import 'dart:convert';
import 'dart:math';
import 'package:flutter/services.dart';

/// Enum representing different encouragement message types
enum EncouragementType {
  general,       // General encouragement messages
  start,         // When starting a focus session
  distraction,   // When user gets distracted
  complete,      // When completing a focus session
  earlyStop,     // When stopping early
}

/// Service to manage encouragement messages for different scenarios
class EncouragementService {
  // Map of encouragement types to their messages
  final Map<EncouragementType, List<String>> _messages = {
    EncouragementType.general: [],
    EncouragementType.start: [],
    EncouragementType.distraction: [],
    EncouragementType.complete: [],
    EncouragementType.earlyStop: [],
  };
  
  final Random _random = Random();

  /// Load encouragement messages from assets
  Future<void> loadMessages() async {
    try {
      final String jsonString = 
          await rootBundle.loadString('assets/encouragements.json');
      final dynamic jsonData = json.decode(jsonString);
      
      // Check if the JSON is a map (new format with categories)
      if (jsonData is Map<String, dynamic>) {
        // Load categorized messages
        _loadCategorizedMessages(jsonData);
      } else if (jsonData is List<dynamic>) {
        // Load legacy format (list of general messages)
        _messages[EncouragementType.general] = jsonData.cast<String>();
        // Initialize other categories with default messages
        _initializeDefaultMessages();
      } else {
        // Invalid format, use defaults
        _initializeDefaultMessages();
      }
    } catch (e) {
      // Fallback to default messages if file can't be loaded
      _initializeDefaultMessages();
    }
  }
  
  /// Load categorized messages from JSON map
  void _loadCategorizedMessages(Map<String, dynamic> jsonData) {
    // Load general messages
    if (jsonData.containsKey('general') && jsonData['general'] is List) {
      _messages[EncouragementType.general] = (jsonData['general'] as List).cast<String>();
    }
    
    // Load start messages
    if (jsonData.containsKey('start') && jsonData['start'] is List) {
      _messages[EncouragementType.start] = (jsonData['start'] as List).cast<String>();
    }
    
    // Load distraction messages
    if (jsonData.containsKey('distraction') && jsonData['distraction'] is List) {
      _messages[EncouragementType.distraction] = (jsonData['distraction'] as List).cast<String>();
    }
    
    // Load complete messages
    if (jsonData.containsKey('complete') && jsonData['complete'] is List) {
      _messages[EncouragementType.complete] = (jsonData['complete'] as List).cast<String>();
    }
    
    // Load early stop messages
    if (jsonData.containsKey('earlyStop') && jsonData['earlyStop'] is List) {
      _messages[EncouragementType.earlyStop] = (jsonData['earlyStop'] as List).cast<String>();
    }
    
    // Ensure all categories have at least some messages
    _ensureAllCategoriesHaveMessages();
  }
  
  /// Initialize default messages for all categories
  void _initializeDefaultMessages() {
    _messages[EncouragementType.general] = [
      "Showing up is half the battle.",
      "Every minute counts.",
      "You're learning, not failing.",
      "Gentleness is strength.",
      "Progress over perfection.",
    ];
    
    _messages[EncouragementType.start] = [
      "You've got this! Let's begin.",
      "Ready to focus? Let's do this.",
      "Every moment is a fresh start.",
      "Let's make this session count.",
      "You're already making progress by showing up.",
    ];
    
    _messages[EncouragementType.distraction] = [
      "It's okay to get distracted. Let's gently come back.",
      "No guilt here! Let's try again.",
      "Distractions happen to everyone. Let's refocus.",
      "You're doing great by noticing and coming back.",
      "Gentle reminder: you can always start again.",
    ];
    
    _messages[EncouragementType.complete] = [
      "🎉 Congratulations! You did it!",
      "Great job completing your focus session!",
      "You should be proud of yourself!",
      "That was amazing! Well done.",
      "You're making wonderful progress!",
    ];
    
    _messages[EncouragementType.earlyStop] = [
      "It's okay to stop early. You tried, and that's what matters.",
      "Every effort counts, even if it's shorter than planned.",
      "You did your best, and that's enough.",
      "Rest when you need to. We'll be here when you're ready.",
      "Progress, not perfection. You're doing great.",
    ];
  }
  
  /// Ensure all categories have at least some messages
  void _ensureAllCategoriesHaveMessages() {
    // If any category is empty, use general messages as fallback
    for (final type in EncouragementType.values) {
      if (_messages[type]?.isEmpty ?? true) {
        _messages[type] = List.from(_messages[EncouragementType.general]!);
      }
    }
  }

  /// Get a random encouragement message for a specific type
  String getRandomMessage([EncouragementType type = EncouragementType.general]) {
    final messages = _messages[type] ?? [];
    if (messages.isEmpty) {
      return "You're doing great!";
    }
    return messages[_random.nextInt(messages.length)];
  }

  /// Get all messages for a specific type (for testing)
  List<String> getAllMessages([EncouragementType type = EncouragementType.general]) {
    return List.from(_messages[type] ?? []);
  }
  
  /// Get all messages for all types (for testing)
  Map<EncouragementType, List<String>> getAllMessagesByType() {
    return Map.from(_messages);
  }
}