package main

import (
	"errors"
	"fmt"
	"io"
	"sort"

	dot "github.com/kishansagathiya/go-dot"
	peer "github.com/libp2p/go-libp2p/core/peer"

	"github.com/ipfs-cluster/ipfs-cluster/api"
)

/*
   These functions are used to write an IPFS Cluster connectivity graph to a
   graphviz-style dot file.  Input an api.ConnectGraphSerial object, makeDot
   does some preprocessing and then passes all 3 link maps to a
   cluster-dotWriter which handles iterating over the link maps and writing
   dot file node and edge statements to make a dot-file graph.  Nodes are
   labeled with the go-libp2p-peer shortened peer id.  IPFS nodes are rendered
   with turquoise boundaries, Cluster nodes with orange.  Currently preprocessing
   consists of moving IPFS swarm peers not connected to any cluster peer to
   the IPFSLinks map in the event that the function was invoked with the
   allIpfs flag.  This allows all IPFS peers connected to the cluster to be
   rendered as nodes in the final graph.
*/

// nodeType specifies the type of node being represented in the dot file:
// either IPFS or Cluster
type nodeType int

const (
	tSelfCluster    nodeType = iota // cluster self node
	tCluster                        // cluster node
	tTrustedCluster                 // trusted cluster node
	tIPFS                           // IPFS node
	tIPFSMissing                    // Missing IPFS node
)

var errUnknownNodeType = errors.New("unsupported node type. Expected cluster or ipfs")

func makeDot(cg api.ConnectGraph, w io.Writer, allIpfs bool) error {
	ipfsEdges := make(map[string][]peer.ID)
	for k, v := range cg.IPFSLinks {
		ipfsEdges[k] = make([]peer.ID, 0)
		for _, id := range v {
			strPid := id.String()
			if _, ok := cg.IPFSLinks[strPid]; ok || allIpfs {
				ipfsEdges[k] = append(ipfsEdges[k], id)
			}
			if allIpfs { // include all swarm peers in the graph
				if _, ok := ipfsEdges[strPid]; !ok {
					// if id in IPFSLinks this will be overwritten
					// if id not in IPFSLinks this will stay blank
					ipfsEdges[strPid] = make([]peer.ID, 0)
				}
			}
		}
	}

	dW := dotWriter{
		w:                w,
		dotGraph:         dot.NewGraph("cluster"),
		self:             cg.ClusterID.String(),
		trustMap:         cg.ClusterTrustLinks,
		idToPeername:     cg.IDtoPeername,
		ipfsEdges:        ipfsEdges,
		clusterEdges:     cg.ClusterLinks,
		clusterIpfsEdges: cg.ClustertoIPFS,
		clusterNodes:     make(map[string]*dot.VertexDescription),
		ipfsNodes:        make(map[string]*dot.VertexDescription),
	}
	return dW.print()
}

type dotWriter struct {
	clusterNodes map[string]*dot.VertexDescription
	ipfsNodes    map[string]*dot.VertexDescription

	w        io.Writer
	dotGraph dot.Graph

	self             string
	idToPeername     map[string]string
	trustMap         map[string]bool
	ipfsEdges        map[string][]peer.ID
	clusterEdges     map[string][]peer.ID
	clusterIpfsEdges map[string]peer.ID
}

func (dW *dotWriter) addSubGraph(sGraph dot.Graph, rank string) {
	sGraph.IsSubGraph = true
	sGraph.Rank = rank
	dW.dotGraph.AddSubGraph(&sGraph)
}

// writes nodes to dot file output and creates and stores an ordering over nodes
func (dW *dotWriter) addNode(graph *dot.Graph, id string, nT nodeType) error {
	node := dot.NewVertexDescription("")
	node.Group = id
	node.ColorScheme = "x11"
	node.FontName = "Arial"
	node.Style = "filled"
	node.FontColor = "black"
	switch nT {
	case tSelfCluster:
		node.ID = fmt.Sprintf("C%d", len(dW.clusterNodes))
		node.Shape = "box3d"
		node.Label = label(dW.idToPeername[id], shorten(id))
		node.Color = "orange"
		node.Peripheries = 2
		dW.clusterNodes[id] = &node
	case tTrustedCluster:
		node.ID = fmt.Sprintf("T%d", len(dW.clusterNodes))
		node.Shape = "box3d"
		node.Label = label(dW.idToPeername[id], shorten(id))
		node.Color = "orange"
		dW.clusterNodes[id] = &node
	case tCluster:
		node.Shape = "box3d"
		node.Label = label(dW.idToPeername[id], shorten(id))
		node.ID = fmt.Sprintf("C%d", len(dW.clusterNodes))
		node.Color = "darkorange3"
		dW.clusterNodes[id] = &node
	case tIPFS:
		node.ID = fmt.Sprintf("I%d", len(dW.ipfsNodes))
		node.Shape = "cylinder"
		node.Label = label("IPFS", shorten(id))
		node.Color = "turquoise3"
		dW.ipfsNodes[id] = &node
	case tIPFSMissing:
		node.ID = fmt.Sprintf("I%d", len(dW.ipfsNodes))
		node.Shape = "cylinder"
		node.Label = label("IPFS", "Errored")
		node.Color = "firebrick1"
		dW.ipfsNodes[id] = &node
	default:
		return errUnknownNodeType
	}

