import 'dart:async';
import 'dart:math';

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:logging/logging.dart';
import 'package:nc_photos/account.dart';
import 'package:nc_photos/app_db.dart';
import 'package:nc_photos/app_localizations.dart';
import 'package:nc_photos/entity/file.dart';
import 'package:nc_photos/entity/file/data_source.dart';
import 'package:nc_photos/entity/share.dart';
import 'package:nc_photos/entity/share/data_source.dart';
import 'package:nc_photos/exception.dart';
import 'package:nc_photos/exception_util.dart' as exception_util;
import 'package:nc_photos/iterable_extension.dart';
import 'package:nc_photos/k.dart' as k;
import 'package:nc_photos/mobile/share.dart';
import 'package:nc_photos/platform/k.dart' as platform_k;
import 'package:nc_photos/remote_storage_util.dart' as remote_storage_util;
import 'package:nc_photos/snack_bar_manager.dart';
import 'package:nc_photos/use_case/copy.dart';
import 'package:nc_photos/use_case/create_dir.dart';
import 'package:nc_photos/use_case/create_share.dart';
import 'package:nc_photos/use_case/download_file.dart';
import 'package:nc_photos/widget/processing_dialog.dart';
import 'package:nc_photos/widget/share_link_multiple_files_dialog.dart';
import 'package:nc_photos/widget/share_method_dialog.dart';
import 'package:nc_photos/widget/simple_input_dialog.dart';
import 'package:tuple/tuple.dart';

/// Handle sharing to other apps
class ShareHandler {
  ShareHandler({
    required this.context,
    this.clearSelection,
  });

  Future<void> shareFiles(Account account, List<File> files) async {
    try {
      final method = await _askShareMethod();
      if (method == null) {
        // user canceled
        return;
      } else if (method == ShareMethod.publicLink) {
        return await _shareAsLink(account, files, false);
      } else if (method == ShareMethod.passwordLink) {
        return await _shareAsLink(account, files, true);
      } else {
        return await _shareAsFile(account, files);
      }
    } catch (e, stackTrace) {
      _log.shout("[shareFiles] Failed while sharing files", e, stackTrace);
      SnackBarManager().showSnackBar(SnackBar(
        content: Text(exception_util.toUserString(e)),
        duration: k.snackBarDurationNormal,
      ));
    } finally {
      if (!isSelectionCleared) {
        clearSelection?.call();
      }
    }
  }

  Future<ShareMethod?> _askShareMethod() {
    return showDialog<ShareMethod>(
        context: context, builder: (context) => const ShareMethodDialog());
  }

  Future<void> _shareAsFile(Account account, List<File> files) async {
    assert(platform_k.isAndroid);
    final controller = StreamController<String>();
    showDialog(
      context: context,
      builder: (context) => StreamBuilder(
        stream: controller.stream,
        builder: (context, snapshot) => ProcessingDialog(
          text: L10n.global().shareDownloadingDialogContent +
              (snapshot.hasData ? " ${snapshot.data}" : ""),
        ),
      ),
    );
    final results = <Tuple2<File, dynamic>>[];
    for (final pair in files.withIndex()) {
      final i = pair.item1, f = pair.item2;
      controller.add("($i/${files.length})");
      try {
        results.add(Tuple2(
            f,
            await DownloadFile()(
              account,
              f,
              shouldNotify: false,
            )));
      } on PermissionException catch (_) {
        _log.warning("[_shareAsFile] Permission not granted");
        SnackBarManager().showSnackBar(SnackBar(
          content: Text(L10n.global().downloadFailureNoPermissionNotification),
          duration: k.snackBarDurationNormal,
        ));
        // dismiss the dialog
        Navigator.of(context).pop();
        rethrow;
      } catch (e, stacktrace) {
        _log.shout("[_shareAsFile] Failed while downloadFile", e, stacktrace);
        SnackBarManager().showSnackBar(SnackBar(
          content: Text(exception_util.toUserString(e)),
          duration: k.snackBarDurationNormal,
        ));
      }
    }
    // dismiss the dialog
    Navigator.of(context).pop();

    final share = AndroidFileShare(
        results.map((e) => e.item2 as String).toList(),
        results.map((e) => e.item1.contentType).toList());
    share.share();
  }

