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

import '../../app/app_theme.dart';
import '../../services/diagnostic_log.dart';
import '../../services/school_page_diagnostic.dart';
import 'feedback_submission.dart';
import '../../widgets/adaptive_page.dart';

typedef FeedbackAttachmentPicker = Future<FeedbackAttachment?> Function();

class FeedbackPage extends StatefulWidget {
  const FeedbackPage({
    super.key,
    this.sender = const UnconfiguredFeedbackSender(),
    this.pickAttachment,
    this.limits = FeedbackLimits.defaults,
  });
  final FeedbackSender sender;
  final FeedbackAttachmentPicker? pickAttachment;
  final FeedbackLimits limits;

  @override
  State<FeedbackPage> createState() => _FeedbackPageState();
}

class _FeedbackPageState extends State<FeedbackPage> {
  final _form = GlobalKey<FormState>();
  final _message = TextEditingController();
  final _contact = TextEditingController();
  final _school = TextEditingController();
  final _attachments = <FeedbackAttachment>[];
  var _kind = FeedbackKind.problem;
  var _submitting = false;
  var _picking = false;
  var _success = false;
  var _uncertain = false;
  var _includeLogs = false;
  var _includeHtml = false;
  String? _error;
  FeedbackSubmission? _pendingSubmission;

  @override
  void dispose() {
    _message.dispose();
    _contact.dispose();
    _school.dispose();
    super.dispose();
  }

  void _changed([String? value]) {
    setState(() {
      _pendingSubmission = null;
      _error = null;
    });
  }

  Future<void> _addAttachment() async {
    if (_picking || _submitting) return;
    if (_attachments.length >= widget.limits.maxAttachments) {
      setState(() => _error = '最多添加 ${widget.limits.maxAttachments} 个附件');
      return;
    }
    setState(() => _picking = true);
    try {
      FeedbackAttachment? attachment;
      if (widget.pickAttachment != null) {
        attachment = await widget.pickAttachment!();
      } else {
        final file = await FilePicker.pickFile(
          type: FileType.custom,
          allowedExtensions: FeedbackAttachment.supportedTypes.keys.toList(),
        );
        if (file != null) {
          final knownSize = file.lengthSync();
          if (knownSize != null && knownSize > widget.limits.maxFileBytes) {
            throw FeedbackException(
              '单个附件不能超过 ${_mb(widget.limits.maxFileBytes)} MB',
            );
          }
          attachment = await FeedbackAttachment.read(
            name: file.name,
            stream: file.readAsByteStream(),
            maxBytes: widget.limits.maxFileBytes,
          );
        }
      }
      if (!mounted || attachment == null) return;
      FeedbackSubmission.validateAttachments([
        ..._attachments,
        attachment,
      ], widget.limits);
      setState(() {
        _attachments.add(attachment!);
        _pendingSubmission = null;
        _error = null;
      });
    } on FeedbackException catch (error) {
      if (mounted) setState(() => _error = error.message);
    } catch (_) {
      if (mounted) setState(() => _error = '无法读取附件，请重新选择');
    } finally {
      if (mounted) setState(() => _picking = false);
    }
  }

  Future<void> _submit() async {
    if (_submitting || _picking) return;
    if (!_uncertain && !(_form.currentState?.validate() ?? false)) return;
    FocusScope.of(context).unfocus();
    setState(() => _submitting = true);
    try {
      final html =
          _pendingSubmission == null &&
              _kind == FeedbackKind.problem &&
              _includeHtml
          ? SchoolPageDiagnostic.instance.export()
          : null;
      if (_pendingSubmission == null &&
          _kind == FeedbackKind.problem &&
          _includeHtml &&
          html == null) {
        throw const FeedbackException(
          '最近10分钟没有可用的学校导入页面。请返回本科或研究生学校页面再尝试导入，然后提交反馈；也可以取消附带HTML。',
        );
      }
      _pendingSubmission ??= _kind == FeedbackKind.problem
          ? FeedbackSubmission.problem(
              id: FeedbackSubmission.newId(),
              message: _message.text,
              contact: _contact.text,
              attachments: _attachments,
              limits: widget.limits,
              diagnosticLog: _includeLogs
                  ? await DiagnosticLog.instance.export()
                  : null,
              diagnosticHtml: html,
            )
          : FeedbackSubmission.development(
              id: FeedbackSubmission.newId(),
              school: _school.text,
              contact: _contact.text,
            );
      setState(() {
        _submitting = true;
        _error = null;
      });
      await widget.sender.send(_pendingSubmission!);
      if (_pendingSubmission?.diagnosticHtml != null) {
        SchoolPageDiagnostic.instance.clear();
      }
      if (mounted) setState(() => _success = true);
    } on FeedbackDeliveryUncertain catch (error) {
      if (mounted) {
        setState(() {
          _uncertain = true;
          _error = error.message;
        });
      }
    } on FeedbackException catch (error) {
      if (mounted) setState(() => _error = error.message);
    } catch (_) {
      if (mounted) setState(() => _error = '提交未完成，请检查网络后重试。填写内容和附件已保留。');
    } finally {
      if (mounted) setState(() => _submitting = false);
    }
  }

