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

import '../core/batch_rename.dart';
import '../core/vfs.dart';
import '../l10n/tr.dart';
import 'theme.dart';

/// 78: 일괄 이름 바꾸기 창 - 규칙을 넣으면 바로 미리 보기 (원래 → 새 이름, 문제는 빨갛게), [바꾸기] 뒤 결과.
/// 돌려주는 값: 바꾼 것 (원래 경로, 새 경로) - 탐색기가 [되돌리기] 에 쓴다. 취소하면 null.
/// 실패하면 이미 바꾼 것은 되돌리고 창에 이유를 보인다.
Future<List<(String, String)>?> showBatchRename(BuildContext context, List<String> paths, {required bool Function(String) isDir}) =>
    showDialog<List<(String, String)>>(
      context: context,
      barrierDismissible: false,
      builder: (_) => _BatchRenameDialog(paths: paths, isDir: isDir),
    );

class _BatchRenameDialog extends StatefulWidget {
  final List<String> paths;
  final bool Function(String) isDir;
  const _BatchRenameDialog({required this.paths, required this.isDir});

  @override
  State<_BatchRenameDialog> createState() => _BatchRenameDialogState();
}

class _BatchRenameDialogState extends State<_BatchRenameDialog> {
  final _template = TextEditingController(text: '[N]');
  final _start = TextEditingController(text: '1');
  final _step = TextEditingController(text: '1');
  final _digits = TextEditingController(text: '2');
  final _find = TextEditingController();
  final _replace = TextEditingController();
  bool _ignoreCase = true;
  String _case = 'keep';

  /// 폴더마다 지금 있는 이름 (읽는 중이면 비어 있음)
  final _siblings = <String, Set<String>>{};
  bool _loading = true;
  bool _running = false;
  String? _error;

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

  Future<void> _loadSiblings() async {
    for (final dir in {for (final x in widget.paths) vDirname(x)}) {
      try {
        _siblings[dir] = {for (final e in await vList(dir)) vBasename(e.path)};
      } catch (_) {
        _siblings[dir] = {};
      }
    }
    if (mounted) setState(() => _loading = false);
  }

  @override
  void dispose() {
    for (final x in [_template, _start, _step, _digits, _find, _replace]) {
      x.dispose();
    }
    super.dispose();
  }

  RenameRule get _rule => RenameRule(
        template: _template.text.isEmpty ? '[N]' : _template.text,
        start: int.tryParse(_start.text.trim()) ?? 1,
        step: int.tryParse(_step.text.trim()) ?? 1,
        digits: (int.tryParse(_digits.text.trim()) ?? 1).clamp(1, 9),
        find: _find.text,
        replace: _replace.text,
        ignoreCase: _ignoreCase,
        caseMode: _case,
      );

  void _insert(String tag) {
    final t = _template;
    final sel = t.selection.isValid ? t.selection : TextSelection.collapsed(offset: t.text.length);
    t.value = TextEditingValue(
      text: t.text.replaceRange(sel.start, sel.end, tag),
      selection: TextSelection.collapsed(offset: sel.start + tag.length),
    );
    setState(() {});
  }

  Future<void> _run(List<RenameRow> rows) async {
    setState(() {
      _running = true;
      _error = null;
    });
    try {
      final done = await runBatchRename([for (final r in rows) (r.path, r.newName)]);
      if (mounted) Navigator.pop(context, done);
    } on BatchRenameException catch (e) {
      if (!mounted) return;
      setState(() {
        _running = false;
        _error = [
          trf('"{0}" 의 이름을 바꾸지 못해 멈췄습니다: {1}', [vBasename(e.path), e.error]),
          if (e.stuck.isEmpty)
            tr('이미 바꾼 것은 모두 원래 이름으로 되돌렸습니다.')
          else
            trf('원래 이름으로 되돌리지 못한 것: {0}', [e.stuck.map(vBasename).join(', ')]),
        ].join('\n');
      });
      // 되돌린 뒤의 실제 이름으로 다시 본다
      _siblings.clear();
      await _loadSiblings();
    }
  }

  Widget _num(TextEditingController c, String label) => SizedBox(
        width: 72,
        child: TextField(
          controller: c,
          keyboardType: const TextInputType.numberWithOptions(signed: true),
          inputFormatters: [FilteringTextInputFormatter.allow(RegExp(r'^-?\d{0,6}'))],
          decoration: InputDecoration(labelText: label, isDense: true),
          onChanged: (_) => setState(() {}),
        ),
      );

