import 'dart:async';
import 'dart:io';

import 'package:crypto/crypto.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:path/path.dart' as p;

import '../core/file_attributes.dart';
import '../core/file_ops.dart' show formatSize;
import '../l10n/tr.dart';
import 'theme.dart';

/// X-plore 비교 P3: 해시 · 16진 보기 · 폴더 속성 (읽기만 - 파일을 바꾸지 않는다)

/// 파일의 MD5 · SHA-256 (조각으로 읽어 큰 파일도 메모리를 쓰지 않음). [onProgress] 0~1, [cancelled] 면 null
Future<({String md5, String sha256})?> fileHashes(String path, {void Function(double)? onProgress, bool Function()? cancelled}) async {
  final f = File(path);
  final total = await f.length();
  final m = _Sink(), s = _Sink();
  final mIn = md5.startChunkedConversion(m), sIn = sha256.startChunkedConversion(s);
  var done = 0;
  await for (final chunk in f.openRead()) {
    if (cancelled?.call() ?? false) return null;
    mIn.add(chunk);
    sIn.add(chunk);
    done += chunk.length;
    onProgress?.call(total == 0 ? 1 : done / total);
  }
  mIn.close();
  sIn.close();
  return (md5: '${m.value}', sha256: '${s.value}');
}

class _Sink implements Sink<Digest> {
  Digest? value;
  @override
  void add(Digest data) => value = data;
  @override
  void close() {}
}

/// 해시 창 - 계산 (진행 · 취소) 뒤 MD5 · SHA-256, 붙여 넣은 값과 비교
Future<void> showFileHash(BuildContext context, String path) async {
  var progress = 0.0;
  var cancelled = false;
  ({String md5, String sha256})? result;
  Object? error;
  final compare = TextEditingController();
  await showDialog<void>(
    context: context,
    builder: (ctx) => StatefulBuilder(builder: (ctx, set) {
      if (result == null && error == null && progress == 0) {
        progress = 0.0001;
        fileHashes(path, onProgress: (v) {
          if (ctx.mounted) set(() => progress = v);
        }, cancelled: () => cancelled)
            .then((r) {
          if (ctx.mounted) set(() => result = r);
        }, onError: (Object e) {
          if (ctx.mounted) set(() => error = e);
        });
      }
      final want = compare.text.trim().toLowerCase();
      final match = result != null && want.isNotEmpty ? (want == result!.md5 || want == result!.sha256) : null;
      Widget line(String name, String v) => Padding(
            padding: const EdgeInsets.only(top: 6),
            child: Row(children: [
              SizedBox(width: 72, child: Text(name, style: const TextStyle(fontWeight: FontWeight.w600))),
              Expanded(child: SelectableText(v, style: const TextStyle(fontFamily: 'monospace', fontSize: 12))),
              IconButton(
                tooltip: tr('복사'),
                icon: const Icon(Icons.copy, size: 16),
                onPressed: () => Clipboard.setData(ClipboardData(text: v)),
              ),
            ]),
          );
      return AlertDialog(
        scrollable: true,
        title: Text(trf('해시 · {0}', [p.basename(path)])),
        content: SizedBox(
          width: 560,
          child: Column(mainAxisSize: MainAxisSize.min, crossAxisAlignment: CrossAxisAlignment.start, children: [
            if (error != null) Text(trf('읽지 못했습니다: {0}', [error]), style: const TextStyle(color: JjColors.danger)),
            if (result == null && error == null) LinearProgressIndicator(value: progress),
            if (result != null) ...[
              line('MD5', result!.md5),
              line('SHA-256', result!.sha256),
              const SizedBox(height: 10),
              TextField(
                controller: compare,
                decoration: InputDecoration(labelText: tr('비교할 값 붙여넣기 (받은 곳의 해시)'), isDense: true),
                onChanged: (_) => set(() {}),
              ),
              if (match != null)
                Padding(
                  padding: const EdgeInsets.only(top: 6),
                  child: Text(match ? tr('같습니다 ✔') : tr('다릅니다 - 파일이 바뀌었거나 다른 파일입니다'),
                      style: TextStyle(color: match ? Colors.greenAccent : JjColors.danger)),
                ),
            ],
          ]),
        ),
        actions: [
          TextButton(
            onPressed: () {
              cancelled = true;
              Navigator.pop(ctx);
            },
            child: Text(result == null && error == null ? tr('취소') : tr('닫기')),
          ),
        ],
      );
    }),
  );
  // 창이 닫히는 동안 (애니메이션) 글 칸이 아직 쓰므로 바로 dispose 하면 "used after being disposed" (15 캡처) - 닫힌 뒤에
  Future<void>.delayed(const Duration(milliseconds: 500), compare.dispose);
}

/// 16진 보기: 한 줄 16 바이트 (위치 · 16진 · 글자). 큰 파일은 [더 읽기]
class HexViewerPage extends StatefulWidget {
  final String path;
  final int chunk;
  const HexViewerPage({super.key, required this.path, this.chunk = 64 * 1024});

  /// 한 줄 ([per] 바이트, 처음 16): "00000010  41 42 ...  AB.."
  static String line(int offset, List<int> bytes, {int per = 16}) {
    final hex = StringBuffer();
    for (var i = 0; i < per; i++) {
      hex.write(i < bytes.length ? bytes[i].toRadixString(16).padLeft(2, '0') : '  ');
      hex.write(i == 7 && per > 8 ? '  ' : ' ');
    }
    final text = String.fromCharCodes([for (final b in bytes) b >= 0x20 && b < 0x7f ? b : 0x2e]);
    return '${offset.toRadixString(16).padLeft(8, '0')}  $hex $text';
  }

