diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..40505c9
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+.venv/
+__pycache__
diff --git a/copy_ref.py b/copy_ref.py
new file mode 100644
index 0000000..e5a0d9b
--- /dev/null
+++ b/copy_ref.py
@@ -0,0 +1 @@
+#!/usr/bin/env python3
diff --git a/datatypes.py b/datatypes.py
new file mode 100644
index 0000000..b167764
--- /dev/null
+++ b/datatypes.py
@@ -0,0 +1,17 @@
+from typing import NewType
+from os import PathLike
+from dataclasses import dataclass
+
+# X11 window id
+WindowId = NewType("WindowId", int)
+# PID int
+ProcessId = NewType("ProcessId", int)
+# page number
+PageNumber = NewType("PageNumber", int)
+
+
+# reference to a specific page in a specific pdf
+@dataclass
+class Reference:
+    filename: PathLike
+    page: PageNumber
diff --git a/pdf_data.py b/pdf_data.py
new file mode 100644
index 0000000..38f0aa2
--- /dev/null
+++ b/pdf_data.py
@@ -0,0 +1,71 @@
+from pathlib import Path
+from datatypes import *
+import pydbus
+import subprocess
+
+
+def get_metadata_pdf() -> Reference:
+    """Find current page of focused PDF reader window.
+
+    Returns
+    -------
+    `Reference` to the current page, or None if not found.
+    """
+    try:
+        res = subprocess.run(
+            ["xdotool", "getactivewindow"], capture_output=True, text=True
+        )
+        window_id: WindowId = WindowId(int(res.stdout))
+        res = subprocess.run(
+            ["xdotool", "getactivewindow", "getwindowpid"],
+            capture_output=True,
+            text=True,
+        )
+        pid: ProcessId = ProcessId(int(res.stdout))
+    except subprocess.CalledProcessError as e:
+        raise Exception(
+            "Could not get currently focused window. Check that `xdotool` is installed."
+        ) from e
+
+    try:
+        res = subprocess.run(
+            ["xprop", "-id", str(window_id), "WM_CLASS"], capture_output=True, text=True
+        )
+        # WM_CLASS(STRING) = "org.pwmt.zathura", "Zathura"
+        wm_class: list[str] = [
+            i.strip('"') for i in res.stdout.split(" = ")[-1].split(", ")
+        ]
+    except subprocess.CalledProcessError as e:
+        raise Exception(
+            "Could not get focused window class. Check that `xprop` is installed."
+        ) from e
+
+    match wm_class[0]:
+        case "Zathura":
+            return get_metadata_zathura(pid)
+        case "org.pwmt.zathura":
+            return get_metadata_zathura(pid)
+        case _:
+            raise NotImplemented("Can not retrieve pdf data from this type of window.")
+
+
+def get_metadata_zathura(pid: ProcessId) -> Reference:
+    """Given the PID of a Zathura instance, find which page of which file it's on.
+
+    Parameters
+    ----------
+    pid
+        Process ID of the Zathura instance to retrieve the reference from.
+
+    Returns
+    -------
+    `Reference` that the Zathura instance is currently on
+    """
+
+    bus = pydbus.SessionBus()
+    obj = bus.get(f"org.pwmt.zathura.PID-{pid}", "/org/pwmt/zathura")
+
+    filename: str = obj.filename
+    pagenumber: PageNumber = obj.pagenumber
+
+    return Reference(filename=Path(filename), page=pagenumber)
diff --git a/requirements.txt b/requirements.txt
new file mode 100644
index 0000000..12c7d9a
--- /dev/null
+++ b/requirements.txt
@@ -0,0 +1,3 @@
+pycairo==1.24.0
+pydbus==0.6.0
+PyGObject==3.44.1