  @override
  Widget build(BuildContext context) {
    final rule = _rule;
    final rows = planRename(widget.paths, rule, isDir: widget.isDir, siblings: _siblings);
    final changed = rows.where((r) => r.changed).length;
    final bad = rows.where((r) => r.problem != null).length;
    final canRun = !_loading && !_running && bad == 0 && changed > 0;
    return AlertDialog(
      title: Text(trf('이름 일괄 바꾸기 · {0}개', [widget.paths.length])),
      content: SizedBox(
        width: 640,
        child: Column(mainAxisSize: MainAxisSize.min, crossAxisAlignment: CrossAxisAlignment.stretch, children: [
          // 이름 틀 + [N] [C] 넣기
          Row(children: [
            Expanded(
              child: TextField(
                controller: _template,
                enabled: !_running,
                decoration: InputDecoration(
                  labelText: tr('이름 틀 (확장자는 그대로)'),
                  helperText: tr('[N] 원래 이름 · [C] 번호  예: Show S01E[C]'),
                  isDense: true,
                ),
                onChanged: (_) => setState(() {}),
              ),
            ),
            const SizedBox(width: 6),
            OutlinedButton(onPressed: _running ? null : () => _insert('[N]'), child: const Text('[N]')),
            const SizedBox(width: 4),
            OutlinedButton(onPressed: _running ? null : () => _insert('[C]'), child: const Text('[C]')),
          ]),
          const SizedBox(height: 6),
          Wrap(spacing: 10, runSpacing: 4, crossAxisAlignment: WrapCrossAlignment.end, children: [
            _num(_start, tr('번호 시작')),
            _num(_step, tr('간격')),
            _num(_digits, tr('자릿수')),
            DropdownButton<String>(
              value: _case,
              items: [
                DropdownMenuItem(value: 'keep', child: Text(tr('대소문자 그대로'))),
                DropdownMenuItem(value: 'lower', child: Text(tr('모두 작게 (abc)'))),
                DropdownMenuItem(value: 'upper', child: Text(tr('모두 크게 (ABC)'))),
                DropdownMenuItem(value: 'title', child: Text(tr('단어 첫 글자만 크게 (Abc)'))),
              ],
              onChanged: _running ? null : (v) => setState(() => _case = v!),
            ),
          ]),
          const SizedBox(height: 6),
          Wrap(spacing: 10, runSpacing: 4, crossAxisAlignment: WrapCrossAlignment.center, children: [
            SizedBox(
              width: 200,
              child: TextField(
                controller: _find,
                enabled: !_running,
                decoration: InputDecoration(labelText: tr('찾을 글'), isDense: true),
                onChanged: (_) => setState(() {}),
              ),
            ),
            SizedBox(
              width: 200,
              child: TextField(
                controller: _replace,
                enabled: !_running,
                decoration: InputDecoration(labelText: tr('바꿀 글 (비우면 지움)'), isDense: true),
                onChanged: (_) => setState(() {}),
              ),
            ),
            Row(mainAxisSize: MainAxisSize.min, children: [
              Checkbox(value: _ignoreCase, onChanged: _running ? null : (v) => setState(() => _ignoreCase = v!)),
              Text(tr('대소문자 무시')),
            ]),
          ]),
          const SizedBox(height: 10),
          Text(
            _loading
                ? tr('폴더를 읽는 중…')
                : bad > 0
                    ? trf('문제 {0}개 - 고치기 전에는 바꾸지 않습니다', [bad])
                    : trf('바뀌는 것 {0}개', [changed]),
            style: TextStyle(fontSize: 12, color: bad > 0 ? JjColors.danger : JjColors.textDim),
          ),
          const SizedBox(height: 4),
          // 미리 보기
          Flexible(
            child: ConstrainedBox(
              constraints: const BoxConstraints(maxHeight: 280),
              child: ListView.builder(
                shrinkWrap: true,
                itemCount: rows.length,
                itemBuilder: (_, i) {
                  final r = rows[i];
                  return Padding(
                    padding: const EdgeInsets.symmetric(vertical: 2),
                    child: Row(crossAxisAlignment: CrossAxisAlignment.start, children: [
                      Expanded(
                        child: Text(r.oldName,
                            maxLines: 1, overflow: TextOverflow.ellipsis, style: const TextStyle(fontSize: 12, color: JjColors.textDim)),
                      ),
                      const Padding(padding: EdgeInsets.symmetric(horizontal: 6), child: Text('→', style: TextStyle(fontSize: 12))),
                      Expanded(
                        child: Text(
                          r.problem == null ? r.newName : '${r.newName}  · ${r.problem}',
                          maxLines: 2,
                          overflow: TextOverflow.ellipsis,
                          style: TextStyle(
                            fontSize: 12,
                            color: r.problem != null ? JjColors.danger : (r.changed ? JjColors.text : JjColors.textDim),
                          ),
                        ),
                      ),
                    ]),
                  );
                },
              ),
            ),
          ),
          if (_error != null)
            Padding(
              padding: const EdgeInsets.only(top: 8),
              child: Text(_error!, style: const TextStyle(fontSize: 12, color: JjColors.danger)),
            ),
        ]),
      ),
      actions: [
        TextButton(onPressed: _running ? null : () => Navigator.pop(context), child: Text(tr('취소'))),
        FilledButton(
          onPressed: canRun ? () => _run(rows) : null,
          child: _running
              ? const SizedBox(width: 16, height: 16, child: CircularProgressIndicator(strokeWidth: 2))
              : Text(trf('바꾸기 ({0}개)', [changed])),
        ),
      ],
    );
  }
}