using NHibernate.Cfg;
using NHibernate.Mapping;

namespace Sample {
    public class Remapper {
        public static Configuration Remap (Configuration config) {
            var remapper = new Remapper (config);
            return remapper.Remap ();
        }

        readonly Configuration config;
        readonly bool isOracle;

        Remapper (Configuration configuration) {
            config = configuration;
            isOracle = config.Properties["dialect"].ToLower ().Contains ("oracle");
        }

        Configuration Remap () {
            foreach (var classMap in config.ClassMappings) {
                RemapTableName (classMap);
                RemapSequence (classMap);
            }

            foreach (var collectionMap in config.CollectionMappings) {
                RemapLinkTableName (collectionMap);
            }

            return config;
        }

        void RemapTableName (PersistentClass classMap) {
            FixOracleName (classMap.Table);
        }

        void RemapLinkTableName (Collection collectionMap) {
            //remapping root table takes care of collectionMap.Table
            FixOracleName (collectionMap.CollectionTable);
        }

        void RemapSequence (PersistentClass classMap) {
            if (isOracle) return;

            if (classMap.Identifier.IsSimpleValue) {
                var simpleVal = classMap.Identifier as SimpleValue;
                simpleVal.IdentifierGeneratorProperties.Remove ("sequence");
            }
        }

        void FixOracleName (Table table) {
            if (isOracle) {
                table.Name = table.Name.Substring (0, 30);
            }
        }
    }
}