using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;

namespace BizTalkCheckmkPulse.Tests
{
    internal static class Program
    {
        private static readonly List<string> Failures = new List<string>();
        private static int ExecutedTests;

        private static int Main()
        {
            Run("SelfTestEmitsAllStableServices", SelfTestEmitsAllStableServices);
            Run("UnavailableSourcesAreUnknown", UnavailableSourcesAreUnknown);
            Run("UnknownApplicationDoesNotCreateService", UnknownApplicationDoesNotCreateService);
            Run("KnownApplicationCreatesService", KnownApplicationCreatesService);
            Run("ServerNamesAreComparedWithoutWql", ServerNamesAreComparedWithoutWql);
            Run("GroupSettingQueryUsesDocumentedSchema", GroupSettingQueryUsesDocumentedSchema);
            Run("ProviderSqlLoginFailureIsPermission", ProviderSqlLoginFailureIsPermission);
            Run("RejectedSqlPrincipalIsExtracted", RejectedSqlPrincipalIsExtracted);
            Run("PlatformPermissionPropagatesToSqlDiscovery", PlatformPermissionPropagatesToSqlDiscovery);
            Run("SnapshotRoundTripPreservesLines", SnapshotRoundTripPreservesLines);
            Run("SnapshotRejectsTampering", SnapshotRejectsTampering);
            Run("SnapshotRejectsStaleData", SnapshotRejectsStaleData);
            Run("SnapshotRejectsDifferentMachine", SnapshotRejectsDifferentMachine);
            Run("SnapshotReportsMissingFile", SnapshotReportsMissingFile);
            Run("SnapshotFailureEmitsStableUnknownServices", SnapshotFailureEmitsStableUnknownServices);

            if (Failures.Count == 0)
            {
                Console.WriteLine("PASS: " + ExecutedTests + " tests");
                return 0;
            }

            foreach (var failure in Failures)
            {
                Console.Error.WriteLine("FAIL: " + failure);
            }

            return 1;
        }

        private static void SelfTestEmitsAllStableServices()
        {
            var lines = new CheckmkLocalFormatter(new MonitoringOptions()).FormatSelfTest().ToArray();
            AssertEqual(6, lines.Length, "self-test line count");
            AssertEqual(6, lines.Distinct(StringComparer.Ordinal).Count(), "unique self-test lines");
            Assert(lines.All(x => x.StartsWith("0 \"BizTalk ", StringComparison.Ordinal)), "every self-test line must be OK");
            Assert(lines.Any(x => x.Contains("\"BizTalk Event Log\"")), "Event Log service missing");
        }

        private static void UnavailableSourcesAreUnknown()
        {
            var lines = new CheckmkLocalFormatter(new MonitoringOptions()).Format(new ProbeResult()).Take(6).ToArray();
            AssertEqual(6, lines.Length, "stable service count");
            Assert(lines.All(x => x.StartsWith("3 \"BizTalk ", StringComparison.Ordinal)), "unavailable sources must be UNKNOWN");
        }

        private static void UnknownApplicationDoesNotCreateService()
        {
            var options = new MonitoringOptions { EmitPerApplicationSuspensionServices = true };
            var result = CreateSuspensionResult("(unknown)");
            var lines = new CheckmkLocalFormatter(options).Format(result).ToArray();
            AssertEqual(6, lines.Length, "unknown application must not create a dynamic service");
        }

        private static void KnownApplicationCreatesService()
        {
            var options = new MonitoringOptions { EmitPerApplicationSuspensionServices = true };
            var result = CreateSuspensionResult("Orders");
            var lines = new CheckmkLocalFormatter(options).Format(result).ToArray();
            AssertEqual(7, lines.Length, "known application should create one dynamic service");
            Assert(lines.Any(x => x.Contains("\"BizTalk Suspended Orders\"")), "known application service missing");
        }

        private static void ServerNamesAreComparedWithoutWql()
        {
            Assert(WmiBizTalkProbe.IsSameServer("BIZTALK01.corp.example", "biztalk01"), "FQDN and short name must match");
            Assert(WmiBizTalkProbe.IsSameServer(@"\\BIZ-TALK+01", "biz-talk+01.example"), "special characters must be compared client-side");
            Assert(!WmiBizTalkProbe.IsSameServer("BIZTALK01", "BIZTALK02"), "different servers must not match");
        }

