import 'dart:typed_data';
import 'package:file_picker/file_picker.dart';
import 'package:flutter/material.dart';
import '../core/app_controller.dart';
import '../core/failure.dart';
import '../l10n/strings.dart';
import '../models/server_profile.dart';
import '../services/local_files.dart';
import '../services/profile_transfer.dart';
import 'adaptive.dart';

/// Imports desktop-compatible `chj-server-profiles` version 1 JSON after a
/// preview and a duplicate policy. Credentials are never part of the file.
Future<void> importProfiles(BuildContext context, AppController c) async {
  final epoch = c.vault.generation;
  final file = await c.withSystemDialog(
    () =>
        FilePicker.pickFile(type: FileType.custom, allowedExtensions: ['json']),
  );
  if (file == null ||
      !context.mounted ||
      epoch != c.vault.generation ||
      !c.vault.unlocked) {
    return;
  }
  final profiles = ProfileTransfer.decode(
    await readBounded(file.readAsByteStream(), ProfileTransfer.maxBytes),
  );
  if (!context.mounted) return;
  final policy = await Navigator.push<String>(
    context,
    MaterialPageRoute(
      builder: (_) => ImportPreview(profiles, c.vault.profiles),
    ),
  );
  if (policy == null || !c.vault.unlocked || epoch != c.vault.generation) {
    return;
  }
  await c.vault.change((d) {
    final list = d['profiles'] as List;
    final seen = {
      for (final p in list)
        ServerProfile.fromJson(Map<String, dynamic>.from(p)).identity: p,
    };
    for (final p in profiles) {
      final match = seen[p.identity];
      if (match != null && policy == 'skipDuplicates') continue;
      final next = ServerProfile(
        id: match != null && policy == 'updateDuplicates' ? match['id'] : null,
        name: p.name,
        host: p.host,
        username: p.username,
        port: p.port,
      );
      if (match != null && policy == 'updateDuplicates') {
        list[list.indexOf(match)] = next.toJson();
        (d['secrets'] as Map).remove(next.id);
      } else {
        list.add(next.toJson());
      }
      seen[p.identity] = list.lastWhere((r) => r['id'] == next.id);
    }
  });
  c.ssh.disconnect(clear: true);
  c.changed();
}

/// Exports profiles as desktop-compatible JSON, without credentials.
Future<void> exportProfiles(AppController c) async {
  if (c.vault.profiles.isEmpty) throw const Failure('invalidImport');
  final bytes = Uint8List.fromList(ProfileTransfer.encode(c.vault.profiles));
  await c.withSystemDialog(
    () => FilePicker.saveFile(
      fileName: 'chj-server-profiles.json',
      bytes: bytes,
      mimeType: 'application/json',
    ),
  );
}

class ImportPreview extends StatefulWidget {
  final List<ServerProfile> profiles, existing;
  const ImportPreview(this.profiles, this.existing, {super.key});
  @override
  State<ImportPreview> createState() => _ImportPreviewState();
}

class _ImportPreviewState extends State<ImportPreview> {
  String policy = 'skipDuplicates';
  @override
  Widget build(BuildContext context) {
    final seen = widget.existing.map((p) => p.identity).toSet();
    final duplicates = widget.profiles.map((p) {
      final found = !seen.add(p.identity);
      return found;
    }).toList();
    return Scaffold(
      appBar: AppBar(title: Text(context.tr('importPreview'))),
      body: SafeArea(
        child: MinHeight(
          minHeight: 320,
          child: Column(
            children: [
              Padding(
                padding: const EdgeInsets.all(16),
                child: Text(context.tr('importAdvice')),
              ),
              Padding(
                padding: const EdgeInsets.symmetric(horizontal: 16),
                child: DropdownButtonFormField<String>(
                  initialValue: policy,
                  isExpanded: true,
                  items:
                      ['skipDuplicates', 'updateDuplicates', 'createDuplicates']
                          .map(
                            (v) => DropdownMenuItem(
                              value: v,
                              child: Text(
                                context.tr(v),
                                overflow: TextOverflow.ellipsis,
                              ),
                            ),
                          )
                          .toList(),
                  onChanged: (v) => setState(() => policy = v!),
                ),
              ),
              Expanded(
                child: ListView.builder(
                  itemCount: widget.profiles.length,
                  itemBuilder: (ctx, i) {
                    final p = widget.profiles[i];
                    return ListTile(
                      title: Text(p.name),
                      subtitle: Text('${p.username}@${p.host}:${p.port}'),
                      trailing: duplicates[i]
                          ? Tooltip(
                              message: ctx.tr('duplicate'),
                              child: const Icon(Icons.copy),
                            )
                          : null,
                    );
                  },
                ),
              ),
              Padding(
                padding: const EdgeInsets.all(16),
                child: FilledButton(
                  onPressed: () => Navigator.pop(context, policy),
                  child: Text(context.tr('importAction')),
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}