#pragma once
#include "vde/core/point.h"
#include <string>
#include <sstream>
#include <iomanip>
#include <cmath>
#include <cstdio>

namespace vde::foundation {

/// Format double with adequate precision for CAD (12 significant digits)
inline std::string fmt_double(double v, int precision = 12) {
    if (std::isnan(v)) return "0.0";
    if (std::isinf(v)) return v > 0 ? "1e30" : "-1e30";
    std::ostringstream ss;
    ss << std::setprecision(precision) << std::scientific << v;
    std::string s = ss.str();
    // Ensure always has exponent sign (e.g., "1.0e+00" not "1.0e00")
    auto epos = s.find('e');
    if (epos != std::string::npos) {
        if (epos + 1 < s.size() && s[epos + 1] != '-' && s[epos + 1] != '+') {
            s.insert(epos + 1, "+");
        }
    }
    return s;
}

/// Format for IGES: uses D exponent
inline std::string fmt_iges_real(double v, int /*precision*/ = 12) {
    auto s = fmt_double(v, 12);
    auto pos = s.find('e');
    if (pos != std::string::npos) s[pos] = 'D';
    return s;
}

/// Format a Point3D as comma-separated reals
inline std::string fmt_point(const core::Point3D& p, bool use_d = false) {
    using FmtFn = std::string (*)(double, int);
    FmtFn fn = use_d ? static_cast<FmtFn>(fmt_iges_real) : fmt_double;
    return fn(p.x(), 12) + "," + fn(p.y(), 12) + "," + fn(p.z(), 12);
}

/// Pad a string to exactly 72 characters with spaces
inline std::string pad72(const std::string& s) {
    std::string result = s;
    if (result.size() > 72) result.resize(72);
    result.resize(72, ' ');
    return result;
}

/// Format an IGES section line: data + section marker (80 columns total)
inline std::string format_iges_line(const std::string& data, char section_char, int seq) {
    std::string line = pad72(data);
    char seq_buf[9];
    std::snprintf(seq_buf, sizeof(seq_buf), "%c%07d", section_char, seq);
    line += std::string(seq_buf);
    return line + "\n";
}

} // namespace vde::foundation