Route link play through multiplayer sessions

src/link/LinkState.lua

@@ -10,6 +10,7 @@ local Net = require("src.link.Net")
 local Protocol = require("src.link.Protocol")
 local Runtime = require("src.mods.Runtime")
 local Screens = require("src.ui.Screens")
+local Session = require("src.link.Session")
 local TextBox = require("src.render.TextBox")
 local Strings = require("src.core.Strings")
 
@@ -44,10 +45,8 @@ local function forceLevelLabel(v)
   return (v == ANY or v == nil) and "ANY" or ("AUTO " .. tostring(v))
 end
 
--- stages before any Net object is meaningfully "this session's link" --
+-- stages before a successful transport has become this link's Session;
--- .net can still be a leftover failed attempt sitting on self, so error/
+-- terminal checks skip them rather than keying off self.net's presence
--- closed checks below skip these rather than keying off self.net's
--- presence alone
 local PRE_CONNECT_STAGES = { menu = true, lanMenu = true, onlineMenu = true }
 
 -- how long the host waits for a v2 hello before deciding the peer predates
@@ -70,6 +69,16 @@ local function ipDigits(ip)
   return digits
 end
 
+local function openSession(role, connect)
+  local transport = Net.new()
+  if connect(transport) then
+    return Session.new(transport, { role = role, kind = "link" })
+  end
+  local detail = transport.error or "?"
+  transport:close()
+  return nil, detail
+end
+
 function LinkState.new(game)
   local self = setmetatable({}, LinkState)
   self.game = game
@@ -89,12 +98,15 @@ end
 -- "connecting with this code", same as if the player had typed it in
 function LinkState.newJoinOnline(game, code)
   local self = LinkState.new(game)
-  self.net = Net.new()
+  local session, detail = openSession("guest", function(transport)
-  if self.net:joinOnline(nil, code) then
+    return transport:joinOnline(nil, code)
+  end)
+  if session then
+    self.net = session
     self.stage = "onlineJoining"
   else
     self.stage = "menu" -- exitWith below needs a real stage to unwind from
-    self:exitWith(Strings("Link error:\n%s", self.net.error or "?"))
+    self:exitWith(Strings("Link error:\n%s", detail))
   end
   return self
 end
@@ -163,21 +175,13 @@ end
 -- take the peer's hello out of the inbox without eating anything that
 -- shares the batch with it
 function LinkState:pollHello()
-  local msgs = self.net:poll()
+  local message
-  local keep, got = {}, false
+  if not self.peerHello then message = self.net:take("hello") end
-  for _, msg in ipairs(msgs) do
+  if message then
-    if msg.type == "hello" and not self.peerHello then
+    self.peerHello = message
-      self.peerHello = msg
+    self.peerName = message.name
-      self.peerName = msg.name
-      got = true
-    else
-      keep[#keep + 1] = msg
-    end
   end
-  for i = #keep, 1, -1 do
+  return message ~= nil, self.net:hasPending()
-    table.insert(self.net.inbox, 1, keep[i])
-  end
-  return got, #keep > 0
 end
 
