using System;

namespace Mammoth.Couscous.java.net {
    internal class URI {
        private readonly Uri _uri;
        
        internal URI(string uri) {
            try {
                _uri = new Uri(uri, UriKind.RelativeOrAbsolute);
            } catch (UriFormatException exception) {
                throw new URISyntaxException(exception.Message);
            }
        }
        
        internal URI(Uri uri) {
            _uri = uri;
        }
        
        internal bool isAbsolute() {
            return _uri.IsAbsoluteUri;
        }
        
        internal URL toURL() {
            return new URL(_uri.ToString());
        }
        
        internal URI resolve(string relativeUri) {
            if (new URI(relativeUri).isAbsolute()) {
                return new URI(relativeUri);
            } else if (_uri.IsAbsoluteUri) {
                return new URI(new Uri(_uri, relativeUri));
            } else {
                var path = _uri.ToString();
                var lastSlashIndex = path.LastIndexOf("/");
                var basePath = lastSlashIndex == -1
                    ?  "."
                    : path.Substring(0, lastSlashIndex + 1);
                return new URI(basePath + relativeUri);
            }
        }
    }
}