// Regression tests for the onboarding recall flows: restoring a master and
// recalling the registered address must land the user in the inbox. The
// client's network operations are stubbed; what is under test is the UI and
// router flow itself.

import "dart:io";
import "dart:math";
import "dart:typed_data";

import "package:flutter/material.dart";
import "package:flutter_riverpod/flutter_riverpod.dart";
import "package:flutter_test/flutter_test.dart";
import "package:hive_flutter/hive_flutter.dart";

import "package:smol_mail/data/providers/providers.dart";
import "package:smol_mail/presentation/app_widget.dart";
import "package:smol_mail/smol/address.dart";
import "package:smol_mail/smol/client.dart";
import "package:smol_mail/smol/errors.dart";
import "package:smol_mail/smol/store.dart";
import "package:smol_mail/smol/ui.dart";

Uint8List randomBytes(int n) => Uint8List.fromList(List.generate(n, (_) => Random.secure().nextInt(256)));

// A syntactically valid server key for the stubbed pin step: the flow under
// test is the UI routing, not the handshake.
const fakePin = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa";

/// A [SmolClient] whose network operations complete instantly, so the test
/// exercises the flow rather than the network. [restoreAndRecall] still
/// enforces the pin gate (SPEC.md §4), since that gate is exactly what the
/// restore flow's UX is regression-tested against.
class StubClient extends SmolClient {
  StubClient(super.store);

  @override
  Future<SmolAddress> restoreAndRecall(String masterHex, String addressText) async {
    final addr = parseAddress(addressText);
    if (store.serverPin(addr.host) == null) {
      throw SmolError("no pinned key for ${addr.host}");
    }
    store.restoreMaster(unhex(masterHex.trim()), 0);
    store.native.setAccount(addr.short);
    return addr;
  }

  @override
  Future<SmolAddress> recallAccount(String addressText) async {
    final addr = parseAddress(addressText);
    store.native.setAccount(addr.short);
    return addr;
  }
}

void main() {
  // Hive box opening is real file IO and must happen outside testWidgets'
  // fake-async zone — including the per-test stores.
  late final SmolStore storeA, storeB, storeC;
  setUpAll(() async {
    TestWidgetsFlutterBinding.ensureInitialized();
    final dir = await Directory.systemTemp.createTemp("smol-recall-flow");
    Hive.init(dir.path);
    storeA = await SmolStore.open(
        dbPath: "${dir.path}/a.db", stateBox: "recall-a-state", readBox: "recall-a-read");
    storeB = await SmolStore.open(
        dbPath: "${dir.path}/b.db", stateBox: "recall-b-state", readBox: "recall-b-read");
    storeC = await SmolStore.open(
        dbPath: "${dir.path}/c.db", stateBox: "recall-c-state", readBox: "recall-c-read");
  });

  Widget app(SmolStore store) => ProviderScope(
        overrides: [
          storeProvider.overrideWithValue(store),
          clientProvider.overrideWithValue(StubClient(store)),
        ],
        child: const AppWidget(),
      );

  testWidgets(
      "restore with an address, but no pin yet, asks for the server key "
      "and then recalls into the inbox", (tester) async {
    final store = storeA;
    final master = randomBytes(32);
    await tester.pumpWidget(app(store));
    await tester.pumpAndSettle();
    expect(find.text("Create Identity"), findsOneWidget);

    await tester.tap(find.text("Restore From Seed"));
    await tester.pumpAndSettle();

    var fields = find.byType(TextField);
    expect(fields, findsNWidgets(2));
    await tester.enterText(fields.at(0), hex(master));
    await tester.enterText(fields.at(1), "randogoth@smol.place");
    await tester.tap(find.text("Restore"));
    await tester.pumpAndSettle();

    // Recall needs the server pinned first (SPEC.md §4) — that's the normal
    // state right after a restore, so this lands on the register step framed
    // for recall (no error, no Invite token field) rather than the inbox yet.
    expect(find.text("Inbox"), findsNothing);
    expect(find.text("Pin this server's public key to finish restoring your address."),
        findsOneWidget);
    expect(find.text("Invite token (optional)"), findsNothing);
    // Restoring has no well-defined "register a new address instead" escape
    // hatch until the rotation index is known (§2).
    expect(find.text("Register a new address instead"), findsNothing);
    fields = find.byType(TextField);
    expect(fields, findsNWidgets(2)); // address (carried over), server key
    await tester.enterText(fields.at(1), fakePin);
    await tester.tap(find.text("Pin and Recall"));
    await tester.pumpAndSettle();

    expect(find.text("Inbox"), findsOneWidget);
    expect(store.master(), master);
    expect(parseAddress(SmolClient(store).accountAddress()!.short).user,
        "randogoth");
  });

  testWidgets("restore requires an address before it will submit",
      (tester) async {
    final store = storeB;
    await tester.pumpWidget(app(store));
    await tester.pumpAndSettle();

    await tester.tap(find.text("Restore From Seed"));
    await tester.pumpAndSettle();

    final fields = find.byType(TextField);
    await tester.enterText(fields.at(0), hex(randomBytes(32)));
    await tester.tap(find.text("Restore"));
    await tester.pumpAndSettle();

    // Nothing was submitted, so nothing was persisted; still on this step.
    expect(find.text("Restore"), findsOneWidget);
    expect(find.text("Inbox"), findsNothing);
    expect(store.master(), isNull);
  });

  testWidgets(
      "restoring after an abandoned Create Identity attempt replaces it "
      "instead of refusing it", (tester) async {
    final store = storeC;
    final realMaster = randomBytes(32);
    await tester.pumpWidget(app(store));
    await tester.pumpAndSettle();

    // First attempt: create a fresh identity but never finish registering —
    // lands on the backup step, master set, no account bound.
    await tester.tap(find.text("Create Identity"));
    await tester.pumpAndSettle();
    expect(store.master(), isNotNull);
    expect(SmolClient(store).accountAddress(), isNull);

    // Simulate returning to onboarding later (e.g. a cold restart). Pumping
    // app(store) directly would just rebuild the existing OnboardingScreen
    // state in place rather than really restarting, so tear the tree down
    // first to force a fresh app state — HomeGuard then sends an
    // identity-without-account back to welcome.
    await tester.pumpWidget(const SizedBox());
    await tester.pumpWidget(app(store));
    await tester.pumpAndSettle();
    expect(find.text("Create Identity"), findsOneWidget);

    // Restoring a different master must not throw "identity already exists".
    await tester.tap(find.text("Restore From Seed"));
    await tester.pumpAndSettle();
    final fields = find.byType(TextField);
    await tester.enterText(fields.at(0), hex(realMaster));
    await tester.enterText(fields.at(1), "randogoth@smol.place");
    await tester.tap(find.text("Restore"));
    await tester.pumpAndSettle();

    // Lands on the recall-framed register step (no pin yet); pin it and finish.
    expect(find.byType(TextField), findsNWidgets(2));
    await tester.enterText(find.byType(TextField).at(1), fakePin);
    await tester.tap(find.text("Pin and Recall"));
    await tester.pumpAndSettle();

    expect(find.text("Inbox"), findsOneWidget);
    expect(store.master(), realMaster);
  });
}