main.swift

import Foundation

let FILE_BUFFER_SIZE = 50000 

// source data
class DebtRec {
    var company: String = ""
    var phones: Array<String> = []
    var debt: Double = 0.0
}

// result data
class Debtor {
    var companies: Set<String> = []
    var phones: Set<String> = []
    var debt: Double = 0.0
}

class Debtors {
    var all: Array<Debtor> = []
    var index_by_phone: Dictionary<String, Int> = [:]
}

func main() {
    var res = Debtors()

    var fflag = 0
    for arg in CommandLine.arguments {
        if arg == "-f" {
            fflag = 1
        }
        else if fflag == 1 {
            fflag = 2
            print("\(arg):")
            let tbegin = Date()

            let (count, errcount) = process_file(fname: arg, res: &res)

            // print("PROCESSED: \(count) objects in \(DateInterval(start: tbegin, end: Date()).duration)s, \(errcount) errors found")
        }
    }

    for (di, d) in res.all.enumerated() {
        print("-------------------------------")
        print("#\(di): debt: \(d.debt)")
        print("companies: \(d.companies)\nphones: \(d.phones)")
    }

    if fflag < 2 {
        print("USAGE: fastpivot -f \"file 1\" -f \"file 2\" ...")
    }
}


func process_file(fname: String, res: inout Debtors) -> (Int, Int) {
    var count = 0
    var errcount = 0
    
    guard let inputStream = InputStream(fileAtPath: fname) else {
        print("ERROR: Unable to open file")
        return (count, errcount)
    }
    
    inputStream.open()
    
    var obj: Array<UInt8> = []
    var braces = 0
    
    var buffer = Array<UInt8>(repeating: 0, count: FILE_BUFFER_SIZE)
    
    while true {
        let r = inputStream.read(&buffer, maxLength: buffer.count)
        if r <= 0 {
            break // EOF
        }
        
        for i in 0..<r {
            let b = buffer[i]
            
            if b == 123 { // {
                braces += 1
                obj.append(b)
            }
            else if b == 125 { // }
                braces -= 1
                obj.append(b)
                
                if braces == 0 { //object formed !
                    
                    do {
                        let o = try JSONSerialization.jsonObject(with: Data(obj))
                        process_object(o: (o as! Dictionary<String, Any>), res: &res)
                    } catch {
                        print("JSON ERROR")
                        errcount += 1
                    }
                    
                    count += 1
                    
                    obj.removeAll(keepingCapacity: true)
                }
            }
            else if braces > 0 {
                obj.append(b)
            }
        }
    }

    return (count, errcount)
}


func process_object(o: Dictionary<String, Any>, res: inout Debtors) {
    let dr = extract_data(o)
    //print("\(dr.company) - \(dr.phones) - \(dr.debt)")

    var di: Optional<Int> = Optional.none //debtor index search result
    for p in dr.phones {
        if let i = res.index_by_phone[p] {
            di = Optional.some(i)
            break
        }
    }
    if let i = di { //existing debtor
        let d = res.all[i]
        d.companies.insert(dr.company)
        for p in dr.phones {
            d.phones.insert(p)
            res.index_by_phone[p] = i
        }
        d.debt += dr.debt
    }
    else { //new debtor
        let d = Debtor()
        let i = res.all.count

        d.companies.insert(dr.company)
        for p in dr.phones {
            d.phones.insert(p)
            res.index_by_phone[p] = i
        }
        d.debt = dr.debt

        res.all.append(d)
    }
}


func extract_data(_ o: Dictionary<String, Any>) -> DebtRec {

    func val2str(_ v: Any) -> String {
        if let vs = (v as? String) {
            return vs
        }
        else if let vi = (v as? Int) {
            return String(vi)
        }
        else {
            return "null"
        }
    }

    let dr = DebtRec()

    let c = o["company"]!
    if let company = (c as? Dictionary<String, Any>) {
        dr.company = val2str(company["name"]!)
    } else {
        dr.company = val2str(c)
    }

    let pp = o["phones"]
    if let pp = (pp as? Array<Any>) {
        for p in pp {
            dr.phones.append(val2str(p))
        }
    } 
    else if pp != nil {
        dr.phones.append(val2str(pp!))
    }       

    let p = o["phone"]
    if p != nil {
        dr.phones.append(val2str(p!))
    }        

    if let d = o["debt"] {
        if let dd = (d as? Double) {
            dr.debt = dd
        }
        else if let ds = (d as? String) {
            dr.debt = Double(ds)!
        }
    }

    return dr
}

main()