//
// SPDX-FileCopyrightText: 2020 Nextcloud GmbH and Nextcloud contributors
// SPDX-License-Identifier: GPL-3.0-or-later
//

import Foundation

// based on https://stackoverflow.com/a/39425959/2512312
extension Character {
    /// A simple emoji is one scalar and presented to the user as an Emoji
    var isSimpleEmoji: Bool {
        guard let firstScalar = unicodeScalars.first else { return false }
        return firstScalar.properties.isEmoji && firstScalar.value > 0x238C
    }

    /// Checks if the scalars will be merged into an emoji
    var isCombinedIntoEmoji: Bool { unicodeScalars.count > 1 && unicodeScalars.first?.properties.isEmoji ?? false }

    var isEmoji: Bool { isSimpleEmoji || isCombinedIntoEmoji }
}

extension String {
    var isSingleEmoji: Bool { count == 1 && containsEmoji }

    var containsEmoji: Bool { contains { $0.isEmoji } }

    var containsOnlyEmoji: Bool { !isEmpty && !contains { !$0.isEmoji } }

    var emojiString: String { emojis.map { String($0) }.reduce("", +) }

    var emojis: [Character] { filter { $0.isEmoji } }

    var emojiScalars: [UnicodeScalar] { filter { $0.isEmoji }.flatMap { $0.unicodeScalars } }
}

extension UIView {
    // https://stackoverflow.com/a/41288197
    // Using a function since `var image` might conflict with an existing variable
    // (like on `UIImageView`)
    func asImage() -> UIImage {
        let renderer = UIGraphicsImageRenderer(bounds: bounds)
        return renderer.image { rendererContext in
            layer.render(in: rendererContext.cgContext)
        }
    }
}

@objc extension NSString {

    public var containsOnlyEmoji: Bool {
        let str = self as String
        return str.containsOnlyEmoji
    }

    public var isSingleEmoji: Bool {
        let str = self as String
        return str.isSingleEmoji
    }

    public var emojiCount: Int {
        let str = self as String
        return str.emojis.count
    }

}