import * as assert from "assert";
import * as fs from "fs";
import * as os from "os";
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/diffview.md";
const docUri = () => vscode.Uri.file(path.join(WS, DOC_REL)).toString();

async function openDoc(): 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;
}
/** Open the doc AND enter coediting (INV-10) — baselines are established only
 *  on entry (Task 2). Idempotent across tests: re-entering an already-coedited
 *  doc is a no-op, so the once-captured baseline survives (order-dependent
 *  suite, same as before). */
async function openAndCoedit(): Promise<vscode.TextDocument> {
  const doc = await openDoc();
  await vscode.commands.executeCommand("cowriting.coeditDocument");
  await settle();
  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?.diffViewController, "extension exports diffViewController");
  return api;
}
const settle = () => new Promise((r) => setTimeout(r, 300));

// The F6 two-pane vscode.diff VIEW was removed in #34 (F10's rendered preview is
// the single review surface); only the baseline DATA layer survives, consumed by
// F7/F10. This suite covers that data layer. Order-dependent (F2–F4 pattern):
// later tests consume earlier state. Owns docs/diffview.md exclusively. The
// baseline works on ANY file (#19), so the last two tests use an out-of-workspace
// file and an untitled buffer.
//
// Native-surfaces migration (Task 2, spec §6.4/INV-7): a baseline is now
// established only once a document ENTERS coediting (not merely opened), and
// the fixture workspace is NOT a git repo, so every doc here resolves to
// SNAPSHOT mode. The shipped machine-landing baseline advance (#48/INV-18) is
// retired — an accepted proposal now stays a visible change-since-baseline
// until "Mark Changes as Reviewed" (D21).
suite("F6 baseline data layer (host E2E — any file, programmatic seam ingress, no LLM)", () => {
  const TARGET = "A target sentence Claude will rewrite via the seam.";
  const REPLACEMENT = "A SENTENCE CLAUDE REWROTE via the seam.";

  test("entering coediting on a snapshot-mode doc captures an `entered` baseline equal to the buffer (INV-7)", async () => {
    const doc = await openAndCoedit();
    const api = await getApi();
    assert.strictEqual(api.diffViewController.modeOf(docUri()), "snapshot", "no git repo → snapshot mode");
    const baseline = api.diffViewController.getBaseline(docUri());
    assert.ok(baseline, "baseline captured on coediting entry");
    assert.strictEqual(baseline!.reason, "entered");
    assert.strictEqual(baseline!.text, doc.getText(), "baseline = entry-time buffer");
  });

  test("typing leaves the baseline unchanged while the buffer diverges", async () => {
    const doc = await openAndCoedit();
    const api = await getApi();
    const before = api.diffViewController.getBaseline(docUri())!.text;
    const edit = new vscode.WorkspaceEdit();
    edit.insert(doc.uri, new vscode.Position(0, 0), "OPERATOR ADDED LINE\n");
    assert.ok(await vscode.workspace.applyEdit(edit), "operator edit applied");
    await settle();
    assert.strictEqual(api.diffViewController.getBaseline(docUri())!.text, before, "baseline unchanged by typing");
    assert.notStrictEqual(doc.getText(), before, "buffer diverged");
  });

  test("accepting a proposal does NOT advance the baseline — the landed text stays a change (INV-7/D21, #48 retired)", async () => {
    const doc = await openAndCoedit();
    const api = await getApi();
    const before = api.diffViewController.getBaseline(docUri())!;
    const start = doc.getText().indexOf(TARGET);
    assert.ok(start >= 0, "fixture contains the target");
    const id = await vscode.commands.executeCommand<string>("cowriting.proposeAgentEdit", {
      uri: doc.uri.toString(),
      start,
      end: start + TARGET.length,
      newText: REPLACEMENT,
      model: "sonnet",
      sessionId: "e2e-diff",
      turnId: "turn-d1",
    });
    assert.ok(id, "propose returns an id");
    assert.ok(await api.proposalController.acceptById(DOC_REL, id!), "accept applies via the seam");
    await settle();
    const baseline = api.diffViewController.getBaseline(docUri())!;
    assert.strictEqual(baseline.reason, before.reason, "baseline reason untouched by the landing");
    assert.strictEqual(baseline.text, before.text, "baseline text untouched by the landing");
    assert.ok(!baseline.text.includes(REPLACEMENT), "landed text is NOT folded into the baseline");
    assert.notStrictEqual(baseline.text, doc.getText(), "baseline != buffer — the landing reads as a change");
  });