        private static void GroupSettingQueryUsesDocumentedSchema()
        {
            var query = WmiBizTalkProbe.GroupSettingQuery;
            Assert(query.Contains("FROM MSBTS_GroupSetting"), "MSBTS_GroupSetting query missing");
            Assert(query.Contains("BizTalkOperatorGroup"), "configured operator group property missing");
            Assert(query.Contains("BizTalkReadOnlyUserGroup"), "configured read-only group property missing");
            Assert(query.Contains("SubscriptionDBServerName"), "master MessageBox server property missing");
            Assert(query.Contains("SubscriptionDBName"), "master MessageBox database property missing");
            Assert(query.IndexOf("MessageBoxSetting", StringComparison.OrdinalIgnoreCase) < 0, "unsupported MessageBoxSetting class present");
        }

        private static void ProviderSqlLoginFailureIsPermission()
        {
            var exception = new COMException(
                "Internal error from OLEDB provider: 'Login failed for user 'BEW\\AV23AGPWBIO1$'.'",
                unchecked((int)0x80131904));
            AssertEqual(
                DiagnosticCategory.Permission,
                WmiBizTalkProbe.ClassifyWmiException(exception),
                "provider SQL login classification");
        }

        private static void RejectedSqlPrincipalIsExtracted()
        {
            var message = "Internal error from OLEDB provider: 'Login failed for user 'BEW\\AV23AGPWBIO1$'.'";
            AssertEqual(
                "BEW\\AV23AGPWBIO1$",
                WmiBizTalkProbe.ExtractSqlLoginPrincipal(message),
                "rejected SQL principal");
        }

        private static void PlatformPermissionPropagatesToSqlDiscovery()
        {
            var result = new ProbeResult();
            result.Diagnostics.Add(new ProbeDiagnostic
            {
                Area = DiagnosticArea.Wmi,
                Category = DiagnosticCategory.Permission,
                Component = "MSBTS_GroupSetting",
                Required = true
            });

            new SqlConnectivityProbe(new MonitoringOptions()).Query(result);

            var discovery = result.Diagnostics.Single(x =>
                x.Area == DiagnosticArea.Sql
                && x.Component == "BizTalk database discovery");
            AssertEqual(
                DiagnosticCategory.Permission,
                discovery.Category,
                "SQL discovery classification");
        }

        private static void SnapshotRoundTripPreservesLines()
        {
            WithTemporarySnapshot((path, store) =>
            {
                var lines = new CheckmkLocalFormatter(new MonitoringOptions()).FormatSelfTest().ToArray();
                var generated = DateTime.UtcNow;
                store.Write(lines, generated, "DOMAIN\\collector$");
                var result = store.Read(generated.AddSeconds(10), TimeSpan.FromMinutes(3));

                Assert(result.IsSuccess, "snapshot should be readable: " + result.Error);
                AssertEqual(lines.Length, result.Lines.Count, "snapshot line count");
                Assert(lines.SequenceEqual(result.Lines), "snapshot payload changed");

                var replacement = lines.Select(x => x.Replace("Self test OK", "Replacement OK")).ToArray();
                store.Write(replacement, generated.AddSeconds(30), "DOMAIN\\collector$");
                var replaced = store.Read(generated.AddSeconds(40), TimeSpan.FromMinutes(3));
                Assert(replaced.IsSuccess, "replaced snapshot should be readable");
                Assert(replacement.SequenceEqual(replaced.Lines), "atomic replacement payload changed");
            });
        }

        private static void SnapshotRejectsTampering()
        {
            WithTemporarySnapshot((path, store) =>
            {
                var lines = new CheckmkLocalFormatter(new MonitoringOptions()).FormatSelfTest().ToArray();
                store.Write(lines, DateTime.UtcNow, "DOMAIN\\collector$");
                var content = File.ReadAllText(path, Encoding.UTF8);
                File.WriteAllText(path, content.Replace("Self test OK", "Tampered output"), new UTF8Encoding(false));

                var result = store.Read(DateTime.UtcNow, TimeSpan.FromMinutes(3));
                Assert(!result.IsSuccess, "tampered snapshot must be rejected");
                Assert(result.Error.IndexOf("SHA-256", StringComparison.OrdinalIgnoreCase) >= 0, "tamper reason should mention SHA-256");
            });
        }

        private static void SnapshotRejectsStaleData()
        {
            WithTemporarySnapshot((path, store) =>
            {
                var lines = new CheckmkLocalFormatter(new MonitoringOptions()).FormatSelfTest().ToArray();
                var generated = DateTime.UtcNow.AddMinutes(-10);
                store.Write(lines, generated, "DOMAIN\\collector$");

