact@spboucher.ai
 * File: packages/shared/src/budgets.ts
 * Description: Hard safety budgets for a research session.
 */

import { z } from "zod";

export const BudgetsSchema = z.object({
  maxSearches: z.number().int().positive().default(12),
  maxScrapes: z.number().int().positive().default(16),
  maxToolCalls: z.number().int().positive().default(60),
  maxModelTurns: z.number().int().positive().default(40),
  deadlineMs: z.number().int().positive().default(8 * 60 * 1000)
});

export type Budgets = z.infer<typeof BudgetsSchema>;

export const DEFAULT_BUDGETS: Budgets = BudgetsSchema.parse({});

export interface BudgetUsage {
  searches: number;
  scrapes: number;
  toolCalls: number;
  modelTurns: number;
  startedAt: number;
}

export function newBudgetUsage(): BudgetUsage {
  return { searches: 0, scrapes: 0, toolCalls: 0, modelTurns: 0, startedAt: Date.now() };
}

/** Returns a human-readable reason when a budget is exhausted, else null. */
export function budgetExceeded(b: Budgets, u: BudgetUsage): string | null {
  if (u.searches >= b.maxSearches) return "search budget exhausted";
  if (u.scrapes >= b.maxScrapes) return "scrape budget exhausted";
  if (u.toolCalls >= b.maxToolCalls) return "tool-call budget exhausted";
  if (u.modelTurns >= b.maxModelTurns) return "model-turn budget exhausted";
  if (Date.now() - u.startedAt >= b.deadlineMs) return "deadline reached";
  return null;
}