//            Copyright Daniel Trebbien 2010.
// Distributed under the Boost Software License, Version 1.0.
//   (See accompanying file LICENSE_1_0.txt or the copy at
//         http://www.boost.org/LICENSE_1_0.txt)

#if defined(_MSC_VER) && !defined(_CRT_SECURE_NO_WARNINGS)
#define _CRT_SECURE_NO_WARNINGS
#endif

#include <fstream>
#include <iostream>
#include <map>
#include <vector>
#include <string>
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/connected_components.hpp>
#include <boost/graph/exception.hpp>
#include <boost/graph/graph_traits.hpp>
#include <boost/graph/read_dimacs.hpp>
#include <boost/graph/stoer_wagner_min_cut.hpp>
#include <boost/graph/property_maps/constant_property_map.hpp>
#include <boost/property_map/property_map.hpp>
#include <boost/test/unit_test.hpp>
#include <boost/tuple/tuple.hpp>

typedef boost::adjacency_list< boost::vecS, boost::vecS, boost::undirectedS,
    boost::no_property, boost::property< boost::edge_weight_t, int > >
    undirected_graph;
typedef boost::property_map< undirected_graph, boost::edge_weight_t >::type
    weight_map_type;
typedef boost::property_traits< weight_map_type >::value_type weight_type;

typedef boost::adjacency_list< boost::vecS, boost::vecS, boost::undirectedS >
    undirected_unweighted_graph;

std::string test_dir;

boost::unit_test::test_suite* init_unit_test_suite(int argc, char* argv[])
{
    if (argc != 2)
    {
        std::cerr << "Usage: " << argv[0] << " path-to-libs-graph-test"
                  << std::endl;
        throw boost::unit_test::framework::setup_error(
            "Invalid command line arguments");
    }
    test_dir = argv[1];
    return 0;
}

struct edge_t
{
    unsigned long first;
    unsigned long second;
};

// the example from Stoer & Wagner (1997)
BOOST_AUTO_TEST_CASE(test0)
{
    edge_t edges[] = { { 0, 1 }, { 1, 2 }, { 2, 3 }, { 0, 4 }, { 1, 4 },
        { 1, 5 }, { 2, 6 }, { 3, 6 }, { 3, 7 }, { 4, 5 }, { 5, 6 }, { 6, 7 } };
    weight_type ws[] = { 2, 3, 4, 3, 2, 2, 2, 2, 2, 3, 1, 3 };
    undirected_graph g(edges, edges + 12, ws, 8, 12);

    weight_map_type weights = get(boost::edge_weight, g);
    std::map< int, bool > parity;
    boost::associative_property_map< std::map< int, bool > > parities(parity);
    int w
        = boost::stoer_wagner_min_cut(g, weights, boost::parity_map(parities));
    BOOST_CHECK_EQUAL(w, 4);
    const bool parity0 = get(parities, 0);
    BOOST_CHECK_EQUAL(parity0, get(parities, 1));
    BOOST_CHECK_EQUAL(parity0, get(parities, 4));
    BOOST_CHECK_EQUAL(parity0, get(parities, 5));
    const bool parity2 = get(parities, 2);
    BOOST_CHECK_NE(parity0, parity2);
    BOOST_CHECK_EQUAL(parity2, get(parities, 3));
    BOOST_CHECK_EQUAL(parity2, get(parities, 6));
    BOOST_CHECK_EQUAL(parity2, get(parities, 7));
}

BOOST_AUTO_TEST_CASE(test1)
{
    { // if only one vertex, can't run `boost::stoer_wagner_min_cut`
        undirected_graph g;
        add_vertex(g);

        BOOST_CHECK_THROW(
            boost::stoer_wagner_min_cut(g, get(boost::edge_weight, g)),
            boost::bad_graph);
    }
    { // three vertices with one multi-edge
        typedef boost::graph_traits< undirected_graph >::vertex_descriptor
            vertex_descriptor;

        edge_t edges[] = { { 0, 1 }, { 1, 2 }, { 1, 2 }, { 2, 0 } };
        weight_type ws[] = { 3, 1, 1, 1 };
        undirected_graph g(edges, edges + 4, ws, 3, 4);

        weight_map_type weights = get(boost::edge_weight, g);
        std::map< int, bool > parity;
        boost::associative_property_map< std::map< int, bool > > parities(
            parity);
        std::map< vertex_descriptor, vertex_descriptor > assignment;
        boost::associative_property_map<
            std::map< vertex_descriptor, vertex_descriptor > >
            assignments(assignment);
        int w = boost::stoer_wagner_min_cut(g, weights,
            boost::parity_map(parities).vertex_assignment_map(assignments));
        BOOST_CHECK_EQUAL(w, 3);
        const bool parity2 = get(parities, 2), parity0 = get(parities, 0);
        BOOST_CHECK_NE(parity2, parity0);
        BOOST_CHECK_EQUAL(parity0, get(parities, 1));
    }
}

