Duplicate Search and Removal Based on File Timestamps

This program is to be a MacOS GUI application - Prefer this program to be written in Swift - Acceptable for it to be written in Objective C - Must function under both MacOS Sierra and OS X El Capitan This program must accept as input a primary folder and one or more additional folders - Prefer to be able to drag and drop selected folders from Finder to add them - Acceptable to browse via standard Finder dialog and add folder paths to a list - Minimum two folders (primary and secondary), maximum determined by you This program must compare every file in every folder and determine: - Is any file in the primary folder identical to a file in a corresponding folder? - (Must use SHA1 hash to verify files are identical) - Does any file have the same or newer creation date as an identical file? - If the same, preserve copy found in primary directory tree and delete all other copies - If different, change timestamp of copy in primary directory to oldest date found then delete all other copies - Is any file unique and not found in the primary directory tree? - Move this file to the primary directory tree under the same relative path Error Handling: 1) THIS PROGRAM MUST WORK WITH NETWORK SHARES (SMB in particular)! Program speed is not the most important issue, so avoid using multithreaded file operations or caching or anything else that might fail if there's even a slight delay compared to local drives. 2) If for some reason there are two files with the same Filename+Filepath but different size or SHA1 hashes, the program should still move both to the primary directory but append an incrementing index (such as -1, -2, -3, etc) to the filename. For example: \PRIMARY\ \SUBFOLDER1\ FILE1 100MB \SECONDARY\ \SUBFOLDER1\ FILE1 20MB Would become: \PRIMARY\ \SUBFOLDER1\ FILE1 100MB FILE1-1 20MB \SECONDARY\ \SUBFOLDER1\ 3) Filenames must be unique regardless of case sensitivity. For example "File1" and "FILE1" and "file1" would become "File1" and "FILE1-1" and "file1-2" when copied to the primary directory tree to ensure that there would be no files overwritten. 4) .DS_Store and .AppleDouble files or folders should either be deleted or ignored to avoid unnecessary file processing. Do not exclude any other hidden dot files or folders unless they cause a significant risk of program failure. 5) All deletions should be performed as the very last step, once the files have been verified to have been successfully copied and their SHA1 hashes match. This way if any files become inaccessible or cannot be copied or fail to copy properly, they are not deleted. 6) Please note that each Filename+Filepath is considered a unique object. If there is more than one copy of the same Filename within multiple subfolders of the same root folder, then these are not to be considered duplicates or removed. 7) There must be some sort of progress indicator, preferably a running log of actions being performed, in order to determine that the program hasn't crashed. If there are any limitations as to the total number of files or filename length or path length these should be disclosed. Accuracy and reliability are of paramount importance. Performance and aesthetics are great, but never at the expense of improper file handling. Thank you for considering my project.