//
// Copyright (c) Microsoft. All rights reserved.
// Licensed under the MIT license. See LICENSE file in the project root for full license information.
//

using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices;
using System.Threading.Tasks;
using Microsoft.SqlTools.ServiceLayer.Connection.Contracts;
using Microsoft.SqlTools.ServiceLayer.Credentials;
using Microsoft.SqlTools.ServiceLayer.Credentials.Contracts;
using Microsoft.SqlTools.ServiceLayer.TestDriver.Driver;
using Xunit;

namespace Microsoft.SqlTools.ServiceLayer.Test.Common
{
    /// <summary>
    /// Service to get connection profiles from the configured settings
    /// to get the credentials, test driver will be used if available otherwise the credential service will be called directly
    /// </summary>
    public class TestConnectionProfileService
    {
        private readonly IEnumerable<TestServerIdentity> _testServers = TestServersLazyInstance.Value;
        private readonly ConnectionSetting _setting = ConnectionSettingLazyInstance.Value;
        private static string _connectionSettingsFilename;
        private static ConcurrentDictionary<TestServerType, ConnectionProfile> _connectionProfilesCache = new ConcurrentDictionary<TestServerType, ConnectionProfile>(); 

        public TestConnectionProfileService(ServiceTestDriver driver)
        {
            Driver = driver;
        }

        public TestConnectionProfileService()
        {
        }

        private static readonly Lazy<IEnumerable<TestServerIdentity>> TestServersLazyInstance = 
            new Lazy<IEnumerable<TestServerIdentity>>(InitTestServerNames);

        private static readonly Lazy<ConnectionSetting> ConnectionSettingLazyInstance =
            new Lazy<ConnectionSetting>(InitSetting);

        private ServiceTestDriver Driver { get; set; }

        private ConnectionProfile GetConnectionProfile(TestServerType serverType)
        {
            ConnectionProfile connectionProfile = null;

            //Get the server or profile name for given type to use for database connection
            TestServerIdentity serverIdentity = _testServers != null ? _testServers.FirstOrDefault(x => x.ServerType == serverType) : null;

            //Search for the connection info in settings.json
            if (serverIdentity == null)
            {
                //If not server name found, try to find the connection info for given type
                connectionProfile = _setting != null && _setting.Connections != null ? _setting.Connections.FirstOrDefault(x => x.ServerType == serverType) : null;
                if (connectionProfile == null && _setting != null && _setting.Connections != null)
                {
                    Console.WriteLine(string.Format(CultureInfo.InvariantCulture, 
                        "Cannot find any connection profile for server type '{0}'. " 
                        + " Make sure the serverType attribute is set in {1}. " +
                        "Or run CreateTestServerNameSettings.cmd to create a template for the server names", serverType, _connectionSettingsFilename));
                }
            }
            else
            {
                //Find the connection info for specific server name or profile name
                connectionProfile = _setting != null ? _setting.GetConnectionProfile(serverIdentity.ProfileName, serverIdentity.ServerName) : null;

            }

            Assert.True(connectionProfile != null, "Cannot find any connection profile for server type " + serverType.ToString());
            
            return connectionProfile;
        }

        /// <summary>
        /// Returns database connection parameters for given server type
        /// </summary>
        public async Task<ConnectParams> GetConnectionParametersAsync(TestServerType serverType = TestServerType.OnPrem, string databaseName = null)
        {
            ConnectionProfile connectionProfile;
            if (!_connectionProfilesCache.TryGetValue(serverType, out connectionProfile))
            {
                connectionProfile = GetConnectionProfile(serverType);

                if (connectionProfile != null)
                {
                    //If the password is empty, get the credential using the service
                    if (connectionProfile.AuthenticationType == AuthenticationType.SqlLogin && string.IsNullOrEmpty(connectionProfile.Password))
                    {
                        Credential credential = await ReadCredentialAsync(connectionProfile.formatCredentialId());
                        connectionProfile.Password = credential.Password;
                    }
                    _connectionProfilesCache.GetOrAdd(serverType, connectionProfile);
                }
            }

            if (connectionProfile != null)
            {
                ConnectParams connenctParam = CreateConnectParams(connectionProfile, serverType, databaseName);
               
                return connenctParam;
            }
            return null;
        }

        /// <summary>
        /// Request a Read Credential for given credential id
        /// </summary>
        private async Task<Credential> ReadCredentialAsync(string credentialId)
        {
            var credentialParams = new Credential();
            credentialParams.CredentialId = credentialId;

            ServiceTestDriver driver = Driver;
            if (driver == null)
            {
                TestServiceProvider.InitializeTestServices();
                return await CredentialService.Instance.ReadCredentialAsync(credentialParams);
            }
            else
            {
                return await Driver.SendRequest(ReadCredentialRequest.Type, credentialParams);
            }
        }

