import { createHash } from "node:crypto";

import { createCanvas } from "@napi-rs/canvas";
import { describe, expect, it } from "vitest";

import {
  createPdfVisualDiffReport,
  renderPdfVisualDiffHtml,
  serializePdfVisualDiffJson,
  type PdfDocumentSnapshot,
  type PdfPageRaster,
} from "../src/index.js";

function raster(color: string): PdfPageRaster {
  const canvas = createCanvas(40, 50);
  const context = canvas.getContext("2d");
  context.fillStyle = "#ffffff";
  context.fillRect(0, 0, 40, 50);
  context.fillStyle = color;
  context.fillRect(10, 10, 20, 20);
  const png = Uint8Array.from(canvas.toBuffer("image/png"));
  return {
    widthPx: 40,
    heightPx: 50,
    dpi: 144,
    sha256: createHash("sha256").update(png).digest("hex"),
    png,
  };
}

function snapshot(label: string, pageRaster: PdfPageRaster): PdfDocumentSnapshot {
  return {
    schemaVersion: 1,
    source: { kind: "custom", label },
    sha256: "a".repeat(64),
    pageCount: 1,
    contentText: "相同正文",
    pages: [
      {
        pageNumber: 1,
        widthPt: 20,
        heightPt: 25,
        rotation: 0,
        items: [],
        lines: [],
        contentText: "相同正文",
        raster: pageRaster,
      },
    ],
  };
}

describe("PDF 视觉差异报告", () => {
  it("汇总栅格门禁并生成内嵌图片的安全 HTML", async () => {
    const report = await createPdfVisualDiffReport(
      snapshot("<基线>", raster("#111111")),
      snapshot("候选", raster("#cc0000")),
      { generatedAt: "2026-07-31T00:00:00.000Z" },
    );
    const html = renderPdfVisualDiffHtml(report);
    expect(report.status).toBe("failed");
    expect(html).toContain("&lt;基线&gt;");
    expect(html).toContain("data:image/png;base64,");
    expect(html).toContain("差异热力图");
    expect(html).not.toContain("<基线>");
  });

  it("JSON 只保留图片字节数和稳定摘要", async () => {
    const page = raster("#111111");
    const report = await createPdfVisualDiffReport(
      snapshot("基线", page),
      snapshot("候选", page),
    );
    const json = serializePdfVisualDiffJson(report);
    expect(json).toContain('"overlaySha256"');
    expect(json).toContain('"byteLength"');
    expect(json).not.toContain('"0": 137');
  });

  it("在报告中展示未配对的溢出页面", async () => {
    const baseline = snapshot("基线", raster("#111111"));
    const candidatePage = snapshot("候选", raster("#111111"));
    const candidate: PdfDocumentSnapshot = {
      ...candidatePage,
      pageCount: 2,
      pages: [
        candidatePage.pages[0]!,
        {
          ...candidatePage.pages[0]!,
          pageNumber: 2,
        },
      ],
    };
    const report = await createPdfVisualDiffReport(baseline, candidate);
    const overflow = report.pages[1];
    expect(overflow?.pair.status).toBe("candidate-only");
    expect(overflow?.unpairedPng?.byteLength).toBeGreaterThan(0);
    expect(renderPdfVisualDiffHtml(report)).toContain("未配对页面");
  });
});