package com.rjconsultores.ventaboletos;

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.Timestamp;
import java.util.Calendar;
import java.util.HashMap;
import java.util.Map;

import javax.sql.DataSource;


import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.flywaydb.core.Flyway;
import org.flywaydb.core.api.callback.FlywayCallback;

import com.rjconsultores.ventaboletos.vo.FlyWayCustomDetail;

public class FlyWay {
	private static final Logger log = LogManager.getLogger(FlyWay.class);
	
	private static final FlyWay INSTANCE = new FlyWay();
	
	final private static String TABELA_FLYWAY = "schema_version_cst";
	final private static String AMBIENTE_DEV = "dev";
	final private static String AMBIENTE_CONSULTA = "consulta";
	final File JBOSS_DATA = getJBossDataDirectory();
	
	private DataSource dataSource = null;
	
	private String url = null;
	private String user = null;
	private String password = null;
	
	private String location = "db.migration";
	private String oldies = "db.backup.oracle";
	
	private FlyWay() {
		
	}

	public static FlyWay getInstance() {
		return INSTANCE;
	}
	
	private File getJBossDataDirectory() {
		try {
			return new File(System.getProperty("jboss.server.data.dir"));
		} catch (Exception e) {
			return null;
		}
	}
	
	public void defineLocation(final String location) {
		this.location = location;
	}
	
	public void defineDataSource(final DataSource dataSource) {
		this.dataSource = dataSource;
		
		fixFiles(dataSource);
	}
	
	public void defineProperties(final String url, final String user, final String password) {
		this.url = url;
		this.user = user;
		this.password = password;
	}
	
	private void fixFiles(final DataSource ds) {
		try {
			Connection c = dataSource.getConnection();
			Statement s = c.createStatement();

			fixVersion(s, "20161710.1833", "20161017.1833", "V20161017_1833__mantis8112.sql");
			fixVersion(s, "20161910.0934", "20161019.0934", "V20161019_0934__mantis7907.sql");
			fixVersion(s, "20162410.1119", "20161024.1119", "V20161024_1119__mantis7904.sql");

			s.close();
			c.close();
			
		} catch (SQLException e) {
			log.error(e.getMessage(), e);
		}
	}

	private void fixVersion(final Statement s, final String oldVersion, final String newVersion, final String newScript) throws SQLException {
		ResultSet rs = s.executeQuery("select count(*) as total from \"schema_version\" where \"version\" like '" + oldVersion + "'");
		
		int total = 0;
		
		while (rs.next()) {
			total = rs.getInt("total");
		}
		
		rs.close();
		
		if (total > 0) {
			log.info("Fix version " + oldVersion + " to new version " + newVersion + " and new script " + newScript);

			StringBuilder sql = new StringBuilder("");
			sql.append(" update \"schema_version\"");
			sql.append(" set \"version\" = '" + newVersion + "', \"script\" = '" + newScript + "'");
			sql.append(" where \"version\" like '" + oldVersion + "'");
			
			s.executeUpdate(sql.toString());
		}
	}

	public boolean start() {
		return start(null, null, false);
	}
	
	public boolean start(Boolean isReloadFyway) {
		return start(null, null, isReloadFyway);
	}

	public boolean startCustom() {
		String location = "db.performance";
		
		if (JBOSS_DATA != null) {
			File data = new File(JBOSS_DATA, "flyway");
			
			if (!data.exists()) {
				data.mkdirs();
			}
			
			if (!validarScripts(data)) {
				return true;
			}
			
			location = "filesystem:" + data.getPath();
		}
		
		return start(location, TABELA_FLYWAY, false);
	}

	public boolean start(final String customLocation, final String customTable, Boolean isReloadFlyway) {
		log.info("Executando Flyway...");
		
		try{			
			String ambiente = System.getProperty("ambiente") ==null || System.getProperty("ambiente").isEmpty()  ?  "" : System.getProperty("ambiente");
			if( (AMBIENTE_DEV.equalsIgnoreCase(ambiente) && AMBIENTE_CONSULTA.equalsIgnoreCase(ambiente)) && Boolean.FALSE.equals(isReloadFlyway) ) {
				log.warn("Flyway não executado. Ambiente = dev ou consulta");
				return true;
			}
			
