//  DecimalFormatter.swift
//  Eureka ( https://github.com/xmartlabs/Eureka )
//
//  Copyright (c) 2016 Xmartlabs SRL ( http://xmartlabs.com )
//
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

import Foundation
import UIKit

/// A custom formatter for numbers with two digits after the decimal mark
open class DecimalFormatter: NumberFormatter, FormatterProtocol {

    /// Creates the formatter with 2 Fraction Digits, Locale set to .current and .decimal NumberFormatter.Style
    public override init() {
        super.init()
        locale = Locale.current
        numberStyle = .decimal
        minimumFractionDigits = 2
        maximumFractionDigits = 2
    }

    required public init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    /// Creates an NSNumber from the given String
    /// - Parameter obj: Pointer to NSNumber object to assign
    /// - Parameter string: String with number assumed to have the configured min. fraction digits.
    /// - Parameter rangep: Unused range parameter
    override open func getObjectValue(_ obj: AutoreleasingUnsafeMutablePointer<AnyObject?>?, for string: String, range rangep: UnsafeMutablePointer<NSRange>?) throws {
        guard obj != nil else { return  }
        let str = string.components(separatedBy: CharacterSet.decimalDigits.inverted).joined(separator: "")
        // Recover the number from the string in a way that forces the formatter's fraction digits
        // numberWithoutDecimals / 10 ^ minimumFractionDigits
        obj?.pointee = NSNumber(value: (Double(str) ?? 0.0)/Double(pow(10.0, Double(minimumFractionDigits))))
    }

    open func getNewPosition(forPosition position: UITextPosition, inTextInput textInput: UITextInput, oldValue: String?, newValue: String?) -> UITextPosition {
        return textInput.position(from: position, offset:((newValue?.count ?? 0) - (oldValue?.count ?? 0))) ?? position
    }
}