//===----------------------------------------------------------------------===//
//                         DuckDB
//
// duckdb/common/types/date.hpp
//
//
//===----------------------------------------------------------------------===//

#pragma once

#include "duckdb/common/common.hpp"
#include "duckdb/common/types.hpp"
#include "duckdb/common/winapi.hpp"
#include "duckdb/common/types/string_type.hpp"
#include "duckdb/common/limits.hpp"

#include <functional>

namespace duckdb {

struct timestamp_t; // NOLINT: primitive case

//! Type used to represent dates (days since 1970-01-01)
struct date_t { // NOLINT
	int32_t days;

	date_t() = default;
	explicit inline date_t(int32_t days_p) : days(days_p) {
	}

	// explicit conversion
	explicit inline operator int32_t() const {
		return days;
	}

	// comparison operators
	inline bool operator==(const date_t &rhs) const {
		return days == rhs.days;
	};
	inline bool operator!=(const date_t &rhs) const {
		return days != rhs.days;
	};
	inline bool operator<=(const date_t &rhs) const {
		return days <= rhs.days;
	};
	inline bool operator<(const date_t &rhs) const {
		return days < rhs.days;
	};
	inline bool operator>(const date_t &rhs) const {
		return days > rhs.days;
	};
	inline bool operator>=(const date_t &rhs) const {
		return days >= rhs.days;
	};

	// arithmetic operators
	inline date_t operator+(const int32_t &days) const {
		return date_t(this->days + days);
	};
	inline date_t operator-(const int32_t &days) const {
		return date_t(this->days - days);
	};

	// in-place operators
	inline date_t &operator+=(const int32_t &days) {
		this->days += days;
		return *this;
	};
	inline date_t &operator-=(const int32_t &days) {
		this->days -= days;
		return *this;
	};

	// special values
	static inline date_t infinity() { // NOLINT
		return date_t(NumericLimits<int32_t>::Maximum());
	}                                  // NOLINT
	static inline date_t ninfinity() { // NOLINT
		return date_t(-NumericLimits<int32_t>::Maximum());
	}                              // NOLINT
	static inline date_t epoch() { // NOLINT
		return date_t(0);
	} // NOLINT
};

//! The Date class is a static class that holds helper functions for the Date type.
class Date {
public:
	static const char *PINF;  // NOLINT
	static const char *NINF;  // NOLINT
	static const char *EPOCH; // NOLINT

	static const string_t MONTH_NAMES[12];
	static const string_t MONTH_NAMES_ABBREVIATED[12];
	static const string_t DAY_NAMES[7];
	static const string_t DAY_NAMES_ABBREVIATED[7];
	static const int32_t NORMAL_DAYS[13];
	static const int32_t CUMULATIVE_DAYS[13];
	static const int32_t LEAP_DAYS[13];
	static const int32_t CUMULATIVE_LEAP_DAYS[13];
	static const int32_t CUMULATIVE_YEAR_DAYS[401];
	static const int8_t MONTH_PER_DAY_OF_YEAR[365];
	static const int8_t LEAP_MONTH_PER_DAY_OF_YEAR[366];

	// min date is 5877642-06-25 (BC) (-2^31+2)
	constexpr static const int32_t DATE_MIN_YEAR = -5877641;
	constexpr static const int32_t DATE_MIN_MONTH = 6;
	constexpr static const int32_t DATE_MIN_DAY = 25;
	// max date is 5881580-07-10 (2^31-2)
	constexpr static const int32_t DATE_MAX_YEAR = 5881580;
	constexpr static const int32_t DATE_MAX_MONTH = 7;
	constexpr static const int32_t DATE_MAX_DAY = 10;
	constexpr static const int32_t EPOCH_YEAR = 1970;

	constexpr static const int32_t YEAR_INTERVAL = 400;
	constexpr static const int32_t DAYS_PER_YEAR_INTERVAL = 146097;

public:
	//! Convert a string in the format "YYYY-MM-DD" to a date object
	DUCKDB_API static date_t FromString(const string &str, bool strict = false);
	//! Convert a string in the format "YYYY-MM-DD" to a date object
	DUCKDB_API static date_t FromCString(const char *str, idx_t len, bool strict = false);
	//! Convert a date object to a string in the format "YYYY-MM-DD"
	DUCKDB_API static string ToString(date_t date);
	//! Try to convert the string as a give "special" date (e.g, PINF, ...)
	//! Returns true if it was successful and updates the scan pos.
	DUCKDB_API static bool TryConvertDateSpecial(const char *buf, idx_t len, idx_t &pos, const char *special);
	//! Try to convert text in a buffer to a date; returns true if parsing was successful
	//! If the date was a "special" value, the special flag will be set.
	DUCKDB_API static bool TryConvertDate(const char *buf, idx_t len, idx_t &pos, date_t &result, bool &special,
	                                      bool strict = false);

