Files
damus/damus/Util/Markdown.swift
2022-12-28 23:02:01 -08:00

44 lines
1.6 KiB
Swift

//
// Markdown.swift
// damus
//
// Created by Lionello Lunesu on 2022-12-28.
//
import Foundation
public struct Markdown {
private let detector = try! NSDataDetector(types: NSTextCheckingResult.CheckingType.link.rawValue)
/// Ensure the specified URL has a scheme by prepending "https://" if it's absent.
static func withScheme(_ url: any StringProtocol) -> any StringProtocol {
return url.contains("://") ? url : "https://" + url
}
public static func parse(content: String) -> AttributedString {
// Similar to the parsing in NoteContentView
let md_opts: AttributedString.MarkdownParsingOptions =
.init(interpretedSyntax: .inlineOnlyPreservingWhitespace)
if let txt = try? AttributedString(markdown: content, options: md_opts) {
return txt
} else {
return AttributedString(stringLiteral: content)
}
}
/// Process the input text and add markdown for any embedded URLs.
public func process(_ input: String) -> AttributedString {
let matches = detector.matches(in: input, options: [], range: NSRange(location: 0, length: input.utf16.count))
var output = input
// Start with the last match, because replacing the first would invalidate all subsequent indices
for match in matches.reversed() {
guard let range = Range(match.range, in: input) else { continue }
let url = input[range]
output.replaceSubrange(range, with: "[\(url)](\(Markdown.withScheme(url)))")
}
// TODO: escape unintentional markdown
return Markdown.parse(content: output)
}
}