back and front key in the middle

gistfile1.txt.py

import math
import pymel.core as pm

def insertKeyframeBetweenKeys():
    try:
        objects = pm.ls(sl=1)
        attrs = pm.selectionConnection('graphEditor1FromOutliner', q=1, object=1)
        
        for attr in attrs:   
            buffer = attr.split(".")
            buffer = buffer[1]
            
            # Get the current time
            currentTime = pm.currentTime(query=True)
            
            # Get the keyframe times of the selected attribute
            keyTimes = pm.keyframe(objects, attribute=buffer, query=True, timeChange=True)
            
            # Sort the keyframe times
            keyTimes.sort()
            
            # Find the keyframes before and after the current time
            prevKeyTime = None
            nextKeyTime = None
            for keyTime in keyTimes:
                if keyTime < currentTime:
                    prevKeyTime = keyTime
                elif keyTime > currentTime:
                    nextKeyTime = keyTime
                    break
            
            # Insert a keyframe between the nearest keyframes, if they exist
            if prevKeyTime is not None and nextKeyTime is not None:
                # Calculate the distance to the nearest keyframes
                prevDistance = currentTime - prevKeyTime
                nextDistance = nextKeyTime - currentTime
                
                # Insert a keyframe at the midpoint between the nearest keyframes
                newKeyTime = (prevKeyTime + nextKeyTime) / 2
                pm.setKeyframe(time=newKeyTime, attribute=buffer, insert=True)
                
                # Check if inserting a keyframe before the current time is necessary
                if prevKeyTime != currentTime:
                    newKeyTime = math.ceil(prevKeyTime + prevDistance / 2)
                    pm.setKeyframe(time=newKeyTime, attribute=buffer, insert=True)
                    
                # Check if inserting a keyframe after the current time is necessary
                if nextKeyTime != currentTime:
                    newKeyTime = math.floor(nextKeyTime - nextDistance / 2
                    pm.setKeyframe(time=newKeyTime, attribute=buffer, insert=True)
                    
            elif prevKeyTime is not None and nextKeyTime is None:
                # If there is only one keyframe after the current time, insert a keyframe after it
                timeDifference = currentTime - prevKeyTime
                newKeyTime = prevKeyTime + (timeDifference * 2)
                pm.setKeyframe(time=newKeyTime, attribute=buffer)
                
            elif prevKeyTime is None and nextKeyTime is not None:
                # If there is only one keyframe before the current time, insert a keyframe before it
                timeDifference = nextKeyTime - currentTime
                newKeyTime = nextKeyTime - (timeDifference * 2)
                pm.setKeyframe(time=newKeyTime, attribute=buffer)
                
        # After inserting all keyframes, snap them
        for obj in objects:
            for attr in attrs:
                pm.snapKey(obj, attribute=attr)
                
        # Adjust keyframes to integers
        for attr in attrs:
            keyTimes = pm.keyframe(objects, attribute=attr, query=True, timeChange=True)
            for keyTime in keyTimes:
                pm.cutKey(objects, time=(keyTime,), attribute=attr)
                pm.setKeyframe(time=round(keyTime), attribute=attr)
                
        # Snap keyframes for all selected objects
        for obj in objects:
            pm.snapKey(obj, timeMultiple=1.0)
                
    except Exception as e:
        print("Error:", e)
        
insertKeyframeBetweenKeys()