package org.openrs2.game.net.login

import io.netty.buffer.Unpooled
import io.netty.channel.ChannelFutureListener
import io.netty.channel.ChannelHandlerContext
import io.netty.channel.SimpleChannelInboundHandler
import io.netty.handler.codec.DelimiterBasedFrameDecoder
import io.netty.handler.codec.string.StringDecoder
import org.openrs2.buffer.copiedBuffer
import org.openrs2.game.net.jaggrab.JaggrabChannelHandler
import org.openrs2.game.net.js5.Js5ChannelHandler
import org.openrs2.protocol.Rs2Decoder
import org.openrs2.protocol.Rs2Encoder
import org.openrs2.protocol.jaggrab.JaggrabRequestDecoder
import org.openrs2.protocol.js5.Js5RequestDecoder
import org.openrs2.protocol.js5.Js5ResponseEncoder
import org.openrs2.protocol.js5.XorDecoder
import org.openrs2.protocol.login.LoginRequest
import org.openrs2.protocol.login.LoginResponse
import javax.inject.Inject
import javax.inject.Provider

public class LoginChannelHandler @Inject constructor(
    private val js5HandlerProvider: Provider<Js5ChannelHandler>,
    private val jaggrabHandler: JaggrabChannelHandler
) : SimpleChannelInboundHandler<LoginRequest>() {
    override fun channelActive(ctx: ChannelHandlerContext) {
        ctx.read()
    }

    override fun channelRead0(ctx: ChannelHandlerContext, msg: LoginRequest) {
        when (msg) {
            is LoginRequest.InitJs5RemoteConnection -> handleInitJs5RemoteConnection(ctx, msg)
            is LoginRequest.InitJaggrabConnection -> handleInitJaggrabConnection(ctx)
        }
    }

    private fun handleInitJs5RemoteConnection(ctx: ChannelHandlerContext, msg: LoginRequest.InitJs5RemoteConnection) {
        if (msg.build != BUILD) {
            ctx.write(LoginResponse.ClientOutOfDate).addListener(ChannelFutureListener.CLOSE)
            return
        }

        ctx.pipeline().addLast(
            XorDecoder(),
            Js5RequestDecoder(),
            Js5ResponseEncoder,
            js5HandlerProvider.get()
        )
        ctx.pipeline().remove(Rs2Decoder::class.java)

        ctx.write(LoginResponse.Js5Ok).addListener {
            ctx.pipeline().remove(Rs2Encoder::class.java)
            ctx.pipeline().remove(this)
        }
    }

    private fun handleInitJaggrabConnection(ctx: ChannelHandlerContext) {
        ctx.pipeline().addLast(
            DelimiterBasedFrameDecoder(JAGGRAB_MAX_FRAME_LENGTH, JAGGRAB_DELIMITER),
            StringDecoder(Charsets.UTF_8),
            JaggrabRequestDecoder,
            jaggrabHandler
        )
        ctx.pipeline().remove(Rs2Decoder::class.java)
        ctx.pipeline().remove(Rs2Encoder::class.java)
        ctx.pipeline().remove(this)
    }

    override fun channelReadComplete(ctx: ChannelHandlerContext) {
        ctx.flush()
    }

    private companion object {
        private const val BUILD = 550
        private const val JAGGRAB_MAX_FRAME_LENGTH = 4096
        private val JAGGRAB_DELIMITER = Unpooled.unreleasableBuffer(copiedBuffer("\n\n"))
    }
}