using AndroidXml;
using ICSharpCode.SharpZipLib.Zip;
using LJLib.Tools.Helper;
using System.IO;
using System.Xml;

namespace LJLib
{
    public class APKHelper
    {
        public string GetVersionName(string apkPath)
        {
            using (var fs = new FileStream(apkPath, FileMode.Open, FileAccess.Read))
            {
                return GetVersionName(fs);
            }
        }

        public string GetVersionName(byte[] apkbytes)
        {
            using (var fs = new MemoryStream(apkbytes))
            {
                return GetVersionName(fs);
            }
        }

        public string GetVersionName(Stream apkStream)
        {
            byte[] xmlbytes;

            using (var zipfile = new ZipFile(apkStream))
            {
                var item = zipfile.GetEntry("AndroidManifest.xml");
                using (var ms = new MemoryStream())
                using (var strm = zipfile.GetInputStream(item))
                {
                    StreamHelper.StreamCopy(ms, strm);
                    xmlbytes = ms.ToArray();
                }
            }

            using (var ms = new MemoryStream(xmlbytes))
            {
                XmlReader reader;
                if (xmlbytes[0] == '<' || char.IsWhiteSpace((char) xmlbytes[0]))
                {
                    // Normal XML file
                    reader = new XmlTextReader(ms)
                    {
                        WhitespaceHandling = WhitespaceHandling.None
                    };
                }
                else
                {
                    // Android binary XML
                    reader = new AndroidXmlReader(ms);
                }
                using (reader)
                while (reader.Read())
                {
                    if (reader.NodeType == XmlNodeType.Element && reader.Name.ToLower() == "manifest")
                    {
                        for (int i = 0; i < reader.AttributeCount; i++)
                        {
                            reader.MoveToAttribute(i);
                            if (reader.LocalName.ToLower() == "versionname")
                            {
                                return reader.Value;
                            }
                        }
                        reader.MoveToElement();
                    }
                }
                return string.Empty;
            }
        }
    }
}