  @override
  Widget build(BuildContext context) => PopScope(
    canPop: !_submitting,
    child: Scaffold(
      appBar: AppBar(title: const Text('反馈与共建')),
      body: AdaptivePage(
        maxWidth: 760,
        child: _success
            ? _successView(context)
            : _uncertain
            ? _uncertainView()
            : Form(
                key: _form,
                child: ListView(
                  padding: const EdgeInsets.all(22),
                  children: [
                    SegmentedButton<FeedbackKind>(
                      segments: const [
                        ButtonSegment(
                          value: FeedbackKind.problem,
                          label: Text('反馈问题和建议'),
                        ),
                        ButtonSegment(
                          value: FeedbackKind.development,
                          label: Text('我要参与开发'),
                        ),
                      ],
                      selected: {_kind},
                      showSelectedIcon: false,
                      onSelectionChanged: _submitting
                          ? null
                          : (value) {
                              setState(() {
                                _kind = value.single;
                                _pendingSubmission = null;
                                _error = null;
                              });
                              _form.currentState?.reset();
                            },
                    ),
                    const SizedBox(height: 18),
                    SurfaceCard(
                      child: Column(
                        crossAxisAlignment: CrossAxisAlignment.start,
                        children: [
                          Text(
                            _kind == FeedbackKind.problem
                                ? '告诉我们哪里需要改进'
                                : '一起让课表变得更好',
                            style: const TextStyle(
                              fontSize: 18,
                              fontWeight: FontWeight.w700,
                            ),
                          ),
                          const SizedBox(height: 8),
                          Text(
                            _kind == FeedbackKind.problem
                                ? '请描述遇到的问题或你的建议。联系方式和图片、视频都可以选填。'
                                : '请留下你的学校和联系方式，方便开发者与你联系。',
                            style: TextStyle(
                              fontSize: 12,
                              height: 1.7,
                              color: ink.withValues(alpha: 0.6),
                            ),
                          ),
                          const SizedBox(height: 20),
                          if (_kind == FeedbackKind.problem)
                            TextFormField(
                              key: const Key('feedback-message'),
                              controller: _message,
                              enabled: !_submitting,
                              minLines: 4,
                              maxLines: 8,
                              maxLength: 5000,
                              decoration: const InputDecoration(
                                labelText: '问题或建议（必填）',
                                alignLabelWithHint: true,
                              ),
                              onChanged: _changed,
                              validator: (value) =>
                                  (value?.trim().isEmpty ?? true)
                                  ? '请填写问题或建议'
                                  : null,
                            )
                          else
                            TextFormField(
                              key: const Key('feedback-school'),
                              controller: _school,
                              enabled: !_submitting,
                              maxLength: 200,
                              decoration: const InputDecoration(
                                labelText: '学校（必填）',
                              ),
                              onChanged: _changed,
                              validator: (value) =>
                                  (value?.trim().isEmpty ?? true)
                                  ? '请填写学校'
                                  : null,
                            ),
                          const SizedBox(height: 14),
                          TextFormField(
                            key: const Key('feedback-contact'),
                            controller: _contact,
                            enabled: !_submitting,
                            maxLength: 200,
                            decoration: InputDecoration(
                              labelText: _kind == FeedbackKind.problem
                                  ? '联系方式（选填）'
                                  : '联系方式（必填）',
                              hintText: '微信、QQ、邮箱等',
                            ),
                            onChanged: _changed,
                            validator: (value) =>
                                _kind == FeedbackKind.development &&
                                    (value?.trim().isEmpty ?? true)
                                ? '请填写联系方式'
                                : null,
                          ),
                          if (_kind == FeedbackKind.problem) ...[
                            CheckboxListTile(
                              key: const Key('feedback-logs'),
                              contentPadding: EdgeInsets.zero,
                              title: const Text('附带近10分钟诊断日志'),
                              subtitle: const Text(
                                '包含登录跳转、课表读取及错误状态，帮助排查问题；不包含密码、验证码或课表内容。',
                              ),
                              value: _includeLogs,
                              onChanged: _submitting
                                  ? null
                                  : (value) {
                                      setState(() {
                                        _includeLogs = value ?? false;
                                        if (!_includeLogs) _includeHtml = false;
                                        _pendingSubmission = null;
                                        _error = null;
                                      });
                                    },
                            ),
                            CheckboxListTile(
                              key: const Key('feedback-html'),
                              contentPadding: EdgeInsets.zero,
                              title: const Text('附带最近一次学校导入页面HTML'),
                              subtitle: const Text(
                                '适用于本科和研究生课表、考试导入。需先勾选日志。网页可能含姓名、学号、课程、教师和考场信息，仅保留最近10分钟，单独作为邮件附件发送。',
                              ),
                              value: _includeHtml,
                              onChanged: _submitting || !_includeLogs
                                  ? null
                                  : (value) async {
                                      var accepted = value ?? false;
                                      if (accepted) {
