// <copyright file="BlastRadiusTestRunner.cs" company="StellaOps">
// Copyright (c) StellaOps. Licensed under BUSL-1.1.
// </copyright>
// Sprint: SPRINT_20260105_002_005_TEST_cross_cutting
// Task: CCUT-002


using System.Collections.Immutable;
using System.Diagnostics;

namespace StellaOps.TestKit.BlastRadius;

/// <summary>
/// Runs tests filtered by blast radius for incident response.
/// </summary>
public static class BlastRadiusTestRunner
{
    /// <summary>
    /// Get xUnit filter for specific blast radii.
    /// </summary>
    /// <param name="blastRadii">Blast radii to filter by.</param>
    /// <returns>xUnit filter string.</returns>
    /// <exception cref="ArgumentException">Thrown when no blast radii provided.</exception>
    public static string GetFilter(params string[] blastRadii)
    {
        if (blastRadii.Length == 0)
        {
            throw new ArgumentException("At least one blast radius required", nameof(blastRadii));
        }

        var filters = blastRadii.Select(br => $"BlastRadius={br}");
        return string.Join("|", filters);
    }

    /// <summary>
    /// Get xUnit filter for specific blast radii (IEnumerable overload).
    /// </summary>
    /// <param name="blastRadii">Blast radii to filter by.</param>
    /// <returns>xUnit filter string.</returns>
    public static string GetFilter(IEnumerable<string> blastRadii)
    {
        return GetFilter(blastRadii.ToArray());
    }

    /// <summary>
    /// Get the dotnet test command for specific blast radii.
    /// </summary>
    /// <param name="testProject">Test project path or solution.</param>
    /// <param name="blastRadii">Blast radii to filter by.</param>
    /// <param name="additionalArgs">Additional dotnet test arguments.</param>
    /// <returns>Complete dotnet test command.</returns>
    public static string GetCommand(
        string testProject,
        IEnumerable<string> blastRadii,
        string? additionalArgs = null)
    {
        var filter = GetFilter(blastRadii);
        var args = $"test {testProject} --filter \"{filter}\"";

        if (!string.IsNullOrWhiteSpace(additionalArgs))
        {
            args += $" {additionalArgs}";
        }

        return $"dotnet {args}";
    }

    /// <summary>
    /// Run tests for specific operational surfaces.
    /// </summary>
    /// <param name="testProject">Test project path or solution.</param>
    /// <param name="blastRadii">Blast radii to run tests for.</param>
    /// <param name="workingDirectory">Working directory for test execution.</param>
    /// <param name="timeoutMs">Timeout in milliseconds.</param>
    /// <param name="ct">Cancellation token.</param>
    /// <returns>Test run result.</returns>
    public static async Task<TestRunResult> RunForBlastRadiiAsync(
        string testProject,
        string[] blastRadii,
        string? workingDirectory = null,
        int timeoutMs = 600000,
        CancellationToken ct = default)
    {
        var filter = GetFilter(blastRadii);

        var startInfo = new ProcessStartInfo
        {
            FileName = "dotnet",
            Arguments = $"test {testProject} --filter \"{filter}\" --logger trx --verbosity normal",
            RedirectStandardOutput = true,
            RedirectStandardError = true,
            UseShellExecute = false,
            CreateNoWindow = true
        };

        if (!string.IsNullOrWhiteSpace(workingDirectory))
        {
            startInfo.WorkingDirectory = workingDirectory;
        }

        var stdout = new List<string>();
        var stderr = new List<string>();
        var sw = Stopwatch.StartNew();

        using var process = new Process { StartInfo = startInfo };

        process.OutputDataReceived += (_, e) =>
        {
            if (e.Data != null)
            {
                stdout.Add(e.Data);
            }
        };

        process.ErrorDataReceived += (_, e) =>
        {
            if (e.Data != null)
            {
                stderr.Add(e.Data);
            }
        };

        process.Start();
        process.BeginOutputReadLine();
        process.BeginErrorReadLine();

        using var cts = CancellationTokenSource.CreateLinkedTokenSource(ct);
        cts.CancelAfter(timeoutMs);

        try
        {
            await process.WaitForExitAsync(cts.Token);
        }
        catch (OperationCanceledException)
        {
            try
            {
                process.Kill(entireProcessTree: true);
            }
            catch
            {
                // Ignore kill errors
            }

            return new TestRunResult(
                ExitCode: -1,
                BlastRadii: [.. blastRadii],
                Filter: filter,
                DurationMs: sw.ElapsedMilliseconds,
                Output: [.. stdout],
                Errors: [.. stderr],
                TimedOut: true);
        }

        sw.Stop();

        return new TestRunResult(
            ExitCode: process.ExitCode,
            BlastRadii: [.. blastRadii],
            Filter: filter,
            DurationMs: sw.ElapsedMilliseconds,
            Output: [.. stdout],
            Errors: [.. stderr],
            TimedOut: false);
    }

