getPallets seemingly working

app/src/main/java/krusty/Database.java

@@ -8,9 +8,12 @@ import java.sql.Connection;
 import java.sql.DriverManager;
 import java.sql.SQLException;
 import java.sql.Statement;
+import java.text.SimpleDateFormat;
 // Likely dependencies for general operations
 import java.io.IOException;
 import java.sql.ResultSet;
+import java.util.Date;
+import java.util.Optional;
 import java.util.StringJoiner;
 import java.util.stream.Collectors;
 import java.nio.file.Files;
@@ -18,12 +21,16 @@ import java.nio.file.Paths;
 import java.util.stream.Stream;
 
 public class Database {
+
 	// Here, we use an in-memory database. This string could be changed to
 	// "jdbc:sqlite:<filename>.sqlite3" to use a file-based database instead.
 	// Nore that ":memory:" is an **SQLite specific** magic string that tells the
 	// underlying SQLite engine to store the database in memory.
 	private static final String jdbcString = "jdbc:sqlite::memory:";
 	// private static final String jdbcString = "jdbc:sqlite:krusty.db";
+
+	// Hold a single connection to the database. Note that this is 
+	// not a pool, so this is not thread-safe nor efficient.
 	private Connection conn = null;
 
 	public String getCustomers(Request req, Response res) {
@@ -52,9 +59,114 @@ public class Database {
 	}
 
 	public String getPallets(Request req, Response res) {
-		// 1. Get query param -> validate cookie type if not null
-		// 2. Figure out if we should return all pallets or just one type
-		// 3. Return pallets as {cookie, blocked}
+		// These queries look like:
+		// http://localhost:8888/api/v1/pallets?cookie=Nut+cookie&from=2024-05-23&to=2024-05-30&blocked=yes
+		// They may contain any combination of the parameters, or none at all.
+
+		Optional<Recipe> r = Optional.empty(); // Holds the ecipe if we have a cookie
+		Optional<Boolean> blocked = Optional.empty(); // Holds the blocked status
+		Optional<Date> from = Optional.empty(); // Holds the from date
+		Optional<Date> to = Optional.empty(); // Holds the to date
+
+		// First we need the cookie parameter
+		String cookie = req.queryParams("cookie");
+
+		// And the blocked parameter
+		String blocked_str = req.queryParams("blocked");
+
+		// Then we need the date parameters
+		String from_str = req.queryParams("from");
+		String to_str = req.queryParams("to");
+
+		// Date from = null;
+		// Date to = null;
+
+		// Fancy functional one-liner to get the recipe if the cookie is present
+		if (cookie != null) {
+			r = Optional.ofNullable(DefaultRecipes.recipes.stream()
+					.filter(recipe -> recipe.name.equals(cookie))
+					.findFirst().orElse(null));
+		}
+
+		if (blocked_str != null) {
+			blocked = switch (blocked_str) {
+				case "yes" -> Optional.of(true);
+				case "no" -> Optional.of(false);
+				default -> Optional.empty();
+			};
+		}
+
+		// Both of these must be present
+		if (from_str != null && to_str != null) {
+			try {
+				// Parse both in the format (2024-05-23), also called ISO 8601
+				from = Optional.of(new SimpleDateFormat("yyyy-MM-dd").parse(from_str));
+				to = Optional.of(new SimpleDateFormat("yyyy-MM-dd").parse(to_str));
+			} catch (Exception e) {
+				// Reset the dates to empty
+				from = Optional.empty();
+				to = Optional.empty();
+				// We have a bad date, maybe log this somewhere
+			}
+
+			// Check so that the dates are in the correct order
+			if (from.isPresent() && to.isPresent() && from.get().after(to.get())) {
+				// We have a bad interval, perhaps set dates to empty agian?
+				// TODO: This obviously need louder error handling
+				from = Optional.empty();
+				to = Optional.empty();
+			}
+		}
+
+		// This type of code is unreadable, error prone and hard to maintain.
+		// The fact that im responsible for this code makes my soul hurt.
+		// This part almost made me write a simple query factory to handle this.
+		//
+		// SqlBuilder exists to 'take the pain out of generating SQL queries',
+		// but it's not in the standard library.
+		//
+		// Helmets, seatbelts and safety goggles on; we need to execute a query.
+		try {
+			Statement stmt = conn.createStatement();
+			StringBuilder query = new StringBuilder("SELECT * FROM pallets JOIN cookies ON pallets.cookie_id = cookies.cookie_id");
+
+			// r is validated here
+			if (r.isPresent()) {
+				query.append(" WHERE cookie_name = '" + r.get().name + "'");
+			}
+
+			if (from != null && to != null) {
+				if (r.isPresent()) {
+					query.append(" AND ");
+				} else {
+					query.append(" WHERE ");
+				}
+
+				query.append("production_date BETWEEN '" + from_str + "' AND '" + to_str + "'");
+			}
+
+			if (blocked.isPresent()) {
+				// WARNING THIS IS NOT CORRECT WARNING
+				if (r.isPresent() || from != null) {
+					query.append(" AND ");
+				}
+
+				// TODO: WARNING This logic is flawed. WARNING
+				// Remember, status can be 'freezer', 'delivered' or 'blocked'
+				query.append("status = " + (blocked.get() ? "'blocked'" : "'freezer'"));
+			}
+
+			query.append(";");
+			ResultSet result = stmt.executeQuery(query.toString());
+			String jsonResult = Jsonizer.toJson(result, "pallets");
+			return jsonResult;
+		} catch (SQLException e) {
+			System.out.printf("Error executing query: \n%s", e);
+		}
+
+		// Statue 500, to give the client a
+		// chance to figure out that something went wrong
+		res.status(500);
 		return "{\"pallets\":[]}";
 	}