import 'package:flutter/material.dart';
import '../api/models.dart';
import '../widgets/prompt_editor.dart';
import '../api/client.dart';

class PipelineEditorScreen extends StatefulWidget {
  final Pipeline? pipeline;

  const PipelineEditorScreen({super.key, this.pipeline});

  @override
  State<PipelineEditorScreen> createState() => _PipelineEditorScreenState();
}

class _PipelineEditorScreenState extends State<PipelineEditorScreen> {
  late TextEditingController _idController;
  late TextEditingController _nameController;
  late TextEditingController _dirController;
  late List<Prompt> _prompts;
  bool _saving = false;
  String? _error;

  late APIClient _api;

  @override
  void initState() {
    super.initState();
    _api = APIClient(baseUrl: _parseBaseUrl());

    if (widget.pipeline != null) {
      _idController = TextEditingController(text: widget.pipeline!.id);
      _nameController = TextEditingController(text: widget.pipeline!.name);
      _dirController = TextEditingController(text: widget.pipeline!.workingDir);
      _prompts = List.from(widget.pipeline!.prompts);
    } else {
      _idController = TextEditingController();
      _nameController = TextEditingController();
      _dirController = TextEditingController();
      _prompts = [];
    }
  }

  @override
  void dispose() {
    _idController.dispose();
    _nameController.dispose();
    _dirController.dispose();
    super.dispose();
  }

  static String _parseBaseUrl() {
    final uri = Uri.base;
    return '${uri.scheme}://${uri.host}${uri.port != 80 && uri.port != 443 ? ':${uri.port}' : ''}';
  }

  void _addPrompt() {
    setState(() {
      _prompts.add(
        Prompt(id: _generateId(), text: '', title: '', order: _prompts.length),
      );
    });
  }

  void _removePrompt(int index) {
    setState(() {
      _prompts.removeAt(index);
      for (int i = index; i < _prompts.length; i++) {
        _prompts[i] = _prompts[i].copyWith(order: i);
      }
    });
  }

  void _updatePrompt(int index, Prompt updated) {
    setState(() {
      _prompts[index] = updated;
    });
  }

  static String _generateId() {
    return DateTime.now().millisecondsSinceEpoch.toRadixString(36);
  }

  bool _validate() {
    if (_idController.text.trim().isEmpty) {
      setState(() => _error = 'ID is required');
      return false;
    }
    if (_nameController.text.trim().isEmpty) {
      setState(() => _error = 'Name is required');
      return false;
    }
    return true;
  }

  Future<void> _save() async {
    if (!_validate()) return;

    setState(() {
      _saving = true;
      _error = null;
    });

    final sortedPrompts = List<Prompt>.from(_prompts)
      ..sort((a, b) => a.order.compareTo(b.order));

    final pipeline = Pipeline(
      id: _idController.text.trim(),
      name: _nameController.text.trim(),
      prompts: sortedPrompts,
      workingDir: _dirController.text.trim(),
      createdAt: widget.pipeline?.createdAt ?? '',
      updatedAt: '',
    );

    try {
      final saved = await _api.createPipeline(pipeline);
      if (mounted) {
        Navigator.pop(context, saved);
      }
    } catch (e) {
      setState(() {
        _error = e.toString();
        _saving = false;
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    final isEdit = widget.pipeline != null;

    return Scaffold(
      appBar: AppBar(
        title: Text(isEdit ? 'Edit Pipeline' : 'Create Pipeline'),
        actions: [
          if (isEdit)
            IconButton(
              icon: const Icon(Icons.check, color: Colors.green),
              onPressed: _saving ? null : _save,
              tooltip: 'Save',
            ),
        ],
      ),
      body: SingleChildScrollView(
        padding: const EdgeInsets.all(20),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            if (_error != null)
              Padding(
                padding: const EdgeInsets.only(bottom: 16),
                child: Card(
                  color: Colors.red.shade50,
                  child: Padding(
                    padding: const EdgeInsets.all(12),
                    child: Row(
                      children: [
                        const Icon(Icons.error_outline, color: Colors.red),
                        const SizedBox(width: 12),
                        Expanded(child: Text(_error!)),
                      ],
                    ),
                  ),
                ),
              ),
            TextField(
              controller: _idController,
              decoration: const InputDecoration(
                labelText: 'ID',
                border: OutlineInputBorder(),
                isDense: true,
              ),
              enabled: !isEdit,
            ),
            const SizedBox(height: 12),
            TextField(
              controller: _nameController,
              decoration: const InputDecoration(
                labelText: 'Name',
                border: OutlineInputBorder(),
                isDense: true,
              ),
            ),
            const SizedBox(height: 12),
            TextField(
              controller: _dirController,
              decoration: const InputDecoration(
                labelText: 'Working Directory',
                border: OutlineInputBorder(),
                isDense: true,
              ),
            ),
            const SizedBox(height: 24),
            Row(
              mainAxisAlignment: MainAxisAlignment.spaceBetween,
              children: [
                const Text(
                  'Prompts',
                  style: TextStyle(fontSize: 20, fontWeight: FontWeight.bold),
                ),
                FilledButton.icon(
                  onPressed: _addPrompt,
                  icon: const Icon(Icons.add, size: 18),
                  label: const Text('Add Step'),
                ),
              ],
            ),
            const SizedBox(height: 12),
            if (_prompts.isEmpty)
              const Padding(
                padding: EdgeInsets.all(20),
                child: Center(
                  child: Text(
                    'No prompts yet. Add a step to get started.',
                    style: TextStyle(color: Colors.grey),
                  ),
                ),
              ),
            for (int i = 0; i < _prompts.length; i++)
              PromptEditor(
                prompt: _prompts[i],
                showDelete: _prompts.length > 1,
                onChanged: (p) => _updatePrompt(i, p),
                onDelete: () => _removePrompt(i),
              ),
            if (_prompts.isNotEmpty)
              Padding(
                padding: const EdgeInsets.only(top: 16),
                child: SizedBox(
                  width: double.infinity,
                  height: 48,
                  child: FilledButton.icon(
                    onPressed: _saving ? null : _save,
                    icon: _saving
                        ? const SizedBox(
                            width: 18,
                            height: 18,
                            child: CircularProgressIndicator(strokeWidth: 2),
                          )
                        : const Icon(Icons.save),
                    label: Text(
                      _saving
                          ? 'Saving...'
                          : (isEdit ? 'Save Changes' : 'Create Pipeline'),
                    ),
                  ),
                ),
              ),
          ],
        ),
      ),
    );
  }
}