Essensbestellungsverwaltung/src/main/java/com/bib/essensbestellungsverwaltung/Database.java

package com.bib.essensbestellungsverwaltung;
/*
    @author Malte Schulze Hobeling
 */

import java.io.File;
import java.io.IOException;
import java.nio.file.Path;
import java.sql.*;
import java.util.ArrayList;
import java.util.List;


public class Database {
    private static final String dbLocation = "jdbc:sqlite:"+Path.of("").toAbsolutePath()+"/database.db";
    protected static boolean init(){
        File db = new File(Path.of("").toAbsolutePath()+"/database.db");
        try {
            return db.createNewFile();
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
    protected static Connection connect(){
        Connection conn = null;
        try{
            conn = DriverManager.getConnection(dbLocation);
        }catch (SQLException e){
            e.printStackTrace();
        }
        return conn;
    }

    protected static void createDb(){
        String[] sql = new String[14];
        sql[0] = """
                CREATE TABLE IF NOT EXISTS address (
                id integer PRIMARY KEY,
                street text,
                number text,
                plz text,
                city text
                );""";
        sql[1] = """
                CREATE TABLE IF NOT EXISTS food_type (
                id integer PRIMARY KEY,
                name text UNIQUE
                );""";
        sql[2] = """
                CREATE TABLE IF NOT EXISTS allergy (
                id integer PRIMARY KEY,
                name text UNIQUE
                );""";
        sql[3] = """
                CREATE TABLE IF NOT EXISTS severity (
                id integer PRIMARY KEY,
                name text UNIQUE
                );""";
        sql[4] = """
                CREATE TABLE IF NOT EXISTS user (
                id integer PRIMARY KEY,
                name text,
                firstname text,
                addressid integer,
                password text,
                email text UNIQUE,
                FOREIGN KEY(addressid) REFERENCES address(id)
                );""";
        sql[5] = """
                CREATE TABLE IF NOT EXISTS child (
                id integer PRIMARY KEY,
                name text,
                firstname text,
                addressid integer,
                FOREIGN KEY(addressid) REFERENCES address(id)
                );""";
        sql[6] = """
                CREATE TABLE IF NOT EXISTS worker (
                userid integer PRIMARY KEY,
                FOREIGN KEY(userid) REFERENCES user(id)
                );""";
        sql[7] = """
                CREATE TABLE IF NOT EXISTS parent (
                userid integer PRIMARY KEY,
                FOREIGN KEY(userid) REFERENCES user(id)
                );""";
        sql[8] = """
                CREATE TABLE IF NOT EXISTS parent_child (
                id integer PRIMARY KEY,
                parentuserid integer,
                childid integer,
                FOREIGN KEY(parentuserid) REFERENCES parent(userid),
                FOREIGN KEY(childid) REFERENCES child(id)
                );""";
        sql[9] = """
                CREATE TABLE IF NOT EXISTS child_allergy (
                id integer PRIMARY KEY,
                childid integer,
                allergyid integer,
                severityid integer,
                FOREIGN KEY(childid) REFERENCES child(id),
                FOREIGN KEY(allergyid) REFERENCES allergy(id),
                FOREIGN KEY(severityid) REFERENCES severity(id)
                );""";
        sql[10] = """
                CREATE TABLE IF NOT EXISTS food (
                id integer PRIMARY KEY,
                name text UNIQUE,
                description text,
                isdessert integer,
                food_typeid integer,
                FOREIGN KEY(food_typeid) REFERENCES food_type(id)
                );""";
        sql[11] = """
                CREATE TABLE IF NOT EXISTS food_plan (
                id integer PRIMARY KEY,
                date text UNIQUE,
                food1 integer,
                food2 integer,
                dessert1 integer,
                dessert2 integer,
                FOREIGN KEY(food1) REFERENCES food(id),
                FOREIGN KEY(food2) REFERENCES food(id),
                FOREIGN KEY(dessert1) REFERENCES food(id),
                FOREIGN KEY(dessert2) REFERENCES food(id)
                );""";
        sql[12] = """
                CREATE TABLE IF NOT EXISTS food_restriction (
                id integer PRIMARY KEY,
                foodid integer,
                allergyid integer,
