import fs from "node:fs";
import os from "node:os";
import path from "node:path";

import { afterEach, beforeEach, describe, expect, it } from "vitest";

import { buildMarkdown, formatDelta, formatKb, indexBaseline, readReport } from "./render-bundle-budget-comment.mjs";

let tmpDir;
beforeEach(() => {
  tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), "bundle-budget-render-"));
});
afterEach(() => {
  fs.rmSync(tmpDir, { recursive: true, force: true });
});

describe("formatKb", () => {
  it("formats bytes as KB to 1 decimal", () => {
    expect(formatKb(2048)).toBe("2.0 KB");
    expect(formatKb(1536)).toBe("1.5 KB");
  });
  it("returns dash for non-numeric", () => {
    expect(formatKb(undefined)).toBe("—");
  });
});

describe("formatDelta", () => {
  it("returns signed KB delta vs baseline", () => {
    expect(formatDelta(3000, 1000)).toBe("+2.0 KB");
    expect(formatDelta(1000, 3000)).toBe("-2.0 KB");
    expect(formatDelta(1000, 1000)).toBe("+0.0 KB");
  });
  it("returns dash when no baseline", () => {
    expect(formatDelta(1000, undefined)).toBe("—");
  });
});

describe("readReport", () => {
  it("returns null for missing path", () => {
    expect(readReport(path.join(tmpDir, "missing.json"))).toBeNull();
  });
  it("returns null for empty file", () => {
    const p = path.join(tmpDir, "empty.json");
    fs.writeFileSync(p, "");
    expect(readReport(p)).toBeNull();
  });
  it("parses valid json", () => {
    const p = path.join(tmpDir, "ok.json");
    fs.writeFileSync(p, JSON.stringify({ a: 1 }));
    expect(readReport(p)).toEqual({ a: 1 });
  });
});

describe("indexBaseline", () => {
  it("indexes by key", () => {
    const idx = indexBaseline({
      entries: [
        { key: "auth/login", gzipSize: 1000 },
        { key: "vendor-react", gzipSize: 200 },
      ],
    });
    expect(idx.get("auth/login")?.gzipSize).toBe(1000);
    expect(idx.get("vendor-react")?.gzipSize).toBe(200);
  });
  it("returns empty map for null", () => {
    expect(indexBaseline(null).size).toBe(0);
  });
});

describe("buildMarkdown", () => {
  it("includes marker for sticky-comment upsert", () => {
    const md = buildMarkdown({ skipped: true });
    expect(md).toContain("<!-- bundle-budget-report -->");
  });
  it("renders summary + per-asset table sorted by severity", () => {
    const current = {
      skipped: false,
      totals: { ok: 1, warning: 1, exceeds: 1, unbudgeted: 0 },
      entries: [
        { key: "auth/login", kind: "route", gzipSize: 50 * 1024, status: "ok", limitKb: 100 },
        { key: "app/$tenant/crm", kind: "route", gzipSize: 270 * 1024, status: "exceeds", limitKb: 250 },
        { key: "vendor-react", kind: "vendor", gzipSize: 140 * 1024, status: "warning", limitKb: 150 },
      ],
    };
    const baseline = {
      entries: [
        { key: "auth/login", gzipSize: 52 * 1024 },
        { key: "app/$tenant/crm", gzipSize: 260 * 1024 },
      ],
    };
    const md = buildMarkdown(current, baseline);
    expect(md).toContain("exceeds=1");
    expect(md).toContain("`app/$tenant/crm`");
    expect(md).toContain("[EXCEED]");
    // exceeds row appears before warning row
    const exceedIdx = md.indexOf("[EXCEED]");
    const warnIdx = md.indexOf("[WARN]");
    expect(exceedIdx).toBeLessThan(warnIdx);
    // delta is rendered for matched key (current 270KB vs baseline 260KB)
    expect(md).toContain("+10.0 KB");
    // unmatched vendor-react has dash delta
    expect(md).toContain("| —");
  });
  it("handles a skipped current report gracefully", () => {
    const md = buildMarkdown({ skipped: true });
    expect(md).toContain("No bundle artifacts measured");
  });
});