import 'package:flutter/material.dart';
import '../services/ai_service.dart';

typedef TextUpdateCallback = void Function(String updatedText);
typedef ProcessingStateCallback = void Function(bool isProcessing);

/// An AI icon button that immediately enhances the text in [textController]
/// when pressed — no dialog, no language detection.
///
/// Provide [promptBuilder] to give the AI field-specific context. It receives
/// the current (trimmed) text and must return the prompt instruction string.
class GeminiButton extends StatefulWidget {
  final TextEditingController textController;
  final TextUpdateCallback onTextUpdated;
  final ProcessingStateCallback? onProcessingStateChanged;
  final String? tooltip;

  /// Optional callback that builds the Gemini prompt instruction from the
  /// current field text (called at press time, so captures live context).
  final String Function(String text)? promptBuilder;

  /// Called when the active AI provider changes.
  /// [isDeepSeek] is true once Gemini fails and DeepSeek takes over.
  /// Called with false again when processing finishes.
  final void Function(bool isDeepSeek)? onProviderChanged;

  const GeminiButton({
    super.key,
    required this.textController,
    required this.onTextUpdated,
    this.onProcessingStateChanged,
    this.tooltip,
    this.promptBuilder,
    this.onProviderChanged,
  });

  @override
  State<GeminiButton> createState() => _GeminiButtonState();
}

class _GeminiButtonState extends State<GeminiButton> {
  bool _isProcessing = false;
  late final AiService _aiService;

  @override
  void initState() {
    super.initState();
    _aiService = AiService();
  }

  Future<void> _enhance(BuildContext context) async {
    final text = widget.textController.text.trim();
    if (text.isEmpty) {
      if (!context.mounted) return;
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(content: Text('Please enter some text first')),
      );
      return;
    }

    setState(() {
      _isProcessing = true;
    });
    widget.onProcessingStateChanged?.call(true);
    widget.onProviderChanged?.call(false);
    try {
      final instruction = widget.promptBuilder?.call(text);
      final improvedText = await _aiService.enhanceText(
        text,
        promptInstruction: instruction,
        onFallbackToDeepSeek: () {
          if (mounted) {
            widget.onProviderChanged?.call(true);
          }
        },
      );
      final trimmed = improvedText.trim();
      widget.textController.text = trimmed;
      widget.onTextUpdated(trimmed);
      if (!context.mounted) return;
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(content: Text('Text improved successfully')),
      );
    } catch (e) {
      if (!context.mounted) return;
      ScaffoldMessenger.of(
        context,
      ).showSnackBar(SnackBar(content: Text('Error: $e')));
    } finally {
      if (mounted) {
        setState(() {
          _isProcessing = false;
        });
      }
      widget.onProcessingStateChanged?.call(false);
      widget.onProviderChanged?.call(false);
    }
  }

  @override
  Widget build(BuildContext context) {
    return IconButton(
      tooltip: widget.tooltip ?? 'Improve with Gemini',
      icon: _isProcessing
          ? const SizedBox(
              width: 24,
              height: 24,
              child: CircularProgressIndicator(strokeWidth: 2),
            )
          : Image.asset(
              'gemini_icon.png',
              width: 24,
              height: 24,
              errorBuilder: (context, error, stackTrace) =>
                  const Icon(Icons.auto_awesome),
            ),
      onPressed: _isProcessing ? null : () => _enhance(context),
    );
  }
}