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

const WS = process.env.E2E_WORKSPACE!;
const DOC_REL = "docs/preview.md";
const docUri = () => vscode.Uri.file(path.join(WS, DOC_REL)).toString();

async function openDoc(rel = DOC_REL): Promise<vscode.TextDocument> {
  const uri = vscode.Uri.file(path.join(WS, rel));
  const doc = await vscode.workspace.openTextDocument(uri);
  await vscode.window.showTextDocument(doc);
  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?.trackChangesPreviewController, "extension exports trackChangesPreviewController");
  return api;
}
const settle = () => new Promise((r) => setTimeout(r, 400));
const kinds = (api: CowritingApi) =>
  (api.trackChangesPreviewController.getLastModel(docUri()) ?? []).map((o) => o.kind);

// Order-dependent (F2–F6 pattern): later tests consume earlier state.
suite("F7 track-changes preview (host E2E — markdown only, programmatic seam, no LLM)", () => {
  const TARGET = "A target sentence Claude will rewrite via the seam.";
  const REPLACEMENT = "A SENTENCE CLAUDE REWROTE via the seam.";

  test("open on a markdown doc → panel open, opened baseline shows no changes (PUC-1)", async () => {
    const doc = await openDoc();
    const api = await getApi();
    assert.strictEqual(api.trackChangesPreviewController.isOpen(docUri()), false, "no panel yet");
    await vscode.commands.executeCommand("cowriting.showTrackChangesPreview");
    await settle();
    assert.strictEqual(api.trackChangesPreviewController.isOpen(docUri()), true, "panel open");
    const model = api.trackChangesPreviewController.getLastModel(docUri());
    assert.ok(model && model.length > 0, "a model was computed");
    assert.ok(
      model!.every((o) => o.kind === "unchanged"),
      "baseline == buffer at open → every block unchanged",
    );
    void doc;
  });

  test("typing produces a changed/added block (PUC-2)", async () => {
    const doc = await openDoc();
    const api = await getApi();
    const edit = new vscode.WorkspaceEdit();
    const end = doc.positionAt(doc.getText().length);
    edit.insert(doc.uri, end, "\n\nA freshly typed paragraph.\n");
    assert.ok(await vscode.workspace.applyEdit(edit), "operator edit applied");
    await settle();
    assert.ok(
      kinds(api).some((k) => k === "added" || k === "changed"),
      "an added/changed block appears after typing",
    );
  });

  test("accepting a proposal advances the baseline; the landed block goes unchanged (PUC-3, INV-18)", async () => {
    const doc = await openDoc();
    const api = await getApi();
    const start = doc.getText().indexOf(TARGET);
    assert.ok(start >= 0, "fixture contains the target sentence");
    const id = await vscode.commands.executeCommand<string>("cowriting.proposeAgentEdit", {
      uri: doc.uri.toString(),
      start,
      end: start + TARGET.length,
      newText: REPLACEMENT,
      model: "sonnet",
      sessionId: "e2e-f7",
      turnId: "turn-f7-1",
    });
    assert.ok(id, "propose returns an id");
    assert.ok(await api.proposalController.acceptById(DOC_REL, id!), "accept applies via the seam");
    await settle();
    // The baseline advanced to include REPLACEMENT, so the buffer == baseline for
    // that block → it is NOT marked. Confirm the replacement is not flagged as a change.
    const model = api.trackChangesPreviewController.getLastModel(docUri()) ?? [];
    const replacementMarked = model.some(
      (o) => o.kind !== "unchanged" && o.block.raw.includes("CLAUDE REWROTE"),
    );
    assert.ok(!replacementMarked, "the just-landed text renders unmarked (baseline advanced)");
  });

  test("pin resets the baseline to now → preview shows no marks (PUC-4)", async () => {
    const doc = await openDoc();
    const api = await getApi();
    await vscode.commands.executeCommand("cowriting.pinDiffBaseline");
    await settle();
    assert.ok(
      kinds(api).every((k) => k === "unchanged"),
      "after pin, every block is unchanged (baseline == buffer)",
    );
    void doc;
  });

  test("a non-markdown doc → command warns and opens no panel (PUC-6, markdown-only)", async () => {
    const txt = await openDoc("docs/notes.txt");
    const api = await getApi();
    const key = txt.uri.toString();
    assert.notStrictEqual(txt.languageId, "markdown", "fixture is not markdown");
    await vscode.commands.executeCommand("cowriting.showTrackChangesPreview");
    await settle();
    assert.strictEqual(api.trackChangesPreviewController.isOpen(key), false, "no panel for non-markdown");
  });
});