/*-
 * ============LICENSE_START=======================================================
 * openECOMP : SDN-C
 * ================================================================================
 * Copyright (C) 2017 AT&T Intellectual Property. All rights
 *             reserved.
 * ================================================================================
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * ============LICENSE_END=========================================================
 */

package org.openecomp.sdnc.sli.resource.sql;

import java.sql.ResultSetMetaData;
import java.util.Map;

import javax.sql.rowset.CachedRowSet;

import org.apache.commons.lang3.StringUtils;
import org.openecomp.sdnc.sli.SvcLogicContext;
import org.openecomp.sdnc.sli.SvcLogicException;
import org.openecomp.sdnc.sli.SvcLogicResource;
import org.openecomp.sdnc.sli.SvcLogicResource.QueryStatus;
import org.openecomp.sdnc.sli.resource.dblib.DBResourceManager;
import org.openecomp.sdnc.sli.resource.dblib.DbLibService;
import org.osgi.framework.Bundle;
import org.osgi.framework.BundleContext;
import org.osgi.framework.FrameworkUtil;
import org.osgi.framework.ServiceReference;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class SqlResource implements SvcLogicResource {

	private static final Logger LOG = LoggerFactory
			.getLogger(SqlResource.class);

	private static final String DBLIB_SERVICE =
	"org.openecomp.sdnc.sli.resource.dblib.DBResourceManager";


	private static String CRYPT_KEY = "";

	public SqlResource() {
	}


	// For sql-resource, is-available is the same as exists
	@Override
	public QueryStatus isAvailable(String resource, String key, String prefix,
			SvcLogicContext ctx) throws SvcLogicException {

		return(exists(resource, key, prefix, ctx));

	}

	@Override
	public QueryStatus exists(String resource, String key, String prefix,
			SvcLogicContext ctx) throws SvcLogicException {

		DbLibService dblibSvc = getDbLibService();
		if (dblibSvc == null) {
			return (QueryStatus.FAILURE);
		}

		String theStmt = resolveCtxVars(key, ctx);

		try {
			CachedRowSet results = dblibSvc.getData(theStmt, null, null);

			if (!results.next()) {
				return (QueryStatus.NOT_FOUND);
			}

			int numRows = results.getInt(1);

			if (numRows > 0) {
				return (QueryStatus.SUCCESS);
			} else {
				return (QueryStatus.NOT_FOUND);
			}
		} catch (Exception e) {
			LOG.error("Caught SQL exception", e);
			return (QueryStatus.FAILURE);
		}
	}

//	@Override
	public QueryStatus query(String resource, boolean localOnly, String select, String key,  String prefix, String orderBy, SvcLogicContext ctx) throws SvcLogicException {


		DbLibService dblibSvc = getDbLibService();

		if (dblibSvc == null) {
			return (QueryStatus.FAILURE);
		}

		String sqlQuery = resolveCtxVars(key, ctx);

		try {

			CachedRowSet results = dblibSvc.getData(sqlQuery, null, null);

			QueryStatus retval = QueryStatus.SUCCESS;

			if (!results.next()) {
				retval = QueryStatus.NOT_FOUND;
				LOG.debug("No data found");
			} else {
				if (ctx != null) {


					if ((prefix != null) && prefix.endsWith("[]")) {
						// Return an array.
						String pfx = prefix.substring(0, prefix.length()-2);
						int idx = 0;
						do {
							ResultSetMetaData rsMeta = results.getMetaData();
							int numCols = rsMeta.getColumnCount();

							for (int i = 0; i < numCols; i++) {
								String colValue = null;
								String tableName = rsMeta.getTableName(i+1);
								if (rsMeta.getColumnType(i+1) == java.sql.Types.VARBINARY) {
									colValue = decryptColumn(tableName, rsMeta.getColumnName(i+1), results.getBytes(i+1), dblibSvc);
								} else {
									colValue = results.getString(i+1);
								}
								LOG.debug("Setting " + pfx
										+ "[" + idx + "]."
										+ rsMeta.getColumnLabel(i + 1)
												.replaceAll("_", "-") + " = " +
										colValue);
								ctx.setAttribute(pfx
										+ "[" + idx + "]."
										+ rsMeta.getColumnLabel(i + 1)
												.replaceAll("_", "-"),
										colValue);
							}
							idx++;
						} while (results.next());
						LOG.debug("Setting "+ pfx + "_length = "+idx);
						ctx.setAttribute(pfx + "_length", ""+idx);
					} else {
						ResultSetMetaData rsMeta = results.getMetaData();
						int numCols = rsMeta.getColumnCount();

