Signal-iOS/SignalUI/Categories/UIKit+Text.swift

//
// Copyright 2023 Signal Messenger, LLC
// SPDX-License-Identifier: AGPL-3.0-only
//

import SignalServiceKit

public extension UISearchBar {

    var textField: UITextField? {
        return searchTextField
    }
}

// MARK: -

public extension UITextField {

    func acceptAutocorrectSuggestion() {
        inputDelegate?.selectionWillChange(self)
        inputDelegate?.selectionDidChange(self)
    }
}

// MARK: -

public extension UITextView {

    func acceptAutocorrectSuggestion() {
        // https://stackoverflow.com/a/27865136/4509555
        inputDelegate?.selectionWillChange(self)
        inputDelegate?.selectionDidChange(self)
    }

    func characterIndex(of location: CGPoint) -> Int? {
        return textContainer.characterIndex(of: location, textStorage: textStorage, layoutManager: layoutManager)
    }
}

// MARK: -

public extension NSTextContainer {

    func characterIndex(
        of location: CGPoint,
        textStorage: NSTextStorage,
        layoutManager: NSLayoutManager
    ) -> Int? {
        guard textStorage.length > 0 else {
            return nil
        }

        let glyphRange = layoutManager.glyphRange(for: self)
        let boundingRect = layoutManager.boundingRect(forGlyphRange: glyphRange, in: self)
        guard boundingRect.contains(location) else {
            return nil
        }

        let glyphIndex = layoutManager.glyphIndex(for: location, in: self)

        // We have the _closest_ index, but that doesn't mean we tapped in a glyph.
        // Check that directly.
        // This will catch the below case, where "*" is the tap location:
        //
        // This is the first line that is long.
        // Tap on the second line.    *
        //
        // The bounding rect includes the empty space below the first line,
        // but the tap doesn't actually lie on any glyph.
        let glyphRect = layoutManager.boundingRect(forGlyphRange: NSRange(location: glyphIndex, length: 1), in: self)
        guard glyphRect.contains(location) else {
            return nil
        }
        let characterIndex = layoutManager.characterIndexForGlyph(at: glyphIndex)
        return characterIndex
    }
}

// MARK: -

extension UILabel {

    // This is somewhat inconsistent; labels with text alignments and who knows what
    // other attributes applied may not do a great job at identifying the index.
    // Eventually this should be removed in favor of using UITextView everywhere.
    public func characterIndex(of location: CGPoint) -> Int? {
        let attrString: NSAttributedString
        if let attributedText {
            attrString = attributedText
        } else if let text {
            attrString = NSAttributedString(string: text, attributes: [.font: self.font as Any])
        } else {
            return nil
        }
        let textStorage = NSTextStorage(attributedString: attrString)
        let layoutManager = NSLayoutManager()
        textStorage.addLayoutManager(layoutManager)

        let textContainer = NSTextContainer(size: self.bounds.size)
        textContainer.lineFragmentPadding = 0
        textContainer.maximumNumberOfLines = self.numberOfLines
        textContainer.lineBreakMode = self.lineBreakMode
        layoutManager.addTextContainer(textContainer)

        return textContainer.characterIndex(of: location, textStorage: textStorage, layoutManager: layoutManager)
    }
}

// MARK: -

public extension NSTextAlignment {

    static var trailing: NSTextAlignment {
        CurrentAppContext().isRTL ? .left : .right
    }
}

// MARK: -

extension NSTextAlignment: CustomStringConvertible {

    public var description: String {
        switch self {
        case .left:
            return "left"
        case .center:
            return "center"
        case .right:
            return "right"
        case .justified:
            return "justified"
        case .natural:
            return "natural"
        @unknown default:
            return "unknown"
        }
    }
}