// BudgetPage — what the page does with the grid's target (#400).
//
// A static render runs no effect, so the grid never reports there. React's
// `useState` is stubbed (technique of AppShell.slot.test.tsx): the page runs
// as a plain function, its state survives from one call to the next as
// between two renders of a mounted component, and its setters keep their
// identity as React's do. The test plays the grid by calling the callback the
// page hands it, then reads what the page hands the card and the grid.
import { describe, it, expect, vi, beforeEach } from "vitest";
import { isValidElement, type ReactElement, type ReactNode } from "react";

const harness = vi.hoisted(() => ({
  slots: [] as unknown[],
  setters: [] as Array<(next: unknown) => void>,
  cursor: 0,
  pathname: "/budget",
  onboarding: null as unknown,
  budget: null as unknown,
}));

vi.mock("react", async (importOriginal) => {
  const actual = await importOriginal<typeof import("react")>();
  return {
    ...actual,
    useState: (init: unknown) => {
      const index = harness.cursor++;
      if (!(index in harness.slots)) {
        harness.slots[index] = typeof init === "function" ? (init as () => unknown)() : init;
      }
      harness.setters[index] ??= (next: unknown) => {
        harness.slots[index] =
          typeof next === "function" ? (next as (previous: unknown) => unknown)(harness.slots[index]) : next;
      };
      return [harness.slots[index], harness.setters[index]];
    },
  };
});
vi.mock("react-router-dom", async (importOriginal) => ({
  ...(await importOriginal<typeof import("react-router-dom")>()),
  useLocation: () => ({ pathname: harness.pathname }),
}));
vi.mock("react-i18next", () => ({
  useTranslation: () => ({ t: (k: string) => `t(${k})`, i18n: { language: "fr" } }),
}));
// The page's modules pull the database: stub the connection.
vi.mock("../services/db", () => ({ getDb: vi.fn(), withTransaction: vi.fn() }));
vi.mock("../contexts/OnboardingContext", () => ({ useOnboarding: () => harness.onboarding }));
vi.mock("../hooks/useReportsPeriod", () => ({
  useReportsPeriod: () => ({ accountIds: [], setAccountIds: () => undefined }),
}));
vi.mock("../hooks/useBudget", async (importOriginal) => ({
  ...(await importOriginal<typeof import("../hooks/useBudget")>()),
  useBudget: () => harness.budget,
}));

import BudgetPage from "./BudgetPage";
import BudgetTable from "../components/budget/BudgetTable";
import OnboardingStepCard from "../components/onboarding/OnboardingStepCard";
import { initialBudgetState, type BudgetState } from "../hooks/useBudget";
import type { OnboardingValue } from "../hooks/useOnboardingChecklist";
import { computeChecklist } from "../utils/onboardingChecklist";
import { budgetCardModel, nextStep, type BudgetCardModel } from "../utils/onboardingPath";
import type { BudgetOnboardingTargetKind, OnboardingCounters } from "../shared/types";

type AnyElement = ReactElement<Record<string, unknown> & { children?: ReactNode }>;

function find(node: ReactNode, pred: (el: AnyElement) => boolean): AnyElement[] {
  if (Array.isArray(node)) return node.flatMap((n) => find(n, pred));
  if (!isValidElement(node)) return [];
  const el = node as AnyElement;
  return [...(pred(el) ? [el] : []), ...find(el.props.children, pred)];
}

/** Steps 2 to 5 done: the next step is the budget. */
const BUDGET_LEFT: OnboardingCounters = {
  sources: 1,
  imports: 1,
  manualCategorized: 1,
  budgetEntries: 0,
  transactions: 41,
};

/** The path latched on /budget (card mode), as the provider shares it. */
function path(counters: OnboardingCounters, overrides: Partial<OnboardingValue> = {}): OnboardingValue {
  const checklist = computeChecklist(counters, { importFolderSet: true, budgetAllowed: true });
  return {
    status: "ready",
    checklist,
    counters,
    hidden: false,
    budgetReady: true,
    nextStep: nextStep(checklist),
    mode: "card",
    cardPage: "/budget",
    hide: vi.fn(async () => undefined),
    show: vi.fn(async () => undefined),
    skip: vi.fn(async () => undefined),
    resume: vi.fn(async () => undefined),
    refresh: vi.fn(async () => undefined),
    ...overrides,
  };
}

/** One render of the mounted page: its hooks are read in the same order each time. */
function render() {
  harness.cursor = 0;
  const page = BudgetPage() as AnyElement;
  const [card] = find(page, (el) => el.type === OnboardingStepCard);
  const [grid] = find(page, (el) => el.type === BudgetTable);
  return {
    page,
    model: card.props.model as BudgetCardModel,
    highlight: grid.props.onboardingTarget as boolean,
    report: grid.props.onOnboardingTargetChange as (kind: BudgetOnboardingTargetKind | null) => void,
  };
}

beforeEach(() => {
  harness.slots = [];
  harness.setters = [];
  harness.pathname = "/budget";
  harness.onboarding = path(BUDGET_LEFT);
  const state: BudgetState = { ...initialBudgetState(), totalInDb: 41 };
  harness.budget = new Proxy({ state } as Record<string, unknown>, {
    get: (target, key) => (key in target ? target[key as string] : vi.fn()),
  });
});

describe("BudgetPage — the grid's target and the card (#400)", () => {
  it("renders the card as the page's first child, ahead of its heading", () => {
    const { page } = render();
    const children = page.props.children as ReactNode[];
    expect((children[0] as AnyElement).type).toBe(OnboardingStepCard);
    expect(find(children[0], (el) => el.type === "h1")).toHaveLength(0);
    expect(find(children.slice(1), (el) => el.type === "h1")).toHaveLength(1);
  });

  it("follows what the grid reports: its sentence, and the ring once a target is known", () => {
    const checklist = (harness.onboarding as OnboardingValue).checklist;
    let view = render();
    expect(view.model).toEqual(budgetCardModel({ target: null }, checklist));
    expect(view.highlight).toBe(false);

    view.report("expandAll");
    view = render();
    expect(view.model.text?.key).toBe("onboarding.card.budget.collapsed");
    expect(view.highlight).toBe(true);

    view.report("cell");
    view = render();
    expect(view.model.text?.key).toBe("onboarding.card.budget.flat");
    expect(view.highlight).toBe(true);

    view.report(null);
    view = render();
    expect(view.model.text).toBeNull();
    expect(view.highlight).toBe(false);
  });

  it("asks for no ring while the card is not on screen", () => {
    for (const overrides of [
      { mode: "banner" as const, cardPage: null },
      { mode: "none" as const, cardPage: null },
      { mode: "complete" as const, cardPage: null },
      { mode: "card" as const, cardPage: "/transactions" },
    ]) {
      harness.slots = [];
      harness.setters = [];
      harness.onboarding = path(BUDGET_LEFT, overrides);
      render().report("cell");
      expect(render().highlight, JSON.stringify(overrides)).toBe(false);
    }
  });

  it("asks for no ring once the step is checked: the card says 'Done.'", () => {
    harness.onboarding = path({ ...BUDGET_LEFT, budgetEntries: 1 });
    render().report("cell");
    const view = render();
    expect(view.model).toEqual({ text: null, done: true, target: null });
    expect(view.highlight).toBe(false);
  });

  it("hands the grid the same callback at every render, so the grid does not report at every render", () => {
    expect(render().report).toBe(render().report);
  });
});