RENAME clip.py to cli.py & RENAME video.py to core.py to better reflect purpose

In addition, added basic mark command

rewind/core.py

@@ -0,0 +1,101 @@
+#!/usr/bin/env python3
+import os
+import datetime
+import subprocess
+import json
+from rewind.paths import load_state
+
+"""
+Retrieves .ts files recorded between the specified timestamps.
+Returns a list of file paths and extra start and end offsets if needed.
+get_duration() is used as little as possible since it is slow.
+end_timestamp of a file is the start time of the next file.
+"""
+def get_ts_files(start_timestamp: float, end_timestamp: float) -> tuple[list[str], float, float]:
+    ts_files = load_state()["files"]
+    selected_files = []
+    start_offset = 0.0
+    end_offset = 0.0
+
+    for i, file_info in enumerate(ts_files):
+        file_start = file_info["timestamp"]
+        file_end = ts_files[i + 1]["timestamp"] if i + 1 < len(ts_files) else get_duration(file_info["path"]) + file_start
+
+        if file_end <= start_timestamp:
+            continue
+        if file_start >= end_timestamp:
+            break
+
+        selected_files.append(file_info["path"])
+
+        if file_start <= start_timestamp < file_end:
+            start_offset = start_timestamp - file_start
+        if file_start < end_timestamp <= file_end:
+            end_offset = file_end - end_timestamp
+
+    return selected_files, start_offset, end_offset
+
+
+def combine_last_x_ts_files(seconds: float, output_file: str) -> None:
+    ts_files = load_state()["files"]
+
+    files, start_offset, end_offset = get_ts_files(
+        datetime.datetime.now().timestamp() - seconds,
+        datetime.datetime.now().timestamp()
+    )
+
+    print(f"Combining files: {files} with start offset {start_offset} and end offset {end_offset}")
+
+    with open("file_list.txt", "w") as f:
+        for file_path in files:
+            f.write(f"file '{file_path}'\n")
+
+    subprocess.run(["ffmpeg", "-y", 
+                    "-ss", str(start_offset),
+                    "-f", "concat", "-safe", "0", "-i", 
+                    "file_list.txt", 
+                    "-c", "copy", 
+                    output_file])
+    
+    os.remove("file_list.txt")
+
+def clip(seconds_from_end: float) -> None:
+    output_file_name = f"{datetime.datetime.now().strftime('%Y-%m-%d %H:%M:%S')}.mp4"
+    combine_last_x_ts_files(seconds_from_end, output_file_name)
+    print(f"Created clip: {output_file_name}")
+
+def mark(name: str) -> None:
+    if not name:
+        raise ValueError("Marker name cannot be empty")
+    
+    # writes marker to json file (not state)
+    markers_file = os.path.join(os.path.dirname(__file__), "markers.json")
+    if os.path.exists(markers_file):
+        with open(markers_file, "r") as f:
+            markers = json.load(f)
+    else:
+        markers = []
+
+    markers.append({
+        "name": name,
+        "timestamp": datetime.datetime.now().timestamp()
+    })
+    
+    with open(markers_file, "w") as f:
+        json.dump(markers, f, indent=4)
+    print(f"Added marker: {name}")
+
+def get_duration(file_path: str) -> float:
+    result = subprocess.run(
+        ["ffprobe", "-v", "error", "-show_entries",
+         "format=duration", "-of",
+         "default=noprint_wrappers=1:nokey=1", file_path],
+        stdout=subprocess.PIPE,
+        stderr=subprocess.STDOUT
+    )
+
+    # error checking
+    if result.returncode != 0:
+        raise RuntimeError(f"ffprobe failed for file {file_path}")
+
+    return float(result.stdout)