using System;
using System.Collections.Generic;
using System.IdentityModel.Tokens.Jwt;
using System.Linq;
using System.Security.Claims;
using System.Threading.Tasks;
using IdentityModel;
using Microsoft.AspNetCore.Identity;
using Microsoft.EntityFrameworkCore;
using xCommons.Constants;
using xCommons.Extensions;
using xExceptions.Constants;
using xIdentityModels;
using xIdentityModels.Constants;
using xIdentityModels.Dtos;
using xIdentityModels.Extensions;
using xIdentityModels.Navigations;

namespace xIds.Providers
{
    public partial class XIdentityManager
    {
        //
        #region User Handlers ...
        /// <summary>
        /// Check a User Exists or not
        /// </summary>
        /// <param name="userSelectByParam">specified user's identifier</param>
        /// <returns>a boolean value</returns>
        public async Task<bool> IsUserExistsAsync(
            string userSelectByParam
        )
        {
            //
            // Validate Args ...
            if (userSelectByParam.IsNullOrEmpty())
            {
                return false;
            }

            //
            var selectType = GetUserSelectByType(userSelectByParam);

            //
            var result = false;
            XUser user = null;
            switch (selectType)
            {
                case XUserSelectBy.MobileNumber:
                    user = await GetUsersDbSet()
                        .Where(ur => ur.PhoneNumber == userSelectByParam)
                        .FirstOrDefaultAsync();
                    break;

                case XUserSelectBy.Email:
                    user = await UserManager
                        .FindByEmailAsync(userSelectByParam);
                    break;

                case XUserSelectBy.Username:
                    user = await UserManager
                        .FindByNameAsync(userSelectByParam);
                    break;

                case XUserSelectBy.ID:
                default:
                    user = await UserManager
                        .FindByIdAsync(userSelectByParam);
                    break;
            }

            //
            result = user != null;

            //
            return result;
        }

        /// <summary>
        /// Check a User Selector is Available for Registration or Not
        /// </summary>
        /// <param name="userSelectByParam">specified user's identifier</param>
        /// <returns>a boolean value</returns>
        public async Task<bool> CanRegister(
            string userSelectByParam
        )
        {
            //
            // Validate ARgs ...
            ValidationProvider.NotEmpty(userSelectByParam);

            //
            var selectByType = GetUserSelectByType(userSelectByParam);

            //
            if (selectByType == XUserSelectBy.Username &&
                !ValidateUserName(userSelectByParam))
            {
                return false;
            }

            //
            var isExists = await IsUserExistsAsync(userSelectByParam);
            if (isExists)
            {
                return false;
            }

            //
            return true;
        }

        /// <summary>
        /// Get a User object
        /// </summary>
        /// <param name="userSelectByParam">specified user's identifier</param>
        /// <param name="containDetails">specifies returned object contains all Navigation Properties or not, default is false</param>
        /// <returns>an instance of <see>XUser</see></returns>
        public async Task<XUser> GetUserAsync(
            string userSelectByParam,
            bool containDetails = false
        )
        {
            //
            var isExists = await IsUserExistsAsync(userSelectByParam);
            if (!isExists)
            {
                XException.NotFound.Throw();
            }

            //
            // Fill User ...
            var selectType = GetUserSelectByType(userSelectByParam);
            XUser user = null;
            var usersStore = GetUsersDbSet(containDetails);

            //
            // Select Type ...
            switch (selectType)
            {
                case XUserSelectBy.MobileNumber:
                    user = await usersStore
                        .FirstOrDefaultAsync(ur => ur.PhoneNumber ==
                            userSelectByParam);
                    break;

                case XUserSelectBy.Email:
                    user = await usersStore
                        .FirstOrDefaultAsync(ur => ur.Email ==
                            userSelectByParam);
                    break;

                case XUserSelectBy.Username:
                    user = await usersStore
                        .FirstOrDefaultAsync(ur => ur.UserName ==
                            userSelectByParam);
                    break;

                case XUserSelectBy.ID:
                default:
                    user = await usersStore
                        .FirstOrDefaultAsync(ur => ur.Id ==
                            userSelectByParam);
                    break;
            }

            //
            return user;
        }

        /// <summary>
        /// Retrieve User Names based on UserIds
        /// </summary>
        /// <param name="userIds">a collection of user identifiers</param>
        /// <returns>a collection of Usernames</returns>
        public async Task<IEnumerable<string>> GetUserNamesAsync(
            IEnumerable<string> userIds
        )
        {
            //
            // Validate Args ...
            if (userIds == null ||
                userIds.Count() == 0)
            {
                return null;
            }

