using System.IO;
using System.Reflection;
using System.Linq;
using System;
using System.Collections.Generic;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Mvc.ApiExplorer;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Microsoft.EntityFrameworkCore;
using Microsoft.AspNetCore.Authentication.JwtBearer;
using Microsoft.IdentityModel.Tokens;
using Microsoft.Extensions.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.OpenApi.Models;
using Microsoft.Extensions.Options;
using Swashbuckle.AspNetCore.SwaggerGen;

using AyaNova.Models;
using AyaNova.Util;
using AyaNova.Generator;
using AyaNova.Biz;
using NLog.Extensions.Logging;

namespace AyaNova
{
    public class Startup
    {
        /////////////////////////////////////////////////////////////
        //
        public Startup(Microsoft.AspNetCore.Hosting.IWebHostEnvironment hostingEnvironment)
        {//ILogger<Startup> logger, ILoggerFactory logFactory,

            // Get the factory for ILogger instances.
            var nlogLoggerProvider = new NLogLoggerProvider();

            // Create an ILogger.
            _newLog = nlogLoggerProvider.CreateLogger("SERVER");

            //x_log = logger;
            _hostingEnvironment = hostingEnvironment;
            //AyaNova.Util.ApplicationLogging.LoggerFactory = logFactory;
            //AyaNova.Util.ApplicationLogging.theLogger = _newLog;
            AyaNova.Util.ApplicationLogging.LoggerProvider = nlogLoggerProvider;

            //this must be set here
            ServerBootConfig.AYANOVA_CONTENT_ROOT_PATH = hostingEnvironment.ContentRootPath;

        }

        private readonly ILogger _newLog;

        // private readonly ILogger<Startup>x_log;
        private string _connectionString = "";
        private readonly Microsoft.AspNetCore.Hosting.IWebHostEnvironment _hostingEnvironment;

        ////////////////////////////////////////////////////////////
        // This method gets called by the runtime. Use this method to add services to the container.
        //
        public void ConfigureServices(IServiceCollection services)
        {
            _newLog.LogDebug("Initializing services...");



            //Server state service for shutting people out of api
            _newLog.LogDebug("ApiServerState");
            services.AddSingleton(new AyaNova.Api.ControllerHelpers.ApiServerState());

            //Init controllers
            _newLog.LogDebug("Controllers");
            var MvcBuilder = services.AddControllers(config =>
                          {
                              // config.Filters.Add(new AyaNova.Api.ControllerHelpers.ApiCustomExceptionFilter(AyaNova.Util.ApplicationLogging.LoggerFactory));
                              config.Filters.Add(new AyaNova.Api.ControllerHelpers.ApiCustomExceptionFilter(_newLog));
                          });




            //Prevent default model binding automatic 400 page so we can consistently show *our* error to our specs
            //https://docs.microsoft.com/en-us/aspnet/core/web-api/index?view=aspnetcore-3.1#automatic-http-400-responses
            MvcBuilder.ConfigureApiBehaviorOptions(options =>
                    {
                        options.SuppressModelStateInvalidFilter = true;
                    });

            _newLog.LogDebug("JSON");

            MvcBuilder.AddNewtonsoftJson(options =>
                {
                    options.SerializerSettings.Formatting = Newtonsoft.Json.Formatting.None;
                    options.SerializerSettings.DateTimeZoneHandling = Newtonsoft.Json.DateTimeZoneHandling.Utc;

                });


            //HTTP CLIENT FACTORY USED BY LICENSE.CS
            //https://docs.microsoft.com/en-us/aspnet/core/fundamentals/http-requests?view=aspnetcore-3.1
            _newLog.LogDebug("HTTPClientFactory");
            services.AddHttpClient();


            //2019-10-17 METRICS will not work just yet with .netcore 3.1 see here https://github.com/AppMetrics/AppMetrics/issues/480
            //awaiting a new release from them
            _newLog.LogDebug("Metrics");
            services.AddMetrics();

            _newLog.LogDebug("Ensuring user and backup folders exist and are separate locations...");
            FileUtil.EnsureUserAndUtilityFoldersExistAndAreNotIdentical(_hostingEnvironment.ContentRootPath);

            #region DATABASE
            _connectionString = ServerBootConfig.AYANOVA_DB_CONNECTION;

