package de.superx.bin.fm;

import java.io.IOException;
import java.io.StringWriter;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import javax.sql.DataSource;

import org.apache.log4j.Logger;
import org.springframework.dao.DataAccessException;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.ResultSetExtractor;
import org.springframework.jdbc.support.rowset.SqlRowSet;

import de.superx.common.TemplateProcessor.SqlVarType;
import de.superx.servlet.SuperXManager;
import freemarker.core.Environment;
import freemarker.template.ObjectWrapper;
import freemarker.template.Template;
import freemarker.template.TemplateDirectiveBody;
import freemarker.template.TemplateDirectiveModel;
import freemarker.template.TemplateException;
import freemarker.template.TemplateModel;
import freemarker.template.TemplateModelException;

public class SqlVarsDirective implements TemplateDirectiveModel {

	/**
	 * sqlvar "datatypes"
	 * 
	 * @author nnguyen, j.hientzsch :)
	 *
	 */

	private static Logger logger = Logger.getLogger(SqlVarsDirective.class);

	private static final String PARAM_VAR_NAME = "name";
	private static final String PARAM_VAR_TYPE = "type";

	private static final boolean PARSE_FTL = true;
	private static final String FTL_ENCODING = "UTF-8";

	@Override
	public void execute(Environment env, @SuppressWarnings("rawtypes") Map params, TemplateModel[] loopvars,
			TemplateDirectiveBody body) throws TemplateException, IOException {

		// default inclusion of templates up for debate
		includeTemplates(env);

		SqlVarType varType = params.get(PARAM_VAR_TYPE) != null
				? SqlVarType.valueOf(params.get(PARAM_VAR_TYPE).toString().trim().toLowerCase())
				: SqlVarType.none;

		if (!params.containsKey(PARAM_VAR_NAME)) {
			throw new TemplateModelException("No variable name is set for sqlvar");
		}

		String varName = params.get(PARAM_VAR_NAME).toString();
		String query = "";

		ObjectWrapper objWrapper = env.getConfiguration().getObjectWrapper();

		if (body != null) {
			StringWriter bodyContent = new StringWriter();
			body.render(bodyContent);
			query = bodyContent.toString();
		} else {
			logger.warn("Sqlvar " + varName + " has no nested content and therefore no effect and can be removed!");
		}

		JdbcTemplate jt = new JdbcTemplate();
		DataSource dataSource = SuperXManager.getBean("dataSource", DataSource.class);
		jt.setDataSource(dataSource);

		Object result = null;
		switch (varType) {

		case none:
		case list: {
			ArrayList<Object> list = buildList(jt, query);
			result = list.size() == 1 ? list.get(0) : list;

			result = result == null ? "" : result;
		}
			break;

		case hash:
		case hashlist: {
			FMListe list = new FMListe();
			list = buildHashList(jt, query);
			result = list.size() == 1 ? list.get(0) : list;
		}
			break;

		case hashsequence: {
			FMListe list = new FMListe();
			list = buildHashList(jt, query);
			result = list;
		}
			break;

		case sicht:
			throw new SqlVarsDirectiveException(
					"SqlVar type sicht is not supported as a freemarker directive instead use in block parsed by de.superx.common.TemplateProcessor");
		case sichtsequence:
			throw new SqlVarsDirectiveException(
					"SqlVar type sichtsequence is not supported as a freemarker directive instead use in block parsed by de.superx.common.TemplateProcessor");

		case string:
			result = query;
			break;

		default:
			throw new SqlVarsDirectiveException("Unknown SqlVar type " + varType.toString());
		}

		env.setVariable(varName, objWrapper.wrap(result));

	}

	/**
	 * Executes query and and places result as SqlVarType.list into out
	 * 
	 * @param jt
	 * @param query
	 * @param out
	 */
	private static ArrayList<Object> buildList(JdbcTemplate jt, String query) {

		ArrayList<Object> out = new ArrayList<>();

		SqlRowSet queryResult = jt.queryForRowSet(query);
		if (queryResult.first()) {
			do {
				out.add(queryResult.getObject(1));
			} while (queryResult.next());
		}else {
			out.add(""); //In case the query does not return a result, freemarker needs an empty string for further conditionals
		}
		return out;
	}

	/**
	 * Executes SQL query and puts result into out as SqlVarType.hashlist
	 * 
	 * @param jt
	 * @param query
	 * @param objWrapper
	 * @param out
	 */
	private static FMListe buildHashList(JdbcTemplate jt, String query) {

		FMListe out = new FMListe();

		jt.query(query, new ResultSetExtractor<Void>() {
			@Override
			public Void extractData(ResultSet rs) throws SQLException, DataAccessException {

				ResultSetMetaData metaData = rs.getMetaData();
				int columnCount = metaData.getColumnCount();
				List<String> columnNames = new ArrayList<>(columnCount);
				for (int i = 1; i <= columnCount; i++) {
					columnNames.add(metaData.getColumnLabel(i));
				}

				while (rs.next()) {
					SxHash row = new SxHash();
					for (String columnName : columnNames) {
						row.put(columnName, rs.getString(columnName) == null ? "" : rs.getString(columnName));
					}
					out.add(row);
				}

				return null;
			}
		});

		return out;
	}

	private static void includeTemplates(Environment env) {
		Template inclTemplate1 = null, inclTemplate2 = null;
		try {
			inclTemplate1 = env.getTemplateForInclusion("SuperX_general", FTL_ENCODING, PARSE_FTL);
			inclTemplate2 = env.getTemplateForInclusion("SQL_lingua_franca", FTL_ENCODING, PARSE_FTL);
		} catch (IOException e) {
			logger.error(
					"Freemarker template inclusion failed for templates SuperX_general and/or SQL_lingua_franca!\n", e);
		}

		if (inclTemplate1 != null && inclTemplate2 != null) {
			try {
				env.include(inclTemplate1);
				env.include(inclTemplate2);
			} catch (TemplateException e) {
				logger.warn("Template inclusion failed in SqlVarsDirective:\n" + e.getStackTrace());
			} catch (IOException e) {
				logger.warn("Template inclusion failed in SqlVarsDirective:\n" + e.getStackTrace());
			}
		}
	}
}