WRNexusJS/packages/language-server/test/html-regions.test.ts

import { expect, test } from "bun:test";
import {
  clearHtmlRegionCache,
  isInsideHtml,
  viewRegions,
  virtualHtmlDocument,
} from "../src/html-regions.ts";

function doc(text: string): { uri: string; text: string; version?: number } {
  return { uri: `file:///${Math.random()}.wrn`, text };
}

const PAGE = `page Home {
  view {
    <div class="card">hello</div>
  }
}
`;

test("the virtual document preserves length and newline offsets", () => {
  // This is what makes position mapping unnecessary. If it breaks, every
  // feature reports positions off by some amount instead of failing loudly.
  const source = doc(PAGE);
  const virtual = virtualHtmlDocument(source);

  expect(virtual.text.length).toBe(source.text.length);
  expect(virtual.languageId).toBe("html");
  for (let i = 0; i < source.text.length; i += 1) {
    if (source.text[i] === "\n") expect(virtual.text[i]).toBe("\n");
  }
});

test("markup survives into the virtual document and everything else is blanked", () => {
  const virtual = virtualHtmlDocument(doc(PAGE));
  expect(virtual.text).toContain('<div class="card">hello</div>');
  expect(virtual.text).not.toContain("page Home");
  expect(virtual.text).not.toContain("view");
});

test("an apostrophe in text content does not swallow later regions", () => {
  // A scanner treating ' as a string delimiter anywhere considers the rest of
  // the file one open string and loses every later region.
  const source = `page A {
  view {
    <p>it's fine</p>
  }
}
component B {
  view {
    <span>second</span>
  }
}
`;
  expect(viewRegions(source)).toHaveLength(2);
  expect(virtualHtmlDocument(doc(source)).text).toContain("<span>second</span>");
});

test("interpolation braces nest without ending the region early", () => {
  const source = `page A {
  view {
    <div class={cond ? "a" : "b"} data-x={{ a: 1 }}>after</div>
  }
}
`;
  const regions = viewRegions(source);
  expect(regions).toHaveLength(1);
  expect(virtualHtmlDocument(doc(source)).text).toContain("after</div>");
});

test("unparseable mid-edit markup still yields a region", () => {
  // Completion fires exactly when the document does not parse.
  const source = `page A {
  view {
    <div class="
  }
}
`;
  expect(viewRegions(source).length).toBe(1);
});

test("a file with no view block yields no regions and a fully blank document", () => {
  const source = `page A {
  functions {
    function go() {}
  }
}
`;
  expect(viewRegions(source)).toEqual([]);
  expect(virtualHtmlDocument(doc(source)).text.trim()).toBe("");
});

test("regions are cached per document version", () => {
  // One keystroke fans out into completion, hover, and tag-close requests.
  const first = doc(PAGE);
  first.version = 1;
  expect(isInsideHtml(first, PAGE.indexOf("<div"))).toBe(true);

  // Same version, mutated text: the cached regions are reused, proving the
  // scan did not run again.
  first.text = "page A { }";
  expect(isInsideHtml(first, PAGE.indexOf("<div"))).toBe(true);

  first.version = 2;
  expect(isInsideHtml(first, PAGE.indexOf("<div"))).toBe(false);
});

test("clearHtmlRegionCache drops a closed document's cached regions", () => {
  // A reopened document commonly restarts at version 1. Without clearing the
  // cache on close, that version would match the stale entry from the prior
  // session and serve regions scanned from the old text.
  const first = doc(PAGE);
  first.version = 1;
  expect(isInsideHtml(first, PAGE.indexOf("<div"))).toBe(true);

  clearHtmlRegionCache(first.uri);

  // Same uri, same version 1, but a document with no view block at all: if
  // the cache had survived, this would still report true from the old scan.
  const reopened = { uri: first.uri, text: "page A { }", version: 1 };
  expect(isInsideHtml(reopened, PAGE.indexOf("<div"))).toBe(false);
});

test("isInsideHtml distinguishes markup from surrounding code", () => {
  const source = doc(PAGE);
  const markupOffset = PAGE.indexOf("<div");
  const keywordOffset = PAGE.indexOf("page");

  expect(isInsideHtml(source, markupOffset)).toBe(true);
  expect(isInsideHtml(source, keywordOffset)).toBe(false);
});

test("documents without a version field scan every time and detect mutations", () => {
  // Without a version, the cache has no key to validate freshness. Mutations
  // must be detected on every call, even when uri and document are reused.
  const source = doc(PAGE);
  // Explicitly verify version is undefined (not set by doc() helper).
  expect(source.version).toBeUndefined();

  const markupOffset = PAGE.indexOf("<div");
  expect(isInsideHtml(source, markupOffset)).toBe(true);

  // Mutate the text: remove the view block.
  source.text = "page A { }";
  // Same uri, same missing version, but different text: mutation must be detected.
  expect(isInsideHtml(source, markupOffset)).toBe(false);
});