using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.EntityFrameworkCore;
using xCommons.Extensions;
using xExceptions.Constants;
using xIdentityModels;
using xIdentityModels.Extensions;
using xIdentityModels.Models;
using xIdentityModels.Navigations;
using xIds.Extensions;

namespace xIds.Providers
{
    public partial class XIdentityManager
    {
        //
        #region Device Actions ...
        /// <summary>
        /// Check a Device Exists or Not
        /// </summary>
        /// <param name="device">an instance of <see>XDevice</see></param>
        /// <returns>a boolean value</returns>
        public async Task<bool> IsDeviceExistsAsync(
            XDevice device
        )
        {
            return await DbContext.Devices
                .AnyAsync(d => d.IsSameAs(device));
        }

        /// <summary>
        /// Add new Device
        /// </summary>
        /// <param name="device">an instance of <see>XDevice</see></param>
        /// <returns>an instance of <see>XDevice</see></returns>
        public async Task<XDevice> AddDeviceAsync(
            XDevice device
        )
        {
            //
            var isDeviceExists = await IsDeviceExistsAsync(device);
            if (isDeviceExists)
            {
                return null;
            }

            //
            await DbContext.Devices
                .AddAsync(device);

            await DbContext.SaveChangesAsync();

            return device;
        }

        /// <summary>
        /// Get a Device 
        /// </summary>
        /// <param name="device">an instance of <see>XDevice</see></param>
        /// <returns>an instance of <see>XDevice</see></returns>
        public Task<XDevice> GetDeviceAsync(
            XDevice device
        )
        {
            //            
            return DbContext.Devices
                .FirstOrDefaultAsync(d =>
                    d.IsSameAs(device));
        }

        /// <summary>
        /// Retrieve a List of User Related Devices
        /// </summary>
        /// <param name="userSelectByParam">user identifier</param>
        /// <param name="checkCanLoginPolicies">check a user can log in in system or not</param>
        /// <param name="checkIsBanned">check user is banned or not</param>
        /// <returns>a collection of <see>XDevice</see> instances which related to user</returns>
        public async Task<ICollection<XDevice>> GetUserDevices(
            string userSelectByParam,
            bool checkCanLoginPolicies = true,
            bool checkIsBanned = true
        )
        {
            //
            // Validate ARgs ...
            ValidationProvider.NotEmpty(userSelectByParam);

            //
            // Validate And Retrieve User ...
            var user = await ValidateUserExistsAndRetrieve(
                userSelectByParam,
                containDetails: true,
                checkCanLoginPolicies: checkCanLoginPolicies,
                checkIsBanned: checkIsBanned
            );

            //
            // Check User Devices ...
            if (!user.Devices.HasChild())
            {
                return new List<XDevice>();
            }

            //
            return user.Devices;
        }

        /// <summary>
        /// Determines a Device is Exists in User's Devices or not 
        /// </summary>
        /// <param name="user">an instance of <see>XUser</see></param>
        /// <param name="device">an instance of <see>XDevice</see></param>
        /// <returns>a boolean value</returns>
        public bool IsDeviceRelateDToUser(
            XUser user,
            XDevice device
        )
        {
            if (!user.Devices.HasChild())
            {
                return false;
            }

            //
            var result = user.Devices.Any(d => d.IsSameAs(device));

            //
            return result;
        }

        /// <summary>
        /// Determines a Device is Exists in User's Devices or not 
        /// </summary>
        /// <param name="userSelectByParam">user identifier</param>
        /// <param name="device">an instance of <see>XDevice</see></param>
        /// <param name="checkCanLoginPolicies">check a user can log in in system or not</param>
        /// <param name="checkIsBanned">check user is banned or not</param>
        /// <returns>a boolean value</returns>
        public async Task<bool> IsDeviceRelateDToUser(
            string userSelectByParam,
            XDevice device,
            bool checkCanLoginPolicies = true,
            bool checkIsBanned = true
        )
        {
            //
            // Validate Args ...
            ValidationProvider.NotEmpty(userSelectByParam);
            ValidationProvider.NotNull(device);