						for (int i = 0; i < numCols; i++) {
							String colValue =results.getString(i+1);

							if (prefix != null) {

								LOG.debug("Setting "+prefix
										+ "."
										+ rsMeta.getColumnLabel(i + 1)
												.replaceAll("_", "-")+" = "+
										colValue);
								ctx.setAttribute(prefix
										+ "."
										+ rsMeta.getColumnLabel(i + 1)
												.replaceAll("_", "-"),
										colValue);
							} else {

								LOG.debug("Setting "+rsMeta.getColumnLabel(i + 1)
										.replaceAll("_", "-")+" = "+colValue);

								ctx.setAttribute(rsMeta.getColumnLabel(i + 1)
										.replaceAll("_", "-"), colValue);
							}
						}
					}
				}
			}

			return (retval);

		} catch (Exception e) {
			LOG.error("Caught SQL exception", e);
			return (QueryStatus.FAILURE);
		}

	}

	// reserve is no-op
	@Override
	public QueryStatus reserve(String resource, String select, String key,
			String prefix, SvcLogicContext ctx) throws SvcLogicException {

		return(QueryStatus.SUCCESS);

	}

	// release is no-op
	@Override
	public QueryStatus release(String resource, String key, SvcLogicContext ctx)
			throws SvcLogicException {

		return(QueryStatus.SUCCESS);
	}

	private QueryStatus executeSqlWrite(String key, SvcLogicContext ctx)
			throws SvcLogicException {
		QueryStatus retval = QueryStatus.SUCCESS;

		DbLibService dblibSvc = getDbLibService();

		if (dblibSvc == null) {
			return (QueryStatus.FAILURE);
		}

		String sqlStmt = resolveCtxVars(key, ctx);

		LOG.debug("key = ["+key+"]; sqlStmt = ["+sqlStmt+"]");
		try {

			if (!dblibSvc.writeData(sqlStmt, null, null)) {
				retval = QueryStatus.FAILURE;
			}
		} catch (Exception e) {
			LOG.error("Caught SQL exception", e);
			retval = QueryStatus.FAILURE;
		}



		return (retval);

	}

	private String resolveCtxVars(String key,
			SvcLogicContext ctx) {
		if (key == null) {
			return (null);
		}

		if (key.startsWith("'") && key.endsWith("'")) {
			key = key.substring(1, key.length() - 1);

			LOG.debug("Stripped outer single quotes - key is now [" + key + "]");
		}

		String[] keyTerms = key.split("\\s+");

		StringBuffer sqlBuffer = new StringBuffer();


		for (int i = 0; i < keyTerms.length; i++) {
			sqlBuffer.append(resolveTerm(keyTerms[i], ctx));
			sqlBuffer.append(" ");
		}


		return (sqlBuffer.toString());
	}


	private String resolveTerm(String term, SvcLogicContext ctx) {
		if (term == null) {
			return (null);
		}

		LOG.debug("resolveTerm: term is " + term);

		if (term.startsWith("$") && (ctx != null)) {
			// Resolve any index variables.

			return ("'" + resolveCtxVariable(term.substring(1), ctx) + "'");
		} else  {
			return (term);
		}

	}

	private String resolveCtxVariable(String ctxVarName, SvcLogicContext ctx) {

		if (ctxVarName.indexOf('[') == -1) {
			// Ctx variable contains no arrays
			return (ctx.getAttribute(ctxVarName));
		}

		// Resolve any array references
		StringBuffer sbuff = new StringBuffer();
		String[] ctxVarParts = ctxVarName.split("\\[");
		sbuff.append(ctxVarParts[0]);
		for (int i = 1; i < ctxVarParts.length; i++) {
			if (ctxVarParts[i].startsWith("$")) {
				int endBracketLoc = ctxVarParts[i].indexOf("]");
				if (endBracketLoc == -1) {
					// Missing end bracket ... give up parsing
					LOG.warn("Variable reference " + ctxVarName
							+ " seems to be missing a ']'");
					return (ctx.getAttribute(ctxVarName));
				}