            //
            var result = await GetUsersDbSet()
                .Where(
                    xu =>
                    userIds
                    .Contains(xu.Id))
                .Select(xt => xt.UserName)
                .ToListAsync();

            //
            return result;
        }

        /// <summary>
        /// get user ids and retrieve corresponding user names
        /// </summary>
        /// <param name="model">an instance of <see>XUserNameIdRequest</see> which represent required UserIds collection</param>
        /// <returns>a collection of <see>XUserNameIdResponse</see> instances</returns>
        public async Task<IEnumerable<XUserNameIdResponse>> GetUserNameIdsAsync(
            XUserNameIdRequest model
        )
        {
            //
            // Validate Args ...
            if (model.IsNull() || !model.Ids.HasChild())
            {
                return null;
            }

            //
            var result = await GetUsersDbSet()
                .Where(
                    xu =>
                    model.Ids.Contains(xu.Id) ||
                    model.Ids.Contains(xu.Email) ||
                    model.Ids.Contains(xu.UserName) ||
                    model.Ids.Contains(xu.PhoneNumber))
                .Select(xt => new XUserNameIdResponse
                {
                    Id = xt.Id,
                    UserName = xt.UserName,
                })
                .ToListAsync();

            //
            return result;
        }

        /// <summary>
        /// Create a User
        /// </summary>
        /// <param name="user">an instance of <see>XUser</see></param>
        /// <param name="password">user's password</param>
        /// <param name="checkCanLoginPolicies">check a user can log in in system or not, default is false</param>
        /// <param name="checkIsBanned">check user is banned or not, default is false</param>
        /// <returns>an instance of <see>IdentityResult</see></returns>
        public async Task<IdentityResult> CreateUserAsync(
            XUser user,
            string password,
            bool checkCanLoginPolicies = false,
            bool checkIsBanned = false
        )
        {
            //
            if (user == null ||
                password.IsNullOrEmpty())
            {
                XException.InvalidArgs.Throw();
            }

            //
            // Get User Select By param
            var userSelectByParam = GetUserSelectByParam(user, excludes: new List<XUserSelectBy> { XUserSelectBy.ID });

            //
            // Check User Created before or not ...
            var isExists = await IsUserExistsAsync(userSelectByParam);
            if (isExists)
            {
                XException.Duplicate.Throw();
            }

            //
            var result = await UserManager.CreateAsync(user, password);
            if (result.Succeeded)
            {
                //
                var claims = await ToJwtClaims(
                    user,
                    checkCanLoginPolicies: checkCanLoginPolicies,
                    checkIsBanned: checkIsBanned);

                //
                var addClaimsResult = await UserManager.AddClaimsAsync(user, claims);

                //
                return addClaimsResult;
            }

            //
            return result;
        }

        /// <summary>
        /// Update a User Information
        /// </summary>
        /// <param name="user">an instance of <see>XUser</see></param>
        /// <param name="checkCanLoginPolicies">check a user can log in in system or not, default is true</param>
        /// <param name="checkIsBanned">check user is banned or not, default is true</param>
        /// <returns>an instance of <see>IdentityResult</see></returns>
        public async Task<IdentityResult> UpdateUserAsync(
            XUser user,
            bool checkCanLoginPolicies = true,
            bool checkIsBanned = true
        )
        {
            //
            var updateResult = await this.UserManager.UpdateAsync(user);
            if (updateResult.Succeeded)
            {
                //
                var claims = await ToJwtClaims(
                    user,
                    checkCanLoginPolicies: checkCanLoginPolicies,
                    checkIsBanned: checkIsBanned
                );
                var existsClaims = await UserManager.GetClaimsAsync(user);

                //
                await UserManager.RemoveClaimsAsync(user, existsClaims);
                var addClaimsResult = await UserManager.AddClaimsAsync(user, claims);

                //
                return addClaimsResult;
            }

            //
            return updateResult;
        }

        /// <summary>
        /// Generate JWT Claims froma DashboardUser object
        /// </summary>
        /// <param name="user">an instance of <see>XUser</see></param>
        /// <param name="checkCanLoginPolicies">check a user can log in in system or not, default is true</param>
        /// <param name="checkIsBanned">check user is banned or not, default is true</param>
        /// <returns>a collection of <see>Claim</see> instances</returns>
        public async Task<Claim[]> ToJwtClaims(
            XUser user,
            bool checkCanLoginPolicies = true,
            bool checkIsBanned = true
        )
        {
            //
            // Get New Instance of Claims ...
            var claims = new List<Claim> {
            //
            // Mapping to User.Identity.Name ...
            new Claim (JwtClaimTypes.Name, user.UserName),

