Wave 1 and 2 Completed

src/Main.java

@@ -6,58 +6,48 @@
 
 public class Main {
     public static void main(String[] args) {
+
+        //Instantiating new scanner
         Scanner s = new Scanner(System.in);
 
+        //Ask user for the file name
         System.out.print("Enter the CSV filename: ");
         String f = s.nextLine();
 
-        List<Map<String, String>> dta = new ArrayList<>();
-        try (Scanner fs = new Scanner(new File(f))) {
-            fs.nextLine();
-
-            while (fs.hasNextLine()) {
-                String[] v = fs.nextLine().split(",");
+        List<Map<String, String>> data = parseCSV(f);
 
-                int chg = Integer.parseInt(v[2]);  
-
-                Map<String, String> mp1 = new HashMap<>();
-                mp1.put("id", v[0]);  
-                mp1.put("tm", v[1]);  
-                mp1.put("chg", String.valueOf(chg));
-                dta.add(mp1);
-            }
-        } catch (FileNotFoundException e) {
-            System.out.println("Error reading the file: " + e.getMessage());
-            s.close();
-            return;
-        }
 
-        Map<String, List<Map<String, String>>> mp2 = new HashMap<>();
-        for (Map<String, String> d : dta) {
+        //Create new map that organize commits by ID
+        //If list is empty, it will add it into a new arrayList
+        Map<String, List<Map<String, String>>> forkCommits = new HashMap<>();
+        for (Map<String, String> d : data) {
             String id = d.get("id");
-            List<Map<String, String>> lst = mp2.get(id);
+            List<Map<String, String>> lst = forkCommits.get(id);
             if (lst == null) {
                 lst = new ArrayList<>();
-                mp2.put(id, lst);
+                forkCommits.put(id, lst);
             }
             lst.add(d);
         }
-        int cnt = mp2.size();
+        int cnt = forkCommits.size();
 
+        //Print out the forks avalaible
         System.out.println("There are " + cnt + " forks available (fork1 to fork" + cnt + ").");
         System.out.print("Enter the fork number to analyze (or 'all' for all forks): ");
         String inp = s.nextLine();
 
+        // Select which commits to analyze dependent on the user input
         List<Map<String, String>> sel;
         if (inp.equalsIgnoreCase("all")) {
-            sel = dta;
+            sel = data;
         } else {
             String id = "fork" + inp; 
-            sel = mp2.get(id);
+            sel = forkCommits.get(id);
         }
 
         int sz = sel.size();
 
+        // Determine the most recent commit
         DateTimeFormatter f1 = DateTimeFormatter.ISO_DATE_TIME;
         LocalDateTime lat = null;
         for (Map<String, String> d : sel) {
@@ -69,27 +59,34 @@ public static void main(String[] args) {
         DateTimeFormatter f2 = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss", Locale.getDefault());
         String latT = lat.format(f2);
 
+        //Calculate statistics from the commits chosen
         double tot = 0.0;
         int tlc = 0;
         for (Map<String, String> d : sel) {
             int lc = Integer.parseInt(d.get("chg"));
             tot += lc;
             tlc += lc;
         }
+        //Calculate average lines changes
         double avg = tot / sz;
 
         int mx = Integer.MIN_VALUE;
         int mn = Integer.MAX_VALUE;
         for (Map<String, String> d : sel) {
+            //Calculate changed lines in csv
             int chg = Integer.parseInt(d.get("chg"));
+            //Check if change is greater than max
+            //If change is greater than max, max = change
             if (chg > mx) {
                 mx = chg;
             }
+            //If change is less than minimum, min = change
             if (chg < mn) {
                 mn = chg;
             }
         }
 
+        //Print Results
         System.out.println("\nStatistics:");
         System.out.println("Number of commits: " + sz);
         System.out.println("Most recent commit timestamp: " + latT);
@@ -98,6 +95,34 @@ public static void main(String[] args) {
         System.out.println("Max lines changed in a commit: " + mx);
         System.out.println("Min lines changed in a commit: " + mn);
 
+        //Close scanner
         s.close();
     }
-}
+
+    //Helper method for parsing the CSV file that the user inputs
+    public static List<Map<String, String>> parseCSV(String filename){
+        List<Map<String, String>> data = new ArrayList<>();
+
+        //Read in the csv files
+        try (Scanner fs = new Scanner(new File(filename))) {
+            fs.nextLine();
+            while (fs.hasNextLine()) {
+                //Split the data apart by ","
+                String[] v = fs.nextLine().split(",");
+
+                //split values and store them into data
+                int chg = Integer.parseInt(v[2]);  
+                Map<String, String> mp2 = new HashMap<>();
+                mp2.put("id", v[0]);  
+                mp2.put("tm", v[1]);  
+                mp2.put("chg", String.valueOf(chg));
+                data.add(mp2);
+            }
+            //Throw error if file is not found
+        } catch (FileNotFoundException e) {
+            System.out.println("Error reading the file: " + e.getMessage());
+        }
+        //return the data List 
+            return data;
+        }
+    }