Get Dropbox Folder Location.swift

#if os(macOS)

import Foundation

/// On init, parses Dropbox's info.json file and populates the pertinent data into variables. Object is nil if info.json file can't be found (which usually means Dropbox is not installed on the system) or there was a generic error parsing the JSON data.
///
/// Properties are populated once upon the struct's init. There is no method to refresh the data. Instead, instance a new copy of `DropboxPaths`.
///
/// - `personalPath`: POSIX path if found; nil if not discoverable
/// - `personalURL`: URL if found; nil if not discoverable
/// - `businessPath`: POSIX path if found; nil if not discoverable
/// - `businessURL`: URL if found; nil if not discoverable
public struct DropboxPaths {
    
    /// POSIX path, `nil` if not discoverable.
    ///
    /// Safe to access repeatedly. (Value is polled from the system only once at the time of the struct's init, so to refresh the value, instance a new copy of `DropboxPaths`.)
    public let personalPath: String?
    
    /// POSIX path, nil if not discoverable. Safe to access repeatedly.
    ///
    /// Safe to access repeatedly. (Value is polled from the system only once at the time of the struct's init, so to refresh the value, instance a new copy of `DropboxPaths`.)
    public let businessPath: String?
    
    /// File URL path, `nil` if not discoverable.
    ///
    /// Safe to access repeatedly. (Value is polled from the system only once at the time of the struct's init, so to refresh the value, instance a new copy of `DropboxPaths`.)
    public var personalURL: URL?
    
    /// File URL path, `nil` if not discoverable.
    ///
    /// Safe to access repeatedly. (Value is polled from the system only once at the time of the struct's init, so to refresh the value, instance a new copy of `DropboxPaths`.)
    public var businessURL: URL?
    
    // Example info.json file:
    // {
    //   "personal": {
    //     "path": "/Users/username/Dropbox",
    //     "subscription_type": "Pro",
    //     "is_team": false,
    //     "host": 1722515629
    //   }
    // }
    
    public init?() {
        
        // attempt to access Dropbox's json meta-data file (in user's home folder)
        
        let url = FileManager.homeDirectoryForCurrentUserCompat
            .appendingPathComponent(".dropbox")
            .appendingPathComponent("info.json")
        
        guard let readJSON = try? Data(contentsOf: url),
              let json = try? JSONSerialization
                .jsonObject(with: readJSON) as? [String: Any] else {
            return nil
        }
        
        if let personalDict = json["personal"] as? [String: Any] {
            personalPath = personalDict["path"] as? String
            
            personalURL = personalPath != nil
                ? URL(fileURLWithPath: personalPath!)
                : nil
        } else {
            personalPath = nil
            personalURL = nil
        }
        
        if let businessDict = json["business"] as? [String: Any] {
            businessPath = businessDict["path"] as? String
            
            businessURL = businessPath != nil
                ? URL(fileURLWithPath: businessPath!)
                : nil
        } else {
            businessPath = nil
            businessURL = nil
        }
        
    }
    
}

extension FileManager {

    public static var homeDirectoryForCurrentUserCompat: URL {
        
        if #available(OSX 10.12, *) {
            // only available on macOS
            return FileManager.default.homeDirectoryForCurrentUser
        } else {
            // available on all Apple platforms
            return URL(fileURLWithPath: NSHomeDirectory(), isDirectory: true)
        }
        
    }

}

#endif