#include "storage_paths.h"

#include <cctype>

namespace roro::storage {

namespace {

// Howard Hinnant's days_from_civil.
int daysFromCivil(int y, int m, int d) {
    y -= m <= 2;
    int era = (y >= 0 ? y : y - 399) / 400;
    int yoe = y - era * 400;
    int doy = (153 * (m + (m > 2 ? -3 : 9)) + 2) / 5 + d - 1;
    int doe = yoe * 365 + yoe / 4 - yoe / 100 + doy;
    return era * 146097 + doe - 719468;
}

bool digits(const std::string& s, size_t pos, size_t n, int& out) {
    if (pos + n > s.size()) return false;
    out = 0;
    for (size_t i = pos; i < pos + n; i++) {
        if (!std::isdigit(static_cast<unsigned char>(s[i]))) return false;
        out = out * 10 + (s[i] - '0');
    }
    return true;
}

int validDay(int y, int m, int d) {
    static const int kDays[] = {31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
    if (y < 1970 || m < 1 || m > 12 || d < 1 || d > kDays[m - 1]) return -1;
    return daysFromCivil(y, m, d);
}

}  // namespace

std::string sanitize(const std::string& name) {
    std::string out;
    for (char c : name) {
        bool forbidden = c == '\\' || c == '/' || c == ':' || c == '*' || c == '?' || c == '"' || c == '<' ||
                         c == '>' || c == '|' || static_cast<unsigned char>(c) < 0x20;
        out += forbidden ? '_' : c;
    }
    if (out.empty() || out == ".") return "_";
    if (out == "..") return "_.";
    return out;
}

std::string dailyLogPath(std::initializer_list<std::string> folders, const std::string& date) {
    std::string path;
    for (auto& f : folders) path += "/" + sanitize(f);
    return path + "/" + (date.empty() ? "undated" : date) + ".log";
}

int fileDay(const std::string& name) {
    int y, m, d;
    if (digits(name, 0, 4, y) && name.size() > 10 && name[4] == '-' && digits(name, 5, 2, m) && name[7] == '-' &&
        digits(name, 8, 2, d))
        return validDay(y, m, d);
    if (digits(name, 0, 4, y) && digits(name, 4, 2, m) && digits(name, 6, 2, d) && name.size() > 8 && name[8] == '-')
        return validDay(y, m, d);
    return -1;
}

int dayFromUtc(int64_t utcSeconds) { return static_cast<int>(utcSeconds / 86400); }

}  // namespace roro::storage