#include "fpgaGraph.hpp"

#include <fstream>

#include <sstream>

#include <iostream>

#include <vector>

#include <queue>

#include <cstdlib>

#include <cstdint>

fpgaGraph::fpgaGraph() {

}

fpgaGraph::~fpgaGraph() {

}

void fpgaGraph::initializeFpgaGraph(std::ifstream& fpgaGraphFile) {

std::string line;

std::getline(fpgaGraphFile, line);

std::istringstream ss(line);

ss >> numNodes;

uint32_t nodeStartIdx = 0;

for (uint32_t i = 0; i < numNodes; i++) {

uint32_t nodeNeighbor;

uint32_t nodeDegree = 0;

ss.clear();

std::getline(fpgaGraphFile, line);

ss.str(line);

while (ss >> nodeNeighbor) {

fpgaNodeNeighborList.push_back(nodeNeighbor);

nodeDegree++;

}

fpgaNodeStartList.push_back(nodeStartIdx);

nodeStartIdx+=nodeDegree;

}

// Padding for the graph edge list starts so you have the last node's end index

fpgaNodeStartList.push_back(nodeStartIdx);

if (std::getline(fpgaGraphFile, line)) {

std::cout << "More nodes in file than specified nodes field" << std::endl;

std::exit(EXIT_FAILURE);

}

return;

}

// Get BFS distances from a single node to all other nodes

std::vector<uint32_t> fpgaGraph::bfs(uint32_t nodeSrc) {

std::queue<uint32_t> nodeQueue;

std::vector<uint32_t> nodeDistances(numNodes, UINT32_MAX);

// Node is zero from itself

nodeDistances[nodeSrc] = 0;

// Run BFS going through all nodes and getting their distances

nodeQueue.push(nodeSrc);

while (!nodeQueue.empty()) {

uint32_t node = nodeQueue.front();

nodeQueue.pop();

// Look at all neighbors of this node

for (uint32_t i = fpgaNodeStartList[node]; i < fpgaNodeStartList[node+1]; i++) {

uint32_t neighborNode = fpgaNodeNeighborList[i];

if (nodeDistances[neighborNode] == UINT32_MAX) {

nodeDistances[neighborNode] = nodeDistances[node] + 1;

nodeQueue.push(neighborNode);

}

}

}

return nodeDistances;

}

void fpgaGraph::calcNodeDistances() {

// Run BFS for each node

for (uint32_t i = 0; i < numNodes; i++) {

fpgaNodeDistances.push_back(bfs(i));

}

}

uint32_t fpgaGraph::getNodeDistance(uint32_t nodeSrc, uint32_t nodeDest) {

return fpgaNodeDistances[nodeSrc][nodeDest];

}

uint32_t fpgaGraph::getNumNodes() {

return numNodes;

}

fpgaGraph::fpgaGraph(std::ifstream& fpgaGraphFile) {

initializeFpgaGraph(fpgaGraphFile);

calcNodeDistances();

}