#include "switchchain.hpp"
#include "exports.hpp"
#include "graph.hpp"
#include "graph_gcm.hpp"
#include "graph_spectrum.hpp"
#include "powerlaw.hpp"
#include <algorithm>
#include <array>
#include <fstream>
#include <iostream>
#include <numeric>
#include <random>
#include <vector>

void getTriangleDegrees(const Graph& g) {
    std::vector<std::array<std::size_t,3>> trids;
    const auto& adj = g.getAdj();
    int triangles = 0;
    for (auto& v : adj) {
        for (unsigned int i = 0; i < v.size(); ++i) {
            for (unsigned int j = i + 1; j < v.size(); ++j) {
                if (g.hasEdge({v[i], v[j]})) {
                    ++triangles;
                    std::array<std::size_t, 3> ds = {{v.size(), adj[v[i]].size(),
                                                     adj[v[j]].size()}};
                    std::sort(ds.begin(), ds.end());
                    trids.push_back(ds);
                }
            }
        }
    }
    assert(triangles % 3 == 0);
    return;
}

int main(int argc, char* argv[]) {
    // Generate a random degree sequence
    std::mt19937 rng(std::random_device{}());

    // Goal:
    // Degrees follow a power-law distribution with some parameter tau
    // Expect:  #tri = const * n^{ something }
    // The goal is to find the 'something' by finding the number of triangles
    // for different values of n and tau
    float tauValues[] = {2.1f, 2.2f, 2.3f, 2.4f, 2.5f, 2.6f, 2.7f, 2.8f, 2.9f};

    Graph g;
    Graph g1;
    Graph g2;

    std::ofstream outfile;

    if (argc >= 2)
        outfile.open(argv[1]);
    else   
        outfile.open("graphdata.m");

    if (!outfile.is_open()) {
        std::cout << "ERROR: Could not open output file.\n";
        return 1;
    }

    outfile << '{';
    bool outputComma = false;

    for (int numVertices = 500; numVertices <= 500; numVertices += 1000) {
        for (float tau : tauValues) {

            DegreeSequence ds(numVertices);
            powerlaw_distribution degDist(tau, 1, numVertices);
            //std::poisson_distribution<> degDist(12);

            // For a single n,tau take samples over several instances of
            // the degree distribution.
            // 500 samples seems to give reasonable results
            for (int degreeSample = 0; degreeSample < 5; ++degreeSample) {
                // Generate a graph
                // might require multiple tries
                for (int i = 1; ; ++i) {
                    std::generate(ds.begin(), ds.end(),
                                  [&degDist, &rng] { return degDist(rng); });
                    // First make the sum even
                    unsigned int sum = std::accumulate(ds.begin(), ds.end(), 0);
                    if (sum % 2) {
                        continue;
                        // Can we do this: ??
                        ds.back()++;
                    }

                    if (g.createFromDegreeSequence(ds))
                        break;

                    // When 10 tries have not worked, output a warning
                    if (i % 10 == 0) {
                        std::cerr << "Warning: could not create graph from "
                                     "degree sequence. Trying again...\n";
                    }
                }

#if 0
                //
                // Test the GCM1 and GCM2 success rate
                //
                std::vector<int> greedyTriangles1;
                std::vector<int> greedyTriangles2;
                int successrate1 = 0;
                int successrate2 = 0;
                for (int i = 0; i < 100; ++i) {
                    Graph gtemp;
                    // Take new highest degree every time
                    if (greedyConfigurationModel(ds, gtemp, rng, false)) {
                        ++successrate1;
                        greedyTriangles1.push_back(gtemp.countTriangles());
                        g1 = gtemp;
                    }
                    // Finish all pairings of highest degree first
                    if (greedyConfigurationModel(ds, gtemp, rng, true)) {
                        ++successrate2;
                        greedyTriangles2.push_back(gtemp.countTriangles());
                        g2 = gtemp;
                    }
                }
#endif

                for (int i = 1; i < 5; ++i) {

                SwitchChain chain;
                if (!chain.initialize(g)) {
                    std::cerr << "Could not initialize Markov chain.\n";
                    return 1;
                }

                std::cout << "Running n = " << numVertices << ", tau = " << tau
                          << ". \t" << std::flush;

                //int mixingTime = (32.0f - 26.0f*(tau - 2.0f)) * numVertices; //40000;
                //constexpr int measurements = 50;
                //constexpr int measureSkip =
                //    200; // Take a sample every ... steps
                int mixingTime = 0;
                constexpr int measurements = 50000;
                constexpr int measureSkip = 1;


                int movesTotal = 0;
                int movesSuccess = 0;

                int triangles[measurements];

                for (int i = 0; i < mixingTime; ++i) {
                    ++movesTotal;
                    if (chain.doMove()) {
                        ++movesSuccess;
                    }
                }

                std::vector<int> successRates;
                successRates.reserve(measurements * measureSkip);
                int successrate = 0;
                for (int i = 0; i < measurements; ++i) {
                    for (int j = 0; j < measureSkip; ++j) {
                        ++movesTotal;
                        if (chain.doMove()) {
                            ++movesSuccess;
                            ++successrate;
                        }
                    }
                    triangles[i] = chain.g.countTriangles();

                    if ((i+1) % 100 == 0) {
                        successRates.push_back(successrate);
                        successrate = 0;
                    }
                }

                std::cout << '('
                          << 100.0f * float(movesSuccess) / float(movesTotal)
                          << "% successrate). " << std::flush;
                // std::cout << std::endl;

                if (outputComma)
                    outfile << ',' << '\n';
                outputComma = true;

                std::sort(ds.begin(), ds.end());
                outfile << '{' << '{' << numVertices << ',' << tau << '}';
                outfile << ',' << triangles;
                outfile << ',' << ds;
#if 0
                outfile << ',' << greedyTriangles1;
                outfile << ',' << greedyTriangles2;

                SwitchChain chain1, chain2;
                if (chain1.initialize(g1)) {
                    movesDone = 0;
                    SwitchChain& c = chain1;
                    for (int i = 0; i < mixingTime; ++i) {
                        if (c.doMove())
                            ++movesDone;
                    }
                    for (int i = 0; i < measurements; ++i) {
                        for (int j = 0; j < measureSkip; ++j)
                            if (c.doMove())
                                ++movesDone;
                        triangles[i] = c.g.countTriangles();
                    }

                    std::cout << movesDone << '/' << mixingTime + measurements * measureSkip
                        << " moves succeeded ("
                        << 100.0f * float(movesDone) /
                        float(mixingTime + measurements * measureSkip)
                        << "%).";

                    outfile << ',' << triangles;
                }
                if (chain2.initialize(g2)) {
                    movesDone = 0;
                    SwitchChain& c = chain2;
                    for (int i = 0; i < mixingTime; ++i) {
                        if (c.doMove())
                            ++movesDone;
                    }
                    for (int i = 0; i < measurements; ++i) {
                        for (int j = 0; j < measureSkip; ++j)
                            if (c.doMove())
                                ++movesDone;
                        triangles[i] = c.g.countTriangles();
                    }

                    std::cout << movesDone << '/' << mixingTime + measurements * measureSkip
                        << " moves succeeded ("
                        << 100.0f * float(movesDone) /
                        float(mixingTime + measurements * measureSkip)
                        << "%).";

                    outfile << ',' << triangles;
                }
#endif

                outfile << ',' << successRates;

                outfile << '}' << std::flush;

                std::cout << std::endl;
                }
            }
        }
    }
    outfile << '}';
    return 0;
}