import 'dart:convert';

import 'package:flutter/material.dart';
// We render Quill deltas here without depending on the flutter_quill editor
// API to avoid analyzer/API mismatches; we support common inline styles.

import '../models/app_version.dart';
import '../services/app_update_service.dart';

/// A reusable dialog that can render both flexible and forced updates and
/// report download progress.  Callers should wrap this with `showDialog` and
/// control ``barrierDismissible`` according to ``info.isForceUpdate``.
class UpdateDialog extends StatefulWidget {
  final AppUpdateInfo info;

  const UpdateDialog({required this.info, super.key});

  @override
  State<UpdateDialog> createState() => _UpdateDialogState();
}

class _UpdateDialogState extends State<UpdateDialog> {
  double _realProgress = 0.0;
  bool _downloading = false;
  bool _failed = false;
  List<dynamic>? _notesDelta;
  String? _notesPlain;

  Future<void> _startDownload() async {
    setState(() {
      _downloading = true;
      _failed = false;
    });

    try {
      await AppUpdateService.instance.downloadAndInstallApk(
        widget.info.latestVersion!.downloadUrl,
        onProgress: (p) => setState(() => _realProgress = p),
      );
      // once the installer launches the app is likely to be stopped; we
      // don't pop the dialog explicitly.
    } catch (err) {
      if (!mounted) return;
      setState(() {
        _failed = true;
        _downloading = false;
      });
      ScaffoldMessenger.of(
        context,
      ).showSnackBar(SnackBar(content: Text('Download failed: $err')));
    }
  }

  @override
  Widget build(BuildContext context) {
    final notes = widget.info.latestVersion?.releaseNotes ?? '';

    // parse release notes into a Quill delta list if possible
    if (_notesDelta == null && _notesPlain == null && notes.isNotEmpty) {
      try {
        final parsed = jsonDecode(notes);
        if (parsed is List) {
          _notesDelta = parsed;
        } else {
          _notesPlain = notes;
        }
      } catch (_) {
        _notesPlain = notes;
      }
    }

    // WillPopScope is deprecated in newer Flutter versions but PopScope
    // has a different API; to avoid breaking changes we continue to use the
    // old widget and suppress the warning.
    // ignore: deprecated_member_use
    return WillPopScope(
      onWillPop: () async {
        // prevent the user from dismissing when download is in progress or
        // when the dialog is forcing an update
        return !widget.info.isForceUpdate && !_downloading;
      },
      child: AlertDialog(
        title: const Text('Update Available'),
        content: Column(
          mainAxisSize: MainAxisSize.min,
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            // Render release notes: prefer Quill delta if available
            if (_notesDelta != null)
              SizedBox(
                height: 250,
                child: SingleChildScrollView(
                  child: RichText(
                    text: _deltaToTextSpan(
                      _notesDelta!,
                      Theme.of(context).textTheme.bodyMedium,
                    ),
                  ),
                ),
              ),
            if (_notesDelta == null &&
                _notesPlain != null &&
                _notesPlain!.isNotEmpty)
              SizedBox(
                height: 250,
                child: SingleChildScrollView(
                  child: SelectableText(_notesPlain!),
                ),
              ),
            const SizedBox(height: 12),
            if (_downloading) ...[
              SizedBox(
                width: double.infinity,
                child: const LinearProgressIndicator(value: null),
              ),
              const SizedBox(height: 8),
              TweenAnimationBuilder<double>(
                tween: Tween(begin: 0.0, end: _realProgress),
                duration: const Duration(milliseconds: 300),
                builder: (context, value, child) {
                  return Text(
                    '${(value * 100).toStringAsFixed(value * 100 >= 10 ? 0 : 1)}%',
                  );
                },
              ),
            ],
            if (_failed)
              const Padding(
                padding: EdgeInsets.only(top: 8.0),
                child: Text(
                  'An error occurred while downloading. Please try again.',
                  style: TextStyle(color: Colors.red),
                ),
              ),
          ],
        ),
        actions: _buildActions(),
      ),
    );
  }

  List<Widget> _buildActions() {
    final actions = <Widget>[];

    if (!widget.info.isForceUpdate && !_downloading) {
      actions.add(
        TextButton(
          onPressed: () => Navigator.of(context).pop(),
          child: const Text('Later'),
        ),
      );
    }

    actions.add(
      FilledButton(
        onPressed: _downloading ? null : _startDownload,
        child: _downloading
            ? const CircularProgressIndicator()
            : const Text('Update Now'),
      ),
    );

    return actions;
  }

  TextSpan _deltaToTextSpan(List<dynamic> delta, TextStyle? baseStyle) {
    final children = <TextSpan>[];

    TextStyle styleFromAttributes(Map? attrs) {
      var s = baseStyle ?? const TextStyle();
      if (attrs == null) return s;
      if (attrs['header'] != null) {
        final level = attrs['header'] is int ? attrs['header'] as int : 1;
        s = s.copyWith(
          fontSize: 18.0 - (level - 1) * 2,
          fontWeight: FontWeight.bold,
        );
      }
      if (attrs['bold'] == true) s = s.copyWith(fontWeight: FontWeight.bold);
      if (attrs['italic'] == true) s = s.copyWith(fontStyle: FontStyle.italic);
      if (attrs['underline'] == true) {
        s = s.copyWith(decoration: TextDecoration.underline);
      }
      if (attrs['strike'] == true) {
        s = s.copyWith(decoration: TextDecoration.lineThrough);
      }
      if (attrs['color'] is String) {
        try {
          final col = attrs['color'] as String;
          // simple support for hex colors like #rrggbb
          if (col.startsWith('#') && (col.length == 7 || col.length == 9)) {
            final hex = col.replaceFirst('#', '');
            final value = int.parse(hex, radix: 16);
            s = s.copyWith(
              color: Color((hex.length == 6 ? 0xFF000000 : 0) | value),
            );
          }
        } catch (_) {}
      }
      return s;
    }

    for (final op in delta) {
      if (op is Map && op.containsKey('insert')) {
        final insert = op['insert'];
        final attrs = op['attributes'] as Map?;
        String text;
        if (insert is String) {
          text = insert;
        } else if (insert is Map && insert.containsKey('image')) {
          // render image as alt text placeholder
          text = '[image]';
        } else {
          text = insert.toString();
        }

        children.add(TextSpan(text: text, style: styleFromAttributes(attrs)));
      }
    }

    return TextSpan(children: children, style: baseStyle);
  }

  @override
  void initState() {
    super.initState();
    // Pre-parse release notes so heavy JSON parsing doesn't block UI later
    final notes = widget.info.latestVersion?.releaseNotes ?? '';
    if (notes.isNotEmpty) {
      try {
        final parsed = jsonDecode(notes);
        if (parsed is List) {
          _notesDelta = parsed;
        } else {
          _notesPlain = notes;
        }
      } catch (_) {
        _notesPlain = notes;
      }
    }
  }

  @override
  void dispose() {
    super.dispose();
  }
}