    /// <summary>
    /// Run tests for a single blast radius.
    /// </summary>
    /// <param name="testProject">Test project path or solution.</param>
    /// <param name="blastRadius">Blast radius to run tests for.</param>
    /// <param name="workingDirectory">Working directory for test execution.</param>
    /// <param name="timeoutMs">Timeout in milliseconds.</param>
    /// <param name="ct">Cancellation token.</param>
    /// <returns>Test run result.</returns>
    public static Task<TestRunResult> RunForBlastRadiusAsync(
        string testProject,
        string blastRadius,
        string? workingDirectory = null,
        int timeoutMs = 600000,
        CancellationToken ct = default)
    {
        return RunForBlastRadiiAsync(testProject, [blastRadius], workingDirectory, timeoutMs, ct);
    }

    /// <summary>
    /// Parse test results from TRX output.
    /// </summary>
    /// <param name="result">Test run result.</param>
    /// <returns>Summary of test results.</returns>
    public static TestRunSummary ParseSummary(TestRunResult result)
    {
        var summary = new TestRunSummary(
            Passed: 0,
            Failed: 0,
            Skipped: 0,
            Total: 0);

        foreach (var line in result.Output)
        {
            // Parse dotnet test output format: "Passed:  X" etc.
            if (line.Contains("Passed:", StringComparison.OrdinalIgnoreCase))
            {
                var match = System.Text.RegularExpressions.Regex.Match(line, @"Passed:\s*(\d+)");
                if (match.Success && int.TryParse(match.Groups[1].Value, out var passed))
                {
                    summary = summary with { Passed = passed };
                }
            }

            if (line.Contains("Failed:", StringComparison.OrdinalIgnoreCase))
            {
                var match = System.Text.RegularExpressions.Regex.Match(line, @"Failed:\s*(\d+)");
                if (match.Success && int.TryParse(match.Groups[1].Value, out var failed))
                {
                    summary = summary with { Failed = failed };
                }
            }

            if (line.Contains("Skipped:", StringComparison.OrdinalIgnoreCase))
            {
                var match = System.Text.RegularExpressions.Regex.Match(line, @"Skipped:\s*(\d+)");
                if (match.Success && int.TryParse(match.Groups[1].Value, out var skipped))
                {
                    summary = summary with { Skipped = skipped };
                }
            }

            if (line.Contains("Total:", StringComparison.OrdinalIgnoreCase))
            {
                var match = System.Text.RegularExpressions.Regex.Match(line, @"Total:\s*(\d+)");
                if (match.Success && int.TryParse(match.Groups[1].Value, out var total))
                {
                    summary = summary with { Total = total };
                }
            }
        }

        return summary;
    }
}

/// <summary>
/// Result of running tests for blast radii.
/// </summary>
/// <param name="ExitCode">Process exit code (0 = success).</param>
/// <param name="BlastRadii">Blast radii that were tested.</param>
/// <param name="Filter">xUnit filter that was used.</param>
/// <param name="DurationMs">Duration of test run in milliseconds.</param>
/// <param name="Output">Standard output lines.</param>
/// <param name="Errors">Standard error lines.</param>
/// <param name="TimedOut">Whether the test run timed out.</param>
public sealed record TestRunResult(
    int ExitCode,
    ImmutableArray<string> BlastRadii,
    string Filter,
    long DurationMs,
    ImmutableArray<string> Output,
    ImmutableArray<string> Errors,
    bool TimedOut)
{
    /// <summary>
    /// Gets a value indicating whether the test run was successful.
    /// </summary>
    public bool IsSuccess => ExitCode == 0 && !TimedOut;
}

/// <summary>
/// Summary of test run results.
/// </summary>
/// <param name="Passed">Number of passed tests.</param>
/// <param name="Failed">Number of failed tests.</param>
/// <param name="Skipped">Number of skipped tests.</param>
/// <param name="Total">Total number of tests.</param>
public sealed record TestRunSummary(
    int Passed,
    int Failed,
    int Skipped,
    int Total);