using System.Diagnostics;
using Microsoft.Extensions.Logging;
using PatchProbe.Shared.Contracts;
using PatchProbe.Shared.Models;

namespace PatchProbe.Cli.Collectors;

public sealed class CbsDismCollector(ILogger<CbsDismCollector> logger) : ICollector<List<CbsPackage>>
{
    public async Task<List<CbsPackage>> CollectAsync(CancellationToken cancellationToken = default)
    {
        logger.LogInformation("Collecting CBS/DISM package state");

        var packages = new List<CbsPackage>();

        try
        {
            var output = await RunDismAsync(cancellationToken);
            packages = ParseDismOutput(output);
            logger.LogInformation("Collected {Count} CBS packages", packages.Count);
        }
        catch (Exception ex)
        {
            logger.LogWarning(ex, "CBS/DISM collection failed");
        }

        return packages;
    }

    private static async Task<string> RunDismAsync(CancellationToken cancellationToken)
    {
        var psi = new ProcessStartInfo
        {
            FileName = "dism.exe",
            Arguments = "/Online /Get-Packages /Format:Table",
            RedirectStandardOutput = true,
            RedirectStandardError = true,
            UseShellExecute = false,
            CreateNoWindow = true,
        };

        using var process = Process.Start(psi) ?? throw new InvalidOperationException("Failed to start dism.exe");
        var output = await process.StandardOutput.ReadToEndAsync(cancellationToken);
        await process.WaitForExitAsync(cancellationToken);
        return output;
    }

    private static List<CbsPackage> ParseDismOutput(string output)
    {
        var packages = new List<CbsPackage>();
        var lines = output.Split('\n', StringSplitOptions.RemoveEmptyEntries);

        // Skip header lines; data rows contain "Package Identity" columns separated by spaces/pipes
        bool inDataSection = false;
        foreach (var line in lines)
        {
            var trimmed = line.Trim();

            if (trimmed.StartsWith("Package Identity", StringComparison.OrdinalIgnoreCase))
            {
                inDataSection = true;
                continue;
            }

            if (!inDataSection || string.IsNullOrWhiteSpace(trimmed) || trimmed.StartsWith('-'))
                continue;

            // DISM table output uses multiple spaces as column separator
            var parts = System.Text.RegularExpressions.Regex.Split(trimmed, @"\s{2,}");
            if (parts.Length >= 2)
            {
                packages.Add(new CbsPackage
                {
                    PackageIdentity = parts[0].Trim(),
                    State = parts.Length > 1 ? parts[1].Trim() : null,
                    ReleaseType = parts.Length > 2 ? parts[2].Trim() : null,
                    InstallTime = parts.Length > 3 ? parts[3].Trim() : null,
                });
            }
        }

        return packages;
    }
}