added db handler

~6h work

src/at/nanopenguin/mtcg/application/service/UserService.java

@@ -1,6 +1,5 @@
 package at.nanopenguin.mtcg.application.service;
 
-import at.nanopenguin.mtcg.application.service.schemas.UserCredentials;
 import at.nanopenguin.mtcg.http.HttpMethod;
 import at.nanopenguin.mtcg.http.HttpRequest;
 import at.nanopenguin.mtcg.http.HttpStatus;

src/at/nanopenguin/mtcg/application/service/schemas/Card.java

@@ -1,11 +1,7 @@
 package at.nanopenguin.mtcg.application.service.schemas;
 
 import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
-import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
-import com.fasterxml.jackson.databind.annotation.JsonSerialize;
 
-@JsonSerialize
-@JsonDeserialize
 @JsonIgnoreProperties(ignoreUnknown = true)
 public record Card(String id, String name, Float damage) {
 }

src/at/nanopenguin/mtcg/application/service/schemas/TradingDeal.java

@@ -1,11 +1,7 @@
 package at.nanopenguin.mtcg.application.service.schemas;
 
 import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
-import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
-import com.fasterxml.jackson.databind.annotation.JsonSerialize;
 
-@JsonSerialize
-@JsonDeserialize
 @JsonIgnoreProperties(ignoreUnknown = true)
 public record TradingDeal(String id, String cardToTrade, String type, Float minimumDamage) {
 }

src/at/nanopenguin/mtcg/application/service/schemas/UserCredentials.java

@@ -1,11 +1,7 @@
 package at.nanopenguin.mtcg.application.service.schemas;
 
 import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
-import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
-import com.fasterxml.jackson.databind.annotation.JsonSerialize;
 
-@JsonSerialize
-@JsonDeserialize
 @JsonIgnoreProperties(ignoreUnknown = true)
 public record UserCredentials(String username, String password) {
 }

src/at/nanopenguin/mtcg/application/service/schemas/UserData.java

@@ -1,12 +1,7 @@
 package at.nanopenguin.mtcg.application.service.schemas;
 
 import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
-import com.fasterxml.jackson.annotation.JsonInclude;
-import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
-import com.fasterxml.jackson.databind.annotation.JsonSerialize;
 
-@JsonSerialize
-@JsonDeserialize
 @JsonIgnoreProperties(ignoreUnknown = true)
 public record UserData(String name, String bio, String image) {
 }

src/at/nanopenguin/mtcg/application/service/schemas/UserStats.java

@@ -1,11 +1,7 @@
 package at.nanopenguin.mtcg.application.service.schemas;
 
 import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
-import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
-import com.fasterxml.jackson.databind.annotation.JsonSerialize;
 
-@JsonSerialize
-@JsonDeserialize
 @JsonIgnoreProperties(ignoreUnknown = true)
 public record UserStats(String name, Integer elo, Integer wins, Integer losses) {
 }

