import { afterEach, describe, expect, it, vi } from "vitest";
import {
  formatLowStockText,
  initLowStockText,
  resolveLowStockCount,
  updateLowStockTextForForm,
  type LowStockSettings,
} from "./lowStockText";

const base: LowStockSettings = {
  enabled: true,
  format: "Only {qty} left",
  hideOnBackorder: true,
};

afterEach(() => {
  vi.useRealTimers();
  document.body.innerHTML = "";
  delete (globalThis as { b3WvsData?: unknown }).b3WvsData;
  delete (window as unknown as { jQuery?: unknown }).jQuery;
});

describe("resolveLowStockCount", () => {
  it("returns the count when enabled and stock is low", () => {
    expect(resolveLowStockCount({ b3wvs_low_stock: 3 }, base)).toBe(3);
  });

  it("returns null when disabled, absent, zero, or false", () => {
    expect(
      resolveLowStockCount({ b3wvs_low_stock: 3 }, { ...base, enabled: false }),
    ).toBeNull();
    expect(resolveLowStockCount({ b3wvs_low_stock: false }, base)).toBeNull();
    expect(resolveLowStockCount({ b3wvs_low_stock: 0 }, base)).toBeNull();
    expect(resolveLowStockCount(undefined, base)).toBeNull();
  });

  it("hides backorderable variations using WooCommerce's native backorders_allowed flag", () => {
    // Shape of a real Woo 11.x get_available_variation() payload: no is_on_backorder key.
    const native = { b3wvs_low_stock: 2, backorders_allowed: true };
    expect(resolveLowStockCount(native, base)).toBeNull();
    expect(
      resolveLowStockCount(native, { ...base, hideOnBackorder: false }),
    ).toBe(2);
  });

  it("still honors the legacy is_on_backorder flag", () => {
    const legacy = { b3wvs_low_stock: 2, is_on_backorder: true };
    expect(resolveLowStockCount(legacy, base)).toBeNull();
    expect(
      resolveLowStockCount(legacy, { ...base, hideOnBackorder: false }),
    ).toBe(2);
  });

  it("shows the text when backorders are not allowed, in every serialized false shape", () => {
    for (const falsy of [false, "false", "0", 0, "", null, undefined]) {
      expect(
        resolveLowStockCount(
          {
            b3wvs_low_stock: 2,
            backorders_allowed: falsy as boolean | string | number,
          },
          base,
        ),
      ).toBe(2);
      expect(
        resolveLowStockCount(
          {
            b3wvs_low_stock: 2,
            is_on_backorder: falsy as boolean | string | number,
          },
          base,
        ),
      ).toBe(2);
    }
  });

  it("treats serialized true shapes as on backorder", () => {
    for (const truthy of [true, "true", "1", 1]) {
      expect(
        resolveLowStockCount(
          {
            b3wvs_low_stock: 2,
            backorders_allowed: truthy as boolean | string | number,
          },
          base,
        ),
      ).toBeNull();
    }
  });
});

describe("formatLowStockText", () => {
  it("substitutes every {qty} placeholder", () => {
    expect(formatLowStockText("Only {qty} left", 4)).toBe("Only 4 left");
    expect(formatLowStockText("{qty} left ({qty})", 1)).toBe("1 left (1)");
  });

  it("falls back to the default when the placeholder is missing", () => {
    expect(formatLowStockText("bad format", 5)).toBe("Only 5 left");
  });
});

describe("low-stock live region", () => {
  it("reads the variation from jQuery's second callback argument", () => {
    (globalThis as { b3WvsData?: unknown }).b3WvsData = {
      settings: { low_stock_text_enabled: true },
    };
    document.body.innerHTML = `
      <form class="variations_form"><div class="single_variation_wrap"></div></form>
    `;
    const form = document.querySelector<HTMLElement>("form")!;
    let foundHandler: ((this: HTMLElement, ...args: unknown[]) => void) | null =
      null;
    const on = vi.fn(
      (
        events: string,
        _selector: string,
        handler: (this: HTMLElement, ...args: unknown[]) => void,
      ) => {
        if (events === "found_variation") foundHandler = handler;
      },
    );
    (window as unknown as { jQuery?: unknown }).jQuery = () => ({ on });

    initLowStockText();
    expect(foundHandler).not.toBeNull();
    (foundHandler as unknown as Function).call(
      form,
      { type: "found_variation" },
      { b3wvs_low_stock: 3 },
    );

    expect(form.querySelector("[role=status]")?.textContent).toBe(
      "Only 3 left",
    );
  });

  it("mounts in the stable variation wrapper before announcing its first value", () => {
    vi.useFakeTimers();
    (globalThis as { b3WvsData?: unknown }).b3WvsData = {
      settings: {
        low_stock_text_enabled: true,
        low_stock_text_format: "Only {qty} left",
      },
    };
    document.body.innerHTML = `
      <form class="variations_form">
        <div class="single_variation_wrap">
          <div class="single_variation"></div>
        </div>
      </form>
    `;
    const form = document.querySelector<HTMLElement>("form")!;

    updateLowStockTextForForm(form, { b3wvs_low_stock: 2 });

    const region = form.querySelector<HTMLElement>("[role=status]")!;
    expect(
      region.parentElement?.classList.contains("single_variation_wrap"),
    ).toBe(true);
    expect(region.textContent).toBe("");

    vi.runAllTimers();
    expect(region.textContent).toBe("Only 2 left");

    form.querySelector(".single_variation")?.remove();
    updateLowStockTextForForm(form, { b3wvs_low_stock: 1 });
    expect(region.isConnected).toBe(true);
    expect(region.textContent).toBe("Only 1 left");
  });
});