(ns Date
  "Elixir Date module — calendar date operations.

   In CljElixir: (Date/utc-today), (Date/new 2024 3 9), etc.")

(defn utc-today
  "Returns today's date in UTC.
   (Date/utc-today) ;=> ~D[2024-03-09]"
  ([])
  ([calendar]))

(defn new
  "Creates a new date.
   (Date/new 2024 3 9) ;=> {:ok ~D[2024-03-09]}"
  ([year month day])
  ([year month day calendar]))

(defn new!
  "Creates a new date. Raises on error.
   (Date/new! 2024 3 9) ;=> ~D[2024-03-09]"
  ([year month day])
  ([year month day calendar]))

(defn from-iso8601
  "Parses ISO 8601 date. Returns {:ok date} or {:error reason}.
   (Date/from-iso8601 \"2024-03-09\") ;=> {:ok ~D[2024-03-09]}"
  ([string])
  ([string calendar]))

(defn from-iso8601!
  "Parses ISO 8601. Raises on error."
  ([string])
  ([string calendar]))

(defn to-iso8601
  "Converts to ISO 8601 string.
   (Date/to-iso8601 date) ;=> \"2024-03-09\""
  ([date])
  ([date format]))

(defn to-string
  "Converts to string.
   (Date/to-string date) ;=> \"2024-03-09\""
  [date])

(defn add
  "Adds days to a date.
   (Date/add date 7) ;=> one week later
   (Date/add date 1 :month)"
  ([date days])
  ([date amount unit]))

(defn diff
  "Returns the difference in days between two dates.
   (Date/diff date1 date2) ;=> 7"
  [date1 date2])

(defn day-of-week
  "Returns the day of the week (1=Monday, 7=Sunday).
   (Date/day-of-week date) ;=> 6 (Saturday)"
  ([date])
  ([date starting-on]))

(defn day-of-year
  "Returns the day of the year (1-366).
   (Date/day-of-year date) ;=> 69"
  [date])

(defn day-of-era
  "Returns the day of the era and era number."
  [date])

(defn days-in-month
  "Returns the number of days in the month.
   (Date/days-in-month date) ;=> 31"
  [date])

(defn months-in-year
  "Returns the number of months in the year."
  [date])

(defn quarter-of-year
  "Returns the quarter (1-4).
   (Date/quarter-of-year date) ;=> 1"
  [date])

(defn year-of-era
  "Returns the year of the era."
  [date])

(defn leap-year?
  "Returns true if the date's year is a leap year.
   (Date/leap-year? date) ;=> true"
  [date])

(defn beginning-of-month
  "Returns the first day of the month.
   (Date/beginning-of-month date)"
  [date])

(defn end-of-month
  "Returns the last day of the month.
   (Date/end-of-month date)"
  [date])

(defn beginning-of-week
  "Returns the first day of the week."
  ([date])
  ([date starting-on]))

(defn end-of-week
  "Returns the last day of the week."
  ([date])
  ([date starting-on]))

(defn range
  "Creates a date range.
   (Date/range date1 date2) ;=> %Date.Range{}"
  ([first last])
  ([first last step]))

(defn compare
  "Compares two dates. Returns :lt, :eq, or :gt."
  [date1 date2])

(defn before?
  "Returns true if `date1` is before `date2`."
  [date1 date2])

(defn after?
  "Returns true if `date1` is after `date2`."
  [date1 date2])

(defn shift
  "Shifts date by a duration.
   (Date/shift date :month 1 :day -3)"
  [date duration])

(defn convert
  "Converts a date to a different calendar."
  ([date calendar]))

(defn convert!
  "Converts to a different calendar. Raises on error."
  ([date calendar]))

(defn from-erl
  "Converts Erlang date tuple to Date.
   (Date/from-erl {2024 3 9}) ;=> {:ok ~D[2024-03-09]}"
  ([tuple])
  ([tuple calendar]))

(defn from-erl!
  "Converts Erlang date tuple. Raises on error."
  ([tuple])
  ([tuple calendar]))

(defn to-erl
  "Converts Date to Erlang date tuple.
   (Date/to-erl date) ;=> {2024 3 9}"
  [date])