using System;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.ComponentModel;
using System.Configuration.Provider;
using System.Linq;
using System.Threading.Tasks;
using System.Web.Security;
using MongoAuth.Properties;
using MongoDB.Bson;
using MongoDB.Bson.Serialization.Attributes;
using MongoDB.Driver;

namespace MongoAuth
{
    public class MongoRoleProvider : RoleProvider
    {
        private const string MEMBER_COLLECTION_NAME = "members";
        private const string ROLE_COLLECTION_NAME = "roles";
        private IMongoCollection<MongoMember> _memberCollection;
        private IMongoCollection<MongoRole> _roleCollection;

        public override string ApplicationName
        {
            get => "";
            set { }
        }

        public override void Initialize(string name, NameValueCollection config)
        {
            base.Initialize(name, config);

            var settings = new MongoClientSettings
            {
                Server = new MongoServerAddress(DatabaseConfig.Host, DatabaseConfig.Port)
            };

            if (!string.IsNullOrEmpty(DatabaseConfig.Username) && !string.IsNullOrEmpty(DatabaseConfig.Password))
            {
                settings.Credential = MongoCredential.CreateCredential(DatabaseConfig.Database,
                    DatabaseConfig.Username,
                    DatabaseConfig.Password);
            }

            var dbClient = new MongoClient(settings);

            _roleCollection = dbClient.GetDatabase(DatabaseConfig.Database)
                .GetCollection<MongoRole>(ROLE_COLLECTION_NAME);
            _memberCollection = dbClient.GetDatabase(DatabaseConfig.Database)
                .GetCollection<MongoMember>(MEMBER_COLLECTION_NAME);
        }

        public override void AddUsersToRoles(string[] usernames, string[] roleNames)
        {
            var roleTask = _roleCollection.Find(r => roleNames.Contains(r.RoleName)).ToListAsync();
            roleTask.Wait();
            var roles = roleTask.Result;

            var userTask = _memberCollection.Find(u => usernames.Contains(u.UserName)).ToListAsync();
            userTask.Wait();
            var users = userTask.Result;

            for (int i = 0; i < roles.Count; i++)
            {
                var newUsers = new List<Guid>();

                if (roles[i].Users != null)
                {
                    newUsers.AddRange(roles[i].Users);
                }

                var usersToAdd = from u in users
                    where newUsers.All(v => v != u.Id)
                    select u.Id;

                newUsers.AddRange(usersToAdd);

                roles[i].Users = newUsers.ToArray();

                var update =
                    _roleCollection.ReplaceOneAsync(Builders<MongoRole>.Filter.Eq(r => r.Id, roles[i].Id), roles[i]);
                update.Wait();
            }
        }

        public override void CreateRole(string roleName)
        {
            var role = _roleCollection.Find(r => r.RoleName == roleName).SingleOrDefaultAsync();
            role.Wait();
            if (role.Result != null)
            {
                return;
            }

            var mr = new MongoRole
            {
                Id = Guid.NewGuid(),
                RoleName = roleName
            };

            Task task = _roleCollection.InsertOneAsync(mr);
            task.Wait();
        }

        public override bool DeleteRole(string roleName, bool throwOnPopulatedRole)
        {
            var role = _roleCollection.Find(r => r.RoleName == roleName).SingleOrDefaultAsync();
            role.Wait();

            if (role.Result != null
                && role.Result.Users.Length > 0
                && throwOnPopulatedRole)
            {
                throw new ProviderException(Resources.RoleNotEmpty);
            }

            var task = _roleCollection.DeleteOneAsync(r => r.RoleName == roleName);
            task.Wait();

            return true;
        }

        public override string[] FindUsersInRole(string roleName, string usernameToMatch)
        {
            var role = _roleCollection.Find(r => r.RoleName == roleName).SingleOrDefaultAsync();
            role.Wait();

            if (role.Result == null)
            {
                return Array.Empty<string>();
            }

            var users = _memberCollection.Find(u
                    => role.Result.Users.Contains(u.Id) && u.UserName.ToLower().Contains(usernameToMatch.ToLower()))
                .ToListAsync();
            users.Wait();

            return users.Result.Select(r => r.UserName).ToArray();
        }

        public override string[] GetAllRoles()
        {
            var roles = _roleCollection.Find(new BsonDocument()).ToListAsync();
            roles.Wait();

            return roles.Result.Select(r => r.RoleName).ToArray();
        }

        public override string[] GetRolesForUser(string username)
        {
            var user = _memberCollection.Find(u => u.UserName.ToLower() == username.ToLower()).SingleOrDefaultAsync();
            user.Wait();

            if (user.Result == null)
            {
                return Array.Empty<string>();
            }

            var role = _roleCollection.Find(r => r.Users != null && r.Users.Contains(user.Result.Id)).ToListAsync();
            role.Wait();

            return role.Result.Select(r => r.RoleName).ToArray();
        }

        public override string[] GetUsersInRole(string roleName)
        {
            var role = _roleCollection.Find(r => r.RoleName == roleName).SingleOrDefaultAsync();
            role.Wait();

            if (role.Result == null)
            {
                return Array.Empty<string>();
            }

            var users = _memberCollection.Find(u => role.Result.Users.Contains(u.Id)).ToListAsync();
            users.Wait();

            return users.Result.Select(u => u.UserName).ToArray();
        }

        public override bool IsUserInRole(string username, string roleName)
        {
            var user = _memberCollection.Find(u => u.UserName.ToLower() == username.ToLower()).SingleOrDefaultAsync();
            var role = _roleCollection.Find(r => r.RoleName == roleName).SingleOrDefaultAsync();
            user.Wait();
            role.Wait();

            if (user.Result == null
                || role.Result?.Users == null)
            {
                return false;
            }

            return role.Result.Users.Contains(user.Result.Id);
        }

        public override void RemoveUsersFromRoles(string[] usernames, string[] roleNames)
        {
            var roleTask = _roleCollection.Find(r => roleNames.Contains(r.RoleName)).ToListAsync();
            roleTask.Wait();
            var roles = roleTask.Result;

            var userTask = _memberCollection.Find(u => usernames.Contains(u.UserName)).ToListAsync();
            userTask.Wait();
            var users = userTask.Result;

            foreach (MongoRole t in roles)
            {
                t.Users = (from u in t.Users
                    where users.All(v => v.Id != u)
                    select u).ToArray();

                var update = _roleCollection.ReplaceOneAsync(Builders<MongoRole>.Filter.Eq(r => r.Id, t.Id), t);
                update.Wait();
            }
        }

        public override bool RoleExists(string roleName)
        {
            var role = _roleCollection.Find(r => r.RoleName == roleName).SingleOrDefaultAsync();
            role.Wait();

            return role.Result != null;
        }
    }

    [DataObject]
    public class MongoRole
    {
        [BsonId]
        public Guid Id { get; set; }

        public string RoleName { get; set; }

        public Guid[] Users { get; set; }
    }
}