using System.Text;
using LANCommander.Packager.Models;
using LANCommander.SDK.Enums;

namespace LANCommander.Packager.Services;

public static class ScriptGeneratorService
{
    public static List<GeneratedScript> Generate(PackageContext context)
    {
        var scripts = new List<GeneratedScript>();

        bool hasRegistry = context.SelectedRegistryEntries.Count > 0;
        bool hasInstallActions = hasRegistry || context.PatchGameSpy;

        if (hasInstallActions)
            scripts.Add(GenerateInstallScript(context));

        if (hasRegistry)
            scripts.Add(GenerateUninstallScript(context));

        return scripts;
    }

    private static GeneratedScript GenerateInstallScript(PackageContext context)
    {
        var sb = new StringBuilder();
        sb.AppendLine("# Install Script - Generated by LANCommander.Packager");
        sb.AppendLine();

        bool requiresAdmin = false;

        if (context.SelectedRegistryEntries.Count > 0)
        {
            var groupedEntries = context.SelectedRegistryEntries
                .GroupBy(e => e.KeyPath, StringComparer.OrdinalIgnoreCase);

            foreach (var group in groupedEntries)
            {
                var keyPath = ConvertToPoShRegistryPath(group.Key);

                if (group.Key.StartsWith("HKLM", StringComparison.OrdinalIgnoreCase) ||
                    group.Key.StartsWith("HKEY_LOCAL_MACHINE", StringComparison.OrdinalIgnoreCase))
                    requiresAdmin = true;

                sb.AppendLine($"New-Item -Path \"{keyPath}\" -Force | Out-Null");

                foreach (var entry in group.Where(e => !string.IsNullOrEmpty(e.ValueName)))
                {
                    var valueName = entry.ValueName;
                    sb.AppendLine($"Set-ItemProperty -Path \"{keyPath}\" -Name \"{valueName}\" -Value \"\"");
                }

                sb.AppendLine();
            }
        }

        if (context.PatchGameSpy)
        {
            sb.AppendLine("# Patch GameSpy references for OpenSpy compatibility");
            sb.AppendLine("Edit-PatchGameSpy -Path $InstallDirectory");
            sb.AppendLine();
        }

        return new GeneratedScript
        {
            Type = ScriptType.Install,
            Contents = sb.ToString(),
            RequiresAdmin = requiresAdmin
        };
    }

    private static GeneratedScript GenerateUninstallScript(PackageContext context)
    {
        var sb = new StringBuilder();
        
        sb.AppendLine("# Uninstall Script - Generated by LANCommander.Packager");
        sb.AppendLine();

        var groupedEntries = context.SelectedRegistryEntries
            .GroupBy(e => e.KeyPath, StringComparer.OrdinalIgnoreCase);

        bool requiresAdmin = false;

        foreach (var group in groupedEntries)
        {
            var keyPath = ConvertToPoShRegistryPath(group.Key);

            if (group.Key.StartsWith("HKLM", StringComparison.OrdinalIgnoreCase) ||
                group.Key.StartsWith("HKEY_LOCAL_MACHINE", StringComparison.OrdinalIgnoreCase))
                requiresAdmin = true;

            foreach (var entry in group.Where(e => !string.IsNullOrEmpty(e.ValueName)))
                sb.AppendLine($"Remove-ItemProperty -Path \"{keyPath}\" -Name \"{entry.ValueName}\" -ErrorAction SilentlyContinue");

            sb.AppendLine($"Remove-Item -Path \"{keyPath}\" -ErrorAction SilentlyContinue");
            sb.AppendLine();
        }

        return new GeneratedScript
        {
            Type = ScriptType.Uninstall,
            Contents = sb.ToString(),
            RequiresAdmin = requiresAdmin
        };
    }

    private static string ConvertToPoShRegistryPath(string keyPath)
    {
        if (keyPath.StartsWith("HKEY_LOCAL_MACHINE\\", StringComparison.OrdinalIgnoreCase))
            return "HKLM:\\" + keyPath["HKEY_LOCAL_MACHINE\\".Length..];

        if (keyPath.StartsWith("HKEY_CURRENT_USER\\", StringComparison.OrdinalIgnoreCase))
            return "HKCU:\\" + keyPath["HKEY_CURRENT_USER\\".Length..];

        if (keyPath.StartsWith("HKEY_CLASSES_ROOT\\", StringComparison.OrdinalIgnoreCase))
            return "HKCR:\\" + keyPath["HKEY_CLASSES_ROOT\\".Length..];

        if (keyPath.StartsWith("HKLM\\", StringComparison.OrdinalIgnoreCase))
            return "HKLM:\\" + keyPath["HKLM\\".Length..];

        if (keyPath.StartsWith("HKCU\\", StringComparison.OrdinalIgnoreCase))
            return "HKCU:\\" + keyPath["HKCU\\".Length..];

        return keyPath;
    }
}