                                        accepted =
                                            await showDialog<bool>(
                                              context: context,
                                              builder: (context) => AlertDialog(
                                                title: const Text('附带网页排查资料？'),
                                                content: const Text(
                                                  '附件可能包含你的姓名、学号、课程及考试信息，将发送给开发者用于排查导入问题。密码、验证码、Cookie和认证参数不会包含在附件中。',
                                                ),
                                                actions: [
                                                  TextButton(
                                                    onPressed: () =>
                                                        Navigator.pop(
                                                          context,
                                                          false,
                                                        ),
                                                    child: const Text('取消'),
                                                  ),
                                                  FilledButton(
                                                    onPressed: () =>
                                                        Navigator.pop(
                                                          context,
                                                          true,
                                                        ),
                                                    child: const Text('同意附带'),
                                                  ),
                                                ],
                                              ),
                                            ) ??
                                            false;
                                      }
                                      if (!mounted) return;
                                      setState(() {
                                        _includeHtml = accepted;
                                        _pendingSubmission = null;
                                        _error = null;
                                      });
                                    },
                            ),
                            const SizedBox(height: 10),
                            const Text(
                              '图片或视频（选填）',
                              style: TextStyle(fontWeight: FontWeight.w600),
                            ),
                            const SizedBox(height: 6),
                            Text(
                              '最多 ${widget.limits.maxAttachments} 个，每个 ${_mb(widget.limits.maxFileBytes)} MB，合计 ${_mb(widget.limits.maxTotalBytes)} MB',
                              style: TextStyle(
                                fontSize: 11,
                                color: ink.withValues(alpha: 0.55),
                              ),
                            ),
                            for (var i = 0; i < _attachments.length; i++)
                              ListTile(
                                contentPadding: EdgeInsets.zero,
                                leading: Icon(
                                  _attachments[i].contentType.startsWith(
                                        'image/',
                                      )
                                      ? Icons.image_outlined
                                      : Icons.videocam_outlined,
                                ),
                                title: Text(
                                  _attachments[i].filename,
                                  maxLines: 2,
                                  overflow: TextOverflow.ellipsis,
                                ),
                                subtitle: Text(
                                  '${(_attachments[i].size / 1024).toStringAsFixed(1)} KB',
                                ),
                                trailing: IconButton(
                                  tooltip: '移除 ${_attachments[i].filename}',
                                  onPressed: _submitting
                                      ? null
                                      : () => setState(() {
                                          _attachments.removeAt(i);
                                          _pendingSubmission = null;
                                          _error = null;
                                        }),
                                  icon: const Icon(Icons.close_rounded),
                                ),
                              ),
                            const SizedBox(height: 8),
                            OutlinedButton.icon(
                              key: const Key('feedback-add-media'),
                              onPressed: _submitting || _picking
                                  ? null
                                  : _addAttachment,
                              icon: const Icon(Icons.attach_file_rounded),
                              label: Text(_picking ? '正在读取附件…' : '添加图片或视频'),
                            ),
                          ],
                        ],
                      ),
                    ),
                    const SizedBox(height: 16),
                    if (_error != null) ...[
                      Text(
                        _error!,
                        style: TextStyle(
                          color: Theme.of(context).colorScheme.error,
                        ),
                        semanticsLabel: _error,
                      ),
                      const SizedBox(height: 14),
                    ],
                    FilledButton(
                      key: const Key('feedback-submit'),
                      onPressed: _submitting || _picking ? null : _submit,
                      child: _submitting
                          ? const Row(
                              mainAxisSize: MainAxisSize.min,
                              children: [
                                SizedBox(
                                  width: 16,
                                  height: 16,
                                  child: CircularProgressIndicator(
                                    strokeWidth: 2,
                                    color: Colors.white,
                                  ),
                                ),
                                SizedBox(width: 10),
                                Text('正在提交…'),
                              ],
                            )
                          : const Text('提交'),
                    ),
                    const SizedBox(height: 12),
                    Text(
                      '点击提交后，仅发送你在当前类型填写的内容和选择的附件。',
                      textAlign: TextAlign.center,
                      style: TextStyle(
                        fontSize: 11,
                        height: 1.6,
                        color: ink.withValues(alpha: 0.5),
                      ),
                    ),
                  ],
                ),
              ),
      ),
    ),
  );

