package processing.app

import androidx.compose.runtime.*

import kotlinx.coroutines.Dispatchers

import kotlinx.coroutines.launch

import java.io.File

import java.io.InputStream

import java.nio.file.*

import java.util.Properties

const val PREFERENCES_FILE_NAME = "preferences.txt"

const val DEFAULTS_FILE_NAME = "defaults.txt"

fun PlatformStart(){

Platform.inst ?: Platform.init()

}

@Composable

fun loadPreferences(): Properties{

PlatformStart()

val settingsFolder = Platform.getSettingsFolder()

val preferencesFile = settingsFolder.resolve(PREFERENCES_FILE_NAME)

if(!preferencesFile.exists()){

preferencesFile.createNewFile()

}

watchFile(preferencesFile)

return Properties().apply {

load(ClassLoader.getSystemResourceAsStream(DEFAULTS_FILE_NAME) ?: InputStream.nullInputStream())

load(preferencesFile.inputStream())

}

}

@Composable

fun watchFile(file: File): Any? {

val scope = rememberCoroutineScope()

var event by remember(file) { mutableStateOf<WatchEvent<*>?> (null) }

DisposableEffect(file){

val fileSystem = FileSystems.getDefault()

val watcher = fileSystem.newWatchService()

var active = true

val path = file.toPath()

val parent = path.parent

val key = parent.register(watcher, StandardWatchEventKinds.ENTRY_MODIFY)

scope.launch(Dispatchers.IO) {

while (active) {

for (modified in key.pollEvents()) {

if (modified.context() != path.fileName) continue

event = modified

}

}

}

onDispose {

active = false

key.cancel()

watcher.close()

}

}

return event

}

val LocalPreferences = compositionLocalOf<Properties> { error("No preferences provided") }

@Composable

fun PreferencesProvider(content: @Composable () -> Unit){

val preferences = loadPreferences()

CompositionLocalProvider(LocalPreferences provides preferences){

content()

}

}