// example by Daniel Trebbien
BOOST_AUTO_TEST_CASE(test2)
{
    edge_t edges[] = { { 5, 2 }, { 0, 6 }, { 5, 6 }, { 3, 1 }, { 0, 1 },
        { 6, 3 }, { 4, 6 }, { 2, 4 }, { 5, 3 } };
    weight_type ws[] = { 1, 3, 4, 6, 4, 1, 2, 5, 2 };
    undirected_graph g(edges, edges + 9, ws, 7, 9);

    std::map< int, bool > parity;
    boost::associative_property_map< std::map< int, bool > > parities(parity);
    int w = boost::stoer_wagner_min_cut(
        g, get(boost::edge_weight, g), boost::parity_map(parities));
    BOOST_CHECK_EQUAL(w, 3);
    const bool parity2 = get(parities, 2);
    BOOST_CHECK_EQUAL(parity2, get(parities, 4));
    const bool parity5 = get(parities, 5);
    BOOST_CHECK_NE(parity2, parity5);
    BOOST_CHECK_EQUAL(parity5, get(parities, 3));
    BOOST_CHECK_EQUAL(parity5, get(parities, 6));
    BOOST_CHECK_EQUAL(parity5, get(parities, 1));
    BOOST_CHECK_EQUAL(parity5, get(parities, 0));
}

// example by Daniel Trebbien
BOOST_AUTO_TEST_CASE(test3)
{
    edge_t edges[] = { { 3, 4 }, { 3, 6 }, { 3, 5 }, { 0, 4 }, { 0, 1 },
        { 0, 6 }, { 0, 7 }, { 0, 5 }, { 0, 2 }, { 4, 1 }, { 1, 6 }, { 1, 5 },
        { 6, 7 }, { 7, 5 }, { 5, 2 }, { 3, 4 } };
    weight_type ws[] = { 0, 3, 1, 3, 1, 2, 6, 1, 8, 1, 1, 80, 2, 1, 1, 4 };
    undirected_graph g(edges, edges + 16, ws, 8, 16);

    weight_map_type weights = get(boost::edge_weight, g);
    std::map< int, bool > parity;
    boost::associative_property_map< std::map< int, bool > > parities(parity);
    int w
        = boost::stoer_wagner_min_cut(g, weights, boost::parity_map(parities));
    BOOST_CHECK_EQUAL(w, 7);
    const bool parity1 = get(parities, 1);
    BOOST_CHECK_EQUAL(parity1, get(parities, 5));
    const bool parity0 = get(parities, 0);
    BOOST_CHECK_NE(parity1, parity0);
    BOOST_CHECK_EQUAL(parity0, get(parities, 2));
    BOOST_CHECK_EQUAL(parity0, get(parities, 3));
    BOOST_CHECK_EQUAL(parity0, get(parities, 4));
    BOOST_CHECK_EQUAL(parity0, get(parities, 6));
    BOOST_CHECK_EQUAL(parity0, get(parities, 7));
}

BOOST_AUTO_TEST_CASE(test4)
{
    typedef boost::graph_traits<
        undirected_unweighted_graph >::vertex_descriptor vertex_descriptor;
    typedef boost::graph_traits< undirected_unweighted_graph >::edge_descriptor
        edge_descriptor;

    edge_t edges[] = { { 0, 1 }, { 1, 2 }, { 2, 3 }, { 0, 4 }, { 1, 4 },
        { 1, 5 }, { 2, 6 }, { 3, 6 }, { 3, 7 }, { 4, 5 }, { 5, 6 }, { 6, 7 },
        { 0, 4 }, { 6, 7 } };
    undirected_unweighted_graph g(edges, edges + 14, 8);

    std::map< vertex_descriptor, bool > parity;
    boost::associative_property_map< std::map< vertex_descriptor, bool > >
        parities(parity);
    std::map< vertex_descriptor, vertex_descriptor > assignment;
    boost::associative_property_map<
        std::map< vertex_descriptor, vertex_descriptor > >
        assignments(assignment);
    int w = boost::stoer_wagner_min_cut(g,
        boost::make_constant_property< edge_descriptor >(weight_type(1)),
        boost::vertex_assignment_map(assignments).parity_map(parities));
    BOOST_CHECK_EQUAL(w, 2);
    const bool parity0 = get(parities, 0);
    BOOST_CHECK_EQUAL(parity0, get(parities, 1));
    BOOST_CHECK_EQUAL(parity0, get(parities, 4));
    BOOST_CHECK_EQUAL(parity0, get(parities, 5));
    const bool parity2 = get(parities, 2);
    BOOST_CHECK_NE(parity0, parity2);
    BOOST_CHECK_EQUAL(parity2, get(parities, 3));
    BOOST_CHECK_EQUAL(parity2, get(parities, 6));
    BOOST_CHECK_EQUAL(parity2, get(parities, 7));
}