  Widget _uncertainView() => ListView(
    padding: const EdgeInsets.all(28),
    children: [
      const Icon(Icons.mail_outline_rounded, color: river, size: 54),
      const SizedBox(height: 18),
      const Text(
        '提交状态待确认',
        textAlign: TextAlign.center,
        style: TextStyle(fontSize: 22, fontWeight: FontWeight.w700),
      ),
      const SizedBox(height: 14),
      Text(
        _error ?? FeedbackDeliveryUncertain.instructions,
        style: const TextStyle(height: 1.7),
      ),
      const SizedBox(height: 20),
      const Text('提交编号（可长按复制）'),
      const SizedBox(height: 8),
      SelectableText(
        _pendingSubmission!.id,
        key: const Key('feedback-uncertain-id'),
      ),
      const SizedBox(height: 20),
      FilledButton(
        key: const Key('feedback-check-original'),
        onPressed: _submitting ? null : _submit,
        child: Text(_submitting ? '正在检查…' : '检查原提交状态'),
      ),
      const SizedBox(height: 10),
      const Text(
        '检查会使用原提交编号和原内容。核对完成前，退出后也请勿创建相同内容的新反馈。',
        style: TextStyle(fontSize: 12, height: 1.6),
      ),
    ],
  );

  Widget _successView(BuildContext context) => Center(
    child: Padding(
      padding: const EdgeInsets.all(28),
      child: Column(
        mainAxisSize: MainAxisSize.min,
        children: [
          const Icon(
            Icons.check_circle_outline_rounded,
            color: river,
            size: 54,
          ),
          const SizedBox(height: 18),
          const Text(
            '提交成功',
            style: TextStyle(fontSize: 22, fontWeight: FontWeight.w700),
          ),
          const SizedBox(height: 10),
          Text(
            _kind == FeedbackKind.problem
                ? '感谢你的反馈，我们已收到。'
                : '感谢你愿意参与，我们已收到你的信息。',
            textAlign: TextAlign.center,
          ),
          const SizedBox(height: 22),
          FilledButton(
            onPressed: () => Navigator.of(context).maybePop(),
            child: const Text('完成'),
          ),
        ],
      ),
    ),
  );

  String _mb(int bytes) => (bytes / (1024 * 1024)).toStringAsFixed(0);
}