                FOREIGN KEY(foodid) REFERENCES food(id),
                FOREIGN KEY(allergyid) REFERENCES allergy(id)
                );""";
        sql[13] = """
                CREATE TABLE IF NOT EXISTS food_selection (
                id integer PRIMARY KEY,
                childid integer,
                food_planid integer,
                foodid integer,
                FOREIGN KEY(childid) REFERENCES child(id),
                FOREIGN KEY(food_planid) REFERENCES food_plan(id),
                FOREIGN KEY(foodid) REFERENCES food(id)
                );""";
        try(Connection conn = connect(); Statement stmt = conn.createStatement()){
            for(int i = 0; i < sql.length; i++){
                stmt.execute(sql[i]);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    protected static void fillDb(){
        List<String> sqls = new ArrayList<>();
        sqls.add("""
                INSERT OR IGNORE INTO food_type (id,name)
                VALUES ('1','Vegan');""");
        sqls.add("""
                INSERT OR IGNORE INTO food_type (id,name)
                VALUES ('2','Vegetarisch');""");
        sqls.add("""
                INSERT OR IGNORE INTO food_type (id,name)
                VALUES ('3','Fleischhaltig');""");
        sqls.add("""
                INSERT OR IGNORE INTO allergy (id,name)
                VALUES('1','Eier');""");
        sqls.add("""
                INSERT OR IGNORE INTO allergy (id,name)
                VALUES('2','Soja');""");
        sqls.add("""
                INSERT OR IGNORE INTO allergy (id,name)
                VALUES('3','Milch');""");
        sqls.add("""
                INSERT OR IGNORE INTO allergy (id,name)
                VALUES('4','Erdnüsse');""");
        sqls.add("""
                INSERT OR IGNORE INTO allergy (id,name)
                VALUES('5','Weichtiere');""");
        sqls.add("""
                INSERT OR IGNORE INTO allergy (id,name)
                VALUES('6','Krebstiere');""");
        sqls.add("""
                INSERT OR IGNORE INTO allergy (id,name)
                VALUES('7','Getreide');""");
        sqls.add("""
                INSERT OR IGNORE INTO allergy (id,name)
                VALUES('8','Senf');""");
        sqls.add("""
                INSERT OR IGNORE INTO allergy (id,name)
                VALUES('9','Sesam');""");
        sqls.add("""
                INSERT OR IGNORE INTO allergy (id,name)
                VALUES('10','Schwefeldioxid und Sulfit');""");
        sqls.add("""
                INSERT OR IGNORE INTO allergy (id,name)
                VALUES('11','Nüsse');""");
        sqls.add("""
                INSERT OR IGNORE INTO allergy (id,name)
                VALUES('12','Sellerie');""");
        sqls.add("""
                INSERT OR IGNORE INTO allergy (id,name)
                VALUES('13','Fische');""");
        sqls.add("""
                INSERT OR IGNORE INTO allergy (id,name)
                VALUES('14','Lupinen');""");
        sqls.add("""
                INSERT OR IGNORE INTO allergy (id,name)
                VALUES('15','Nitrit-Pökelsalz');""");
        sqls.add("""
                INSERT OR IGNORE INTO allergy (id,name)
                VALUES('16','Phosphat');""");
        sqls.add("""
                INSERT OR IGNORE INTO allergy (id,name)
                VALUES('17','Nitrat');""");
        sqls.add("""
                INSERT OR IGNORE INTO allergy (id,name)
                VALUES('18','Antioxidationsmittel');""");
        sqls.add("""
                INSERT OR IGNORE INTO allergy (id,name)
                VALUES('19','Farbstoff');""");
        sqls.add("""
                INSERT OR IGNORE INTO allergy (id,name)
                VALUES('20','Geschmacksverstärker');""");
        sqls.add("""
                INSERT OR IGNORE INTO allergy (id,name)
                VALUES('21','Süßungsmittel');""");
        sqls.add("""
                INSERT OR IGNORE INTO allergy (id,name)
                VALUES('22','Konservierungsstoff');""");
        sqls.add("""
                INSERT OR IGNORE INTO severity (id,name)
                VALUES('1','Harmlos');""");
        sqls.add("""
                INSERT OR IGNORE INTO severity (id,name)
                VALUES('2','Warnung');""");
        sqls.add("""
                INSERT OR IGNORE INTO severity (id,name)
                VALUES('3','Kritisch');""");
        try(Connection conn = connect(); Statement stmt = conn.createStatement()){
            for (String sql : sqls) {
                stmt.execute(sql);
            }
        }catch (SQLException e){
            e.printStackTrace();
        }
    }