            //Check DB server exists and can be connected to
            _newLog.LogDebug("Testing database server connection...");

            //parse the connection string properly
            DbUtil.ParseConnectionString(_newLog, _connectionString);

            //Probe for database server
            //Will retry every 10 seconds for up to 5 minutes before bailing
            if (!DbUtil.DatabaseServerExists(_newLog, "Waiting for db server "))
            {
                var err = $"E1000 - AyaNova can't connect to the database server after trying for 5 minutes (connection string is:\"{DbUtil.DisplayableConnectionString}\")";
                _newLog.LogCritical(err);
                throw new System.ApplicationException(err);
            }



            _newLog.LogInformation("Connected to database server - {0}", DbUtil.DisplayableConnectionString);


            //ensure database is ready and present
            DbUtil.EnsureDatabaseExists(_newLog);

            bool LOG_SENSITIVE_DATA = false;

#if (DEBUG)
            LOG_SENSITIVE_DATA = false;//############################################################################

#endif

            _newLog.LogDebug("EF Core");

            services.AddEntityFrameworkNpgsql().AddDbContext<AyContext>(
                options => options.UseNpgsql(_connectionString
                //,opt => opt.EnableRetryOnFailure()//REMOVED THIS BECAUSE IT WAS INTEFERING WITH TRANSACTIONS BUT THEN DIDN'T USE THE TRANSACTION BUT IT SEEMS FASTER WITHOUT IT AS WELL SO...??
                )//http://www.npgsql.org/efcore/misc.html?q=execution%20strategy#execution-strategy
                            .ConfigureWarnings(warnings => //https://livebook.manning.com/#!/book/entity-framework-core-in-action/chapter-12/v-10/85
                                    warnings.Throw( //Throw an exception on client eval, not necessarily an error but a smell
                                                    // Microsoft.EntityFrameworkCore.Diagnostics.RelationalEventId.QueryClientEvaluationWarning
                                    ))
                            .EnableSensitiveDataLogging(LOG_SENSITIVE_DATA)
                );




            #endregion


            // Add service and create Policy with options
            _newLog.LogDebug("CORS");
            services.AddCors(options =>
            {
                options.AddPolicy("CorsPolicy",
                    builder => builder.AllowAnyOrigin()
                    .AllowAnyMethod()
                    .AllowAnyHeader()
                    //.AllowCredentials()
                    );
            });




            #region Swagger

            services
                 .AddApiVersioning(options =>
                 {
                     options.AssumeDefaultVersionWhenUnspecified = true;
                     options.DefaultApiVersion = Microsoft.AspNetCore.Mvc.ApiVersion.Parse("8.0");
                     options.ReportApiVersions = true;
                 });
            services.AddVersionedApiExplorer(options =>
            {

                // add the versioned api explorer, which also adds IApiVersionDescriptionProvider service
                // note: the specified format code will format the version as "'v'major[.minor][-status]"
                options.GroupNameFormat = "'v'VVV";

                // note: this option is only necessary when versioning by url segment. the SubstitutionFormat
                // can also be used to control the format of the API version in route templates

                //THIS IS WHAT ADDS THE API version PARAMETER AUTOMATICALLY so you don't need to type an 8 in every swagger-ui route test
                options.SubstituteApiVersionInUrl = true;
            });
            services.AddTransient<IConfigureOptions<SwaggerGenOptions>, ConfigureSwaggerOptions>();
            services.AddSwaggerGen(
                c =>
                {
                    // integrate xml comments
                    c.IncludeXmlComments(XmlCommentsFilePath);

                    //https://stackoverflow.com/questions/56234504/migrating-to-swashbuckle-aspnetcore-version-5
                    //First we define the security scheme
                    c.AddSecurityDefinition("Bearer", //Name the security scheme
                        new OpenApiSecurityScheme
                        {
                            Description = "JWT Authorization header using the Bearer scheme.",
                            Type = SecuritySchemeType.Http, //We set the scheme type to http since we're using bearer authentication
                            Scheme = "bearer" //The name of the HTTP Authorization scheme to be used in the Authorization header. In this case "bearer".
                        });

                    c.AddSecurityRequirement(new OpenApiSecurityRequirement{
                                    {
                                        new OpenApiSecurityScheme{
                                            Reference = new OpenApiReference{
                                                Id = "Bearer", //The name of the previously defined security scheme.
                                                Type = ReferenceType.SecurityScheme
                                            }
                                        },new List<string>()
                                    }
                                });
                }
            );


