From 1fd59e615629c46432f4825db29b8bbd2815ce86 Mon Sep 17 00:00:00 2001
From: Julian Kornberger <jk+github@digineo.de>
Date: Mon, 7 Mar 2016 02:29:31 +0100
Subject: [PATCH] Started implementing the graph

---
 main.go         |   7 ++--
 models/graph.go | 103 ++++++++++++++++++++++++++++++++++++++++++++++++
 models/nodes.go |  18 ++++-----
 3 files changed, 116 insertions(+), 12 deletions(-)
 create mode 100644 models/graph.go

diff --git a/main.go b/main.go
index 5542f31..13cc396 100644
--- a/main.go
+++ b/main.go
@@ -23,7 +23,7 @@ var (
 	wsserverForNodes *websocketserver.Server
 	respondDaemon    *respond.Daemon
 	nodes            = models.NewNodes()
-	aliases          = models.NewNodes()
+	//aliases          = models.NewNodes()
 )
 
 func main() {
@@ -35,10 +35,11 @@ func main() {
 	saveInterval := time.Second * time.Duration(config.Nodes.SaveInterval)
 
 	if config.Nodes.Enable {
-		go nodes.Saver(config.Nodes.NodesPath, saveInterval)
+		go nodes.Saver(config.Nodes.NodesPath, config.Nodes.GraphsPath, saveInterval)
 	}
 	if config.Nodes.AliasesEnable {
-		go aliases.Saver(config.Nodes.AliasesPath, saveInterval)
+		// FIXME what does this do?
+		//go aliases.Saver(config.Nodes.AliasesPath, saveInterval)
 	}
 
 	if config.Webserver.Enable {
diff --git a/models/graph.go b/models/graph.go
new file mode 100644
index 0000000..16d6f33
--- /dev/null
+++ b/models/graph.go
@@ -0,0 +1,103 @@
+package models
+
+import (
+	"fmt"
+	"strings"
+)
+
+type Graph struct {
+	Version int `json:"version"`
+	Batadv  struct {
+		Links []*GraphLink `json:"links"`
+	} `json:"batadv"`
+}
+
+type GraphLink struct {
+	Source   string  `json:"source"`
+	Target   string  `json:"target"`
+	VPN      bool    `json:"vpn"`
+	TQ       float32 `json:"tq"`
+	Bidirect bool    `json:"bidirect"`
+}
+
+type GraphBuilder struct {
+	macToID map[string]string     // mapping from MAC address to node id
+	links   map[string]*GraphLink // mapping from $idA-$idB to existing link
+}
+
+func (nodes *Nodes) BuildGraph() *Graph {
+	builder := &GraphBuilder{
+		macToID: make(map[string]string),
+		links:   make(map[string]*GraphLink),
+	}
+
+	builder.readNodes(nodes.List)
+
+	graph := &Graph{Version: 2}
+	graph.Batadv.Links = builder.Links()
+	return graph
+}
+
+func (builder *GraphBuilder) readNodes(nodes map[string]*Node) {
+	// Fill mac->id map
+	for sourceId, node := range nodes {
+		if neighbours := node.Neighbours; neighbours != nil {
+			for sourceAddress, _ := range neighbours.Batadv {
+				builder.macToID[sourceAddress] = sourceId
+			}
+		}
+	}
+
+	// Add links
+	for sourceId, node := range nodes {
+		if neighbours := node.Neighbours; neighbours != nil {
+			for _, batadvNeighbours := range neighbours.Batadv {
+				for targetAddress, link := range batadvNeighbours.Neighbours {
+					if targetId, found := builder.macToID[targetAddress]; found {
+						builder.addLink(targetId, sourceId, link.Tq)
+					}
+				}
+			}
+		}
+	}
+}
+
+func (builder *GraphBuilder) Links() []*GraphLink {
+	i := 0
+	links := make([]*GraphLink, len(builder.links))
+
+	for _, link := range builder.links {
+		links[i] = link
+		i += 1
+	}
+	return links
+}
+
+func (builder *GraphBuilder) addLink(targetId string, sourceId string, linkTq int) {
+	// Order IDs to get generate the key
+	var key string
+	if strings.Compare(sourceId, targetId) > 0 {
+		key = fmt.Sprintf("%s-%s", sourceId, targetId)
+	} else {
+		key = fmt.Sprintf("%s-%s", targetId, sourceId)
+	}
+
+	var tq float32
+	if linkTq > 0 {
+		tq = float32(1.0 / (float32(linkTq) / 255.0))
+	}
+
+	if link, ok := builder.links[key]; !ok {
+		builder.links[key] = &GraphLink{
+			Source: sourceId,
+			Target: targetId,
+			TQ:     tq,
+		}
+	} else {
+		// Use lowest of both link qualities
+		if tq < link.TQ {
+			link.TQ = tq
+		}
+		link.Bidirect = true
+	}
+}
diff --git a/models/nodes.go b/models/nodes.go
index 861e09d..8616913 100644
--- a/models/nodes.go
+++ b/models/nodes.go
@@ -62,25 +62,25 @@ func (nodes *Nodes) Get(nodeID string) *Node {
 }
 
 // Saves the cached DB to json file periodically
-func (nodes *Nodes) Saver(outputFile string, saveInterval time.Duration) {
+func (nodes *Nodes) Saver(nodesPath string, graphPath string, saveInterval time.Duration) {
 	c := time.Tick(saveInterval)
 
 	for range c {
-		nodes.save(outputFile)
+		log.Println("saving", len(nodes.List), "nodes")
+		nodes.Timestamp = time.Now()
+		nodes.Lock()
+		save(nodes, nodesPath)
+		save(nodes.BuildGraph(), graphPath)
+		nodes.Unlock()
 	}
 }
 
-func (nodes *Nodes) save(outputFile string) {
-	nodes.Timestamp = time.Now()
-
-	nodes.Lock()
-	data, err := json.Marshal(nodes)
-	nodes.Unlock()
+func save(input interface{}, outputFile string) {
+	data, err := json.Marshal(input)
 
 	if err != nil {
 		log.Panic(err)
 	}
-	log.Println("saving", len(nodes.List), "nodes")
 
 	tmpFile := outputFile + ".tmp"