/**
 * Round-trip tests for the spike's pure transformation layer.
 *
 * These tests are CE-WP-0002-T02's machine-verifiable evidence that the
 * adapter's data round-trip is lossless: a captured PDF selection becomes
 * a `Selector[]`, the `Selector[]` round-trips through JSON
 * (localStorage-equivalent), and the reconstructed PDF rect + page match
 * the original. The browser-side selection-capture path is exercised in
 * T09 against production code.
 */

import { describe, expect, it } from "vitest";
import {
  findPdfRectSelector,
  findTextQuoteSelector,
  selectorsFromPdfCapture,
  unionRect,
} from "./pdf-selector-math";
import type { PdfSelectionCapture } from "./types";
import type { NormalizedRect, Selector } from "@shared/selector";

const SAMPLE_CAPTURE: PdfSelectionCapture = {
  kind: "pdf",
  text: "Mitglied beim Lohnsteuerhilfeverein Vereinigte Lohnsteuerhilfe e.V.",
  page: 1,
  rects: [
    { x: 0.12, y: 0.34, width: 0.55, height: 0.02 },
    { x: 0.12, y: 0.37, width: 0.31, height: 0.02 },
  ],
  boundingRect: { x: 0.12, y: 0.34, width: 0.55, height: 0.05 },
};

describe("selectorsFromPdfCapture", () => {
  it("produces a TextQuoteSelector and PdfRectSelector from a normal capture", () => {
    const sels = selectorsFromPdfCapture(SAMPLE_CAPTURE);
    expect(sels.map((s) => s.type)).toEqual(["TextQuoteSelector", "PdfRectSelector"]);
  });

  it("includes the verbatim quote on the TextQuoteSelector", () => {
    const tq = findTextQuoteSelector(selectorsFromPdfCapture(SAMPLE_CAPTURE));
    expect(tq?.exact).toBe(SAMPLE_CAPTURE.text);
  });

  it("preserves page + rects 1:1 on the PdfRectSelector", () => {
    const rect = findPdfRectSelector(selectorsFromPdfCapture(SAMPLE_CAPTURE));
    expect(rect?.page).toBe(SAMPLE_CAPTURE.page);
    expect(rect?.rects).toEqual(SAMPLE_CAPTURE.rects);
  });

  it("omits TextQuoteSelector when text is empty", () => {
    const sels = selectorsFromPdfCapture({ ...SAMPLE_CAPTURE, text: "" });
    expect(sels.map((s) => s.type)).toEqual(["PdfRectSelector"]);
  });

  it("omits PdfRectSelector when no rects are present", () => {
    const sels = selectorsFromPdfCapture({ ...SAMPLE_CAPTURE, rects: [] });
    expect(sels.map((s) => s.type)).toEqual(["TextQuoteSelector"]);
  });
});

describe("Selector[] JSON round-trip", () => {
  it("survives JSON.stringify/parse without loss (the localStorage path)", () => {
    const original = selectorsFromPdfCapture(SAMPLE_CAPTURE);
    const blob = JSON.stringify(original);
    const restored = JSON.parse(blob) as Selector[];
    expect(restored).toEqual(original);
  });

  it("the restored PdfRectSelector still resolves to the same page and rects", () => {
    const restored = JSON.parse(JSON.stringify(selectorsFromPdfCapture(SAMPLE_CAPTURE))) as Selector[];
    const rect = findPdfRectSelector(restored);
    expect(rect).not.toBeNull();
    expect(rect?.page).toBe(SAMPLE_CAPTURE.page);
    expect(rect?.rects).toEqual(SAMPLE_CAPTURE.rects);
  });
});

describe("unionRect", () => {
  it("returns null for an empty input", () => {
    expect(unionRect([])).toBeNull();
  });

  it("returns the single rect when given exactly one", () => {
    const r: NormalizedRect = { x: 0.1, y: 0.2, width: 0.3, height: 0.4 };
    const u = unionRect([r]);
    expect(u).not.toBeNull();
    expect(u!.x).toBeCloseTo(r.x, 9);
    expect(u!.y).toBeCloseTo(r.y, 9);
    expect(u!.width).toBeCloseTo(r.width, 9);
    expect(u!.height).toBeCloseTo(r.height, 9);
  });

  it("computes the bounding box of multi-line text rects", () => {
    const u = unionRect(SAMPLE_CAPTURE.rects);
    expect(u).not.toBeNull();
    expect(u!.x).toBeCloseTo(0.12, 5);
    expect(u!.y).toBeCloseTo(0.34, 5);
    expect(u!.width).toBeCloseTo(0.55, 5);
    expect(u!.height).toBeCloseTo(0.05, 5);
  });

  it("is order-independent", () => {
    const reversed = [...SAMPLE_CAPTURE.rects].reverse();
    const forward = unionRect(SAMPLE_CAPTURE.rects)!;
    const back = unionRect(reversed)!;
    expect(back.x).toBeCloseTo(forward.x, 9);
    expect(back.y).toBeCloseTo(forward.y, 9);
    expect(back.width).toBeCloseTo(forward.width, 9);
    expect(back.height).toBeCloseTo(forward.height, 9);
  });
});