#include "nucleotide_count.h"

#include <stdexcept>
#include <unordered_set>


namespace dna {

using namespace std;


static const unordered_set<char> valid_nucleotides = {'A', 'T', 'C', 'G'};

static inline bool is_valid_nucleotide(char c)
{
    return valid_nucleotides.find(c) != valid_nucleotides.cend();
}

counter::counter(const string &str)
{
    for (auto c : valid_nucleotides)
        nucleotide_counts_[c] = 0;

    for (auto c : str) {

        if (!is_valid_nucleotide(c))
            throw invalid_argument("invalid sequence");

        ++nucleotide_counts_[c];
    }
}

NucleotideCounts counter::nucleotide_counts() const
{
    return nucleotide_counts_;
}

int counter::count(char c) const
{
    if (!is_valid_nucleotide(c))
        throw invalid_argument("invalid nucleotide");

    return nucleotide_counts_.at(c);
}

}