fix-filenames-with-#Uxxxx-symbols.kt

import java.nio.file.Files
import java.nio.file.Path
import java.nio.file.Paths
import java.util.regex.Pattern

fun main(args: Array<String>) {
    val filesSrcDir = Paths.get(args[0])

    val renames: MutableMap<Path, String> = hashMapOf()

    Files.walk(filesSrcDir)
            .filter { Files.isRegularFile(it) }
            .forEach { process(it, renames) }

    renames.forEach { entry ->
        val source = entry.key
        val newName = entry.value
        println("${source.toString()} -> $newName")
        Files.move(source, source.resolveSibling(newName));
    }
}

fun process(path: Path, renames: MutableMap<Path, String>) {
    val pattern = Pattern.compile("\\#U(\\p{XDigit}\\p{XDigit}\\p{XDigit}\\p{XDigit})")
    val matcher = pattern.matcher(path.fileName.toString())

    val sb = StringBuffer()
    while (matcher.find()){
        val s = matcher.group(1)
        val ch = Integer.parseInt(s, 16).toChar()
        matcher.appendReplacement(sb, ch.toString())
    }
    matcher.appendTail(sb)

    val oldName = path.fileName.toString()
    val newName = sb.toString()
    if (oldName != newName) {
        renames.put(path, newName)
    }
}