            //
            var userDevices = await GetUserDevices(
                userSelectByParam,
                checkCanLoginPolicies: checkCanLoginPolicies,
                checkIsBanned: checkIsBanned
            );
            if (!userDevices.HasChild())
            {
                return false;
            }

            //
            var result = userDevices.Any(d => d.IsSameAs(device));

            //
            return result;
        }

        /// <summary>
        /// Add a Device to a User Related Devices
        /// </summary>
        /// <param name="user">an instance of <see>XUser</see></param>
        /// <param name="device">an instance of <see>XDevice</see></param>
        /// <returns>a boolean value</returns>
        public async Task<bool> AddUserRelatedDevice(
            XUser user,
            XDevice device
        )
        {
            //
            var isExists = user.Devices.Any(d =>
                d.IsSameAs(device));
            if (isExists)
            {
                return true;
            }

            //
            user.Devices.Add(device);
            try
            {
                var result = await UpdateUserAsync(user);
                return result.Succeeded;
            }
            catch
            {
                throw XException.ActionFailed.ToException();
            }
        }

        /// <summary>
        /// Add a Device to a User
        /// </summary>
        /// <param name="userSelectByParam">user identifier</param>
        /// <param name="device">an instance of <see>XDevice</see></param>
        /// <param name="checkCanLoginPolicies">check a user can log in in system or not</param>
        /// <param name="checkIsBanned">check user is banned or not</param>
        /// <returns>a boolean value</returns>
        public async Task<bool> AddUserRelatedDevice(
            string userSelectByParam,
            XDevice device,
            bool checkCanLoginPolicies = true,
            bool checkIsBanned = true
        )
        {
            //
            // Validate Args ...
            ValidationProvider.NotEmpty(userSelectByParam);
            ValidationProvider.NotNull(device);

            //
            // Check Device Related ...
            var isDeviceRelatedToUser = await IsDeviceRelateDToUser(
                userSelectByParam,
                device,
                checkCanLoginPolicies: checkCanLoginPolicies,
                checkIsBanned: checkIsBanned);
            if (isDeviceRelatedToUser)
            {
                return true;
            }

            //
            // Retrieve User ...
            var user = await ValidateUserExistsAndRetrieve(
                userSelectByParam,
                containDetails: true,
                checkCanLoginPolicies: checkCanLoginPolicies,
                checkIsBanned: checkIsBanned
            );

            //
            // Add User Device ...
            user.Devices.Add(device);

            //
            var result = await UpdateUserAsync(
                user,
                checkCanLoginPolicies: false,
                checkIsBanned: false
            );

            //
            return result.Succeeded;
        }

        /// <summary>
        /// Remove a Device from a User Related Devices List
        /// </summary>
        /// <param name="user">an instance of <see>XUser</see></param>
        /// <param name="device">an instance of <see>XDevice</see></param>
        /// <returns>a boolean value</returns>
        public async Task<bool> RemoveUserRelatedDevice(
            XUser user,
            XDevice device
        )
        {
            //
            var isRelated = IsDeviceRelateDToUser(user, device);
            if (!isRelated)
            {
                return false;
            }

            //
            var instanse = user.Devices
                .FirstOrDefault(d =>
                    d.IsSameAs(device));

            //
            user.Devices.Remove(instanse);

            //
            var result = await UpdateUserAsync(
                user,
                checkCanLoginPolicies: false,
                checkIsBanned: false
            );

            //
            return result.Succeeded;
        }

        /// <summary>
        /// Remove a Device from a User Devices 
        /// </summary>
        /// <param name="userSelectByParam">user identifier</param>
        /// <param name="device">an instance of <see>XDevice</see></param>
        /// <param name="checkCanLoginPolicies">check a user can log in in system or not</param>
        /// <param name="checkIsBanned">check user is banned or not</param>
        /// <returns>a boolean value</returns>
        public async Task<bool> RemoveUserRelatedDevice(
            string userSelectByParam,
            XDevice device,
            bool checkCanLoginPolicies = true,
            bool checkIsBanned = true
        )
        {
            //
            // Validate Args ...
            ValidationProvider.NotEmpty(userSelectByParam);
            ValidationProvider.NotNull(device);

