#pragma once

#include <stddef.h>
#include <stdint.h>

namespace dnf90_premium_clock {

constexpr size_t kNativeBodySize = 77; // success:u8, action:u16, blob74
constexpr size_t kServerHeaderSize = 16;
constexpr size_t kClockTrailerSize = 8;
constexpr size_t kPacketSize = kServerHeaderSize + kNativeBodySize + kClockTrailerSize;

inline uint32_t ReadU32(const unsigned char* bytes) {
    return uint32_t(bytes[0]) | (uint32_t(bytes[1]) << 8) |
        (uint32_t(bytes[2]) << 16) | (uint32_t(bytes[3]) << 24);
}

// Only our exact marked server16/class1/op903 action1 packet is eligible.
// The unchanged native prefix remains owned by the original handler.
inline bool Decode(const unsigned char* bytes, size_t available, int* serverUnix) {
    if (!bytes || !serverUnix || available < kPacketSize ||
        bytes[0] != 1 || bytes[1] != 0x87 || bytes[2] != 3 ||
        ReadU32(bytes + 3) != kPacketSize ||
        bytes[16] != 1 || bytes[17] != 1 || bytes[18] != 0) return false;
    const unsigned char* trailer = bytes + kServerHeaderSize + kNativeBodySize;
    if (trailer[0] != 'T' || trailer[1] != 'I' ||
        trailer[2] != 'M' || trailer[3] != 'E') return false;
    uint32_t timestamp = ReadU32(trailer + 4);
    // The native clock uses signed time32. Refuse zero, wrapped and out-of-era
    // timestamps rather than writing arbitrary values to native globals.
    if (timestamp < 946684800u || timestamp > 0x7fffffffu) return false;
    *serverUnix = static_cast<int>(timestamp);
    return true;
}

} // namespace dnf90_premium_clock