diff --git a/action.yml b/action.yml
index 70c902b7..00bac98a 100644
--- a/action.yml
+++ b/action.yml
@@ -147,40 +147,31 @@ runs:
   using: "composite"
   steps:
     - run: |
-        # "Set base sha..."
-        if [[ -n "${{ inputs.since }}" ]]; then
-          BASE_SHA=$(git log --format="%H" --date=local --since="${{ inputs.since }}" --reverse | head -n 1)
-          if [[ -z "$BASE_SHA" ]]; then
-            echo "::warning::The BASE_SHA for date '${{ inputs.since }}' couldn't be determined."
-          fi
-          echo "::set-output name=base_sha::$BASE_SHA"
-        elif [[ -n "${{ inputs.base_sha }}" ]]; then
-          echo "::set-output name=base_sha::${{ inputs.base_sha }}"
-        else
-          LAST_REMOTE_COMMIT="${{ github.event.before }}"
-          if [[ -z "$LAST_REMOTE_COMMIT" || "$LAST_REMOTE_COMMIT" == "0000000000000000000000000000000000000000" ]]; then
-            LAST_REMOTE_COMMIT=$(git rev-parse $(git branch -r --sort=-committerdate | head -1))
-          fi
-          if [[ "${{ inputs.sha }}" == "$LAST_REMOTE_COMMIT" ]]; then
-            LAST_REMOTE_COMMIT=$(git rev-parse "${{ inputs.sha }}^1")
-          fi
-          echo "::set-output name=base_sha::$LAST_REMOTE_COMMIT"
-        fi
+        # "Calculate the base sha..."
+        bash $GITHUB_ACTION_PATH/get-base-sha.sh
       id: base-sha
       shell: bash
+      env:
+        GITHUB_WORKSPACE: ${{ github.workspace }}
+        GITHUB_EVENT_BEFORE: ${{ github.event.before }}
+        # INPUT_<VARIABLE_NAME> is not available in Composite run steps
+        # https://docs.github.com/en/actions/creating-actions/metadata-syntax-for-github-actions#example-specifying-inputs
+        INPUT_SINCE: ${{ inputs.since }}
+        INPUT_BASE_SHA: ${{ inputs.base_sha }}
+        INPUT_SHA: ${{ inputs.sha }}
+        INPUT_PATH: ${{ inputs.path }}
     - run: |
-        # "Set the sha..."
-        if [[ -n "${{ inputs.until }}" ]]; then
-          SHA=$(git log -1 --format="%H" --date=local --until="${{ inputs.until }}")
-          if [[ -z "$SHA" ]]; then
-            echo "::warning::The SHA for date '${{ inputs.until }}' couldn't be determined, falling back to the current sha."
-          fi
-          echo "::set-output name=sha::$SHA"
-        else
-          echo "::set-output name=sha::${{ inputs.sha }}"
-        fi
+        # "Calculate the sha..."
+        bash $GITHUB_ACTION_PATH/get-sha.sh
       id: sha
       shell: bash
+      env:
+        GITHUB_WORKSPACE: ${{ github.workspace }}
+        # INPUT_<VARIABLE_NAME> is not available in Composite run steps
+        # https://docs.github.com/en/actions/creating-actions/metadata-syntax-for-github-actions#example-specifying-inputs
