spellcheck

#!/usr/bin/env swift

//
//  All Contributions by Match Group
//
//  Copyright © 2025 Tinder (Match Group, LLC)
//
//  Licensed under the Match Group Modified 3-Clause BSD License.
//  See https://github.com/Tinder/spellcheck-cli/blob/main/LICENSE for license information.
//

import AppKit

let arguments: [String] = CommandLine.arguments

let spellChecker: NSSpellChecker = .shared

if arguments.contains("-h") || arguments.contains("--help") {
    print("Available Languages:")
    print(spellChecker.availableLanguages.joined(separator: "\n"))
    exit(EXIT_SUCCESS)
}

let json: Bool = arguments.contains("--json")

let language: String?

if let index: Int = arguments.firstIndex(of: "--language"), index < arguments.count - 1 {
    language = arguments[index + 1]
} else {
    language = ProcessInfo.processInfo.environment["SPELLCHECK_CLI_LANGUAGE"]
}

struct MisspelledWord: Codable {

    let word: String
    let guesses: [String]
}

func readStandardInput() -> String {
    var input: String = ""
    while let line: String = readLine(strippingNewline: false) {
        input.append(line)
    }
    return input
}

func misspelledWords(in text: String) -> [MisspelledWord] {

    _ = language.flatMap(spellChecker.setLanguage)

    var misspelledWords: [MisspelledWord] = []

    var location: Int = 0

    while location < NSMaxRange(NSRange(text.startIndex..., in: text)) {

        let range: NSRange = spellChecker.checkSpelling(of: text, startingAt: location)

        guard range.location != NSNotFound,
              range.location >= location
        else { break }

        let guesses: [String] = spellChecker.guesses(forWordRange: range,
                                                     in: text,
                                                     language: nil,
                                                     inSpellDocumentWithTag: 0) ?? []

        if let range: Range = .init(range, in: text) {
            let misspelledWord: MisspelledWord = .init(word: String(text[range]),
                                                       guesses: guesses)
            misspelledWords.append(misspelledWord)
        }

        location = NSMaxRange(range)
    }

    return misspelledWords
}

let misspelledWords: [MisspelledWord] = misspelledWords(in: readStandardInput())

if json {
    let data: Data = try JSONEncoder().encode(misspelledWords)
    print(String(decoding: data, as: UTF8.self))
    exit(EXIT_SUCCESS)
}

for misspelledWord in misspelledWords {
    misspelledWord.guesses.isEmpty
        ? print(misspelledWord.word)
        : print(misspelledWord.word, "->", misspelledWord.guesses.joined(separator: " "))
}

misspelledWords.isEmpty
    ? exit(EXIT_SUCCESS)
    : exit(EXIT_FAILURE)