package ru.dbotthepony.kstarbound.lua

import com.google.gson.JsonArray
import com.google.gson.JsonElement
import org.apache.logging.log4j.LogManager
import ru.dbotthepony.kstarbound.util.ActionPacer
import ru.dbotthepony.kstarbound.util.sbIntern

class LuaMessageHandlerComponent(val lua: LuaThread, val nameProvider: () -> String) {
	private val handlers = HashMap<String, LuaHandle>()

	private fun setHandler(args: LuaThread.ArgStack): Int {
		val name = args.nextString()
		val peek = args.peek()

		if (peek.isNothing) {
			handlers.remove(name)?.close()
		} else if (peek == LuaType.FUNCTION) {
			args.lua.dup(2)
			val handle = args.lua.createHandle()
			handlers.put(name.sbIntern(), handle)?.close()
		}

		return 0
	}

	init {
		lua.pushTable()
		lua.dup()
		lua.storeGlobal("message")
		lua.setTableValue("setHandler", ::setHandler)
		lua.pop()
	}

	val logPacer = ActionPacer(1, 5)

	fun lookupHandler(name: String): LuaHandle? {
		return handlers[name]
	}

	inline fun handle(message: String, isLocal: Boolean, arguments: LuaThread.() -> Int): JsonElement? {
		val handler = lookupHandler(message) ?: return null
		val top = lua.stackTop

		try {
			lua.push(handler)
			lua.push(isLocal)
			val amountOfArguments = arguments(lua)
			check(amountOfArguments >= 0) { "Invalid amount of arguments to pass to Lua handler: $amountOfArguments" }

			lua.call(amountOfArguments + 1, 1)

			return lua.getJson()
		} catch (err: Throwable) {
			if (logPacer.consumeAndReturnDeadline() <= 0L)
				LOGGER.error("${nameProvider.invoke()}: Exception while handling message '$message'", err)

			throw err
		} finally {
			lua.setTop(top)
		}
	}

	fun handle(message: String, isLocal: Boolean, arguments: JsonArray): JsonElement? {
		return handle(message, isLocal) {
			ensureExtraCapacity(arguments.size() + 4)

			for (argument in arguments) {
				push(argument)
			}

			arguments.size()
		}
	}

	companion object {
		val LOGGER = LogManager.getLogger()
	}
}