src/at/nanopenguin/mtcg/db/DbQuery.java

@@ -0,0 +1,138 @@
+package at.nanopenguin.mtcg.db;
+
+import lombok.Builder;
+import lombok.NonNull;
+import lombok.Singular;
+import lombok.val;
+
+import java.sql.*;
+import java.util.*;
+import java.util.stream.Collectors;
+
+@Builder
+public final class DbQuery {
+    private static final String connectionString = "jdbc:postgres://localhost:5432/mydb?user=postgres&password=postgres";
+
+    @NonNull
+    private final SqlCommand command;
+    @NonNull
+    private final Table table;
+    @Singular
+    private List<String> columns;
+    @Singular
+    private SortedMap<String, Object> parameters;
+    @Singular
+    private SortedMap<String, Object> conditions;
+
+    public static class DbQueryBuilder {
+        public ResultSet executeQuery() throws SQLException {
+            DbQuery dbQuery = this.build();
+            if (dbQuery.command != SqlCommand.SELECT) throw new SQLException();
+            return dbQuery.read();
+        }
+
+        public int executeUpdate() throws SQLException {
+            DbQuery dbQuery = this.build();
+            return switch (dbQuery.command) {
+                case INSERT -> dbQuery.create();
+                case UPDATE -> dbQuery.update();
+                case DELETE -> dbQuery.delete();
+                default -> throw new SQLException();
+            };
+        }
+    }
+
+    private static Connection connect() throws SQLException {
+        return DriverManager.getConnection(connectionString);
+    }
+
+    private String buildParameterizedString(@NonNull SortedMap<String, Object> parameters) {
+        if (!parameters.isEmpty()) {
+            return String.join(" = ?, ", parameters.keySet()) + " = ?";
+        }
+        return "";
+    }
+
+    private int create() throws SQLException {
+        if (this.parameters.isEmpty()) throw new SQLException("No parameters provided for INSERT statement.");
+
+        try (Connection connection = connect()) {
+            String columns = this.parameters.keySet().stream()
+                    .filter(columnName -> columnName.matches("[a-zA-Z0-9_]+"))
+                    .collect(Collectors.joining(", "));
+
+            String sql = String.format("INSERT INTO %s (%s) VALUES (%s);", table.table, columns, String.join(", ", Collections.nCopies(this.parameters.size(), "?")));
+
+            try (PreparedStatement preparedStatement = connection.prepareStatement(sql)) {
+                int i = 1;
+                for (val entry : this.parameters.entrySet()) {
+                    preparedStatement.setObject(i++, entry.getValue());
+                }
+
+                return preparedStatement.executeUpdate();
+            }
+        }
+    }
+
+    private ResultSet read() throws SQLException {
+        try (Connection connection = connect()) {
+            StringJoiner columnJoiner = new StringJoiner(", ");
+            if (this.columns.isEmpty()) {
+                columnJoiner.add("*");
+            }
+            this.columns.forEach(columnJoiner::add);
+
+            String sql = String.format("SELECT %s FROM %s%s;", columnJoiner, table.table,
+                    this.conditions.isEmpty() ? "" : " WHERE (" + this.buildParameterizedString(this.conditions) + ")");
+
+            try (PreparedStatement preparedStatement = connection.prepareStatement(sql)) {
+                int i = 1;
+                for (val entry : this.conditions.entrySet()) {
+                    preparedStatement.setObject(i++, entry.getValue());
+                }
+
+                return preparedStatement.executeQuery();
+            }
+        }
+    }
+
+    private int update() throws SQLException {
+        if (this.parameters.isEmpty()) throw new SQLException();
+        if (this.conditions.isEmpty()) throw new SQLException();
+
+        try (Connection connection = connect()) {
+            String sql = String.format("UPDATE %s SET %s WHERE (%s);", table.table,
+                    this.buildParameterizedString(this.parameters),
+                    this.buildParameterizedString(this.conditions));
+
+            PreparedStatement preparedStatement = connection.prepareStatement(sql);
+
+            int i = 1;
+            for (val entry : this.parameters.entrySet()) {
+                preparedStatement.setObject(i++, entry.getValue());
+            }
+            for (val entry : this.conditions.entrySet()) {
+                preparedStatement.setObject(i++, entry.getValue());
+            }
+
+            return preparedStatement.executeUpdate();
+        }
+    }
+
+    private int delete() throws SQLException {
+        if (this.conditions.isEmpty()) throw new SQLException();
+        try (Connection connection = connect()) {
+
+            String sql = String.format("DELETE FROM %s WHERE (%s);", table.table, this.buildParameterizedString(this.conditions));
+
+            try (PreparedStatement preparedStatement = connection.prepareStatement(sql)) {
+                int i = 1;
+                for (val entry : this.conditions.entrySet()) {
+                    preparedStatement.setObject(i++, entry.getValue());
+                }
+
+                return preparedStatement.executeUpdate();
+            }
+        }
+    }
+}

src/at/nanopenguin/mtcg/db/SqlCommand.java

@@ -0,0 +1,8 @@
+package at.nanopenguin.mtcg.db;
+
+public enum SqlCommand {
+    INSERT,
+    SELECT,
+    UPDATE,
+    DELETE,
+}

src/at/nanopenguin/mtcg/db/Table.java

@@ -0,0 +1,10 @@
+package at.nanopenguin.mtcg.db;
+
+import lombok.RequiredArgsConstructor;
+
+@RequiredArgsConstructor
+public enum Table {
+    USERS("users");
+
+    public final String table;
+}

src/at/nanopenguin/mtcg/http/HttpStatus.java

@@ -1,5 +1,8 @@
 package at.nanopenguin.mtcg.http;
 
+import lombok.RequiredArgsConstructor;
+
+@RequiredArgsConstructor
 public enum HttpStatus {
     OK(200, "OK"),
     CREATED(201, "Created"),
@@ -15,9 +18,4 @@ public enum HttpStatus {
 
     public final int statusCode;
     public final String statusMessage;
-
-    HttpStatus(int code, String message) {
-        this.statusCode = code;
-        this.statusMessage = message;
-    }
 }

src/at/nanopenguin/mtcg/http/RequestHandler.java

@@ -2,6 +2,7 @@ package at.nanopenguin.mtcg.http;
 
 import at.nanopenguin.mtcg.application.service.Service;
 import com.fasterxml.jackson.core.JsonProcessingException;
+import lombok.RequiredArgsConstructor;
 
 import java.io.BufferedReader;
 import java.io.IOException;
@@ -9,15 +10,11 @@ import java.io.InputStreamReader;
 import java.io.OutputStream;
 import java.net.Socket;
 
+@RequiredArgsConstructor
 public class RequestHandler implements Runnable {
     private final Socket serviceSocket;
     private final Router router;
 
-    public RequestHandler(Socket serviceSocket, Router router) {
-        this.serviceSocket = serviceSocket;
-        this.router = router;
-    }
-
     @Override
     public void run() {
         try {

src/at/nanopenguin/mtcg/http/Server.java

@@ -1,22 +1,19 @@
 package at.nanopenguin.mtcg.http;
 
+import lombok.RequiredArgsConstructor;
+
 import java.io.IOException;
 import java.net.ServerSocket;
 import java.net.Socket;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 
+@RequiredArgsConstructor
 public class Server {
     private final int port; // 16-bit unsigned, not enforced
     private final int threads;
     private final Router router;
 
-    public Server(int port, int threads, Router router) {
-        this.port = port;
-        this.threads = threads;
-        this.router = router;
-    }
-
     public void  start() throws IOException {
         try (ServerSocket listener = new ServerSocket(this.port)) {