import * as assert from "assert";
import * as fs from "fs";
import * as path from "path";
import * as vscode from "vscode";
import type { CowritingApi } from "../../../src/extension";
import type { Artifact } from "../../../src/model";

const WS = process.env.E2E_WORKSPACE!;
const DOC_REL = "docs/sample.md";

function sidecarPath(): string {
  return path.join(WS, ".threads", "docs", "sample.md.json");
}
function readSidecar(): Artifact {
  return JSON.parse(fs.readFileSync(sidecarPath(), "utf8")) as Artifact;
}
async function openSample(): Promise<vscode.TextDocument> {
  const uri = vscode.Uri.file(path.join(WS, DOC_REL));
  const doc = await vscode.workspace.openTextDocument(uri);
  await vscode.window.showTextDocument(doc);
  return doc;
}

// Simulate an EXTERNAL change to the document (e.g. a git pull): write the file
// on disk, then force the open editor buffer to reload from disk with `revert`
// (openTextDocument otherwise returns VS Code's cached in-memory buffer).
async function externalWriteAndReload(uri: vscode.Uri, content: string): Promise<vscode.TextDocument> {
  fs.writeFileSync(uri.fsPath, content, "utf8");
  const doc = await vscode.workspace.openTextDocument(uri);
  await vscode.window.showTextDocument(doc);
  await vscode.commands.executeCommand("workbench.action.files.revert");
  return doc;
}
async function getApi(): Promise<CowritingApi> {
  const ext = vscode.extensions.getExtension("benstull.vscode-cowriting-plugin")!;
  const api = (await ext.activate()) as CowritingApi;
  assert.ok(api?.threadController, "extension should export threadController");
  return api;
}

// Reaches the controller's internal docs map for reply/resolve handlers (which
// expect a live vscode.CommentThread). Spec §6.8 "drive the ThreadController and
// assert Comments-controller state" fallback.
function findVsThread(api: CowritingApi, threadId: string): vscode.CommentThread {
  const rendered = api.threadController.getRendered(DOC_REL);
  assert.ok(rendered.some((r) => r.id === threadId), "thread is rendered");
  return (
    api.threadController as unknown as {
      docs: Map<string, { vsThreads: Map<string, vscode.CommentThread> }>;
    }
  ).docs
    .get(DOC_REL)!
    .vsThreads.get(threadId)!;
}
function setStatusViaApi(api: CowritingApi, threadId: string, status: "open" | "resolved"): void {
  const vsThread = findVsThread(api, threadId);
  void vscode.commands.executeCommand(
    status === "resolved" ? "cowriting.resolveThread" : "cowriting.reopenThread",
    vsThread,
  );
}

suite("F2 region-anchored threads (host E2E)", () => {
  test("create on selection persists a thread sidecar", async () => {
    const doc = await openSample();
    const api = await getApi();
    const start = doc.getText().indexOf("quick brown fox");
    const editor = vscode.window.activeTextEditor!;
    editor.selection = new vscode.Selection(doc.positionAt(start), doc.positionAt(start + "quick brown fox".length));

    const threadId = await api.threadController.createThreadOnSelection("First note");
    assert.ok(threadId, "createThreadOnSelection returns an id");
    assert.ok(fs.existsSync(sidecarPath()), "sidecar written to disk");

    const art = readSidecar();
    assert.strictEqual(art.threads.length, 1);
    assert.strictEqual(art.threads[0].status, "open");
    assert.strictEqual(art.threads[0].messages[0].body, "First note");
    const anchorId = art.threads[0].anchorId;
    assert.strictEqual(art.anchors[anchorId].fingerprint.text, "quick brown fox");

    const rendered = api.threadController.getRendered(DOC_REL);
    assert.strictEqual(rendered.length, 1);
    assert.strictEqual(rendered[0].orphaned, false);
  });

  test("reply appends and resolve flips status, both persisted", async () => {
    const api = await getApi();
    const art0 = readSidecar();
    const threadId = art0.threads[0].id;

    api.threadController.reply({ thread: findVsThread(api, threadId), text: "A reply" } as vscode.CommentReply);
    const art1 = readSidecar();
    assert.deepStrictEqual(
      art1.threads[0].messages.map((m) => m.body),
      ["First note", "A reply"],
    );

    setStatusViaApi(api, threadId, "resolved");
    const art2 = readSidecar();
    assert.strictEqual(art2.threads[0].status, "resolved");
  });

  test("reload renders the persisted thread at its anchor", async () => {
    const doc = await openSample();
    const api = await getApi();
    api.threadController.renderAll(doc);
    const rendered = api.threadController.getRendered(DOC_REL);
    assert.strictEqual(rendered.length, 1);
    assert.strictEqual(rendered[0].orphaned, false);
    const anchorLine = doc.positionAt(doc.getText().indexOf("quick brown fox")).line;
    assert.strictEqual(rendered[0].range.startLine, anchorLine);
  });

  test("external edit that moves the text re-anchors; deleting it orphans (INV-1)", async () => {
    const uri = vscode.Uri.file(path.join(WS, DOC_REL));
    const original = fs.readFileSync(uri.fsPath, "utf8");

    // Move the anchored text down by prepending lines (external change).
    let doc = await externalWriteAndReload(uri, "PREPENDED LINE ONE\nPREPENDED LINE TWO\n" + original);
    const api = await getApi();
    api.threadController.renderAll(doc);
    let rendered = api.threadController.getRendered(DOC_REL);
    assert.strictEqual(rendered[0].orphaned, false, "still anchored after a move");
    const movedLine = doc.positionAt(doc.getText().indexOf("quick brown fox")).line;
    assert.strictEqual(movedLine, 4, "fox moved from line 2 to line 4 after prepending two lines");
    assert.strictEqual(rendered[0].range.startLine, movedLine);

    // Now delete the anchored text entirely → must orphan, not move.
    const deleted =
      "PREPENDED LINE ONE\nThe slow grey cat\n" +
      original.replace("The quick brown fox jumps over the lazy dog.", "The slow grey cat naps.");
    doc = await externalWriteAndReload(uri, deleted);
    assert.strictEqual(doc.getText().includes("quick brown fox"), false, "anchored text is gone from the buffer");
    api.threadController.renderAll(doc);
    rendered = api.threadController.getRendered(DOC_REL);
    assert.strictEqual(rendered[0].orphaned, true, "deleted anchor must orphan (INV-1)");
  });
});