import { describe, it, expect } from "vitest";
import { readFileSync } from "node:fs";
import { fileURLToPath } from "node:url";
import { loadConfig } from "./configLoader";
import { estimate } from "./engine";

// Read the actual shipped config that gets served at runtime.
const configPath = fileURLToPath(new URL("../public/config.json", import.meta.url));
const rawConfig = JSON.parse(readFileSync(configPath, "utf-8"));

describe("real config sanity", () => {
  const result = loadConfig(rawConfig);

  it("loads the shipped config without errors", () => {
    expect(result.ok).toBe(true);
  });

  it("produces sensible first-plan numbers partway through the term", () => {
    if (!result.ok) throw new Error("config failed to load");
    const config = result.config;
    const plan = config.plans[0];

    // Target a date roughly in the middle of the meal window.
    const midMs =
      (config.mealStartDate.getTime() + config.mealEndDate.getTime()) / 2;
    const midDate = new Date(midMs);

    const r = estimate(config, {
      selectedPlanId: plan.id,
      targetDate: midDate,
      activeMissingPeriodIds: new Set(),
      extraExcludedDays: 0,
      actualMealBlocks: null,
      actualFlexDollars: null,
    });

    // Per-week rate matches the plan total spread over the active days.
    expect(r.perWeekMealBlocks).toBeCloseTo(
      (plan.totalMealBlocks / r.totalActiveDays) * 7,
      2
    );
    // Consumed + remaining conserves the plan totals.
    expect(r.consumedMealBlocks + r.remainingMealBlocks).toBeCloseTo(
      plan.totalMealBlocks
    );
    expect(r.consumedFlexDollars + r.remainingFlexDollars).toBeCloseTo(
      plan.totalFlexDollars
    );
    // Partway through, consumption is strictly between 0 and the total.
    expect(r.consumedMealBlocks).toBeGreaterThan(0);
    expect(r.consumedMealBlocks).toBeLessThan(plan.totalMealBlocks);
  });

  it("checking a break reduces total active days", () => {
    if (!result.ok) throw new Error("config failed to load");
    const config = result.config;
    if (config.missingPeriods.length === 0) return; // nothing to check

    const plan = config.plans[0];
    const period = config.missingPeriods[0];
    const endDate = config.mealEndDate;

    const base = estimate(config, {
      selectedPlanId: plan.id,
      targetDate: endDate,
      activeMissingPeriodIds: new Set(),
      extraExcludedDays: 0,
      actualMealBlocks: null,
      actualFlexDollars: null,
    });
    const withBreak = estimate(config, {
      selectedPlanId: plan.id,
      targetDate: endDate,
      activeMissingPeriodIds: new Set([period.id]),
      extraExcludedDays: 0,
      actualMealBlocks: null,
      actualFlexDollars: null,
    });

    expect(withBreak.totalActiveDays).toBeLessThan(base.totalActiveDays);
    // Per-week rate rises because the same total spreads over fewer days.
    expect(withBreak.perWeekMealBlocks).toBeGreaterThan(base.perWeekMealBlocks);
  });
});