(ns java-time.single-field

(:require [clojure.string :as string]

[java-time.zone :as jt.z]

[java-time.format :as jt.f]

[java-time.core :as jt.c]

[java-time.util :as jt.u]

[java-time.clock :as jt.clock]

[java-time.defconversion :refer (conversion!)])

(:import [java.time.temporal TemporalAccessor TemporalAmount TemporalUnit ChronoUnit]

[java.time.format DateTimeFormatter]

[java.time Clock Year Month YearMonth MonthDay DayOfWeek ZoneId Instant]))

(defn- get-only-unit-value ^long [^TemporalAmount a, ^TemporalUnit u]

(let [non-zero-units

(->> (.getUnits a)

(map (fn [^TemporalUnit tu] (vector tu (.get a tu))))

(filter (fn [[_ uv]] (not (zero? uv)))))

[our-unit our-value] (first (filter (fn [[tu]] (= tu u)) non-zero-units))]

(when-not our-unit

(throw (java.time.temporal.UnsupportedTemporalTypeException.

(format "No unit: %s found in %s!" u a))))

(when (> (count non-zero-units) 1)

(throw (java.time.temporal.UnsupportedTemporalTypeException.

(format "Cannot use: %s, expected only %s to be non-zero!" a u))))

(long our-value)))

(defmacro enumerated-entity [tp doc & {:keys [unit]}]

(let [fname (with-meta (symbol (jt.u/dashize (str tp))) {:tag tp})

fields (symbol (str fname "-fields"))]

`(do

(def ~fields

(->> (jt.u/get-static-fields-of-type ~tp TemporalAccessor)

(vals)

(map (fn [m#] [(keyword (string/lower-case (str m#))) m#]))

(into {})))

(defn ^{:doc ~(str "True if `" tp "`.")} ~(symbol (str fname "?"))

[o#]

(instance? ~tp o#))

(conversion! ~tp Number jt.c/value)

(defn ~fname ~doc

([] (. ~tp from (jt.z/zoned-date-time)))

([v#] (cond (keyword? v#)

(v# ~fields)

(number? v#)

(. ~tp of (int v#))

(instance? TemporalAccessor v#)

(. ~tp from v#)))

([fmt# arg#]

(~fname (jt.f/parse fmt# arg#))))

(extend-type ~tp

jt.c/Ordered

(single-after? [d# o#]

(> (.getValue d#) (.getValue (~fname o#))))

(single-before? [d# o#]

(< (.getValue d#) (.getValue (~fname o#)))))

;; Enum-based entities do not implement `Temporal`, thus we don't have an easy

;; option to add/subtract a TemporalAmount.

~@(when unit

(for [[protocol proto-op op] [[`jt.c/Plusable 'seq-plus 'plus]

[`jt.c/Minusable 'seq-minus 'minus]]]

(let [typed-arg (with-meta (gensym) {:tag tp})]

`(extend-type ~tp ~protocol

(~proto-op [o# os#]

(reduce

(fn [~typed-arg v#]

(cond (number? v#)

(. ~typed-arg ~op (long v#))

(instance? TemporalAmount v#)

(. ~typed-arg ~op (get-only-unit-value v# ~unit))))

o# os#)))))))))

(defmacro single-field-entity [tp doc & {:keys [parseable?]}]

(let [fname (with-meta (symbol (jt.u/dashize (str tp))) {:tag tp})

arg (gensym)]

`(do

(defn ^{:doc ~(str "True if `" tp "`.")} ~(symbol (str fname "?"))

[o#]

(instance? ~tp o#))

(conversion! ~tp Number jt.c/value)

(defn ~fname ~doc

([] (. ~tp from (jt.z/zoned-date-time)))

([~arg] (cond (number? ~arg)

(. ~tp of (int ~arg))

(instance? TemporalAccessor ~arg)

(. ~tp from ~arg)

(instance? Clock ~arg)

(. ~tp now ~(with-meta arg {:tag `Clock}))

(instance? ZoneId ~arg)

(. ~tp now ~(with-meta arg {:tag `ZoneId}))

~@(when parseable?

