// Agent execution engine
// Spawns and manages agent instances

import 'dart:async';

import '../api/openrouter_client.dart';
import '../chat/tool_loop_service.dart';
import '../local_state.dart';
import 'agent_context.dart';

/// Executes a single agent
class AgentExecutor {
  static final AgentExecutor _instance = AgentExecutor._internal();
  factory AgentExecutor() => _instance;
  AgentExecutor._internal();

  final Map<String, _RunningAgent> _agents = {};
  int _idCounter = 1;

  /// Spawn and run an agent
  Future<String> spawnAgent({
    required AgentDefinition definition,
    required AgentContext context,
    required String task,
    required String apiKey,
    required String model,
  }) async {
    final agentId = 'agent_${_idCounter++}';

    final agent = _RunningAgent(
      id: agentId,
      definition: definition,
      context: context.createChildContext(childAgentId: agentId),
      task: task,
      apiKey: apiKey,
      model: model,
    );

    _agents[agentId] = agent;

    // Start agent in background
    agent.run().then((result) {
      // Agent completed
      context.recordSubAgentResult(agentId, result);
    }).catchError((e) {
      print('Agent $agentId failed: $e');
      context.recordSubAgentResult(
        agentId,
        AgentResult.failure(agentId: agentId, error: e.toString()),
      );
    });

    return agentId;
  }

  /// Get agent result (non-blocking)
  AgentResult? getResult(String agentId) {
    final agent = _agents[agentId];
    if (agent == null) {
      return null;
    }

    return agent.result;
  }

  /// Wait for agent completion
  Future<AgentResult> waitForAgent(String agentId,
      {Duration timeout = const Duration(hours: 24)}) async {
    final agent = _agents[agentId];
    if (agent == null) {
      throw Exception('Agent $agentId not found');
    }

    return agent.waitForCompletion(timeout: timeout);
  }

  /// Get all running agents
  List<Map<String, dynamic>> getAllAgents() {
    return _agents.entries.map((e) {
      return {
        'id': e.key,
        'type': e.value.definition.type,
        'task': e.value.task,
        'status': e.value.isComplete ? 'completed' : 'running',
        'result': e.value.result?.toJson(),
      };
    }).toList();
  }

  /// Cancel an agent
  Future<bool> cancelAgent(String agentId) async {
    final agent = _agents[agentId];
    if (agent == null) {
      return false;
    }

    agent.cancel();
    _agents.remove(agentId);
    return true;
  }
}

/// Represents a running agent instance
class _RunningAgent {
  final String id;
  final AgentDefinition definition;
  final AgentContext context;
  final String task;
  final String apiKey;
  final String model;

  DateTime _startTime = DateTime.now();
  DateTime? _endTime;
  AgentResult? result;
  bool _cancelled = false;

  final Completer<AgentResult> _completer = Completer();

  _RunningAgent({
    required this.id,
    required this.definition,
    required this.context,
    required this.task,
    required this.apiKey,
    required this.model,
  });

  bool get isComplete => _endTime != null;

  /// Run the agent
  Future<AgentResult> run() async {
    try {
      // Create API client for this agent
      final client = OpenRouterClient(
        config: OpenRouterConfig(
          apiKey: apiKey,
          model: model,
        ),
      );

      // Create tool loop for this agent
      final toolLoop = ToolLoopService();

      // Build agent-specific system prompt
      final systemPrompt = '''${definition.getSystemPrompt()}

Task: $task

Context:
- Session ID: ${context.sessionId}
- Working Directory: ${context.workingDirectory}
- Parent Agent: ${context.parentAgentId}
${context.sharedState.isNotEmpty ? '- Shared State: ${context.sharedState}' : ''}

Use available tools to complete this task. Report your findings clearly.''';

      // Run the tool loop for this agent
      final toolResult = await toolLoop.runTurn(
        client: client,
        model: model,
        apiKey: apiKey,
        getSettings: () => context.settings,
        apiMessages: context.conversationHistory,
        userText: task,
        workingDirectory: context.workingDirectory,
      );

      // Extract output
      final output = toolResult.responseText;

      // Create result
      result = AgentResult.success(
        agentId: id,
        output: output,
        data: {
          'messages_exchanged': toolResult.apiMessages.length,
          'web_searches': toolResult.webSearchRequests,
          'web_fetches': toolResult.webFetchRequests,
        },
        duration: DateTime.now().difference(_startTime),
      );

      _endTime = DateTime.now();
      _completer.complete(result!);

      return result!;
    } catch (e, st) {
      result = AgentResult.failure(
        agentId: id,
        error: e.toString(),
        duration: DateTime.now().difference(_startTime),
      );

      _endTime = DateTime.now();
      _completer.completeError(e, st);

      return result!;
    }
  }

  /// Wait for agent to complete
  Future<AgentResult> waitForCompletion({Duration timeout = const Duration(hours: 24)}) {
    return _completer.future.timeout(timeout);
  }

  /// Cancel this agent
  void cancel() {
    _cancelled = true;
  }
}