Feat: adds Mohamed's CsvDataLoader to display current Library items, checked out items, and a guest list (#310)

* Feat: added a CsvDataLoader to display current Library items, checked out items, and a guest list

* Fix: Changed formating

* Fix: Changed file path to look more clean

---------

Co-authored-by: Mohamed <“[email protected]”>

Author: Moibrahi7

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

@@ -0,0 +1,163 @@
+package com.codedifferently.lesson12.factory.mohamedibrahim;
+
+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 java.io.BufferedReader;
+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;
+
+/** LibraryCsvDataLoaderSolid */
+@Service
+public class CsvDataLoader implements LibraryCsvDataLoader {
+  public static void main(String[] args) throws IOException {
+
+    new CsvDataLoader().loadData();
+  }
+
+  @Override
+  public LibraryDataModel loadData() throws IOException {
+    LibraryDataModel libraryData = new LibraryDataModel();
+
+    libraryData.guests = readGuestList("csv/guests.csv");
+    libraryData.mediaItems = readMediaItems("csv/media_items.csv");
+    Map<String, List<CheckoutModel>> checkoutsByGuestEmail =
+        readCheckedOutByEmail("csv/checked_out_items.csv");
+    // Gives each guest a list of their checked out books.
+    for (var guest : libraryData.guests) {
+      var checkouts = checkoutsByGuestEmail.get(guest.email);
+      if (checkouts != null) {
+        guest.checkedOutItems = checkouts;
+      } else {
+        guest.checkedOutItems = new ArrayList<>();
+      }
+    }
+
+    return libraryData;
+  }
+
+  /**
+   * Gets data from csv file and makes a list of all media items in the library.
+   *
+   * @param path The file path
+   * @return
+   */
+  public static List<MediaItemModel> readMediaItems(String path) {
+    try (var reader = new BufferedReader(new FileReader(new ClassPathResource(path).getFile()))) {
+      // The list that will be returned at the end of the function.
+      var items = new ArrayList<MediaItemModel>();
+      String line;
+      // Skips the headers in the csv file.
+      line = reader.readLine();
+      while ((line = reader.readLine()) != null) {
+        // Puts the line read from the csv in an array.
+        var parts = line.split(",", 8);
+        // Temp item that will latter be added to a list.
+        var item = new MediaItemModel();
+
+        // Puts data in the temp item.
+        item.type = parts[0];
+        item.id = UUID.fromString(parts[1]);
+        item.title = parts[2];
+        item.isbn = parts[3];
+        item.authors = List.of(parts[4]);
+
+        // Checks if the index for this variable is empty and sets it to 0.
+        if (parts[5].equals("")) item.pages = 0;
+        else item.pages = Integer.parseInt(parts[5]);
+
+        // Checks if the index for this variable is empty and sets it to 0.
+        if (parts[6].equals("")) item.runtime = 0;
+        else item.runtime = Integer.parseInt(parts[6]);
+        item.edition = parts[7];
+
+        items.add(item);
+      }
+      reader.close();
+      return items;
+    } catch (IOException e) {
+      throw new RuntimeException("Failed to read media items", e);
+    }
+  }
+
+  /**
+   * Gets data from csv file and makes list of guests in the library.
+   *
+   * @param path The file path
+   * @return
+   */
+  private List<LibraryGuestModel> readGuestList(String path) {
+    try (var reader = new BufferedReader(new FileReader(new ClassPathResource(path).getFile()))) {
+      // The list that will be returned at the end of the function.
+      var guests = new ArrayList<LibraryGuestModel>();
+      String line;
+      // Skips the headers in the csv file.
+      line = reader.readLine();
+      while ((line = reader.readLine()) != null) {
+        // Puts the line read from the csv in an array.
+        var parts = line.split(",");
+        // Temp guest that will latter be added to a list.
+        var guest = new LibraryGuestModel();
+
+        // Puts data in the guest item.
+        guest.type = parts[0];
+        guest.name = parts[1];
+        guest.email = parts[2];
+
+        guests.add(guest);
+      }
+      reader.close();
+      return guests;
+    } catch (IOException e) {
+      throw new RuntimeException("Failed to read media items", e);
+    }
+  }
+
+  /**
+   * Gets data from csv file and makes a map of items checked out by guest email.
+   *
+   * @param path The file path.
+   * @return
+   */
+  private static Map<String, List<CheckoutModel>> readCheckedOutByEmail(String path) {
+    try (var reader = new BufferedReader(new FileReader(new ClassPathResource(path).getFile()))) {
+      // The hashmap that will be returned at the end of the function.
+      var checkedOutItems = new HashMap<String, List<CheckoutModel>>();
+      String line;
+      // Skips the headers in the csv file.
+      line = reader.readLine();
+      while ((line = reader.readLine()) != null) {
+        // Puts the line read from the csv in an array.
+        var parts = line.split(",");
+        // Temp item that will latter be added to a list.
+        var item = new CheckoutModel();
+
+        // Puts data in the temp item.
+        item.itemId = UUID.fromString(parts[1]);
+        item.dueDate = Instant.parse(parts[2]);
+        // Checks if the map already had this email.
+        if (checkedOutItems.containsKey(parts[0])) {
+          checkedOutItems.get(parts[0]).add(item);
+        } else {
+          List<CheckoutModel> checkOut = new ArrayList<>();
+          checkOut.add(item);
+          checkedOutItems.put(parts[0], checkOut);
+        }
+      }
+      reader.close();
+      return checkedOutItems;
+    } catch (IOException e) {
+      throw new RuntimeException("Failed to read media items", e);
+    }
+  }
+}