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

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[] = {2.5f};
    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_etmt.m");

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

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

    for (int numVertices = 100; numVertices <= 1000; numVertices += 100) {
        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 < 200; ++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";
                    }
                }

                // Multiple runs from the same degree sequence
                for (int i = 0; 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;
                    }
                }

                for (int i = 0; i < measurements; ++i) {
                    for (int j = 0; j < measureSkip; ++j) {
                        ++movesTotal;
                        if (chain.doMove()) {
                            ++movesSuccess;
                        }
                    }
                    triangles[i] = chain.g.countTriangles();
                }

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

                // Take the average over the last 20%
                auto trianglesTotal = 0uL;
                auto count = 0u;
                for (int i = measurements - (measurements / 5); i < measurements; ++i) {
                    trianglesTotal += triangles[i];
                    count++;
                }
                double trianglesAvg = double(trianglesTotal)/double(count);

                // Find the ETMT
                int ETMT = 0;
                for (int i = 0; i < measurements; ++i) {
                    if (triangles[i] < trianglesAvg) {
                        ETMT = i;
                        break;
                    }
                }

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

                std::sort(ds.begin(), ds.end());
                outfile << '{' << '{' << numVertices << ',' << tau << '}';
                outfile << ',' << ETMT;
                outfile << '}' << std::flush;

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