	//! Create a string "YYYY-MM-DD" from a specified (year, month, day)
	//! combination
	DUCKDB_API static string Format(int32_t year, int32_t month, int32_t day);

	//! Extract the year, month and day from a given date object
	DUCKDB_API static void Convert(date_t date, int32_t &out_year, int32_t &out_month, int32_t &out_day);
	//! Create a Date object from a specified (year, month, day) combination
	DUCKDB_API static date_t FromDate(int32_t year, int32_t month, int32_t day);
	DUCKDB_API static bool TryFromDate(int32_t year, int32_t month, int32_t day, date_t &result);

	//! Returns true if (year) is a leap year, and false otherwise
	DUCKDB_API static bool IsLeapYear(int32_t year);

	//! Returns true if the specified (year, month, day) combination is a valid
	//! date
	DUCKDB_API static bool IsValid(int32_t year, int32_t month, int32_t day);

	//! Returns true if the specified date is finite
	static inline bool IsFinite(date_t date) {
		return date != date_t::infinity() && date != date_t::ninfinity();
	}

	//! The max number of days in a month of a given year
	DUCKDB_API static int32_t MonthDays(int32_t year, int32_t month);

	//! Extract the epoch from the date (seconds since 1970-01-01)
	DUCKDB_API static int64_t Epoch(date_t date);
	//! Extract the epoch from the date (nanoseconds since 1970-01-01)
	DUCKDB_API static int64_t EpochNanoseconds(date_t date);
	//! Extract the epoch from the date (microseconds since 1970-01-01)
	DUCKDB_API static int64_t EpochMicroseconds(date_t date);
	//! Extract the epoch from the date (milliseconds since 1970-01-01)
	DUCKDB_API static int64_t EpochMilliseconds(date_t date);
	//! Convert the epoch (seconds since 1970-01-01) to a date_t
	DUCKDB_API static date_t EpochToDate(int64_t epoch);

	//! Extract the number of days since epoch (days since 1970-01-01)
	DUCKDB_API static int32_t EpochDays(date_t date);
	//! Convert the epoch number of days to a date_t
	DUCKDB_API static date_t EpochDaysToDate(int32_t epoch);

	//! Extract year of a date entry
	DUCKDB_API static int32_t ExtractYear(date_t date);
	//! Extract month of a date entry
	DUCKDB_API static int32_t ExtractMonth(date_t date);
	//! Extract day of a date entry
	DUCKDB_API static int32_t ExtractDay(date_t date);
	//! Extract the day of the week (1-7)
	DUCKDB_API static int32_t ExtractISODayOfTheWeek(date_t date);
	//! Extract the day of the year
	DUCKDB_API static int32_t ExtractDayOfTheYear(date_t date);
	//! Extract the day of the year
	DUCKDB_API static int64_t ExtractJulianDay(date_t date);
	//! Extract the ISO week number
	//! ISO weeks start on Monday and the first week of a year
	//! contains January 4 of that year.
	//! In the ISO week-numbering system, it is possible for early-January dates
	//! to be part of the 52nd or 53rd week of the previous year.
	DUCKDB_API static void ExtractISOYearWeek(date_t date, int32_t &year, int32_t &week);
	DUCKDB_API static int32_t ExtractISOWeekNumber(date_t date);
	DUCKDB_API static int32_t ExtractISOYearNumber(date_t date);
	//! Extract the week number as Python handles it.
	//! Either Monday or Sunday is the first day of the week,
	//! and any date before the first Monday/Sunday returns week 0
	//! This is a bit more consistent because week numbers in a year are always incrementing
	DUCKDB_API static int32_t ExtractWeekNumberRegular(date_t date, bool monday_first = true);
	//! Returns the date of the monday of the current week.
	DUCKDB_API static date_t GetMondayOfCurrentWeek(date_t date);

	//! Helper function to parse two digits from a string (e.g. "30" -> 30, "03" -> 3, "3" -> 3)
	DUCKDB_API static bool ParseDoubleDigit(const char *buf, idx_t len, idx_t &pos, int32_t &result);

	DUCKDB_API static string ConversionError(const string &str);
	DUCKDB_API static string ConversionError(string_t str);

private:
	static void ExtractYearOffset(int32_t &n, int32_t &year, int32_t &year_offset);
};

} // namespace duckdb

namespace std {

//! Date
template <>
struct hash<duckdb::date_t> {
	std::size_t operator()(const duckdb::date_t &k) const {
		using std::hash;
		return hash<int32_t>()((int32_t)k);
	}
};
} // namespace std
