// This file is part of Kiwix for iOS & macOS.
//
// Kiwix is free software; you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 3 of the License, or
// any later version.
//
// Kiwix is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Kiwix; If not, see https://www.gnu.org/licenses/.

import Foundation

enum Formatter {
    static let dateShort: DateFormatter = {
        let formatter = DateFormatter()
        formatter.dateStyle = .short
        formatter.timeStyle = .none
        return formatter
    }()

    static let dateMedium: DateFormatter = {
        let formatter = DateFormatter()
        formatter.dateStyle = .medium
        formatter.timeStyle = .none
        return formatter
    }()

    static let size: ByteCountFormatter = {
        let formatter = ByteCountFormatter()
        formatter.countStyle = .file
        return formatter
    }()

    static let number: NumberFormatter = {
        let formatter = NumberFormatter()
        formatter.numberStyle = .decimal
        return formatter
    }()

    static let percent: NumberFormatter = {
        let formatter = NumberFormatter()
        formatter.numberStyle = .percent
        return formatter
    }()

    static func largeNumber(_ value: Int64) -> String {
        let sign = ((value < 0) ? "-" : "" )
        let abs = Swift.abs(value)
        guard abs >= 1000 else {return "\(sign)\(abs)"}
        let exp = Int(log10(Double(abs)) / log10(1000))
        let units = ["K", "M", "G", "T", "P", "E"]
        let rounded = round(10 * Double(abs) / pow(1000.0, Double(exp))) / 10
        return "\(sign)\(rounded)\(units[exp-1])"
    }
}