			final Flyway flyway = new Flyway();
			
			if (customTable != null) {
				flyway.setTable(customTable);
			}
			
			if (customLocation != null) {
				flyway.setLocations(customLocation);
			} else if (this.location != null && !this.location.equals("db.migration")) {
				flyway.setLocations(this.location);
			}else {
				flyway.setLocations(this.oldies, this.location);
			}
			
			if (dataSource != null) {
				flyway.setDataSource(dataSource);
			} else {
				flyway.setDataSource(url, user, password);
				
				dataSource = flyway.getDataSource(); 
			}

			execute(flyway);
			log.info("Flyway executado.");

		}catch(Throwable t){
			log.error("Erro ao executar o Flyway",t);			
			return false;
		}
		
		return true;
	}
	
	public void execute(final Flyway flyway) {
		flyway.setValidateOnMigrate(false);
		flyway.setIgnoreFutureMigrations(true);
		flyway.setOutOfOrder(true);
		flyway.setBaselineOnMigrate(true);

		if (flyway.getTable().equals(TABELA_FLYWAY)) {
			FlyWayCallback errorCallback = new FlyWayCallback();
			
			FlywayCallback[] callbacks = new FlywayCallback[]{ errorCallback };
			flyway.setCallbacks(callbacks);
			
			boolean reexecute = false;
			
			do {
				reexecute = false;
				
				try {
				    flyway.migrate();
				} catch (final Exception e) {
					if (errorCallback.getScriptError() != null && JBOSS_DATA != null) {
						reexecute = true;

						log.error("[Flyway] Erro ao executar o script: " + errorCallback.getScriptError() + ". Este script sera desabilitado na tabela FLYWAY_SCRIPTS.");
						
						File scriptFile = new File(JBOSS_DATA, "flyway");
						scriptFile = new File(scriptFile, errorCallback.getScriptError());
						
						if (scriptFile.exists()) {
							boolean success = scriptFile.delete();
							
							log.info("[Flyway] Excluindo fisicamente o script: " + errorCallback.getScriptError() + ". " + (success ? "OK" : "ERROR"));
							
							if (!success) {
								reexecute = false;
							}
						}
						
						Connection c = null;
						PreparedStatement ps = null;
						
						try {
							c = flyway.getDataSource().getConnection();
							ps = c.prepareStatement("update flyway_scripts set activo = 0 where nome like ?");
							ps.setString(1, errorCallback.getScriptError().replace(".sql", ""));
							ps.executeUpdate();
							
						} catch (SQLException e1) {
						} finally {
							if (ps != null) {
								try { ps.close(); } catch (SQLException e1) {}
							}
							
							if (c != null) {
								try { c.close(); } catch (SQLException e1) {}
							}
						}
					}
					
					flyway.repair();
				}
			} while (reexecute);
		} else {
			flyway.migrate();
		}
	}
	
	private boolean validarScripts(File data) {
		Map<String, FlyWayCustomDetail> scripts = new HashMap<String, FlyWayCustomDetail>(0);
		
		try {
			StringBuilder sb = new StringBuilder();
			
			boolean existe = existeSchema(dataSource.getConnection());

			if (existe) {
				sb.append(" select nome as nome_arquivo, sql as sql_arquivo, sql_erro as erro, datahora_execucao as datahora");
				sb.append(" from flyway_scripts");
				sb.append(" where activo = 1 and nome not in (select replace(\"script\", '.sql', '') from \"schema_version_cst\")");
				sb.append(" order by nome_arquivo");
			} else {
				sb.append(" select nome as nome_arquivo, sql as sql_arquivo, sql_erro as erro, datahora_execucao as datahora");
				sb.append(" from flyway_scripts");
				sb.append(" where activo = 1");
				sb.append(" order by nome_arquivo");
			}
			
			Connection c = dataSource.getConnection();
			Statement s = c.createStatement();
			