    /**
     * inserts data into table and returns its id
     * @param table name of the database table
     * @param header String[] order should match with values
     * @param values String[] order should match with header
     * @return id of dataset or -1
     */
    protected static long insert(String table, String[] header, String[] values){
        long id = -1;
        try (Connection conn = connect()){
            String query = queryBuilder("exists",table,header,values);
            PreparedStatement psQuery = conn.prepareStatement(query);
            ResultSet rsQuery = psQuery.executeQuery();
            if(rsQuery.next()){
                boolean found = rsQuery.getBoolean(1);
                if(!found){
                    String sql = queryBuilder("insert",table,header,values);
                    String[] rowId = {"id"};
                    PreparedStatement ps = conn.prepareStatement(sql,rowId);
                    ps.execute();
                    ResultSet rs = ps.getGeneratedKeys();
                    if(rs.next()){
                        id = rs.getLong(1);
                    }

                }else{
                    query = queryBuilder("selectMatch",table,header,values);
                    psQuery = conn.prepareStatement(query);
                    rsQuery = psQuery.executeQuery();
                    if(rsQuery.next()) {
                        id = rsQuery.getLong(1);
                    }
                }
            }

        } catch (SQLException e) {
            return id;
        }
        return id;
    }

    protected static long getSingleId(String table, String[] header, String[] values){
        long id = -1;
        try(Connection conn = connect()){
            String sql = queryBuilder("selectMatch",table,header,values);
            PreparedStatement ps = conn.prepareStatement(sql);
            ResultSet rs = ps.executeQuery();
            if(rs.next()){
                id = rs.getLong(1);
                if(rs.next()){
                    id = -1;
                }
            }
        }catch (SQLException e){
            e.printStackTrace();
            return id;
        }
        return id;
    }

    protected static void printSampleQuery(){
        String sql = """
                SELECT * FROM food_type WHERE id > ?;""";
        String sql1 = """
                SELECT * FROM allergy WHERE id > ?;""";
        try(Connection conn = connect()){
            PreparedStatement ps = conn.prepareStatement(sql);
            PreparedStatement ps1 = conn.prepareStatement(sql1);
            ps.setInt(1,0);
            ResultSet rs = ps.executeQuery();
            System.out.println("food_type");
            while (rs.next()){
                System.out.println("ID: " + rs.getInt("id") + ", Name: " + rs.getString("name"));
            }
            System.out.println("allergy");
            ps1.setInt(1,0);
            rs = ps1.executeQuery();
            while (rs.next()){
                System.out.println("ID: " + rs.getInt("id") + ", Name: " + rs.getString("name"));
            }
        }catch (SQLException e){
            e.printStackTrace();
        }
    }

    protected static void delete(String table, long id){
        String sql = "DELETE FROM " + table + " WHERE id = ?;";
        try(Connection conn = connect();PreparedStatement ps = conn.prepareStatement(sql)){
            ps.setLong(1,id);
            ps.executeUpdate();
        }catch (SQLException e){
            e.printStackTrace();
        }
    }

