#include "beer_song.h"

#include <cctype>
#include <sstream>

namespace beer {

using namespace std;

string verse(int index)
{
    auto count_str = [](int count) -> string {

        if (0 == count)
            return "no more bottles ";

        if (1 == count)
            return "1 bottle ";

        ostringstream oss;
        oss << count << " bottles ";

        return oss.str();
    };

    auto capitalize_first = [](const string &str) -> string {

        string result = str;
        result.front() = toupper(result.front());
        return result;
    };

    return capitalize_first(count_str(index))
        + "of beer on the wall, "
        + count_str(index)
        + "of beer.\n"
        + (index ? string("Take ")
                    + (index == 1 ? "it" : "one")
                    + " down and pass it around, "
                 : string("Go to the store and buy some more, "))
        + count_str(index ? index - 1 : 99)
        + "of beer on the wall.\n";
}

string sing(int from_index, int to_index)
{
    string result;

    for (int i = from_index; i >= to_index; --i) {

        result += (i == from_index ? "" : "\n");
        result += verse(i);
    }

    return result;
}

}