            #endregion

            #region JWT AUTHENTICATION
            //get the key if specified
            var secretKey = ServerBootConfig.AYANOVA_JWT_SECRET;

            //If no key specified make a unique one
            //This means the jwt creds won't survive a server reboot
            //so in that case users need to specify an AyaNova_JWT_SECRET environment variable
            if (string.IsNullOrWhiteSpace(secretKey))
            {
                secretKey = Util.Hasher.GenerateSalt();
            }
            //WAS "UNLICENSED5G*QQJ8#bQ7$Xr_@sXfHq4"


            //If secretKey is less than 32 characters, pad it
            if (secretKey.Length < 32)
            {
                secretKey = secretKey.PadRight(32, '-');
            }

            ServerBootConfig.AYANOVA_JWT_SECRET = secretKey;
            var signingKey = new SymmetricSecurityKey(System.Text.Encoding.ASCII.GetBytes(ServerBootConfig.AYANOVA_JWT_SECRET));

            _newLog.LogDebug("Authorization");
            services.AddAuthentication(options =>
            {
                options.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;
                options.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;
            }).AddJwtBearer(options =>
                {
                    // options.AutomaticAuthenticate = true;
                    // options.AutomaticChallenge = true;
                    options.TokenValidationParameters = new TokenValidationParameters
                    {
                        // Token signature will be verified using a private key.
                        ValidateIssuerSigningKey = true,
                        RequireSignedTokens = true,
                        IssuerSigningKey = signingKey,
                        ValidateIssuer = true,
                        ValidIssuer = "ayanova.com",
                        ValidateAudience = false,
                        //ValidAudience = "http://localhost:7575/"

                        // Token will only be valid if not expired yet, with 5 minutes clock skew.
                        ValidateLifetime = true,
                        RequireExpirationTime = true,
                        ClockSkew = new TimeSpan(0, 5, 0),
                    };
                });



            #endregion

            _newLog.LogDebug("Generator");
            services.AddSingleton<IHostedService, GeneratorService>();

        }



        ////////////////////////////////////////////////////////////
        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        //
        public void Configure(IApplicationBuilder app, Microsoft.AspNetCore.Hosting.IWebHostEnvironment env,
        AyContext dbContext, IApiVersionDescriptionProvider provider, AyaNova.Api.ControllerHelpers.ApiServerState apiServerState, IServiceProvider serviceProvider)
        {
            _newLog.LogDebug("Configuring request pipeline...");

            //this *may* be useful in the event of an issue so uncomment if necessary but errors during dev are handled equally by the logging, I think
            // if (env.IsDevelopment())
            // {
            //     app.UseDeveloperExceptionPage();
            // }


            //Store a reference to the dependency injection service for static classes 
            ServiceProviderProvider.Provider = app.ApplicationServices;

            //Enable ability to handle reverse proxy
            app.UseForwardedHeaders(new ForwardedHeadersOptions
            {
                ForwardedHeaders = Microsoft.AspNetCore.HttpOverrides.ForwardedHeaders.XForwardedFor | Microsoft.AspNetCore.HttpOverrides.ForwardedHeaders.XForwardedProto
            });


            //If want to add a header to all (or filtered in here) requests
            // app.Use(async (context, next) =>
            // {
            //     context.Response.Headers.Add("X-Developed-By", "Ground Zero Tech-Works inc.");
            //     await next.Invoke();
            // });


            #region STATIC FILES
            _newLog.LogDebug("Static files");
            app.UseDefaultFiles();
            app.UseStaticFiles();
            //Might need the following if the page doesn't update in the client properly
            //however the vue build process will automatically uniquify each build file names so maybe not required
            // app.UseStaticFiles(new StaticFileOptions
            // {
            //     OnPrepareResponse = context =>
            //     {
            //         if (context.File.Name == "index.html")
            //         {
            //             context.Context.Response.Headers.Add("Cache-Control", "no-cache, no-store");
            //             context.Context.Response.Headers.Add("Expires", "-1");
            //         }
            //     }
            // });
            #endregion

            _newLog.LogDebug("Routing pipeline");
            app.UseRouting();//this wasn't here for 2.2 but added for 3.0, needs to come before the stuff after 

