Update all photo dates from filename. Useful for bulk import into iCloud from Google Photos.

photo-redate.swift

//
//  main.swift
//  photo-redate
//
//  Created by Pengcheng on 19.01.2024.
//

import Foundation
import Photos
import os

@main
struct App {
    static func main() async throws {
        if PHPhotoLibrary.authorizationStatus() != .authorized {
            let status = await PHPhotoLibrary.requestAuthorization(for: .readWrite)
            print("Authorization status: \(status)")
        } else {
            print("Already authorized")
        }
        
        let logger = Logger(subsystem: "moe.jsteward.photo-redate", category: "default")
        
        // format date
        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = "dd.MM.yyyy"
        let date = dateFormatter.date(from: "13.01.2024")!
        print("Filtering for photos with creationDate = \(date)")
        
        // create date range; https://stackoverflow.com/a/71482203/5520728
        let calendar = Calendar.current
        let start = calendar.startOfDay(for: date)
        let end = calendar.date(byAdding: .day, value: 1, to: start)!
        
        // get all photos created that day
        let allPhotosOptions = PHFetchOptions()
        allPhotosOptions.predicate = NSPredicate(format: "creationDate >= %@ AND creationDate < %@", argumentArray: [start, end])
        allPhotosOptions.includeHiddenAssets = true
        
        let assets = PHAsset.fetchAssets(with: allPhotosOptions)
        print("Got \(assets.count) photos")
        
        var changes = [(PHAsset, Date)]()
        
        assets.enumerateObjects { asset, idx, _ in
            print("#\(idx): ", terminator: "")
            let resources = PHAssetResource.assetResources(for: asset)
            print("\(resources.count) resources, ", terminator: "")
            if (resources.count > 1) {
                // most likely not imported photo
                print("skipping")
                return
            }
            let fname = resources.first!.originalFilename
            print("filename: \(fname), ", terminator: "")
            
            var actualDate: Date
            let imgDateFormatter = DateFormatter()
            imgDateFormatter.dateFormat = "yyyyMMdd_HHmmss"
            // most pictures in GMT+8
            imgDateFormatter.timeZone = TimeZone(secondsFromGMT: 8 * 3600)
            let imgDateFormatter2 = DateFormatter()
            imgDateFormatter2.dateFormat = "yyyy-MM-dd HH.mm.ss"
            imgDateFormatter2.timeZone = TimeZone(secondsFromGMT: 8 * 3600)
            
            // check filename formats
            if let match = fname.firstMatch(of: /(?:wx_camera_|mmexport|microMsg.|da_|IMG_|)(\d{13}).*.(?:jpg|mp4|jpeg)/) {
                // UNIX timestamp
                let sinceEpoch = Double(match.output.1)!
                actualDate = Date(timeIntervalSince1970: TimeInterval(sinceEpoch / 1000.0))
            } else if let match = fname.firstMatch(of: /(?:IMG_|)(\d{8}_\d{6}).*.(?:jpg|gif)/) {
                actualDate = imgDateFormatter.date(from: String(match.output.1))!
            } else if let match = fname.firstMatch(of: /(\d{4}-\d{2}-\d{2} \d{2}.\d{2}.\d{2}).*.jpg/) {
                actualDate = imgDateFormatter2.date(from: String(match.output.1))!
            } else {
                print("unsupported format!")
                logger.warning("Unsupported filename: \(fname)")
                return
            }
            print("parsed actual date: \(actualDate)")
            
            // enqueue for request
            changes.append((asset, actualDate))
        }
        
        // send metadata update requests
        for (asset, date) in changes {
            try await PHPhotoLibrary.shared().performChanges {
                let req = PHAssetChangeRequest(for: asset)
                req.creationDate = date
            }
            print("Updated photo on \(date)")
        }
    }
}