  Future<void> _shareAsLink(
      Account account, List<File> files, bool isPasswordProtected) async {
    if (files.length == 1) {
      String? password;
      if (isPasswordProtected) {
        password = await _askPassword();
        if (password == null) {
          // user canceled
          return;
        }
      }
      return _shareFileAsLink(account, files.first, password);
    } else {
      final result = await _askDirDetail(context, isPasswordProtected);
      if (result == null) {
        // user canceled
        return;
      }
      _log.info("[_shareAsLink] Share as folder: ${result.albumName}");
      ScaffoldFeatureController? controller =
          SnackBarManager().showSnackBar(SnackBar(
        content: Text(L10n.global().createShareProgressText),
        duration: k.snackBarDurationShort,
      ));
      controller?.closed.whenComplete(() {
        controller = null;
      });
      clearSelection?.call();
      isSelectionCleared = true;

      final fileRepo = FileRepo(FileCachedDataSource(AppDb()));
      final path = await _createDir(fileRepo, account, result.albumName);
      await _copyFilesToDir(fileRepo, account, files, path);
      controller?.close();
      return _shareFileAsLink(
        account,
        File(
          path: path,
          isCollection: true,
        ),
        result.password,
      );
    }
  }

  Future<void> _shareFileAsLink(
      Account account, File file, String? password) async {
    final shareRepo = ShareRepo(ShareRemoteDataSource());
    try {
      final share = await CreateLinkShare(shareRepo)(
        account,
        file,
        password: password,
      );
      await Clipboard.setData(ClipboardData(text: share.url));
      SnackBarManager().showSnackBar(SnackBar(
        content: Text(L10n.global().linkCopiedNotification),
        duration: k.snackBarDurationNormal,
      ));

      if (platform_k.isAndroid) {
        final textShare = AndroidTextShare(share.url!);
        textShare.share();
      }
    } catch (e, stackTrace) {
      _log.shout(
          "[_shareFileAsLink] Failed while CreateLinkShare", e, stackTrace);
      SnackBarManager().showSnackBar(SnackBar(
        content: Text(exception_util.toUserString(e)),
        duration: k.snackBarDurationNormal,
      ));
    }
  }

  Future<String?> _askPassword() {
    return showDialog<String>(
      context: context,
      builder: (context) => SimpleInputDialog(
        hintText: L10n.global().passwordInputHint,
        buttonText: MaterialLocalizations.of(context).okButtonLabel,
        validator: (value) {
          if (value?.isNotEmpty != true) {
            return L10n.global().passwordInputInvalidEmpty;
          }
          return null;
        },
        obscureText: true,
      ),
    );
  }

  Future<ShareLinkMultipleFilesDialogResult?> _askDirDetail(
      BuildContext context, bool isPasswordProtected) {
    return showDialog<ShareLinkMultipleFilesDialogResult>(
      context: context,
      builder: (_) => ShareLinkMultipleFilesDialog(
        shouldAskPassword: isPasswordProtected,
      ),
    );
  }

  Future<String> _createDir(
      FileRepo fileRepo, Account account, String name) async {
    // add a intermediate dir to allow shared dirs having the same name. Since
    // the dir names are public, we can't add random pre/suffix
    final timestamp = DateTime.now().millisecondsSinceEpoch;
    final random = Random().nextInt(0xFFFFFF);
    final dirName =
        "${timestamp.toRadixString(16)}-${random.toRadixString(16).padLeft(6, "0")}";
    final path =
        "${remote_storage_util.getRemoteLinkSharesDir(account)}/$dirName/$name";
    await CreateDir(fileRepo)(account, path);
    return path;
  }

  Future<void> _copyFilesToDir(FileRepo fileRepo, Account account,
      List<File> files, String dirPath) async {
    var failureCount = 0;
    for (final f in files) {
      try {
        await Copy(fileRepo)(account, f, "$dirPath/${f.filename}");
      } catch (e, stackTrace) {
        _log.severe(
            "[_copyFilesToDir] Failed while copying file: $f", e, stackTrace);
        ++failureCount;
      }
    }
    if (failureCount != 0) {
      SnackBarManager().showSnackBar(SnackBar(
        content: Text(L10n.global().copyItemsFailureNotification(failureCount)),
        duration: k.snackBarDurationNormal,
      ));
    }
  }

  final BuildContext context;
  final VoidCallback? clearSelection;
  var isSelectionCleared = false;

  static final _log = Logger("share_handler.ShareHandler");
}