			ResultSet rs = s.executeQuery(sb.toString());
			
			while (rs.next()) {
				if (!isRegistroValido(rs.getString("nome_arquivo"), rs.getString("sql_arquivo"))) {
					continue;
				}
				
				Timestamp timestamp = rs.getTimestamp("datahora");
				
				FlyWayCustomDetail detail = new FlyWayCustomDetail();
				detail.setVersion(rs.getString("nome_arquivo"));
				detail.setSql(rs.getString("sql_arquivo"));
				detail.setErrorCode(rs.getString("erro"));
				
				if (timestamp != null) {
					detail.setDatetimeExecute(new java.util.Date(timestamp.getTime()));
				}
				
				scripts.put(rs.getString("nome_arquivo"), detail);
			}
			
			rs.close();
			s.close();
			c.close();
			
		} catch (SQLException e) {
			log.error(e.getMessage(), e);
		}
		
		if (scripts.isEmpty()) {
			return false;
		}
		
		boolean retorno = false;
		
		Writer writer = null;
		
		for (Map.Entry<String, FlyWayCustomDetail> entry : scripts.entrySet()) {
			if (entry.getValue().getDatetimeExecute() != null) {
				Calendar atual = Calendar.getInstance();
				
				if (atual.getTime().before(entry.getValue().getDatetimeExecute())) {
					continue;
				}
			}
			
			File scriptFile = new File(data, entry.getKey() + ".sql");
			
			if (scriptFile.exists()) {
				scriptFile.delete();
			}
			
			if (!scriptFile.exists()) {
				StringBuilder sb = new StringBuilder();
				
				if (entry.getValue().getErrorCode() != null) {
					sb.append("declare").append("\n");
					sb.append("  object_exists exception;").append("\n").append("\n");
					sb.append("  pragma exception_init (object_exists , ").append(entry.getValue().getErrorCode()).append(");").append("\n");
					sb.append("begin").append("\n");
					sb.append("  execute immediate '").append(entry.getValue().getSql()).append("';").append("\n");
					sb.append("  exception when object_exists then null;").append("\n");
					sb.append("end;");
				} else {
					sb.append(entry.getValue().getSql());
				}
				
				try {
				    writer = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(scriptFile), "utf-8"));
				    writer.write(sb.toString());
				    
				    log.info("[Flyway] Script gerado: " + scriptFile.toString());
				    
				    retorno = true;
				} catch (IOException ex) {
				} finally {
				   try {writer.close();} catch (Exception ex) {log.info(ex.getMessage(), ex);}
				}			
			}
		}
		
		return retorno;
	}

	private boolean isRegistroValido(String versao, String sql) {
		boolean valido = true;
		
		String v[] = versao.split("_");
		
		if (!versao.startsWith("V")) {
			valido = false;
		} else {
			if (!(v.length == 4)) {
				valido = false;
			}
		}
		
		if (!valido) {
			Connection c = null;
			PreparedStatement ps = null;
			
			try {
				c = dataSource.getConnection();
				ps = c.prepareStatement("update flyway_scripts set activo = 0 where nome like ?");
				ps.setString(1, versao);
				ps.executeUpdate();
				
			} catch (SQLException e1) {
			} finally {
				if (ps != null) {
					try { ps.close(); } catch (SQLException e1) {}
				}
				
				if (c != null) {
					try { c.close(); } catch (SQLException e1) {}
				}
			}
		}

		return valido;
	}

	private boolean existeSchema(Connection c) {
		StringBuilder sb = new StringBuilder();
		sb.append("SELECT count(table_name) as existe FROM user_tables WHERE table_name = 'schema_version_cst'");
		
		try {
			Statement s = c.createStatement();
			ResultSet rs = s.executeQuery(sb.toString());
			
			int existe = 0;
			
			while (rs.next()) {
				existe = rs.getInt("existe");
			}
			
			rs.close();
			s.close();
			c.close();
			
			if (existe > 0) {
				return true;
			}
			
		} catch (SQLException e) {
			log.error(e.getMessage(), e);
		}

		return false;
	}
}