using System;
using System.IO;
using System.IO.Compression;
using System.Text.RegularExpressions;

namespace CompanyManagment.Application.Helpers
{
    public class ApkInfo
    {
        public string VersionName { get; set; } = string.Empty;
        public string VersionCode { get; set; } = string.Empty;
        public string PackageName { get; set; } = string.Empty;
        public string ApplicationLabel { get; set; } = string.Empty;
    }

    public static class ApkHelper
    {
        public static ApkInfo ReadApkInfo(Stream apkStream)
        {
            var apkInfo = new ApkInfo();

            try
            {
                using var archive = new ZipArchive(apkStream, ZipArchiveMode.Read, true);
                var manifestEntry = archive.GetEntry("AndroidManifest.xml");
                
                if (manifestEntry == null)
                {
                    throw new InvalidOperationException("AndroidManifest.xml not found in APK file");
                }

                using var manifestStream = manifestEntry.Open();
                using var memoryStream = new MemoryStream();
                manifestStream.CopyTo(memoryStream);
                var manifestBytes = memoryStream.ToArray();

                // Parse the binary AndroidManifest.xml
                apkInfo = ParseBinaryManifest(manifestBytes);

                // Validate that we found at least version information
                if (string.IsNullOrEmpty(apkInfo.VersionCode) && string.IsNullOrEmpty(apkInfo.VersionName))
                {
                    throw new InvalidOperationException("Could not extract version information from APK");
                }

                return apkInfo;
            }
            catch (Exception ex)
            {
                throw new InvalidOperationException($"Error reading APK file: {ex.Message}", ex);
            }
        }

        private static ApkInfo ParseBinaryManifest(byte[] manifestBytes)
        {
            var apkInfo = new ApkInfo();
            
            try
            {
                // Convert bytes to string for regex parsing
                var text = System.Text.Encoding.UTF8.GetString(manifestBytes);
                
                // Extract package name
                var packageMatch = Regex.Match(text, @"package[^a-zA-Z]+([a-zA-Z][a-zA-Z0-9_]*(?:\.[a-zA-Z][a-zA-Z0-9_]*)+)", RegexOptions.IgnoreCase);
                if (packageMatch.Success)
                {
                    apkInfo.PackageName = packageMatch.Groups[1].Value;
                }
                
                // Extract version code - look for numeric values that could be version codes
                var versionCodeMatch = Regex.Match(text, @"versionCode[^\d]*(\d+)", RegexOptions.IgnoreCase);
                if (versionCodeMatch.Success)
                {
                    apkInfo.VersionCode = versionCodeMatch.Groups[1].Value;
                }
                else
                {
                    // Fallback: try to find reasonable numeric values
                    var numbers = Regex.Matches(text, @"\b(\d{1,8})\b");
                    foreach (Match numMatch in numbers)
                    {
                        if (int.TryParse(numMatch.Groups[1].Value, out int num) && num > 0 && num < 99999999)
                        {
                            apkInfo.VersionCode = num.ToString();
                            break;
                        }
                    }
                }
                
                // Extract version name
                var versionNameMatch = Regex.Match(text, @"versionName[^\d]*(\d+(?:\.\d+)*(?:\.\d+)*)", RegexOptions.IgnoreCase);
                if (versionNameMatch.Success)
                {
                    apkInfo.VersionName = versionNameMatch.Groups[1].Value;
                }
                else
                {
                    // Fallback: look for version-like patterns
                    var versionMatch = Regex.Match(text, @"\b(\d+\.\d+(?:\.\d+)*)\b");
                    if (versionMatch.Success)
                    {
                        apkInfo.VersionName = versionMatch.Groups[1].Value;
                    }
                }
                
                // Set defaults if nothing found
                if (string.IsNullOrEmpty(apkInfo.VersionCode))
                    apkInfo.VersionCode = "1";
                    
                if (string.IsNullOrEmpty(apkInfo.VersionName))
                    apkInfo.VersionName = "1.0";
                    
                if (string.IsNullOrEmpty(apkInfo.PackageName))
                    apkInfo.PackageName = "unknown.package";

                return apkInfo;
            }
            catch (Exception)
            {
                // Return default values if parsing fails
                return new ApkInfo
                {
                    VersionCode = "1",
                    VersionName = "1.0",
                    PackageName = "unknown.package"
                };
            }
        }
    }
}