MongoView/MongoView/ExtendedJSON.swift

//
//  ExtendedJSON.swift
//  MongoView
//
//  Created by Shadowfacts on 4/4/20.
//  Copyright © 2020 Shadowfacts. All rights reserved.
//

import Foundation
import JavaScriptCore
import MongoSwift

struct ExtendedJSON {
    private init() {}
    
    private static let context: JSContext = {
        let context = JSContext()!
        let objectId: @convention(block) (String) -> [String: String] = { (id) in
            return ["$oid": id]
        }
        context.setObject(objectId, forKeyedSubscript: "ObjectId" as NSString)
        let date: @convention(block) (String) -> [String: String] = { (date) in
            return ["$date": date]
        }
        context.setObject(date, forKeyedSubscript: "Date" as NSString)
        return context
    }()
    
    static func normalize(_ string: String) -> String? {
        return context.evaluateScript("JSON.stringify(\(string))")?.toString()
    }
    
    private static func fromExtJSON(_ string: String) -> BSONDocument? {
        do {
            let doc = try BSONDocument(fromJSON: string)
            return doc
        } catch {
            print("Unable to create document from extended JSON: \(error)")
            return nil
        }
    }
    
    static func toDocument(_ string: String) -> BSONDocument? {
        guard let normalized = normalize(string),
            let doc = fromExtJSON(normalized) else {
                return nil
        }
        return doc
    }
    
}