Swiftgram/submodules/Postbox/Sources/StringIndexTokens.swift

import Foundation
import StringTransliteration

public enum StringIndexTokenTransliteration {
    case none
    case combined
    case transliterated
}

public func stringIndexTokens(_ string: String, transliteration: StringIndexTokenTransliteration) -> [ValueBoxKey] {
    var nsString = string.lowercased() as NSString
    
    var isLatin = true
    for i in 0 ..< nsString.length {
        let c = nsString.character(at: i)
        if c >= 128 {
            isLatin = false
            break
        }
    }
    
    if !isLatin {
        nsString = postboxTransformedString(nsString, transliteration == .transliterated, transliteration == .combined) as NSString
    }
    
    let flag = UInt(kCFStringTokenizerUnitWord)
    let tokenizer = CFStringTokenizerCreate(kCFAllocatorDefault, nsString, CFRangeMake(0, nsString.length), flag, CFLocaleCopyCurrent())
    var tokenType = CFStringTokenizerAdvanceToNextToken(tokenizer)
    var tokens: [ValueBoxKey] = []
    
    var addedTokens = Set<ValueBoxKey>()
    while tokenType != [] {
        let currentTokenRange = CFStringTokenizerGetCurrentTokenRange(tokenizer)
        
        if currentTokenRange.location >= 0 && currentTokenRange.length != 0 {
            let token = ValueBoxKey(length: currentTokenRange.length * 2)
            nsString.getCharacters(token.memory.assumingMemoryBound(to: unichar.self), range: NSMakeRange(currentTokenRange.location, currentTokenRange.length))
            if !addedTokens.contains(token) {
                tokens.append(token)
                addedTokens.insert(token)
            }
        }
        tokenType = CFStringTokenizerAdvanceToNextToken(tokenizer)
    }
    
    return tokens
}

public func matchStringIndexTokens(_ tokens: [ValueBoxKey], with other: [ValueBoxKey]) -> Bool {
    if other.isEmpty {
        return false
    } else if other.count == 1 {
        let otherToken = other[0]
        for token in tokens {
            if otherToken.isPrefix(to: token) {
                return true
            }
        }
    } else {
        for otherToken in other {
            var found = false
            for token in tokens {
                if otherToken.isPrefix(to: token) {
                    found = true
                    break
                }
            }
            if !found {
                return false
            }
        }
        return true
    }
    return false
}