using Android.Content;
using Android.Gms.Extensions;
using Android.Runtime;
using Firebase;
using Firebase.Firestore;
using Java.Util;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace aa
{
    internal class Firebase
    {
        private static FirebaseFirestore DB;

        public static void Initialize(Context context)
        {
            FirebaseApp app = FirebaseApp.InitializeApp(context);
            if (app == null)
            {
                FirebaseOptions options = new FirebaseOptions.Builder()
                    .SetProjectId("")
                    .SetApplicationId("")
                    .SetApiKey("")
                    .SetStorageBucket("")
                    .Build();

                app = FirebaseApp.InitializeApp(context, options);

                DB = FirebaseFirestore.GetInstance(app);
                DB.FirestoreSettings = new FirebaseFirestoreSettings.Builder().SetPersistenceEnabled(false).Build();
            }
            else
            {
                DB = FirebaseFirestore.GetInstance(app);
            }
        }

        public static async Task CreateList(string username, string listName)
        {
            HashMap newList = new HashMap();

            newList.Put(listName, new JavaList());  // new list
            await DB.Collection("Users").Document(username).Collection("Information").Document("List").Set(newList, SetOptions.Merge());
        }

        public static async Task RemoveList(string username, string listName)
        {
            HashMap newList = new HashMap();

            newList.Put(listName, FieldValue.Delete());  // new list

            await DB.Collection("Users").Document(username).Collection("Information").Document("List").Set(newList, SetOptions.Merge());  // remove list in my user

            HashMap otherUsersNewList = new HashMap();

            otherUsersNewList.Put($"{listName} ({username})", FieldValue.Delete());  // new list

            foreach (string user in await GetUsers())
            {
                await DB.Collection("Users").Document(user).Collection("Information").Document("List").Set(otherUsersNewList, SetOptions.Merge());  // remove list from every user (also not from not me, in the next pattern: 'ListName (owner)' this is because when some user joins the list,  he sees this list in THIS specific pattern
            }
        }

        public static async Task AddToList(string username, string listName, string item)
        {
            JavaList data = await GetListData(username, listName);
            data.Add(item);

            HashMap newData = new HashMap();
            newData.Put(listName, data);

            await DB.Collection("Users").Document(username).Collection("Information").Document("List").Set(newData, SetOptions.Merge());
        }

        public static async Task RemoveFromList(string username, string listName, string item)
        {
            JavaList removedItemData = await GetListData(username, listName);
            removedItemData.Remove(item);

            HashMap newData = new HashMap();
            newData.Put(listName, removedItemData);

            await DB.Collection("Users").Document(username).Collection("Information").Document("List").Set(newData);  // without merge other items, we are OVERWRITTING them
        }

        public static async Task<List<string>> GetUsers()
        {
            List<string> usersList = new List<string>();

            QuerySnapshot querySnapshot = (QuerySnapshot)await DB.Collection("Users").Get();
            foreach (DocumentSnapshot document in querySnapshot.Documents)
            {
                usersList.Add(document.Id);
            }

            return usersList;
        }

        public static async Task<JavaList> GetListData(string username, string listName)
        {
            DocumentSnapshot snap = (DocumentSnapshot)await DB.Collection("Users").Document(username).Collection("Information").Document("List").Get();

            if (snap != null && snap.Exists())  // check if username exists (or it will return that document doesn't exists)
            {
                if (snap.Data.ContainsKey(listName))
                {
                    return (JavaList)snap.Data[listName];
                }
                else
                    return null;
            }
            return null;
        }

        public static async Task<List<string>> GetLists(string username)
        {
            DocumentSnapshot snap = (DocumentSnapshot)await DB.Collection("Users").Document(username).Collection("Information").Document("List").Get();

            if (snap != null && snap.Exists())  // check if username exists (or it will return that document doesn't exists)
                return snap.Data.Keys.ToList();
            else
                return null;
        }

        public static async Task<string> GetPassword(string username)
        {
            DocumentSnapshot snap = (DocumentSnapshot)await DB.Collection("Users").Document(username).Collection("Information").Document("Login").Get();

            if (snap != null && snap.Exists())  // check if username exists (or it will return that document doesn't exists)
                return (string)snap.Data["Password"];
            else
                return null;
        }

        public static void CreateUser(string username, string password)
        {
            HashMap data = new HashMap();
            data.Put("Created", true);

            HashMap login = new HashMap();
            login.Put("Password", password);

            DB.Collection("Users").Document(username).Set(data);  // in order to create and 'confirm' the user document, we need to add some field to this document (document can't be without any fields)

            DB.Collection("Users").Document(username).Collection("Information").Document("Login").Set(login);
        }
    }
}