import "package:flutter/foundation.dart";
import "dart:typed_data";

import "../../src/chat/tool_loop_service.dart";
import "../../src/compact/compact_service.dart";
import "../../src/hooks/hook_loader.dart";
import "../../src/hooks/hook_runner.dart";
import "../../src/permissions/permission_types.dart";
import "../../src/session/session_runtime.dart";
import "../../src/session/session_types.dart";
import "../models/attachment.dart";
import "settings_provider.dart";


// ChatProvider is now a thin registry over SessionRuntime instances.
//
// Each thread gets its own SessionRuntime which holds all the mutable state
// that used to live here — api messages, the http client, loading flags, etc.
// Switching threads just changes _activeSessionId. Background threads keep
// running and save themselves to disk; when you switch back you see their
// live state.
class ChatProvider extends ChangeNotifier {
  ChatProvider(this._settingsProvider) {
    _initHooks();
  }

  final SettingsProvider _settingsProvider;

  ToolLoopService _toolLoopService = ToolLoopService();
  HookRunner? _hookRunner;

  final Map<String, SessionRuntime> _runtimes = {};
  String? _activeSessionId;

  // ─── hooks ──────────────────────────────────────────────────────────────────

  Future<void> _initHooks() async {
    try {
      final hooks = await HookLoader.loadHooks();
      _hookRunner = HookRunner(hooks: hooks);
      _toolLoopService = ToolLoopService(hookRunner: _hookRunner);
    } catch (e) {
      print("Hook init failed: $e");
    }
  }

  // ─── active runtime accessors ────────────────────────────────────────────────

  SessionRuntime? get _active =>
      _activeSessionId != null ? _runtimes[_activeSessionId] : null;

  List<Message> get messages => _active?.messages ?? const [];
  int get messageCount => messages.length;
  String? get workingDirectory => _active?.workingDirectory;
  bool get hasConversation => _active != null;
  bool get isLoading => _active?.isLoading ?? false;
  bool get isCompacting => _active?.isCompacting ?? false;
  bool get isStopping => _active?.isStopping ?? false;
  int get queuedMessageCount => _active?.queuedMessageCount ?? 0;
  List<String> get queuedMessages => _active?.queuedMessages ?? const [];
  PendingPermission? get pendingPermission => _active?.pendingPermission;
  String? get lastCompactSummary => _active?.lastCompactSummary;
  TokenWarningState? get tokenWarningState => _active?.tokenWarningState;

  String get threadPermissionMode => _active?.permissionModeOverride ?? "default";

  Future<void> setThreadPermissionMode(String mode) =>
      _active?.setPermissionModeOverride(mode) ?? Future.value();

  bool isSessionRunning(String sessionId) {
    final r = _runtimes[sessionId];
    return r != null && (r.isLoading || r.isCompacting);
  }

  bool sessionNeedsAttention(String sessionId) {
    final r = _runtimes[sessionId];
    return r != null && r.pendingPermission != null;
  }

  bool sessionHasUnreadResult(String sessionId) {
    final r = _runtimes[sessionId];
    return r != null && r.hasUnreadResult;
  }

  int get contextTokens {
    final msgs = messages;
    for (var i = msgs.length - 1; i >= 0; i--) {
      final ct = msgs[i].contextTokens;
      if (ct != null && ct > 0) return ct;
    }
    return 0;
  }

  // ─── session lifecycle ───────────────────────────────────────────────────────

  // Called when the user switches to (or creates) a session.
  // Creates a new runtime if one doesn't already exist for this session.
  void activateSession(ConversationSession session) {
    final id = session.id;

    if (!_runtimes.containsKey(id)) {
      _runtimes[id] = SessionRuntime(
        session: session,
        toolLoopService: _toolLoopService,
        hookRunner: _hookRunner,
        getSettings: () => _settingsProvider.settings,
        normalizeModelId: (m) => _settingsProvider.normalizeModelId(m),
        onChanged: notifyListeners,
      );
    }

    _activeSessionId = id;
    _runtimes[id]?.markRead();
    notifyListeners();
  }

  // Fast-path: switch focus to an already-running runtime without touching disk.
  void activateSessionById(String sessionId) {
    if (_runtimes.containsKey(sessionId)) {
      _activeSessionId = sessionId;
      _runtimes[sessionId]?.markRead();
      notifyListeners();
    }
  }

  // Called when the user starts a new blank chat — no session exists yet.
  void clearConversation() {
    _activeSessionId = null;

    // prune dead runtimes that are done
    _runtimes.removeWhere((_, r) => !r.isLoading && !r.isCompacting);

    notifyListeners();
  }

  // Legacy compat — kept so HomeCoordinator doesn't need parallel changes
  // for paths that still call this. Routes to activateSession.
  void setConversation(ConversationSession session) => activateSession(session);

  // ─── actions — delegate to active runtime ───────────────────────────────────

  Future<void> sendMessage(
    String text, {
    QueuePriority priority = QueuePriority.next,
    List<Attachment>? attachments,
  }) async {
    final runtime = _active;
    if (runtime == null) return;

    final adapted = attachments
        ?.map((a) => AttachmentData(
              name: a.name,
              mimeType: a.mimeType,
              data: a.data,
            ))
        .toList();

    await runtime.sendMessage(text, priority: priority, attachments: adapted);
  }

  void stopGenerating() => _active?.stopGenerating();

  Future<void> runCompact({String? customInstructions}) =>
      _active?.runCompact(customInstructions: customInstructions) ??
      Future.value();

  Future<void> resolvePermission(PermissionDecision decision) =>
      _active?.resolvePermission(decision) ?? Future.value();

  void removeQueuedMessage(int index) => _active?.removeQueuedMessage(index);

  // ─── dispose ────────────────────────────────────────────────────────────────

  @override
  void dispose() {
    for (final r in _runtimes.values) {
      r.dispose();
    }
    super.dispose();
  }
}