`[(string? ~arg)

(try (. ~tp parse ~arg)

(catch java.time.format.DateTimeParseException _#

(. ~tp now (jt.z/zone-id ~arg))))])))

([fmt# arg#]

(~fname (jt.f/parse fmt# arg#))))

(extend-type ~tp

jt.c/Ordered

(single-after? [d# o#]

(> (.getValue d#) (.getValue (~fname o#))))

(single-before? [d# o#]

(< (.getValue d#) (.getValue (~fname o#))))))))

(defmacro two-field-entity [tp doc & {:keys [major-field-types major-field-ctor

minor-field-ctor minor-field-default]}]

(let [[major-field-ctor major-field-type] major-field-ctor

[minor-field-ctor minor-field-type] minor-field-ctor

fname (with-meta (symbol (jt.u/dashize (str tp))) {:tag tp})

arg (gensym)

tmp-major (with-meta (gensym) {:tag major-field-type})

tmp-minor (with-meta (gensym) {:tag minor-field-type})]

`(do

(defn ^{:doc ~(str "True if `" tp "`.") } ~(symbol (str fname "?"))

[o#]

(instance? ~tp o#))

(defn ~fname ~doc

([] (. ~tp from (jt.z/zoned-date-time)))

([~arg] (cond (some (fn [x#] (instance? x# ~arg)) ~major-field-types)

(let [~tmp-major (~major-field-ctor ~arg)]

(. ~tp of ~tmp-major ~minor-field-default))

(instance? TemporalAccessor ~arg)

(. ~tp from ~arg)

(instance? Clock ~arg)

(. ~tp now ~(with-meta arg {:tag `Clock}))

(instance? ZoneId ~arg)

(. ~tp now ~(with-meta arg {:tag `ZoneId}))

(string? ~arg)

(try (. ~tp parse ~arg)

(catch java.time.format.DateTimeParseException _#

(. ~tp now (jt.z/zone-id ~arg))))

:else (let [~tmp-major (~major-field-ctor ~arg)]

(. ~tp of ~tmp-major ~minor-field-default))))

([a# b#]

(if (and (or (instance? DateTimeFormatter a#) (string? a#)) (string? b#))

(~fname (jt.f/parse a# b#))

(let [~tmp-major (~major-field-ctor a#)

~tmp-minor (~minor-field-ctor b#)]

(. ~tp of ~tmp-major ~tmp-minor)))))

(extend-type ~tp

jt.c/Ordered

(single-after? [d# o#]

(.isAfter d# o#))

(single-before? [d# o#]

(.isBefore d# o#))))))

(enumerated-entity DayOfWeek

"Returns the `DayOfWeek` for the given day keyword name (e.g. `:monday`),

:unit ChronoUnit/DAYS)

(enumerated-entity Month

"Returns the `Month` for the given month keyword name (e.g. `:january`),

:unit ChronoUnit/MONTHS)

(single-field-entity Year

"Returns the `Year` for the given entity, string, clock, zone or number.

:parseable? true)

(two-field-entity MonthDay

"Returns the `MonthDay` for the given entity, string, clock, zone or

:major-field-ctor [month Month]

:major-field-types [Month Number]

:minor-field-ctor [(comp int jt.c/value) int]

:minor-field-default 1)

(two-field-entity YearMonth

"Returns the `YearMonth` for the given entity, string, clock, zone or

:major-field-ctor [(comp int jt.c/value) int]

:major-field-types [Year Number]

:minor-field-ctor [month Month]

:minor-field-default 1)

(jt.u/when-threeten-extra

(import [org.threeten.extra AmPm DayOfMonth DayOfYear Quarter YearQuarter])

(enumerated-entity AmPm

"Returns the `AmPm` for the given keyword name (`:am` or `:pm`),

ordinal or entity. Current AM/PM if no arguments given.")

(enumerated-entity Quarter

"Returns the `Quarter` for the given quarter keyword name (e.g. `:q1`),

:unit java.time.temporal.IsoFields/QUARTER_YEARS)

(single-field-entity DayOfMonth

"Returns the `DayOfMonth` for the given entity, clock, zone or day of month.

Current day of month if no arguments given.")

(single-field-entity DayOfYear

"Returns the `DayOfYear` for the given entity, clock, zone or day of year.

Current day of year if no arguments given.")

(defn ^Integer year-to-int [x]

(if (number? x) (int x)

(.getValue ^Year x)))

(two-field-entity YearQuarter

"Returns the `YearQuarter` for the given entity, clock, zone or year with quarter.

:major-field-ctor [year-to-int int]

:major-field-types [Year Number]

:minor-field-ctor [quarter Quarter]

:minor-field-default 1))