Implementation of mmif rewinder

mmif/utils/__init__.py

@@ -1 +1,2 @@
 from mmif.utils import video_document_helper
+from mmif.utils import rewinder

mmif/utils/rewinder.py

@@ -0,0 +1,105 @@
+import argparse
+from pathlib import Path as P
+
+import mmif
+
+
+def is_valid_choice(choice):
+    try:
+        ichoice = int(choice)
+        if 0 <= ichoice:
+            return ichoice
+        else:
+            raise ValueError(f"\nInvalid argument for -n. Please enter a positive integer.")
+    except ValueError:
+        raise argparse.ArgumentTypeError(f"\nInvalid argument for -n. Please enter a positive integer.")
+
+def user_choice(mmif_obj:mmif.Mmif) -> int:
+    """
+    Function to ask user to choose the rewind range.
+
+    :param mmif_obj: mmif object
+    :return: int option number
+    """
+
+    ## Give a user options (#, "app", "timestamp") - time order
+    n = len(mmif_obj.views)
+    i = 0  # option number
+    # header
+    print("\n" + "{:<4} {:<30} {:<100}".format("num", "timestamp", "app"))
+    for view in mmif_obj.views:
+        option = "{:<4} {:<30} {:<100}".format(n-i, str(view.metadata.timestamp), str(view.metadata.app))
+        print(option)
+        i += 1
+
+    ## User input
+    while True:
+        choice = int(input("\nEnter the number to delete from that point by rewinding: "))
+        try:
+            if 0 <= choice <= n:
+                return choice
+            else:
+                print(f"\nInvalid choice. Please enter an integer in the range [0, {n}].")
+        except ValueError:
+            print("\nInvalid input. Please enter a valid number.")
+
+
+def rewind_mmif(mmif_obj: mmif.Mmif, choice: int, choice_is_viewnum: bool = True) -> mmif.Mmif:
+    """
+    Rewind MMIF by deleting the last N views. 
+    The number of views to rewind is given as a number of "views", or number of "producer apps". 
+    By default, the number argument is interpreted as the number of "views".
+
+    :param mmif_obj: mmif object
+    :param choice: number of views to rewind
+    :param choice_is_viewnum: if True, choice is the number of views to rewind. If False, choice is the number of producer apps to rewind.
+    :return: rewound mmif object
+    """
+    if choice_is_viewnum:
+        for vid in list(v.id for v in mmif_obj.views)[-1:-choice-1:-1]:
+            mmif_obj.views._items.pop(vid)
+    else:
+        app_count = 0
+        cur_app = ""
+        vid_to_pop = []
+        for v in reversed(mmif_obj.views):
+            if app_count >= choice:
+                break
+            if v.metadata.app != cur_app:
+                app_count += 1
+                cur_app = v.metadata.app
+            vid_to_pop.append(v.id)
+        for vid in vid_to_pop:
+            mmif_obj.views._items.pop(vid)
+    return mmif_obj
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(description="Process MMIF file.")
+    parser.add_argument("mmif_file", help="Path to the MMIF file")
+    parser.add_argument("-o", '--output', default="rewound.mmif", type=str, help="Path to the rewound MMIF output file (default: rewound.mmif)")
+    parser.add_argument("-p", '--pretty', action='store_true', help="Pretty print (default: pretty=True)")
+    parser.add_argument("-n", '--number', default="0", type=is_valid_choice, help="Number of views to rewind (default: 0)")
+    args = parser.parse_args()
+
+    mmif_obj = mmif.Mmif(open(args.mmif_file).read())
+
+    if args.number == 0: # If user doesn't know how many views to rewind, give them choices.
+        choice = user_choice(mmif_obj)
+    else:
+        choice = args.number
+
+
+    # Check if the same file name exist in the path and avoid overwriting.
+    output_fp = P(args.output)
+    if output_fp.is_file():
+        parent = output_fp.parent
+        stem = output_fp.stem
+        suffix = output_fp.suffix
+        count = 1
+        while (parent / f"{stem}_{count}{suffix}").is_file():
+            count += 1
+        output_fp = parent / f"{stem}_{count}{suffix}"
+
+    with open(output_fp, 'w') as mmif_file:
+        mmif_file.write(rewind_mmif(mmif_obj, choice, args.output).serialize(pretty=args.pretty))