				String idxVarName = ctxVarParts[i].substring(1, endBracketLoc);
				String remainder = ctxVarParts[i].substring(endBracketLoc);

				sbuff.append("[");
				sbuff.append(ctx.getAttribute(idxVarName));
				sbuff.append(remainder);

			} else {
				// Index is not a variable reference
				sbuff.append("[");
				sbuff.append(ctxVarParts[i]);
			}
		}

		return (ctx.getAttribute(sbuff.toString()));
	}



	@Override
	public QueryStatus save(String resource, boolean force, boolean localOnly,
			String key, Map<String, String> parms, String prefix,
			SvcLogicContext ctx) throws SvcLogicException {

		return(executeSqlWrite(key, ctx));
	}

	private DbLibService getDbLibService() {

		// Try to get dblib as an OSGI service
		DbLibService dblibSvc = null;
		BundleContext bctx = null;
		ServiceReference sref = null;

		Bundle bundle =  FrameworkUtil.getBundle(SqlResource.class);

		if (bundle != null) {
				bctx = bundle.getBundleContext();
		}

		if (bctx != null) {
			sref = bctx.getServiceReference(DBLIB_SERVICE);
		}

		if (sref == null) {
			LOG.warn("Could not find service reference for DBLIB service ("
					+ DBLIB_SERVICE + ")");
		} else {
			dblibSvc = (DbLibService) bctx.getService(sref);
			if (dblibSvc == null) {

				LOG.warn("Could not find service reference for DBLIB service ("
						+ DBLIB_SERVICE + ")");
			}
		}

		if (dblibSvc == null) {
			// Must not be running in an OSGI container.  See if you can load it as a
			// a POJO then.
			try {
			dblibSvc = DBResourceManager.create(System.getProperties());
			} catch (Exception e) {
				LOG.error("Caught exception trying to create dblib service", e);
			}

			if (dblibSvc == null) {
				LOG.warn("Could not create new DBResourceManager");
			}
		}

		return (dblibSvc);
	}



	@Override
	public QueryStatus notify(String resource, 	String action,	String key, SvcLogicContext ctx) throws SvcLogicException {
		if(LOG.isDebugEnabled()) {
			LOG.debug("SqlResource.notify called with resource="+resource+", action="+action);
		}


		return QueryStatus.SUCCESS;
	}


	@Override
	public QueryStatus delete(String resource, String key, SvcLogicContext ctx)
			throws SvcLogicException {

		return(executeSqlWrite(key, ctx));
	}


	public QueryStatus update(String resource, String key,
			Map<String, String> parms, String prefix, SvcLogicContext ctx)
			throws SvcLogicException {

		return(executeSqlWrite(key, ctx));
	}

	private String encryptColValue(String value) {
		return("AES_ENCRYPT('"+value+"','"+CRYPT_KEY+"')");
	}

	private String decryptColumn(String tableName, String colName, byte[] colValue,  DbLibService dblibSvc)
	{
		String strValue = new String(colValue);

		if (StringUtils.isAsciiPrintable(strValue)) {

			// If printable, not encrypted
			return(strValue);
		} else {
			try {
				CachedRowSet results = dblibSvc.getData("SELECT CAST(AES_DECRYPT('"+strValue+"','"+CRYPT_KEY+"') AS CHAR(50)) FROM DUAL", null, null);

				if (results.next()) {
					strValue = results.getString(1);
					LOG.debug("Decrypted value is "+strValue);
				} else {
					LOG.warn("Cannot decrypt "+tableName+"."+colName);
				}
			} catch (Exception e) {
				LOG.error("Caught exception trying to decrypt "+tableName+"."+colName, e);
			}
		}

		return(strValue);
	}

	public static String getCryptKey() {
		return(CRYPT_KEY);
	}

	public static String setCryptKey(String key) {
		CRYPT_KEY = key;
		return(CRYPT_KEY);
	}


}