+        INPUT_UNTIL: ${{ inputs.until }}
+        INPUT_SHA: ${{ inputs.sha }}
+        INPUT_PATH: ${{ inputs.path }}
     - run: |
         # "Calculating the previous and current SHA..."
         bash $GITHUB_ACTION_PATH/diff-sha.sh
@@ -191,7 +182,6 @@ runs:
         GITHUB_REPOSITORY: ${{ github.repository }}
         GITHUB_BASE_REF: ${{ github.base_ref }}
         GITHUB_HEAD_REF: ${{ github.head_ref }}
-        GITHUB_ACTION_PATH: ${{ github.action_path }}
         GITHUB_WORKSPACE: ${{ github.workspace }}
         GITHUB_PULL_REQUEST_BASE_SHA: ${{ github.event.pull_request.base.sha }}
         # INPUT_<VARIABLE_NAME> is not available in Composite run steps
@@ -220,7 +210,6 @@ runs:
       id: changed-files
       shell: bash
       env:
-        GITHUB_ACTION_PATH: ${{ github.action_path }}
         GITHUB_WORKSPACE: ${{ github.workspace }}
         # INPUT_<VARIABLE_NAME> is not available in Composite run steps
         # https://docs.github.com/en/actions/creating-actions/metadata-syntax-for-github-actions#example-specifying-inputs
diff --git a/get-base-sha.sh b/get-base-sha.sh
new file mode 100644
index 00000000..9cd65e77
--- /dev/null
+++ b/get-base-sha.sh
@@ -0,0 +1,34 @@
+#!/usr/bin/env bash
+
+set -eu
+
+if [[ -n $INPUT_PATH ]]; then
+  REPO_DIR="$GITHUB_WORKSPACE/$INPUT_PATH"
+
+  echo "Resolving repository path: $REPO_DIR"
+  if [[ ! -d "$REPO_DIR" ]]; then
+    echo "::error::Invalid repository path: $REPO_DIR"
+    exit 1
+  fi
+  cd "$REPO_DIR"
+fi
+
+if [[ -n "$INPUT_SINCE" ]]; then
+  BASE_SHA=$(git log --format="%H" --date=local --since="$INPUT_SINCE" --reverse | head -n 1)
+  if [[ -z "$BASE_SHA" ]]; then
+    echo "::warning::The BASE_SHA for date '$INPUT_SINCE' couldn't be determined."
+  fi
+  echo "::set-output name=base_sha::$BASE_SHA"
+elif [[ -n "$INPUT_BASE_SHA" ]]; then
+  echo "::set-output name=base_sha::$INPUT_BASE_SHA"
+else
+  LAST_REMOTE_COMMIT="$GITHUB_EVENT_BEFORE"
+
+  if [[ -z "$LAST_REMOTE_COMMIT" || "$LAST_REMOTE_COMMIT" == "0000000000000000000000000000000000000000" ]]; then
+    LAST_REMOTE_COMMIT=$(git rev-parse "$(git branch -r --sort=-committerdate | head -1)")
+  fi
+  if [[ "$INPUT_SHA" == "$LAST_REMOTE_COMMIT" ]]; then
+    LAST_REMOTE_COMMIT=$(git rev-parse "$INPUT_SHA^1")
+  fi
+  echo "::set-output name=base_sha::$LAST_REMOTE_COMMIT"
+fi
\ No newline at end of file
diff --git a/get-sha.sh b/get-sha.sh
new file mode 100644
index 00000000..e94a9d79
--- /dev/null
+++ b/get-sha.sh
@@ -0,0 +1,24 @@
+#!/usr/bin/env bash
+
+set -eu
+
+if [[ -n $INPUT_PATH ]]; then
+  REPO_DIR="$GITHUB_WORKSPACE/$INPUT_PATH"
+
+  echo "Resolving repository path: $REPO_DIR"
+  if [[ ! -d "$REPO_DIR" ]]; then
+    echo "::error::Invalid repository path: $REPO_DIR"
+    exit 1
+  fi
+  cd "$REPO_DIR"
+fi
+
+if [[ -n "$INPUT_UNTIL" ]]; then
+  SHA=$(git log -1 --format="%H" --date=local --until="$INPUT_UNTIL")
+  if [[ -z "$SHA" ]]; then
+    echo "::warning::The SHA for date '$INPUT_UNTIL' couldn't be determined, falling back to the current sha."
+  fi
+  echo "::set-output name=sha::$SHA"
+else
+  echo "::set-output name=sha::$INPUT_SHA"
+fi
\ No newline at end of file