#pragma once

#include <cstddef>
#include <cstdint>

namespace roro::meshtastic {

// Radio settings shared by every Meshtastic preset (firmware src/mesh/RadioInterface.h).
constexpr uint8_t kSyncWord = 0x2B;
constexpr uint16_t kPreambleLength = 16;

// The default Channel key ("AQ==", expanded): public, so the default Channel is readable by anyone.
extern const uint8_t kDefaultKey[16];

// A modem preset: bandwidth, spreading factor and coding rate (4/cr). Named as Meshtastic shows them.
struct Preset {
    const char* name;
    float bwKHz;
    uint8_t sf;
    uint8_t cr;
};

// The presets Meshtastic allows in EU_868, its order, LongFast (the default) first.
extern const Preset kEu868Presets[];
extern const size_t kEu868PresetCount;
const Preset* findPreset(const char* name);  // nullptr when EU_868 doesn't allow it

// djb2, as Meshtastic hashes a Channel's name to pick a frequency slot.
uint32_t djb2(const char* s);

// The byte in every packet header naming its Channel: the name's bytes XORed with the key's.
uint8_t channelHash(const char* name, const uint8_t* key, size_t keyLen);

// EU_868 is 869.4 to 869.65 MHz: the slot comes from the Channel's name (the preset's name for
// an unnamed Channel, which is the default).
uint32_t eu868FrequencyHz(const Preset& preset, const char* channelName = nullptr);

}  // namespace roro::meshtastic