From 2fb7d43c311517c53abcef51b249c88863036d01 Mon Sep 17 00:00:00 2001
From: mkwcat <cat@mkw.re>
Date: Tue, 31 Oct 2023 10:30:28 -0400
Subject: [PATCH] Matchmaking: Basic filter handling

---
 matchmaking/filter.go | 77 +++++++++++++++++++++++++++++++++++++++++++
 matchmaking/server.go |  6 ++--
 2 files changed, 80 insertions(+), 3 deletions(-)
 create mode 100644 matchmaking/filter.go

diff --git a/matchmaking/filter.go b/matchmaking/filter.go
new file mode 100644
index 0000000..5444f39
--- /dev/null
+++ b/matchmaking/filter.go
@@ -0,0 +1,77 @@
+package matchmaking
+
+import (
+	"github.com/logrusorgru/aurora/v3"
+	"regexp"
+	"strconv"
+	"wwfc/logging"
+)
+
+// TODO: Even if we don't use it in the end, we could still implement parsing the filter string.
+// DWC makes requests in the following two formats:
+// Matching: dwc_mver = %d and dwc_pid != %u and maxplayers = %d and numplayers < %d and dwc_mtype = %d and dwc_hoststate = %u and dwc_suspend = %u and (%s)
+// ...OR
+// Self Lookup: dwc_pid = %u
+
+// Example: dwc_mver = 90 and dwc_pid != 43 and maxplayers = 11 and numplayers < 11 and dwc_mtype = 0 and dwc_hoststate = 0 and dwc_suspend = 0 and (rk = 'vs' and ev >= 4250 and ev <= 5750 and p = 0)
+
+var (
+	regexSelfLookup  = regexp.MustCompile(`^dwc_pid = (\d{1,10})$`)
+	regexMatchmaking = regexp.MustCompile(`^dwc_mver = -?(\d{1,10}) and dwc_pid != (\d{1,10}) and maxplayers = -?(\d{1,10}) and numplayers < -?(\d{1,10}) and dwc_mtype = -?(\d{1,10}) and dwc_hoststate = (\d{1,10}) and dwc_suspend = (\d{1,10}) and \((.*)\)$`)
+)
+
+func FilterServers(servers []map[string]string, queryGame string, filter string) []map[string]string {
+	if match := regexSelfLookup.FindStringSubmatch(filter); match != nil {
+		dwc_pid := match[1]
+
+		// Search for where the profile ID matches
+		for _, server := range servers {
+			if server["dwc_pid"] == dwc_pid {
+				logging.Info(ModuleName, "Self lookup from", aurora.Cyan(dwc_pid), "ok")
+				return []map[string]string{server}
+			}
+		}
+
+		logging.Error(ModuleName, "Could not find server with dwc_pid", aurora.Cyan(dwc_pid))
+		return []map[string]string{}
+	}
+
+	if match := regexMatchmaking.FindStringSubmatch(filter); match != nil {
+		dwc_mver := match[1]
+		dwc_pid := match[2]
+		maxplayers := match[3]
+		numplayers, err := strconv.ParseInt(match[4], 10, 32)
+		if err != nil {
+			logging.Error(ModuleName, "Invalid numplayers:", aurora.Cyan(match[4]), "from", aurora.Cyan(match))
+			return []map[string]string{}
+		}
+		dwc_mtype := match[5]
+		dwc_hoststate := match[6]
+		dwc_suspend := match[7]
+		// gameFilter := match[8]
+
+		filtered := []map[string]string{}
+
+		// Find servers that match the requested parameters
+		// TODO: Handle game specific filters (i.e. Regionals or MKW VR search)
+		for _, server := range servers {
+			if server["dwc_mver"] == dwc_mver && server["dwc_pid"] != dwc_pid && server["maxplayers"] == maxplayers && server["dwc_mtype"] == dwc_mtype && server["dwc_hoststate"] == dwc_hoststate && server["dwc_suspend"] == dwc_suspend {
+				server_numplayers, err := strconv.ParseInt(server["numplayers"], 10, 32)
+				if err != nil {
+					logging.Error(ModuleName, "Invalid numplayers:", aurora.Cyan(match[4]))
+					continue
+				}
+
+				if server_numplayers < numplayers {
+					filtered = append(filtered, server)
+				}
+			}
+		}
+
+		logging.Info(ModuleName, "Matched", aurora.BrightCyan(len(filtered)), "servers")
+		return filtered
+	}
+
+	logging.Error(ModuleName, "Unable to match filter for", aurora.Cyan(filter))
+	return []map[string]string{}
+}
diff --git a/matchmaking/server.go b/matchmaking/server.go
index 7f02087..fe20c34 100644
--- a/matchmaking/server.go
+++ b/matchmaking/server.go
@@ -38,9 +38,9 @@ const (
 	LimitResultCountOption  = 1 << 7 // 0x80 / 128
 )
 
-func FindServers(gueryGame string, filter string) ([]map[string]string, error) {
+func FindServers(queryGame string, filter string) ([]map[string]string, error) {
 	// TODO: Handle gueryGame, filter
-	return qr2.GetSessionServers(), nil
+	return FilterServers(qr2.GetSessionServers(), queryGame, filter), nil
 }
 
 func popString(buffer []byte, index int) (string, int) {
@@ -65,7 +65,7 @@ func handleServerListRequest(conn net.Conn, buffer []byte) {
 	fields, index := popString(buffer, index)
 	options, index := popUint32(buffer, index)
 
-	logging.Notice(ModuleName, "queryGame:", aurora.Cyan(queryGame).String(), "- gameName:", aurora.Cyan(gameName).String(), "- filter:", aurora.Cyan(filter).String(), "- fields:", aurora.Cyan(fields).String())
+	logging.Info(ModuleName, "queryGame:", aurora.Cyan(queryGame).String(), "- gameName:", aurora.Cyan(gameName).String(), "- filter:", aurora.Cyan(filter).String(), "- fields:", aurora.Cyan(fields).String())
 
 	var output []byte
 	for _, s := range strings.Split(strings.Split(conn.RemoteAddr().String(), ":")[0], ".") {