  @override
  State<HexViewerPage> createState() => _HexViewerPageState();
}

class _HexViewerPageState extends State<HexViewerPage> {
  final _data = <int>[];
  int _size = 0;
  Object? _error;

  @override
  void initState() {
    super.initState();
    _more();
  }

  Future<void> _more() async {
    try {
      final f = File(widget.path);
      _size = await f.length();
      final to = (_data.length + widget.chunk).clamp(0, _size);
      await for (final x in f.openRead(_data.length, to)) {
        _data.addAll(x);
      }
    } catch (e) {
      _error = e;
    }
    if (mounted) setState(() {});
  }

  @override
  Widget build(BuildContext context) {
    // 좁은 화면 (폰 세로) 은 한 줄 8 바이트 - 16 이면 끝의 글자 칸이 화면 밖으로 잘렸다 (15 캡처, 412 폭)
    final per = MediaQuery.sizeOf(context).width < 560 ? 8 : 16;
    final rows = (_data.length + per - 1) ~/ per;
    return Scaffold(
      appBar: AppBar(title: Text(trf('16진 보기 · {0}', [p.basename(widget.path)]), maxLines: 1, overflow: TextOverflow.ellipsis)),
      body: _error != null
          ? Center(child: Text(trf('읽지 못했습니다: {0}', [_error])))
          : Column(children: [
              Expanded(
                child: Scrollbar(
                  child: ListView.builder(
                    padding: const EdgeInsets.all(8),
                    itemCount: rows,
                    itemExtent: 18,
                    itemBuilder: (_, i) => Text(
                      HexViewerPage.line(i * per, _data.sublist(i * per, (i * per + per).clamp(0, _data.length)), per: per),
                      style: const TextStyle(fontFamily: 'monospace', fontSize: 12),
                      maxLines: 1,
                      softWrap: false,
                    ),
                  ),
                ),
              ),
              if (_data.length < _size)
                SafeArea(
                  top: false,
                  child: Padding(
                    padding: const EdgeInsets.all(6),
                    child: Row(children: [
                      Expanded(
                        child: Text(trf('{0} / {1} 읽음', [formatSize(_data.length), formatSize(_size)]),
                            style: const TextStyle(fontSize: 12, color: JjColors.textDim)),
                      ),
                      FilledButton.tonal(onPressed: _more, child: Text(tr('더 읽기'))),
                    ]),
                  ),
                ),
            ]),
    );
  }
}

/// 폴더 속성: 안의 파일 · 폴더 수, 크기, 만든 · 바뀐 때 (링크 · junction 은 따라가지 않음)
Future<({int files, int folders, int bytes, int links})> folderStats(String dir, {bool Function()? cancelled}) async {
  var files = 0, folders = 0, bytes = 0, links = 0;
  await for (final e in Directory(dir).list(recursive: true, followLinks: false).handleError((_) {})) {
    if (cancelled?.call() ?? false) break;
    if (e is Link) {
      links++;
    } else if (e is Directory) {
      folders++;
    } else if (e is File) {
      files++;
      try {
        bytes += await e.length();
      } catch (_) {}
    }
  }
  return (files: files, folders: folders, bytes: bytes, links: links);
}

Future<void> showFolderProperties(BuildContext context, String dir) async {
  var cancelled = false;
  final stat = await FileStat.stat(dir);
  final attrs = readFileAttributes(dir);
  if (!context.mounted) return;
  String date(DateTime d) =>
      '${d.year}-${d.month.toString().padLeft(2, '0')}-${d.day.toString().padLeft(2, '0')} ${d.hour.toString().padLeft(2, '0')}:${d.minute.toString().padLeft(2, '0')}';
  final future = folderStats(dir, cancelled: () => cancelled);
  await showDialog<void>(
    context: context,
    builder: (ctx) => AlertDialog(
      scrollable: true,
      title: Text(trf('폴더 속성 · {0}', [p.basename(dir)])),
      content: SizedBox(
        width: 480,
        child: FutureBuilder(
          future: future,
          builder: (_, s) {
            final r = s.data;
            return Column(mainAxisSize: MainAxisSize.min, crossAxisAlignment: CrossAxisAlignment.start, children: [
              SelectableText(dir, style: const TextStyle(fontSize: 12, color: JjColors.textDim)),
              const SizedBox(height: 8),
              if (r == null) const LinearProgressIndicator(),
              if (r != null) ...[
                Text(trf('크기: {0} ({1} 바이트)', [formatSize(r.bytes), r.bytes])),
                Text(trf('파일 {0}개 · 폴더 {1}개', [r.files, r.folders])),
                if (r.links > 0) Text(trf('링크 · junction {0}개 (따라가지 않고 세지 않음)', [r.links])),
              ],
              const SizedBox(height: 6),
              // 관리자 지시 10/18: 만든 때 · 숨김 · 읽기 전용 (보기만)
              if (attrs?.created != null) Text(trf('만든 때: {0}', [date(attrs!.created!)])),
              Text(trf('바뀐 때: {0}', [date(stat.modified)])),
              Text(trf('열어 본 때: {0}', [date(stat.accessed)])),
              Text(trf('속성: {0}', [attrs == null || attrs.labels.isEmpty ? tr('없음') : attrs.labels.join(' · ')])),
            ]);
          },
        ),
      ),
      actions: [
        TextButton(
          onPressed: () {
            cancelled = true;
            Navigator.pop(ctx);
          },
          child: Text(tr('닫기')),
        ),
      ],
    ),
  );
  cancelled = true;
}