Complete the document of the algorithm for finding payment path

[neocarmack]

this issue is the 11 bug in issue 53: #53

11. (to to) func (manager *htlcManager) getPath(msgData string) (path interface{}, err error) shoud have a document: the main flow,and how to use the returned value.

obd/tracker/service/htlc_service.go

Lines 40 to 83 in 5829315

	func (manager *htlcManager) getPath(obdClient *ObdNode, msgData string) (path interface{}, err error) {
	manager.mu.Lock()
	defer manager.mu.Unlock()
	log.Println("getPath", msgData)
	if tool.CheckIsString(&msgData) == false {
	return "", errors.New("wrong inputData")
	}
	pathRequest := &bean.HtlcPathRequest{}
	err = json.Unmarshal([]byte(msgData), pathRequest)
	if err != nil {
	return "", err
	}
	if tool.CheckIsString(&pathRequest.RealPayerPeerId) == false {
	return "", errors.New("wrong realPayerPeerId")
	}
	if tool.CheckIsString(&pathRequest.PayeePeerId) == false {
	return "", errors.New("wrong SendeePeerId")
	}
	if pathRequest.Amount < tool.GetOmniDustBtc() {
	return "", errors.New("wrong amount")
	}
	manager.createChannelNetwork(pathRequest.RealPayerPeerId, pathRequest.PayeePeerId, pathRequest.PropertyId, pathRequest.Amount, nil, true)
	resultIndex := manager.getPathIndex()
	retNode := make(map[string]interface{})
	retNode["senderPeerId"] = pathRequest.RealPayerPeerId
	retNode["h"] = pathRequest.H
	retNode["amount"] = pathRequest.Amount
	retNode["path"] = ""
	if resultIndex != -1 {
	splitArr := strings.Split(manager.openList[resultIndex].ChannelIds, ",")
	path := ""
	for i := len(splitArr) - 1; i > -1; i-- {
	path += splitArr[i] + ","
	}
	path = strings.TrimSuffix(path, ",")
	retNode["path"] = path
	}
	log.Println("return path info", retNode)
	return retNode, nil
	}

[neocarmack]

path-finding-strategies

currently implemented path finding algorithm is the greedy best-first search algorithm.

[neocarmack]

Dijkstra algorithm and A star algorithm should be implemented.