// (C) Copyright 2008-2009 SDML (www.sdml.info)
//
// Use, modification and distribution is subject to the Boost Software
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)

// Copyright Andrew Sutton 2007
//
// Use, modification and distribution are subject to the
// Boost Software License, Version 1.0. (See accompanying file
// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

#ifndef BOOST_FCA_WRITE_TABLE_HPP
#define BOOST_FCA_WRITE_TABLE_HPP

#include <iostream>
#include <sstream>
#include <iomanip>
#include <string>
#include <vector>

namespace boost {
namespace fca {

    template <typename Relation>
    void write_table(std::ostream& os, const Relation& rel)
    {
        using namespace std;
        using namespace boost;

        typedef typename Relation::context_type Context;

        typedef typename Relation::object_type Object;
        typedef typename Relation::object_set ObjectSet;
        typedef typename ObjectSet::const_iterator ObjectIterator;

        typedef typename Relation::attribute_type Attribute;
        typedef typename Relation::attribute_set AttributeSet;
        typedef typename AttributeSet::const_iterator AttributeIterator;

        typedef std::vector<std::string> StringVector;
        typedef std::vector<std::size_t> SizeVector;

        const Context& cxt = rel.context();

        // Create a vector to store the width of each column - note the
        // first column stores objects.
        StringVector onames(cxt.num_objects());
        SizeVector sizes(1, 0);

        // This is actually a fairly tedious little algorithm because we have
        // to correctly size the outputs. Start by iterative over the objects
        // in order to find the max-with'd name there.
        ObjectIterator o, o_end = cxt.objects().end();
        for(o = cxt.objects().begin(); o != o_end; ++o) {
            const Object& obj = *o;

            // Write this into a string so we can get the length of it. Note
            // that Object must be output-streamable.
            stringstream ss;
            ss << obj;
            onames.push_back(ss.str());

            // Is this the longest string?
            if(onames.back().size() > sizes[0]) {
                sizes[0] = onames.back().size();
            }
        }


        // Star the printing! First, we need to write out the headers. This
        // includes all attributes.
        os << setw(sizes[0]) << " " << "|";
        AttributeIterator a, a_end = cxt.attributes().end();
        for(a = cxt.attributes().begin(); a != a_end; ++a) {
            stringstream ss;
            ss << *a;

            // Add this the size to the array of sizes and write the header./
            string att = ss.str();
            sizes.push_back(att.size());
            os << setw(sizes.back()) << att << "|";
        }
        os << endl;

        // Write out each row in the table.
        for(o = cxt.objects().begin(); o != o_end; ++o) {
            os << setw(sizes[0]) << *o << "|";

            // Iterate over the atts for each object and write an X if the
            // attribute exists or nothing if it doesn't.
            int x = 1;
            for(a = cxt.attributes().begin(); a != a_end; ++a, ++x) {
                os << setw(sizes[x]) << (rel.test(*o, *a) ? "X" : " ") << "|";
            }
            os << endl;
       }
        os << endl;
    }

} /* namespace fca */
} /* namespace boost */

#endif