diff --git a/ext/ddcov/ddcov.c b/ext/ddcov/ddcov.c
index 417949de..7dc2bc09 100644
--- a/ext/ddcov/ddcov.c
+++ b/ext/ddcov/ddcov.c
@@ -8,10 +8,15 @@ static bool prefix(const char *pre, const char *str)
   return strncmp(pre, str, strlen(pre)) == 0;
 }
 
+// const
+#define DD_COVERAGE_TARGET_FILES 1
+#define DD_COVERAGE_TARGET_LINES 2
+
 // Data structure
 struct dd_cov_data
 {
   char *root;
+  int mode;
   VALUE coverage;
 };
 
@@ -56,14 +61,39 @@ static VALUE dd_cov_allocate(VALUE klass)
 }
 
 // DDCov methods
-static VALUE dd_cov_initialize(VALUE self, VALUE rb_root)
+static VALUE dd_cov_initialize(int argc, VALUE *argv, VALUE self)
 {
-  // printf("INITIALIZE\n");
+  VALUE opt;
+  int mode;
+
+  rb_scan_args(argc, argv, "10", &opt);
+  VALUE rb_root = rb_hash_lookup(opt, ID2SYM(rb_intern("root")));
+  if (!RTEST(rb_root))
+  {
+    rb_raise(rb_eArgError, "root is required");
+  }
+
+  VALUE rb_mode = rb_hash_lookup(opt, ID2SYM(rb_intern("mode")));
+  if (!RTEST(rb_mode) || rb_mode == ID2SYM(rb_intern("files")))
+  {
+    mode = DD_COVERAGE_TARGET_FILES;
+  }
+  else if (rb_mode == ID2SYM(rb_intern("lines")))
+  {
+    mode = DD_COVERAGE_TARGET_LINES;
+  }
+  else
+  {
+    rb_raise(rb_eArgError, "mode is invalid");
+  }
+
+  printf("MODE IS %d\n", mode);
   struct dd_cov_data *dd_cov_data;
   TypedData_Get_Struct(self, struct dd_cov_data, &dd_cov_data_type, dd_cov_data);
 
   // printf("struct got\n");
   dd_cov_data->root = StringValueCStr(rb_root);
+  dd_cov_data->mode = mode;
   // printf("root set\n");
 
   return Qnil;
@@ -91,7 +121,28 @@ static void dd_cov_update_line_coverage(rb_event_flag_t event, VALUE data, VALUE
   unsigned long len_filename = strlen(filename);
 
   VALUE rb_str_source_file = rb_str_new(filename, len_filename);
-  rb_hash_aset(dd_cov_data->coverage, rb_str_source_file, Qtrue);
+
+  if (dd_cov_data->mode == DD_COVERAGE_TARGET_FILES)
+  {
+    rb_hash_aset(dd_cov_data->coverage, rb_str_source_file, Qtrue);
+    return;
+  }
+
+  if (dd_cov_data->mode == DD_COVERAGE_TARGET_LINES)
+  {
+    VALUE rb_lines = rb_hash_aref(dd_cov_data->coverage, rb_str_source_file);
+    if (rb_lines == Qnil)
+    {
+      rb_lines = rb_ary_new();
+      rb_hash_aset(dd_cov_data->coverage, rb_str_source_file, rb_lines);
+    }
+
+    VALUE line_number = INT2FIX(rb_sourceline());
+    if (rb_ary_includes(rb_lines, line_number) == Qfalse)
+    {
+      rb_ary_push(rb_lines, line_number);
+    }
+  }
 }
 
 static VALUE dd_cov_start(VALUE self)
@@ -109,7 +160,7 @@ static VALUE dd_cov_stop(VALUE self)
 {
   // get current thread
   VALUE thval = rb_thread_current();
-  // remove event hook
+  // remove event hook for the current thread
   rb_thread_remove_event_hook(thval, dd_cov_update_line_coverage);
 
   struct dd_cov_data *dd_cov_data;
@@ -128,7 +179,7 @@ void Init_ddcov(void)
 
   rb_define_alloc_func(cDDCov, dd_cov_allocate);
 
-  rb_define_method(cDDCov, "initialize", dd_cov_initialize, 1);
+  rb_define_method(cDDCov, "initialize", dd_cov_initialize, -1);
   rb_define_method(cDDCov, "start", dd_cov_start, 0);
   rb_define_method(cDDCov, "stop", dd_cov_stop, 0);
 }
diff --git a/lib/datadog/ci/itr/coverage/collector.rb b/lib/datadog/ci/itr/coverage/collector.rb
index b58b2125..0c4c4460 100644
--- a/lib/datadog/ci/itr/coverage/collector.rb
+++ b/lib/datadog/ci/itr/coverage/collector.rb
@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+require "coverage"
+
 require_relative "../../utils/git"
 require_relative "../../../../ddcov/ddcov"
 
@@ -8,23 +10,31 @@ module CI
     module Itr
       module Coverage
         class Collector
-          def initialize
+          def initialize(mode: :files, enabled: true)
             # TODO: make this thread local
+            # modes available: :files, :lines
+            @mode = mode
+            @enabled = enabled
+
+            if @enabled
+              @ddcov = DDCov.new(root: Utils::Git.root, mode: mode)
+            end
           end
 
           def setup
-            p "RUNNING WITH CODE COVERAGE ENABLED"
+            if @enabled
+              p "RUNNING WITH CODE COVERAGE ENABLED"
+            else
+              p "RUNNING WITH CODE COVERAGE DISABLED"
+            end
           end
 
           def start
-            @ddcov = DDCov.new(Utils::Git.root)
-            @ddcov.start
+            @ddcov.start if @enabled
           end
 
           def stop
-            @ddcov.stop
-            # p "RAW"
-            # p result.count
+            @ddcov.stop if @enabled
           end
         end
       end
diff --git a/lib/datadog/ci/test_visibility/recorder.rb b/lib/datadog/ci/test_visibility/recorder.rb
index c306f960..bf444e01 100644
--- a/lib/datadog/ci/test_visibility/recorder.rb
+++ b/lib/datadog/ci/test_visibility/recorder.rb
@@ -41,7 +41,7 @@ def initialize(
           @global_context = Context::Global.new
           @codeowners = codeowners
 
-          @coverage_collector = Itr::Coverage::Collector.new
+          @coverage_collector = Itr::Coverage::Collector.new(mode: :lines, enabled: true)
           begin
             @coverage_collector.setup
           rescue => e
@@ -333,6 +333,20 @@ def validate_test_suite_level_visibility_correctness(test)
         def on_test_end(test)
           coverage = @coverage_collector.stop
           if coverage
+            if ENV["DD_COV_REPORT"]
+              # append to report.log file
+              File.open("report.log", "a") do |f|
+                f.write("#{test.name}\n")
+                f.write("---------------------------------------------------\n")
+
+                coverage.each do |filename, lines|
+                  f.write("#{filename}\n")
+                  sorted_lines = lines.uniq.sort
+                  f.write("#{sorted_lines}\n")
+                end
+                f.write("---------------------------------------------------\n")
+              end
+            end
             # p "FILTERED"
             # p coverage.count
             # p coverage