using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Xml.Linq;
using UnityEditor;

namespace Azerion.BlueStack.Editor.Android
{
    public class ManifestProcessor
    {
        private const string MANIFEST_FILE_PATH = "Assets/Plugins/Android/AndroidManifest.xml";

        public const string MANIFEST_FILE_MISSING = MANIFEST_FILE_PATH +
                                                    " is missing. Please add `Custom Main Manifest` for android via `Project Settings -> Player -> Publish Settings`.";

        public const string INVALID_MANIFEST_FILE = "AndroidManifest.xml is not valid. Try re-importing the plugin.";

        public const string APPLICATION_TAG_MISSING =
            "AndroidManifest.xml is not valid. Application tag is missing. Try re-importing the plugin.";

        public const string APP_IDS_MISSING =
            "AdMob app id is missing. Please provide the AdMob app id via  Azerion > BlueStack > Settings";

        private const string META_ADMOB_APP_ID = "com.google.android.gms.ads.APPLICATION_ID";
        private XNamespace ANDROID_NS = "http://schemas.android.com/apk/res/android";

        public static ManifestProcessor Instance { get; } = new ManifestProcessor();

        public void process(string path)
        {
            string manifestPath = Path.GetFullPath(path);

            XDocument manifest = null;
            try
            {
                manifest = XDocument.Load(manifestPath);
            }
            catch (IOException e)
            {
                StopBuildWithMessage(MANIFEST_FILE_MISSING +" : " + e.Message );
            }

            XElement elemManifest = manifest.Element("manifest");
            if (elemManifest == null)
            {
                StopBuildWithMessage(INVALID_MANIFEST_FILE);
            }

            XElement elemApplication = elemManifest.Element("application");
            if (elemApplication == null)
            {
                StopBuildWithMessage(APPLICATION_TAG_MISSING);
            }

            if (string.IsNullOrEmpty(BlueStackSettings.Instance.AdmobAppIdAndroid))
            {
                StopBuildWithMessage(APP_IDS_MISSING);
            }

            IEnumerable<XElement> metas = elemApplication.Descendants()
                .Where(elem => elem.Name.LocalName.Equals("meta-data"));

            XElement adMobAppMetaElement = GetMetaElement(metas, META_ADMOB_APP_ID);
            if (adMobAppMetaElement == null)
            {
                elemApplication.Add(CreateMetaElement(META_ADMOB_APP_ID, BlueStackSettings.Instance.AdmobAppIdAndroid));
            }
            else
            {
                adMobAppMetaElement.SetAttributeValue(ANDROID_NS + "value",
                    BlueStackSettings.Instance.AdmobAppIdAndroid);
            }

            elemManifest.Save(manifestPath);
        }

        private XElement CreateMetaElement(string name, object value)
        {
            return new XElement("meta-data",
                new XAttribute(ANDROID_NS + "name", name), new XAttribute(ANDROID_NS + "value", value));
        }

        private XElement GetMetaElement(IEnumerable<XElement> metas, string metaName)
        {
            foreach (XElement elem in metas)
            {
                IEnumerable<XAttribute> attrs = elem.Attributes();
                foreach (XAttribute attr in attrs)
                {
                    if (attr.Name.Namespace.Equals(ANDROID_NS)
                        && attr.Name.LocalName.Equals("name") && attr.Value.Equals(metaName))
                    {
                        return elem;
                    }
                }
            }

            return null;
        }

        private void StopBuildWithMessage(string message)
        {
            string prefix = "[BlueStack] ";
#if UNITY_2017_1_OR_NEWER
            throw new BuildPlayerWindow.BuildMethodException(prefix + message);
#else
        throw new OperationCanceledException(prefix + message);
#endif
        }
    }
}