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

import 'package:fimber/fimber.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:gitjournal/apis/git_migration.dart';
import 'package:gitjournal/appstate.dart';
import 'package:gitjournal/core/note.dart';
import 'package:gitjournal/core/notes_cache.dart';
import 'package:gitjournal/core/notes_folder.dart';
import 'package:gitjournal/core/git_repo.dart';
import 'package:gitjournal/settings.dart';
import 'package:path/path.dart' as p;
import 'package:shared_preferences/shared_preferences.dart';
import 'package:flutter_crashlytics/flutter_crashlytics.dart';

class StateContainer with ChangeNotifier {
  final AppState appState;

  // FIXME: The gitRepo should never be changed once it has been setup
  //        We should always just be modifying the 'git remotes'
  //        With that, the StateContainer can be a StatelessWidget
  GitNoteRepository _gitRepo;
  NotesCache _notesCache;

  StateContainer(this.appState) {
    assert(appState.localGitRepoConfigured);

    String repoPath;
    if (appState.remoteGitRepoConfigured) {
      repoPath =
          p.join(appState.gitBaseDirectory, appState.remoteGitRepoFolderName);
    } else if (appState.localGitRepoConfigured) {
      repoPath =
          p.join(appState.gitBaseDirectory, appState.localGitRepoFolderName);
    }

    _gitRepo = GitNoteRepository(gitDirPath: repoPath);
    appState.notesFolder = NotesFolder(null, _gitRepo.gitDirPath);

    // Just a fail safe
    if (!appState.remoteGitRepoConfigured) {
      removeExistingRemoteClone();
    }

    var cachePath = p.join(appState.gitBaseDirectory, "cache.json");
    _notesCache = NotesCache(
      filePath: cachePath,
      notesBasePath: _gitRepo.gitDirPath,
    );

    _loadFromCache();
    _syncNotes();
  }

  void _loadFromCache() async {
    await _notesCache.load(appState.notesFolder);
    Fimber.i("Finished loading the notes cache");

    await _loadNotes();
    Fimber.i("Finished loading all the notes");
  }

  void removeExistingRemoteClone() async {
    var remoteGitDir = Directory(
        p.join(appState.gitBaseDirectory, appState.remoteGitRepoFolderName));
    var dotGitDir = Directory(p.join(remoteGitDir.path, ".git"));

    bool exists = dotGitDir.existsSync();
    if (exists) {
      await remoteGitDir.delete(recursive: true);
    }
  }

  Future<void> _loadNotes() async {
    // FIXME: We should report the notes that failed to load
    await appState.notesFolder.loadRecursively();
    await _notesCache.buildCache(
      appState.notesFolder,
      Settings.instance.sortingMode,
    );
  }

  Future<void> syncNotes({bool doNotThrow = false}) async {
    if (!appState.remoteGitRepoConfigured) {
      Fimber.d("Not syncing because RemoteRepo not configured");
      return true;
    }

    appState.syncStatus = SyncStatus.Loading;
    notifyListeners();

    try {
      await _gitRepo.sync();

      Fimber.d("Synced!");
      appState.syncStatus = SyncStatus.Done;
      notifyListeners();
    } catch (e, stacktrace) {
      Fimber.d("Failed to Sync");
      appState.syncStatus = SyncStatus.Error;
      notifyListeners();
      if (shouldLogGitException(e)) {
        await FlutterCrashlytics().logException(e, stacktrace);
      }
      if (!doNotThrow) rethrow;
    }
    await _loadNotes();
  }

  Future<void> _syncNotes() async {
    var freq = Settings.instance.remoteSyncFrequency;
    if (freq != RemoteSyncFrequency.Automatic) {
      return;
    }
    return syncNotes(doNotThrow: true);
  }

  void createFolder(NotesFolder parent, String folderName) async {
    var newFolderPath = p.join(parent.folderPath, folderName);
    var newFolder = NotesFolder(parent, newFolderPath);
    newFolder.create();

    Fimber.d("Created New Folder: " + newFolderPath);
    parent.addFolder(newFolder);

    _gitRepo.addFolder(newFolder).then((NoteRepoResult _) {
      _syncNotes();
    });
  }

  void removeFolder(NotesFolder folder) {
    Fimber.d("Removing Folder: " + folder.folderPath);

    folder.parent.removeFolder(folder);
    _gitRepo.removeFolder(folder.folderPath).then((NoteRepoResult _) {
      _syncNotes();
    });
  }

  void renameFolder(NotesFolder folder, String newFolderName) {
    var oldFolderPath = folder.folderPath;
    folder.rename(newFolderName);

    _gitRepo
        .renameFolder(oldFolderPath, folder.folderPath)
        .then((NoteRepoResult _) {
      _syncNotes();
    });
  }

  void renameNote(Note note, String newFileName) {
    var oldNotePath = note.filePath;
    note.rename(newFileName);

    _gitRepo.renameNote(oldNotePath, note.filePath).then((NoteRepoResult _) {
      _syncNotes();
    });
  }

  void moveNote(Note note, NotesFolder destFolder) {
    if (destFolder.folderPath == note.parent.folderPath) {
      return;
    }
    var oldNotePath = note.filePath;
    note.move(destFolder);

    _gitRepo.moveNote(oldNotePath, note.filePath).then((NoteRepoResult _) {
      _syncNotes();
    });
  }

  void addNote(Note note) {
    Fimber.d("State Container addNote");
    note.parent.insert(0, note);
    note.updateModified();
    _gitRepo.addNote(note).then((NoteRepoResult _) {
      _syncNotes();
    });
  }

  void removeNote(Note note) {
    // FIXME: What if the Note hasn't yet been saved?
    note.parent.remove(note);
    _gitRepo.removeNote(note.filePath).then((NoteRepoResult _) async {
      // FIXME: Is there a way of figuring this amount dynamically?
      // The '4 seconds' is taken from snack_bar.dart -> _kSnackBarDisplayDuration
      // We wait an aritfical amount of time, so that the user has a change to undo
      // their delete operation, and that commit is not synced with the server, till then.
      await Future.delayed(const Duration(seconds: 4));
      _syncNotes();
    });
  }

  void undoRemoveNote(Note note) {
    note.parent.insert(0, note);
    _gitRepo.resetLastCommit().then((NoteRepoResult _) {
      _syncNotes();
    });
  }

  void updateNote(Note note) {
    Fimber.d("State Container updateNote");
    note.updateModified();
    _gitRepo.updateNote(note).then((NoteRepoResult _) {
      _syncNotes();
    });
  }

  void completeGitHostSetup() {
    () async {
      appState.remoteGitRepoConfigured = true;
      appState.remoteGitRepoFolderName = "journal";

      await migrateGitRepo(
        fromGitBasePath: appState.localGitRepoFolderName,
        toGitBaseFolder: appState.remoteGitRepoFolderName,
        gitBasePath: appState.gitBaseDirectory,
      );

      var repoPath =
          p.join(appState.gitBaseDirectory, appState.remoteGitRepoFolderName);
      _gitRepo = GitNoteRepository(gitDirPath: repoPath);
      appState.notesFolder.reset(_gitRepo.gitDirPath);

      await _persistConfig();
      _loadNotes();
      _syncNotes();

      notifyListeners();
    }();
  }

  void completeOnBoarding() {
    appState.onBoardingCompleted = true;
    _persistConfig();
    notifyListeners();
  }

  Future _persistConfig() async {
    var pref = await SharedPreferences.getInstance();
    await appState.save(pref);
  }
}