	graph.AddVertex(&node)
	return nil
}

func shorten(id string) string {
	return id[:2] + "*" + id[len(id)-6:]
}

func label(peername, id string) string {
	return fmt.Sprintf("< <B> %s </B> <BR/> <B> %s </B> >", peername, id)
}

func (dW *dotWriter) print() error {
	dW.dotGraph.AddComment("The nodes of the connectivity graph")
	dW.dotGraph.AddComment("The cluster-service peers")
	// Write cluster nodes, use sorted order for consistent labels
	sGraphCluster := dot.NewGraph("")
	sGraphCluster.IsSubGraph = true
	sortedClusterEdges := sortedKeys(dW.clusterEdges)
	for _, k := range sortedClusterEdges {
		var err error
		if k == dW.self {
			err = dW.addNode(&sGraphCluster, k, tSelfCluster)
		} else if dW.trustMap[k] {
			err = dW.addNode(&sGraphCluster, k, tTrustedCluster)
		} else {
			err = dW.addNode(&sGraphCluster, k, tCluster)
		}
		if err != nil {
			return err
		}
	}
	dW.addSubGraph(sGraphCluster, "min")
	dW.dotGraph.AddNewLine()

	dW.dotGraph.AddComment("The ipfs peers")
	sGraphIPFS := dot.NewGraph("")
	sGraphIPFS.IsSubGraph = true
	// Write ipfs nodes, use sorted order for consistent labels
	for _, k := range sortedKeys(dW.ipfsEdges) {
		err := dW.addNode(&sGraphIPFS, k, tIPFS)
		if err != nil {
			return err
		}
	}

	for _, k := range sortedClusterEdges {
		if _, ok := dW.clusterIpfsEdges[k]; !ok {
			err := dW.addNode(&sGraphIPFS, k, tIPFSMissing)
			if err != nil {
				return err
			}
		}
	}

	dW.addSubGraph(sGraphIPFS, "max")
	dW.dotGraph.AddNewLine()

	dW.dotGraph.AddComment("Edges representing active connections in the cluster")
	dW.dotGraph.AddComment("The connections among cluster-service peers")
	// Write cluster edges
	for _, k := range sortedClusterEdges {
		v := dW.clusterEdges[k]
		for _, id := range v {
			toNode := dW.clusterNodes[k]
			fromNode := dW.clusterNodes[id.String()]
			dW.dotGraph.AddEdge(toNode, fromNode, true, "")
		}
	}
	dW.dotGraph.AddNewLine()

	dW.dotGraph.AddComment("The connections between cluster peers and their ipfs daemons")
	// Write cluster to ipfs edges
	for _, k := range sortedClusterEdges {
		var fromNode *dot.VertexDescription
		toNode := dW.clusterNodes[k]
		ipfsID, ok := dW.clusterIpfsEdges[k]
		if !ok {
			fromNode, ok2 := dW.ipfsNodes[k]
			if !ok2 {
				logger.Error("expected a node at this id")
				continue
			}
			dW.dotGraph.AddEdge(toNode, fromNode, true, "dotted")
			continue
		}

		fromNode, ok = dW.ipfsNodes[ipfsID.String()]
		if !ok {
			logger.Error("expected a node at this id")
			continue
		}
		dW.dotGraph.AddEdge(toNode, fromNode, true, "")
	}
	dW.dotGraph.AddNewLine()

	dW.dotGraph.AddComment("The swarm peer connections among ipfs daemons in the cluster")
	// Write ipfs edges
	for _, k := range sortedKeys(dW.ipfsEdges) {
		v := dW.ipfsEdges[k]
		toNode := dW.ipfsNodes[k]
		for _, id := range v {
			idStr := id.String()
			fromNode, ok := dW.ipfsNodes[idStr]
			if !ok {
				logger.Error("expected a node here")
				continue
			}
			dW.dotGraph.AddEdge(toNode, fromNode, true, "")
		}
	}
	return dW.dotGraph.Write(dW.w)
}

func sortedKeys(dict map[string][]peer.ID) []string {
	keys := make([]string, len(dict))
	i := 0
	for k := range dict {
		keys[i] = k
		i++
	}
	sort.Strings(keys)
	return keys
}