//
//  MongoEvaluator.swift
//  MongoView
//
//  Created by Shadowfacts on 1/12/20.
//  Copyright © 2020 Shadowfacts. All rights reserved.
//

import Foundation
import JavaScriptCore
import MongoSwift

struct MongoEvaluator {
    
    static let context: JSContext = {
        let context = JSContext()!
        let date: @convention(block) (JSValue) -> Dictionary<String, Any> = { (input) in
            ["$date": input]
        }
        let functions: [NSString: @convention(block) (JSValue) -> Dictionary<String, Any>] = [
            "ObjectId": { (input) in
                ["$oid": input]
            },
            "NumberLong": { (input) in
                ["$numberLong": input]
            },
            "NumberInt": { (input) in
                ["$numberInt": input]
            },
            "NumberDecimal": { (input) in
                ["$numberDecimal": input]
            },
            "Date": date,
            "ISODate": date,
        ]
        functions.forEach { (key, value) in
            context.setObject(value, forKeyedSubscript: key)
        }
        let dbRef: @convention(block) (String, String) -> Dictionary<String, Any> = { (ref, id) in
            ["$ref": ref, "$id": ["$oid": id]]
        }
        context.setObject(dbRef, forKeyedSubscript: "DBRef" as NSString)
        return context
    }()

    static func parse(shellJSON: String) -> Document? {
        guard !shellJSON.isEmpty,
            let result = context.evaluateScript("JSON.stringify(\(shellJSON))") else {
                return nil
        }
        do {
            return try Document(fromJSON: result.toString())
        } catch {
            print("Unable to parse Document: \(error)")
            return nil
        }
    }
    
    static func eval(command: String, connectingTo connStr: String) -> [Document] {
        print("Running command \"\(command)\" against \(connStr)")
        
        let mongoOutputPipe = Pipe()

        let mongoProcess = Process()
        mongoProcess.launchPath = "/usr/local/bin/mongo"
        mongoProcess.arguments = [connStr, "--quiet", "--norc", "--eval", command]
        mongoProcess.standardOutput = mongoOutputPipe
        mongoProcess.launch()
        
        let mongoOutputHandle = mongoOutputPipe.fileHandleForReading
        
        var strs = [String]()
        var data: Data!
        repeat {
            data = mongoOutputHandle.availableData
            strs.append(String(data: data, encoding: .utf8)!)
        } while (data.count > 0)
        mongoOutputHandle.closeFile()
        
        let lines = strs.joined(separator: "").components(separatedBy: "\n")
        return lines.compactMap(parse(shellJSON:))
    }
    
}