            //
            // Validate user exists and Retrieve it based on userselectbyparam ...
            var user = await ValidateUserExistsAndRetrieve(
                userSelectByParam,
                containDetails: true,
                checkCanLoginPolicies: checkCanLoginPolicies,
                checkIsBanned: checkIsBanned
            );

            //
            return await RemoveUserRelatedDevice(
                user,
                device
            );
        }
        #endregion

        //
        #region Banned Device Actions ...
        /// <summary>
        /// Check a Device is exists in Banned Devices or not
        /// </summary>
        /// <param name="device">an instance of <see>XDevice</see></param>
        /// <returns>a boolean value</returns>
        public async Task<bool> IsBannedDeviceExists(
            XDevice device
        )
        {
            //
            var result = false;
            var bannedDeviceEnumerable = DbContext.BannedDevices.AsAsyncEnumerable();
            await
            foreach (var bannedDevice in bannedDeviceEnumerable)
            {
                //
                if (bannedDevice.Device.IsSameAs(device))
                {
                    //
                    result = true;
                    break;
                }
            }

            //
            return result;
        }

        /// <summary>
        /// Find First Banned Device
        /// </summary>
        /// <param name="device">an instance of <see>XDevice</see></param>
        /// <returns>an instance of <see>XDevice</see></returns>
        public async Task<XBannedDevice> BannedDeviceFindOne(
            XDevice device
        )
        {
            //
            var result = await DbContext.BannedDevices
                .FirstOrDefaultAsync(bd =>
                    bd.Device.IsSameAs(device)
                );

            //
            return result;
        }

        /// <summary>
        /// Remove Banned Device 
        /// </summary>
        /// <param name="model">an instance of <see>XBannedDevice</see></param>
        /// <returns></returns>
        public async Task BannedDeviceRemove(
            XBannedDevice model
        )
        {
            //
            var isExists = await IsBannedDeviceExists(model.Device);
            if (!isExists)
            {
                return;
            }

            //
            var item = await BannedDeviceFindOne(model.Device);
            if (item == null)
            {
                return;
            }

            //
            DbContext.BannedDevices.Remove(item);
            await DbContext.SaveChangesAsync();
        }

        /// <summary>
        /// Check a Device is Banned or not
        /// </summary>
        /// <param name="device">an instance of <see>XDevice</see></param>
        /// <returns>a boolean value</returns>
        private async Task<bool> IsDeviceBanned(
            XDevice device
        )
        {
            //
            var result = await IsBannedDeviceExists(device);
            return result;
        }

        /// <summary>
        /// Retrieve Specific Banned Device 
        /// </summary>
        /// <param name="device">an instance of <see>XDevice</see></param>
        /// <returns>an instance of <see>XBannedDevice</see></returns>
        private async Task<XBannedDevice> GetBannedDevice(
            XDevice device
        )
        {
            //
            var result = await BannedDeviceFindOne(device);
            return result;
        }

        /// <summary>
        /// Is a Banned Device passed Banning Time 
        /// </summary>
        /// <param name="bannedDevice">an instance of <see>XBannedDevice</see></param>
        /// <returns>a boolean value</returns>
        private bool IsDelayTimePassed(
            XBannedDevice bannedDevice
        )
        {
            //
            // Validate Args ...
            if (bannedDevice == null ||
                Configuration == null)
            {
                XException.InvalidArgs.Throw();
            }

            //
            var isPassed = bannedDevice
                .IsDelayTimePassed(Configuration.BannedDeviceTimeout);

            //
            return isPassed;
        }

        /// <summary>
        /// Retrieve Passed Time from Banning Time of specific Device
        /// </summary>
        /// <param name="bannedDevice">an instance of <see>XBannedDevice</see></param>
        /// <returns>an instance of <see>DateTime</see> which represent Passed Time</returns>
        private DateTime GetPassedTime(
            XBannedDevice bannedDevice
        )
        {
            //
            var result = bannedDevice.BannedOn
                .AddSeconds(Configuration.BannedDeviceTimeout);

            //
            return result;
        }
        #endregion
    }
}