feat(date): fix invalid datetime string, add error handling

Signed-off-by: Miguel Nogueira <me@nogueira.codes>

main.rb

@@ -42,8 +42,11 @@ end
 # Returns the date in the current line
 def get_line_date(line)
   pattern = /\[(.*?)\]/
-  match = line.match(pattern)[0] if line.match(pattern)
-
+  if line.match(pattern)
+    match = line.match(pattern)[0]
+  else
+    raise StandardError("Invalid datetime data detected!")
+  end
   # [12/Apr/2023:13:56:41 +0100] -> 12/Apr/2023:13:56:41 +0100 -> Apr/2023
   Date.parse(match.gsub('[', '').gsub(']', '')).strftime('%b/%Y')
 end
@@ -110,7 +113,12 @@ lines.each do |line|
   ip = get_line_ip(line).to_s
   code = get_line_code(line)
   ua = get_line_ua(line)
-  date = get_line_date(line)
+
+  begin
+    date = get_line_date(line)
+  rescue StandardError
+    date = 'N/A'
+  end
 
   if is_client_err?(code.to_i)
     if client_errors[ip]
@@ -153,7 +161,7 @@ end
 monthly_visits.each do |ip, visits|
   puts "IP #{ip} had the following visits:"
   visits.each do |date, count|
-    puts "  #{date}: #{count} visits"
+    puts "#{date}: #{count} visits"
   end
 end