            //
            // Mapping to User.Identity.Name ...
            new Claim (JwtRegisteredClaimNames.UniqueName, user.UserName),

            //
            // Other Usefull User Related Data ...
            new Claim (JwtClaimTypes.GivenName, user.FirstName),
            new Claim (JwtClaimTypes.FamilyName, user.LastName),

            //
            // User Gendre ...
            new Claim (JwtClaimTypes.Gender, user.Gender.ToString (), ClaimValueTypes.Integer),

            //
            // User Profile Picture ...
            new Claim (JwtClaimTypes.Picture, !user.Avatar.IsNullOrEmpty () ?
            user.Avatar.ToString () :
            ""),

            //
            // The Unique Identifier for Each Token ...
            new Claim (JwtRegisteredClaimNames.Jti, Guid.NewGuid ().ToString ()),

            //
            // Add isEnable and isBanned feature ...
            new Claim (
            XCustomClaims.IsEnabled,
            user.IsEnable.ToString (),
            ClaimValueTypes.Boolean
            ),
            new Claim (
            XCustomClaims.IsBanned,
            user.IsBanned.ToString (),
            ClaimValueTypes.Boolean
            ),
            };

            //
            #region Set Claims based on Profile Policies ...
            //
            if (Configuration.Policy.Profile.ContainsDateOfBirth)
            {
                claims.Add(new Claim(JwtRegisteredClaimNames.Birthdate, user.DateOfBirth.ToString()));
            }

            //
            if (Configuration.Policy.Profile.ContainsEmail)
            {
                claims.Add(new Claim(JwtClaimTypes.Email, user.Email));
                claims.Add(new Claim(
                    JwtClaimTypes.EmailVerified,
                    user.EmailConfirmed.ToString(),
                    ClaimValueTypes.Boolean));
            }

            //
            if (Configuration.Policy.Profile.ContainsPhoneNumber)
            {
                claims.Add(new Claim(JwtClaimTypes.PhoneNumber, user.PhoneNumber));
                claims.Add(new Claim(
                    JwtClaimTypes.PhoneNumberVerified,
                    user.PhoneNumberConfirmed.ToString(),
                    ClaimValueTypes.Boolean));
            }

            //
            if (Configuration.Policy.Profile.ContainsRoles)
            {
                var roleNames = await GetRoleNamesAsync(
                    user.UserName,
                    checkCanLoginPolicies: checkCanLoginPolicies,
                    checkIsBanned: checkIsBanned);
                roleNames.ToList()
                    .ForEach(rn =>
                    {
                        claims.Add(new Claim(JwtClaimTypes.Role, rn));
                    });
            }

            //
            if (Configuration.Policy.Profile.ContainsLastLogin)
            {
                claims.Add(new Claim(
                    JwtClaimTypes.AuthenticationTime,
                    user.LastLogin.ToString(),
                    ClaimValueTypes.DateTime));
            }
            #endregion

            //
            // Return Result ...
            return claims.ToArray();
        }

        /// <summary>
        /// Check User and Password relation
        /// </summary>
        /// <param name="user">an instance of <see>XUser</see></param>
        /// <param name="password">user's password</param>
        /// <param name="device">an instance of <see>XDevice</see></param>
        /// <param name="language">specify destination language</param>
        /// <param name="lockoutOnFailure">specify account lockout on failure log in</param>
        /// <param name="isForced">specify log in force without checking <see>XDevice</see> and lang relation</param>
        /// <returns>an instance of <see>SignInResult</see></returns>
        public async Task<SignInResult> CheckPasswordSignInAsync(
            XUser user,
            string password,
            XDevice device,
            string language,
            bool lockoutOnFailure,
            bool isForced = true
        )
        {
            //
            var result = await SignInManager.CheckPasswordSignInAsync(
                user, password, lockoutOnFailure
            );

            //
            if (result.Succeeded && isForced)
            {
                //
                var isExistsDevice = user.Devices.Any(d => d.IsSameAs(device));
                if (!isExistsDevice && !user.Email.IsNullOrEmpty() && user.EmailConfirmed)
                {
                    //
                    user.Devices.Add(device);

                    //
                    var updateUserResult = await UpdateUserAsync(user);
                    if (updateUserResult.Succeeded)
                    {
                        //
                        try
                        {
                            //
                            var xMessage = GetUserNewDeviceLoggedInMessage(
                                language,
                                user.Email,
                                device
                            );

                            //
                            await MessageProvider.SendMailAsync(xMessage);
                        }
                        catch { }
                    }
                }
            }

            //
            return result;
        }
        #endregion
    }
}