  test("an operator edit after the landing keeps baseline ≠ buffer (the operator delta)", async () => {
    const doc = await openAndCoedit();
    const api = await getApi();
    const edit = new vscode.WorkspaceEdit();
    edit.insert(doc.uri, new vscode.Position(0, 0), "POST-LANDING OPERATOR LINE\n");
    assert.ok(await vscode.workspace.applyEdit(edit));
    await settle();
    assert.notStrictEqual(
      api.diffViewController.getBaseline(docUri())!.text,
      doc.getText(),
      "operator changes show against the untouched baseline",
    );
  });

  test("markReviewed resets the baseline to now: baseline == buffer, reason pinned", async () => {
    const doc = await openAndCoedit();
    const api = await getApi();
    await vscode.commands.executeCommand("cowriting.markReviewed");
    await settle();
    const baseline = api.diffViewController.getBaseline(docUri())!;
    assert.strictEqual(baseline.reason, "pinned");
    assert.strictEqual(baseline.text, doc.getText(), "pinned baseline == current buffer (change-marks empty)");
  });

  test("the baseline is persisted in GLOBAL storage, never the repo (INV-19)", async () => {
    await openAndCoedit();
    const api = await getApi();
    const p = api.diffViewController.baselineFilePath(docUri());
    assert.ok(p, "storage-backed baseline path is available for a file: doc");
    assert.ok(fs.existsSync(p!), `baseline file exists at ${p}`);
    const onDisk = JSON.parse(fs.readFileSync(p!, "utf8"));
    assert.strictEqual(onDisk.uri, docUri(), "baseline records the document URI");
    assert.strictEqual(onDisk.reason, "pinned", "last epoch (markReviewed) persisted");
    assert.strictEqual(onDisk.text, api.diffViewController.getBaseline(docUri())!.text, "on-disk == in-memory");
    // INV-19: baseline lives under the extension's storage dir, not the repo.
    assert.ok(!p!.includes(`${path.sep}.threads${path.sep}`), "baseline is NOT in the sidecar tree");
    assert.ok(!p!.startsWith(WS + path.sep), "baseline is NOT under the workspace folder");
    assert.ok(p!.includes(`${path.sep}baselines${path.sep}`), "baseline lives under <globalStorage>/baselines/");
  });

  test("a baseline is captured + persisted for a file OUTSIDE the workspace folder (#19)", async () => {
    const api = await getApi();
    const outsideDir = fs.mkdtempSync(path.join(os.tmpdir(), "cowriting-outside-"));
    const outsidePath = path.join(outsideDir, "outside.md");
    fs.writeFileSync(outsidePath, "# Outside the workspace\n\nThe operator edits this too.\n", "utf8");
    const outsideUri = vscode.Uri.file(outsidePath);
    const doc = await vscode.workspace.openTextDocument(outsideUri);
    await vscode.window.showTextDocument(doc);
    await vscode.commands.executeCommand("cowriting.coeditDocument");
    await settle();
    // Captured on coediting entry even though it is NOT under the workspace folder.
    const baseline = api.diffViewController.getBaseline(outsideUri.toString());
    assert.ok(baseline, "baseline captured for an out-of-folder file");
    assert.strictEqual(baseline!.reason, "entered");
    const fp = api.diffViewController.baselineFilePath(outsideUri.toString());
    assert.ok(fp && fs.existsSync(fp), "outside-file baseline persisted in global storage");
    assert.ok(!fp!.startsWith(WS + path.sep), "not under the workspace folder");
    fs.rmSync(outsideDir, { recursive: true, force: true });
    void doc;
  });

  test("an UNTITLED buffer gets an in-memory baseline, never persisted to disk (#19)", async () => {
    const api = await getApi();
    const untitled = await vscode.workspace.openTextDocument({ content: "scratch line\n", language: "markdown" });
    await vscode.window.showTextDocument(untitled);
    await vscode.commands.executeCommand("cowriting.coeditDocument");
    await settle();
    const key = untitled.uri.toString();
    assert.strictEqual(untitled.uri.scheme, "untitled", "it really is an untitled buffer");
    const baseline = api.diffViewController.getBaseline(key);
    assert.ok(baseline, "untitled buffer got an in-memory baseline");
    assert.strictEqual(api.diffViewController.baselineFilePath(key), undefined, "untitled is NOT persisted to disk");
  });
});