 function LinkState:sendHello(mode)
@@ -220,13 +224,15 @@ function LinkState:update(dt)
   local input = self.game.input
   if self.net then
     self.net:update()
-    if self.net.error and not PRE_CONNECT_STAGES[self.stage] then
+    local status = self.net:getStatus()
-      self:exitWith(Strings("Link error:\n%s", self.net.error:sub(1, 60)))
+    if status == "failed" and not PRE_CONNECT_STAGES[self.stage] then
+      self:exitWith(Strings("Link error:\n%s",
+        (self.net.error or "?"):sub(1, 60)))
       return
     end
-    -- the peer vanished without a bye (only once the inbox is drained,
+    -- the peer vanished without a bye (only once the session FIFO drains,
     -- so a final message travelling with the disconnect still counts)
-    if self.net.closed and #self.net.inbox == 0
+    if status == "closed"
        and not PRE_CONNECT_STAGES[self.stage] and self.stage ~= "addrEntry"
        and self.stage ~= "codeEntry" and self.stage ~= "notice"
        and self.stage ~= "battleRunning" then
@@ -269,12 +275,15 @@ function LinkState:update(dt)
       self.stage = "menu"
       self.index = 1
     elseif input:wasPressed("a") then
-      self.net = Net.new()
       if self.index == 1 then
-        if self.net:host() then
+        local session, detail = openSession("host", function(transport)
+          return transport:host()
+        end)
+        if session then
+          self.net = session
           self.stage = "hosting"
         else
-          self:exitWith(Strings("Link error:\n%s", self.net.error or "?"))
+          self:exitWith(Strings("Link error:\n%s", detail))
         end
       else
         self.stage = "addrEntry"
@@ -289,11 +298,14 @@ function LinkState:update(dt)
       self.index = 2
     elseif input:wasPressed("a") then
       if self.index == 1 then
-        self.net = Net.new()
+        local session, detail = openSession("host", function(transport)
-        if self.net:hostOnline() then
+          return transport:hostOnline()
+        end)
+        if session then
+          self.net = session
           self.stage = "onlineHosting"
         else
-          self:exitWith(Strings("Link error:\n%s", self.net.error or "?"))
+          self:exitWith(Strings("Link error:\n%s", detail))
         end
       else
         self.stage = "codeEntry"
@@ -327,11 +339,14 @@ function LinkState:update(dt)
       CodeEntry.right(self.codeEntry)
     elseif input:wasPressed("a") then
       local code = CodeEntry.text(self.codeEntry)
-      self.net = Net.new()
+      local session, detail = openSession("guest", function(transport)
-      if self.net:joinOnline(nil, code) then
+        return transport:joinOnline(nil, code)
+      end)
+      if session then
+        self.net = session
         self.stage = "onlineJoining"
       else
-        self:exitWith(Strings("Link error:\n%s", self.net.error or "?"))
+        self:exitWith(Strings("Link error:\n%s", detail))
       end
     end
 
@@ -367,10 +382,15 @@ function LinkState:update(dt)
                                   + self.addr[base + 2] * 10
                                   + self.addr[base + 3])
       end
-      if self.net:join(table.concat(octets, ".")) then
+      local address = table.concat(octets, ".")
+      local session, detail = openSession("guest", function(transport)
+        return transport:join(address)
+      end)
+      if session then
+        self.net = session
         self.stage = "joining"
       else
-        self:exitWith(Strings("Link error:\n%s", self.net.error or "?"))
+        self:exitWith(Strings("Link error:\n%s", detail))
       end
     end
 
@@ -428,19 +448,11 @@ function LinkState:update(dt)
 
   elseif self.stage == "waitMode" then -- guest waits for host's pick
     if input:wasPressed("b") then self:exitWith(nil) return end
-    local msgs = self.net:poll()
+    local message = self.net:take("hello")
-    for i, msg in ipairs(msgs) do
+    if message then
-      if msg.type == "hello" then
+      self.peerHello = message
-        self.peerHello = msg
+      self.peerName = message.name
-        self.peerName = msg.name
+      self:decideCompat(message.mode, false)
-        -- the host's next messages (party, ...) can share this batch;
-        -- put them back so the new stage's poll sees them
-        for j = #msgs, i + 1, -1 do
-          table.insert(self.net.inbox, 1, msgs[j])
-        end
-        self:decideCompat(msg.mode, false)
-        break
-      end
     end
 
   elseif self.stage == "notice" then
@@ -456,40 +468,34 @@ function LinkState:update(dt)
 