            _newLog.LogDebug("CORS pipeline");
            app.UseCors("CorsPolicy");


            #region AUTH / ROLES CUSTOM MIDDLEWARE
            _newLog.LogDebug("Authentication pipeline");
            //Use authentication middleware
            app.UseAuthentication();

            _newLog.LogDebug("Authorization pipeline");
            app.UseAuthorization();


            //Custom middleware to ensure token still valid and to
            //get user roles and put them into the request so 
            //they can be authorized in routes.
            app.Use(async (context, next) =>
            {
                if (!context.User.Identity.IsAuthenticated)
                {
                    context.Request.HttpContext.Items["AY_ROLES"] = 0;
                    await next.Invoke();
                }
                else
                {
                    //Get user ID from claims
                    long userId = Convert.ToInt64(context.User.FindFirst(c => c.Type == "id").Value);

                    //Get JWT
                    string JWT = string.Empty;
                    var AuthHeaders = context.Request.Headers[Microsoft.Net.Http.Headers.HeaderNames.Authorization];
                    foreach (String s in AuthHeaders)
                    {
                        if (s.ToLowerInvariant().Contains("bearer"))
                        {
                            JWT = s.Split(' ')[1];
                            break;
                        }
                    }

                    //Get the database context
                    var ct = context.RequestServices.GetService<AyContext>();                   

                    //get the user record
                    var u = await ct.User.AsNoTracking().Where(a => a.Id == userId).Select(m => new { roles = m.Roles, name = m.Name, id = m.Id, translationId = m.UserOptions.TranslationId, currentAuthToken = m.CurrentAuthToken }).FirstAsync();
                    context.Request.HttpContext.Items["AY_ROLES"] = u.roles;
                    context.Request.HttpContext.Items["AY_USERNAME"] = u.name;
                    context.Request.HttpContext.Items["AY_USER_ID"] = u.id;
                    context.Request.HttpContext.Items["AY_TRANSLATION_ID"] = u.translationId;

                    //CHECK JWT
                    if (!context.Request.Path.Value.EndsWith("/auth") && u.currentAuthToken != JWT)//except "/api/v8/auth" so user can login
                    {
                        context.Response.StatusCode = 401;
                        context.Response.Headers.Add("X-AyaNova-Authorization-Error", "E2006 - Authorization token replaced by more recent login");
                        await context.Response.WriteAsync("E2006 - Authorization token replaced by more recent login");
                    }
                    else
                    {
                        await next.Invoke();
                    }
                }

            });

            #endregion

            _newLog.LogDebug("Endpoints pipeline");
            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllers();
            });

            #region SWAGGER

            _newLog.LogDebug("API explorer pipeline");
            // Enable middleware to serve generated Swagger as a JSON endpoint.          
            app.UseSwagger();
            app.UseSwaggerUI(
                   options =>
                   {
                       foreach (var description in provider.ApiVersionDescriptions)
                       {
                           options.SwaggerEndpoint(
                               $"/swagger/{description.GroupName}/swagger.json",
                               description.GroupName.ToUpperInvariant());
                       }
                       options.DocExpansion(Swashbuckle.AspNetCore.SwaggerUI.DocExpansion.None);
                       options.DefaultModelsExpandDepth(-1);//This is meant to hide the Models section that would appear at the bottom of the swagger ui showing *all* models from the api
                       options.DocumentTitle = "AyaNova API explorer";
                       options.RoutePrefix = "api-docs";
                   });


            #endregion swagger


            // ******************************************************************
            // ******************** TESTING WIPE DB *****************************
            //
            //Set this to true to wipe the db and reinstall a trial license and re-seed the data
            //DEPRECATED, now use boot setting AYANOVA_SERVER_TEST_MODE
            //             var TESTING_REFRESH_DB = true;//#######################################################################################

            // #if (DEBUG)

