Lesson 12 feat: Corrected line split (#313)

* feat: Created methods for guest model and checkout model

* fix: Fixed package

* fix:added reader.readline to each method

* feat: corrected line.split

* feat:added items

* feat:Implemented Csv Readers

* fix: Fixed mmethods

Author: NatayaP

lesson_12/io/io_app/src/main/java/com/codedifferently/lesson12/factory/natayaprice/CsvDataLoader.java

@@ -0,0 +1,118 @@
+package com.codedifferently.lesson12.factory.natayaprice;
+
+import com.codedifferently.lesson12.factory.LibraryCsvDataLoader;
+import com.codedifferently.lesson12.models.CheckoutModel;
+import com.codedifferently.lesson12.models.LibraryDataModel;
+import com.codedifferently.lesson12.models.LibraryGuestModel;
+import com.codedifferently.lesson12.models.MediaItemModel;
+import com.opencsv.CSVReader;
+import com.opencsv.exceptions.CsvValidationException;
+import java.io.FileReader;
+import java.io.IOException;
+import java.time.Instant;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.UUID;
+import org.springframework.core.io.ClassPathResource;
+import org.springframework.stereotype.Service;
+
+@Service
+public class CsvDataLoader implements LibraryCsvDataLoader {
+
+  @Override
+  public LibraryDataModel loadData() {
+    LibraryDataModel libraryDataModel = new LibraryDataModel();
+    try {
+      libraryDataModel.mediaItems = readMediaItemsFromCsv("csv/media_items.csv");
+      libraryDataModel.guests = readGuestsFromCsv("csv/guests.csv");
+      populateGuestsWithCheckouts("csv/checked_out_items.csv", libraryDataModel.guests);
+    } catch (IOException | CsvValidationException e) {
+      throw new RuntimeException("Failed to load data from CSV files", e);
+    }
+    return libraryDataModel;
+  }
+
+  private List<MediaItemModel> readMediaItemsFromCsv(String filePath)
+      throws IOException, CsvValidationException {
+    List<MediaItemModel> mediaItems = new ArrayList<>();
+    try (CSVReader reader =
+        new CSVReader(new FileReader(new ClassPathResource(filePath).getFile()))) {
+      String[] header = reader.readNext(); // Skip header
+      String[] line;
+      while ((line = reader.readNext()) != null) {
+        MediaItemModel mediaItem = parseMediaItem(line);
+        mediaItems.add(mediaItem);
+      }
+    }
+    return mediaItems;
+  }
+
+  private MediaItemModel parseMediaItem(String[] line) {
+    MediaItemModel mediaItem = new MediaItemModel();
+    mediaItem.type = line[0];
+    mediaItem.id = UUID.fromString(line[1]);
+    mediaItem.title = line[2];
+    mediaItem.isbn = line[3];
+    mediaItem.authors = List.of(line[4].split("\\s*,\\s*"));
+    mediaItem.pages = parseInteger(line[5]);
+    mediaItem.runtime = parseInteger(line[6]);
+    mediaItem.edition = line[7];
+    return mediaItem;
+  }
+
+  private int parseInteger(String value) {
+    try {
+      return Integer.parseInt(value);
+    } catch (NumberFormatException e) {
+      return 0;
+    }
+  }
+
+  private List<LibraryGuestModel> readGuestsFromCsv(String filePath)
+      throws IOException, CsvValidationException {
+    List<LibraryGuestModel> guests = new ArrayList<>();
+    try (CSVReader reader =
+        new CSVReader(new FileReader(new ClassPathResource(filePath).getFile()))) {
+      String[] header = reader.readNext(); // Skip header
+      String[] line;
+      while ((line = reader.readNext()) != null) {
+        LibraryGuestModel guest = new LibraryGuestModel();
+        guest.type = line[0];
+        guest.name = line[1];
+        guest.email = line[2];
+        guests.add(guest);
+      }
+    }
+    return guests;
+  }
+
+  private void populateGuestsWithCheckouts(String filePath, List<LibraryGuestModel> guests)
+      throws IOException, CsvValidationException {
+    Map<String, List<CheckoutModel>> checkoutsByGuestEmail = new HashMap<>();
+    try (CSVReader reader =
+        new CSVReader(new FileReader(new ClassPathResource(filePath).getFile()))) {
+      String[] header = reader.readNext(); // Skip header
+      String[] line;
+      while ((line = reader.readNext()) != null) {
+        String email = line[0];
+        CheckoutModel checkout = parseCheckout(line);
+        checkoutsByGuestEmail.computeIfAbsent(email, k -> new ArrayList<>()).add(checkout);
+      }
+    }
+    // Assign checked-out items to respective guests
+    for (LibraryGuestModel guest : guests) {
+      List<CheckoutModel> checkouts =
+          checkoutsByGuestEmail.getOrDefault(guest.email, new ArrayList<>());
+      guest.checkedOutItems = checkouts;
+    }
+  }
+
+  private CheckoutModel parseCheckout(String[] line) {
+    CheckoutModel checkout = new CheckoutModel();
+    checkout.itemId = UUID.fromString(line[1]);
+    checkout.dueDate = Instant.parse(line[2]);
+    return checkout;
+  }
+}