                var result = store.Read(DateTime.UtcNow, TimeSpan.FromMinutes(3));
                Assert(!result.IsSuccess, "stale snapshot must be rejected");
                Assert(result.Error.IndexOf("stale", StringComparison.OrdinalIgnoreCase) >= 0, "stale reason missing");
            });
        }

        private static void SnapshotRejectsDifferentMachine()
        {
            WithTemporarySnapshot((path, store) =>
            {
                var lines = new CheckmkLocalFormatter(new MonitoringOptions()).FormatSelfTest().ToArray();
                store.Write(lines, DateTime.UtcNow, "DOMAIN\\collector$");
                var content = File.ReadAllText(path, Encoding.UTF8);
                var currentMachine = Convert.ToBase64String(Encoding.UTF8.GetBytes(Environment.MachineName));
                var otherMachine = Convert.ToBase64String(Encoding.UTF8.GetBytes("OTHER-SERVER"));
                File.WriteAllText(
                    path,
                    content.Replace("machineBase64=" + currentMachine, "machineBase64=" + otherMachine),
                    new UTF8Encoding(false));

                var result = store.Read(DateTime.UtcNow, TimeSpan.FromMinutes(3));
                Assert(!result.IsSuccess, "snapshot for another machine must be rejected");
                Assert(result.Error.IndexOf("different machine", StringComparison.OrdinalIgnoreCase) >= 0, "machine mismatch reason missing");
            });
        }

        private static void SnapshotReportsMissingFile()
        {
            WithTemporarySnapshot((path, store) =>
            {
                var result = store.Read(DateTime.UtcNow, TimeSpan.FromMinutes(3));
                Assert(!result.IsSuccess, "missing snapshot must be rejected");
                Assert(result.Error.IndexOf("does not exist", StringComparison.OrdinalIgnoreCase) >= 0, "missing file reason missing");
            });
        }

        private static void SnapshotFailureEmitsStableUnknownServices()
        {
            var lines = new CheckmkLocalFormatter(new MonitoringOptions())
                .FormatSnapshotFailure("Snapshot file does not exist.")
                .ToArray();
            AssertEqual(6, lines.Length, "snapshot failure stable service count");
            Assert(lines.All(x => x.StartsWith("3 \"BizTalk ", StringComparison.Ordinal)), "snapshot failure must be UNKNOWN");
            Assert(lines.All(x => x.Contains("Scheduled Task")), "snapshot failure must contain provider action");
        }

        private static void WithTemporarySnapshot(Action<string, SnapshotStore> test)
        {
            var directory = Path.Combine(Path.GetTempPath(), "BizTalkCheckmkPulse.Tests." + Guid.NewGuid().ToString("N"));
            Directory.CreateDirectory(directory);
            var path = Path.Combine(directory, "snapshot.txt");
            try
            {
                test(path, new SnapshotStore(path, 1048576));
            }
            finally
            {
                if (Directory.Exists(directory))
                {
                    Directory.Delete(directory, true);
                }
            }
        }

        private static ProbeResult CreateSuspensionResult(string applicationName)
        {
            var result = new ProbeResult();
            result.Platform.SuspendedInstancesDataAvailable = true;
            result.SuspendedInstances.Add(new SuspendedInstance
            {
                ApplicationName = applicationName,
                ServiceName = "TestService",
                Kind = SuspendedKind.Resumable
            });
            return result;
        }

        private static void Run(string name, Action test)
        {
            ExecutedTests++;
            try
            {
                test();
            }
            catch (Exception ex)
            {
                Failures.Add(name + ": " + ex.Message);
            }
        }

        private static void Assert(bool condition, string message)
        {
            if (!condition)
            {
                throw new InvalidOperationException(message);
            }
        }

        private static void AssertEqual(int expected, int actual, string label)
        {
            if (expected != actual)
            {
                throw new InvalidOperationException(label + ": expected " + expected + ", actual " + actual);
            }
        }

        private static void AssertEqual(DiagnosticCategory expected, DiagnosticCategory actual, string label)
        {
            if (expected != actual)
            {
                throw new InvalidOperationException(label + ": expected " + expected + ", actual " + actual);
            }
        }

        private static void AssertEqual(string expected, string actual, string label)
        {
            if (!string.Equals(expected, actual, StringComparison.Ordinal))
            {
                throw new InvalidOperationException(label + ": expected " + expected + ", actual " + actual);
            }
        }
    }
}