   elseif self.stage == "battleWait" then
     if input:wasPressed("b") then self:exitWith(nil) return end
-    local msgs = self.net:poll()
+    local message = self.net:take("party")
-    for i, msg in ipairs(msgs) do
+    if message then
-      if msg.type == "party" then
+      -- the host owns this rule (same as mode); the guest only learns
-        -- the host owns this rule (same as mode); the guest only learns
+      -- it here, off the host's own party message
-        -- it here, off the host's own party message
+      if not self.isHost then self.forceLevel = message.forceLevel end
-        if not self.isHost then self.forceLevel = msg.forceLevel end
+      local LinkBattle = require("src.link.LinkBattle")
-        local LinkBattle = require("src.link.LinkBattle")
+      local opts = {
-        local opts = {
+        myParty = Protocol.packParty(self.game.save.party),
-          myParty = Protocol.packParty(self.game.save.party),
+        theirParty = message.mons,
-          theirParty = msg.mons,
+        theirName = self.peerName or "FOE",
-          theirName = self.peerName or "FOE",
+        seed = self.isHost and self.linkSeed or message.seed,
-          seed = self.isHost and self.linkSeed or msg.seed,
+        verdict = self.verdict,
-          verdict = self.verdict,
+        strict = Handshake.strict(self.verdict),
-          strict = Handshake.strict(self.verdict),
+        forceLevel = self.forceLevel,
-          forceLevel = self.forceLevel,
+      }
-        }
+      local battle, why
-        local battle, why
+      if self.isHost then
-        if self.isHost then
+        battle, why = LinkBattle.newHost(self.game, self.net, opts)
-          battle, why = LinkBattle.newHost(self.game, self.net, opts)
+      else
-        else
+        battle, why = LinkBattle.newGuest(self.game, self.net, opts)
-          battle, why = LinkBattle.newGuest(self.game, self.net, opts)
-        end
-        if not battle then
-          self.net:send({ type = "bye" })
-          self:exitWith(why or Strings("Link battle\ncan't start."), "error")
-          return
-        end
-        self.game.stack:push(battle)
-        self.stage = "battleRunning"
-        for j = #msgs, i + 1, -1 do
-          table.insert(self.net.inbox, 1, msgs[j])
-        end
-        break
       end
+      if not battle then
+        self.net:send({ type = "bye" })
+        self:exitWith(why or Strings("Link battle\ncan't start."), "error")
+        return
+      end
+      self.game.stack:push(battle)
+      self.stage = "battleRunning"
     end
 
   elseif self.stage == "battleRunning" then

tests/engine/link_session.lua

@@ -42,6 +42,13 @@ local function fakeTransport(options)
   return transport
 end
 
+local function readFile(path)
+  local handle = assert(io.open(path, "rb"))
+  local body = handle:read("*a")
+  handle:close()
+  return body
+end
+
 do
   local host, guest = sessionPair()
   T.eq(host:getRole(), "host", "host role is assigned locally")
@@ -299,4 +306,22 @@ do
   T.eq(transport:poll()[1].name, "RED", "valid application packet stays intact")
 end
 
+do
+  local source = readFile("src/link/LinkState.lua")
+  T.check(source:find('require("src.link.Session")', 1, true) ~= nil,
+    "LinkState depends on the session boundary")
+  T.check(source:find('kind = "link"', 1, true) ~= nil,
+    "LinkState assigns the link session kind locally")
+  T.check(source:find("self.net.inbox", 1, true) == nil,
+    "LinkState never mutates a transport inbox")
+  T.check(source:find("self.net = Net.new()", 1, true) == nil,
+    "LinkState stores only successful session wrappers")
+  T.check(source:find(':take("hello")', 1, true) ~= nil,
+    "LinkState retrieves hello without draining unrelated packets")
+  T.check(source:find(':take("party")', 1, true) ~= nil,
+    "LinkState leaves battle handoff packets in session order")
+  T.check(source:find("getStatus()", 1, true) ~= nil,
+    "LinkState uses the session lifecycle instead of raw terminal flags")
+end
+
 T.finish("link_session")