    private static String queryBuilder(String type,String table, String[] header, String[] values){
        String sql;
        StringBuilder sb = new StringBuilder();
        switch (type) {
            case "exists" -> {
                sb = new StringBuilder("SELECT (count(*) > 0) as found FROM ");
                sb.append(table);
                sb.append(" WHERE ");
                sb.append(header[0]);
                sb.append(" LIKE '");
                sb.append(values[0]);
                sb.append("'");
                for (int i = 1; i < header.length; i++) {
                    sb.append(" AND ");
                    sb.append(header[i]);
                    sb.append(" LIKE '");
                    sb.append(values[i]);
                    sb.append("'");
                }
            }
            case "selectMatch" -> {
                sb = new StringBuilder("SELECT * FROM ");
                sb.append(table);
                sb.append(" WHERE ");
                sb.append(header[0]);
                sb.append(" LIKE '");
                sb.append(values[0]);
                sb.append("'");
                for (int i = 1; i < header.length; i++) {
                    sb.append(" AND ");
                    sb.append(header[i]);
                    sb.append(" LIKE '");
                    sb.append(values[i]);
                    sb.append("'");
                }
            }
            case "insert" -> {
                sb = new StringBuilder("INSERT OR IGNORE INTO ");
                sb.append(table);
                sb.append(" (");
                sb.append(header[0]);
                for (int i = 1; i < header.length; i++) {
                    sb.append(",");
                    sb.append(header[i]);
                }
                sb.append(") VALUES('");
                sb.append(values[0]);
                sb.append("'");
                for (int i = 1; i < values.length; i++) {
                    sb.append(",'");
                    sb.append(values[i]);
                    sb.append("'");
                }
                sb.append(");");
            }
        }
        sql = sb.toString();
        return sql;
    }

    protected static List<String> getTable(String table){
        List<String> data = new ArrayList<>();
        StringBuilder sb;
        try(Connection conn = connect()) {
            String sql = "SELECT * FROM " + table;
            PreparedStatement ps = conn.prepareStatement(sql);
            ResultSet rs = ps.executeQuery();
            ResultSetMetaData rsmd = rs.getMetaData();
            int count = rsmd.getColumnCount();
            while (rs.next()){
                sb = new StringBuilder();
                sb.append(rs.getString(1));
                for(int i = 2; i <= count; i++){
                    sb.append(":");
                    sb.append(rs.getString(i));
                }
                data.add(sb.toString());
            }
        }catch (SQLException e){
            return new ArrayList<>();
        }
        return data;
    }

    protected static List<String> select(String table,String[] header, String[] values){
        List<String> data = new ArrayList<>();
        StringBuilder sb;
        String sql = queryBuilder("selectMatch",table,header,values);
        try(Connection conn = connect()) {
            PreparedStatement ps = conn.prepareStatement(sql);
            ResultSet rs = ps.executeQuery();
            ResultSetMetaData rsmd = rs.getMetaData();
            int count = rsmd.getColumnCount();
            while (rs.next()){
                sb = new StringBuilder();
                sb.append(rs.getString(1));
                for(int i = 2; i <= count; i++){
                    sb.append(":");
                    sb.append(rs.getString(i));
                }
                data.add(sb.toString());
            }
        }catch (SQLException e){
            e.printStackTrace();
            return data;
        }
        return data;
    }

    protected static List<String> getEntryById(String table, long id){
        List<String> data = new ArrayList<>();
        StringBuilder sb;
        String sql = "SELECT * FROM " + table + " WHERE id = ?;";
        try (Connection conn = connect()) {
            PreparedStatement ps = conn.prepareStatement(sql);
            ps.setLong(1,id);
            ResultSet rs = ps.executeQuery();
            ResultSetMetaData rsmd = rs.getMetaData();
            int count = rsmd.getColumnCount();
            while (rs.next()){
                sb = new StringBuilder();
                sb.append(rs.getString(1));
                for(int i = 2; i <= count; i++){
                    sb.append(":");
                    sb.append(rs.getString(i));
                }
                data.add(sb.toString());
            }
        } catch (SQLException e) {
            e.printStackTrace();
            return data;
        }
        return data;
    }
}