// The input for the `test_prgen` family of tests comes from a program, named
// `prgen`, that comes with a package of min-cut solvers by Chandra Chekuri,
// Andrew Goldberg, David Karger, Matthew Levine, and Cliff Stein. `prgen` was
// used to generate input graphs and the solvers were used to verify the return
// value of `boost::stoer_wagner_min_cut` on the input graphs.
//
// http://www.columbia.edu/~cs2035/code.html
//
// Note that it is somewhat more difficult to verify the parities because
// "`prgen` graphs" often have several min-cuts. This is why only the cut
// weight of the min-cut is verified.

// 3 min-cuts
BOOST_AUTO_TEST_CASE(test_prgen_20_70_2)
{
    typedef boost::graph_traits< undirected_graph >::vertex_descriptor
        vertex_descriptor;

    std::ifstream ifs(
        (test_dir + "/prgen_input_graphs/prgen_20_70_2.net").c_str());
    undirected_graph g;
    boost::read_dimacs_min_cut(
        g, get(boost::edge_weight, g), boost::dummy_property_map(), ifs);

    std::map< vertex_descriptor, std::size_t > component;
    boost::associative_property_map<
        std::map< vertex_descriptor, std::size_t > >
        components(component);
    BOOST_CHECK_EQUAL(boost::connected_components(g, components),
        1U); // verify the connectedness assumption

    typedef boost::shared_array_property_map< weight_type,
        boost::property_map< undirected_graph,
            boost::vertex_index_t >::const_type >
        distances_type;
    distances_type distances = boost::make_shared_array_property_map(
        num_vertices(g), weight_type(0), get(boost::vertex_index, g));
    typedef std::vector< vertex_descriptor >::size_type index_in_heap_type;
    typedef boost::shared_array_property_map< index_in_heap_type,
        boost::property_map< undirected_graph,
            boost::vertex_index_t >::const_type >
        indicesInHeap_type;
    indicesInHeap_type indicesInHeap = boost::make_shared_array_property_map(
        num_vertices(g), index_in_heap_type(-1), get(boost::vertex_index, g));
    boost::d_ary_heap_indirect< vertex_descriptor, 22, indicesInHeap_type,
        distances_type, std::greater< weight_type > >
        pq(distances, indicesInHeap);

    int w = boost::stoer_wagner_min_cut(
        g, get(boost::edge_weight, g), boost::max_priority_queue(pq));
    BOOST_CHECK_EQUAL(w, 3407);
}

// 7 min-cuts
BOOST_AUTO_TEST_CASE(test_prgen_50_40_2)
{
    typedef boost::graph_traits< undirected_graph >::vertex_descriptor
        vertex_descriptor;

    std::ifstream ifs(
        (test_dir + "/prgen_input_graphs/prgen_50_40_2.net").c_str());
    undirected_graph g;
    boost::read_dimacs_min_cut(
        g, get(boost::edge_weight, g), boost::dummy_property_map(), ifs);

    std::map< vertex_descriptor, std::size_t > component;
    boost::associative_property_map<
        std::map< vertex_descriptor, std::size_t > >
        components(component);
    BOOST_CHECK_EQUAL(boost::connected_components(g, components),
        1U); // verify the connectedness assumption

    int w = boost::stoer_wagner_min_cut(g, get(boost::edge_weight, g));
    BOOST_CHECK_EQUAL(w, 10056);
}

// 6 min-cuts
BOOST_AUTO_TEST_CASE(test_prgen_50_70_2)
{
    typedef boost::graph_traits< undirected_graph >::vertex_descriptor
        vertex_descriptor;

    std::ifstream ifs(
        (test_dir + "/prgen_input_graphs/prgen_50_70_2.net").c_str());
    undirected_graph g;
    boost::read_dimacs_min_cut(
        g, get(boost::edge_weight, g), boost::dummy_property_map(), ifs);

    std::map< vertex_descriptor, std::size_t > component;
    boost::associative_property_map<
        std::map< vertex_descriptor, std::size_t > >
        components(component);
    BOOST_CHECK_EQUAL(boost::connected_components(g, components),
        1U); // verify the connectedness assumption

    int w = boost::stoer_wagner_min_cut(g, get(boost::edge_weight, g));
    BOOST_CHECK_EQUAL(w, 21755);
}