            //             //TESTING
            //             if (TESTING_REFRESH_DB)
            //                 ServerBootConfig.AYANOVA_PERMANENTLY_ERASE_DATABASE = TESTING_REFRESH_DB;
            //             //TESTING
            // #endif


            if (ServerBootConfig.AYANOVA_PERMANENTLY_ERASE_DATABASE || ServerBootConfig.AYANOVA_SERVER_TEST_MODE)
            {
                if (ServerBootConfig.AYANOVA_SERVER_TEST_MODE)
                {
                    _newLog.LogWarning("AYANOVA_SERVER_TEST_MODE, dropping and recreating database");
                }
                else
                {
                    _newLog.LogWarning("AYANOVA_PERMANENTLY_ERASE_DATABASE, dropping and recreating database");
                }
                Util.DbUtil.DropAndRecreateDbAsync(_newLog).Wait();
                AySchema.CheckAndUpdateAsync(dbContext, _newLog).Wait();
            }

            //Check schema
            _newLog.LogDebug("DB schema check");
            AySchema.CheckAndUpdateAsync(dbContext, _newLog).Wait();

            //Check database integrity
            _newLog.LogDebug("DB integrity check");
            DbUtil.CheckFingerPrintAsync(AySchema.EXPECTED_COLUMN_COUNT, AySchema.EXPECTED_INDEX_COUNT, _newLog).Wait();

            //Initialize license
            AyaNova.Core.License.InitializeAsync(apiServerState, dbContext, _newLog).Wait();

            //Set static global biz settings
            _newLog.LogDebug("Global settings");
            ServerGlobalBizSettings.Initialize(null, dbContext);

            _newLog.LogDebug("Ops settings");
            ServerGlobalOpsSettingsCache.Initialize(dbContext);

            //Ensure translations are present, not missing any keys and that there is a server default translation that exists          
            TranslationBiz lb = new TranslationBiz(dbContext, 1, ServerBootConfig.AYANOVA_DEFAULT_TRANSLATION_ID, AuthorizationRoles.OpsAdminFull);
            lb.ValidateTranslationsAsync().Wait();


            //TESTING
            if (ServerBootConfig.AYANOVA_SERVER_TEST_MODE)
            {
                _newLog.LogInformation($"Server test mode seeding, level is {ServerBootConfig.AYANOVA_SERVER_TEST_MODE_SEEDLEVEL}, tz offset is {ServerBootConfig.AYANOVA_SERVER_TEST_MODE_TZ_OFFSET}");
                AyaNova.Core.License.FetchKeyAsync(apiServerState, dbContext, _newLog).Wait();
                //NOTE: For unit testing make sure the time zone is same as tester to ensure list filter by date tests will work because server is on same page as user in terms of time
                Util.Seeder.SeedDatabaseAsync(Util.Seeder.StringToSeedLevel(ServerBootConfig.AYANOVA_SERVER_TEST_MODE_SEEDLEVEL), ServerBootConfig.AYANOVA_SERVER_TEST_MODE_TZ_OFFSET).Wait();
            }
            //TESTING


            //SPA FALLBACK ROUTE                 
            app.Use(async (context, next) =>
            {
                //to support html5 pushstate routing in spa
                //this ensures that a refresh at the client will not 404 but rather force back to the index.html app page and then handled internally by the client 
                await next();
                if (!context.Response.HasStarted && context.Request.Path.Value != "/docs" && context.Response.StatusCode == 404 && !Path.HasExtension(context.Request.Path.Value))
                {
                    context.Request.Path = "/index.html";
                    context.Response.StatusCode = 200;
                    context.Response.ContentType = "text/html";
                    await context.Response.SendFileAsync(Path.Combine(env.WebRootPath, "index.html"));
                }
            });


            //Log the active user count so it's in the log record
            _newLog.LogInformation($"Active techs - {UserBiz.ActiveCountAsync().Result}");

            //Log the license info so it's on the record
            _newLog.LogInformation($"License - [{AyaNova.Core.License.LicenseInfoLogFormat}]");



            //Open up the server for visitors
            apiServerState.SetOpen();

            //final startup log
            _newLog.LogInformation("Boot complete - server open");

#if (DEBUG)
            //Show in dev console that server is open (so I don't need to look in the log to see it)
            System.Diagnostics.Debugger.Log(1, "BOOT", "Startup.cs -> BOOT: COMPLETED - SERVER IS NOW OPEN");

#endif

        }


        #region Swagger and API Versioning utilities

        static string XmlCommentsFilePath
        {
            get
            {
                var basePath = AppContext.BaseDirectory;
                var fileName = typeof(Startup).GetTypeInfo().Assembly.GetName().Name + ".xml";
                return Path.Combine(basePath, fileName);
            }
        }


        #endregion
    }
}