        /// <summary>
        /// Create a connection parameters object
        /// </summary>
        private ConnectParams CreateConnectParams(ConnectionProfile connectionProfile, TestServerType serverType, string databaseName)
        {
            ConnectParams connectParams = new ConnectParams();
            connectParams.Connection = new ConnectionDetails();
            connectParams.Connection.ServerName = connectionProfile.ServerName;
            connectParams.Connection.DatabaseName = connectionProfile.Database;
            connectParams.Connection.UserName = connectionProfile.User;
            connectParams.Connection.Password = connectionProfile.Password;
            connectParams.Connection.AuthenticationType = connectionProfile.AuthenticationType.ToString();
            if (!string.IsNullOrEmpty(databaseName))
            {
                connectParams.Connection.DatabaseName = databaseName;
            }
            if (serverType == TestServerType.Azure)
            {
                connectParams.Connection.ConnectTimeout = 30;
                connectParams.Connection.Encrypt = true;
                connectParams.Connection.TrustServerCertificate = false;
            }
            return connectParams;
        }

        private static IEnumerable<TestServerIdentity> InitTestServerNames()
        {
            try
            {
                string testServerNamesFileContent = GetTestServerNamesFileContent();
                if (!string.IsNullOrEmpty(testServerNamesFileContent))
                {
                    return Newtonsoft.Json.JsonConvert.DeserializeObject<IList<TestServerIdentity>>(testServerNamesFileContent);
                }
                else
                {
                    return Enumerable.Empty<TestServerIdentity>();
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine("Failed to load the database connection server name settings. error: " + ex.Message);
                return Enumerable.Empty<TestServerIdentity>();
            }
        }

        private static ConnectionSetting InitSetting()
        {
            try
            {
                string settingsFileContents = GetSettingFileContent();
                ConnectionSetting setting = Newtonsoft.Json.JsonConvert.DeserializeObject<ConnectionSetting>(settingsFileContents);
                Console.WriteLine("Connection Settings loaded successfully");
                return setting;
            }
            catch (Exception ex)
            {
                Console.WriteLine("Failed to load the connection settings. error: " + ex.Message);
                return new ConnectionSetting();
            }
        }

        /// <summary>
        /// Get the location of testServerNames.json. Returns the value of environment variable 'SettingsFileName' and if it's empty returns
        /// the location of vs code testServerNames.json
        /// </summary>
        /// <returns></returns>
        private static string GetTestServerNamesFileContent()
        {
            var testServerNameFilePath = Environment.GetEnvironmentVariable("TestServerNamesFile");
            string testServerFileName = "testServerNames.json";

            if (string.IsNullOrEmpty(testServerNameFilePath))
            {
                if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
                {
                    testServerNameFilePath = Environment.GetEnvironmentVariable("APPDATA") + @"\\" + testServerFileName;
                }
                else if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
                {
                    testServerNameFilePath = Environment.GetEnvironmentVariable("HOME") + @"/" + testServerFileName;
                }
                else
                {
                    testServerNameFilePath = Environment.GetEnvironmentVariable("HOME") + @"/" + testServerFileName;
                }
            }
            string testServerNamesFileContent = string.IsNullOrEmpty(testServerNameFilePath) ? string.Empty : File.ReadAllText(testServerNameFilePath);

            return testServerNamesFileContent;
        }

        /// <summary>
        /// Get the location of setting.json. Returns the value of environment variable 'SettingsFileName' and if it's empty returns
        /// the location of vs code settings.json
        /// </summary>
        /// <returns></returns>
        private static string GetSettingFileContent()
        {
            var settingsFilename = Environment.GetEnvironmentVariable("SettingsFileName");

            if (string.IsNullOrEmpty(settingsFilename))
            {
                if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
                {
                    settingsFilename = Environment.GetEnvironmentVariable("APPDATA") + @"\Code\User\settings.json";
                }
                else if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
                {
                    settingsFilename = Environment.GetEnvironmentVariable("HOME") + @"/Library/Application Support/Code/User/settings.json";
                }
                else
                {
                    settingsFilename = Environment.GetEnvironmentVariable("HOME") + @"/.config/Code/User/settings.json";
                }
            }

            if (string.IsNullOrEmpty(settingsFilename))
            {
                Console.WriteLine("Cannot find any connection settings. Please run CreateConnectionSettings.cmd to generate a template for the connection settings.");
            }
            else
            {
                Console.WriteLine("Connection settings: " + settingsFilename);
                _connectionSettingsFilename = settingsFilename;
            }

            string settingsFileContents = string.IsNullOrEmpty(settingsFilename) ? string.Empty : File.ReadAllText(settingsFilename);

            return settingsFileContents;
        }
    }
}