#pragma once

#include <Arduino.h>
#include <Wire.h>

namespace tbeam {

struct DateTime {
  uint16_t year = 0;
  uint8_t month = 0;
  uint8_t day = 0;
  uint8_t hour = 0;
  uint8_t minute = 0;
  uint8_t second = 0;
  uint8_t weekday = 0;
};

struct ClockConfig {
  uint8_t rtcAddress = 0x51;
  int sda = -1;
  int scl = -1;
  bool beginWire = true;
};

class TBeamClock {
 public:
  explicit TBeamClock(TwoWire& wire = Wire1);

  bool begin(const ClockConfig& config = ClockConfig{});
  void update();

  bool readRtc(DateTime& out, bool& lowVoltageFlag) const;
  bool readValidRtc(DateTime& out, int64_t* epochOut = nullptr) const;
  bool writeRtc(const DateTime& dt) const;

  bool ready() const { return ready_; }
  bool valid() const { return valid_; }
  bool lowVoltage() const { return lowVoltage_; }
  const DateTime& lastRtc() const { return lastRtc_; }
  int64_t lastEpoch() const { return lastEpoch_; }
  const char* lastError() const { return lastError_; }

  static bool isValidDateTime(const DateTime& dt);
  static int64_t toEpochSeconds(const DateTime& dt);
  static bool fromEpochSeconds(int64_t seconds, DateTime& out);
  static void formatIsoUtc(const DateTime& dt, char* out, size_t outSize);
  static void formatCompactUtc(const DateTime& dt, char* out, size_t outSize);
  static void makeRunId(const DateTime& dt, const char* boardId, char* out, size_t outSize);
  static bool parseDateTime(const char* text, DateTime& out);

 private:
  static uint8_t toBcd(uint8_t value);
  static uint8_t fromBcd(uint8_t value);
  static bool isLeapYear(uint16_t year);
  static uint8_t daysInMonth(uint16_t year, uint8_t month);
  static int64_t daysFromCivil(int year, unsigned month, unsigned day);

  void setError(const char* message) const;
  void clearError() const;

  TwoWire& wire_;
  ClockConfig config_{};
  bool ready_ = false;
  bool valid_ = false;
  bool lowVoltage_ = false;
  DateTime lastRtc_{};
  int64_t lastEpoch_ = 0;
  mutable char lastError_[128] = {};
};

}  // namespace tbeam