;; lib/events/tests/ical.sx — iCalendar (RFC 5545) export.

(define ev-ic-pass 0)
(define ev-ic-fail 0)
(define ev-ic-failures (list))

(define
  ev-ic-check!
  (fn
    (name got expected)
    (if
      (= got expected)
      (set! ev-ic-pass (+ ev-ic-pass 1))
      (do
        (set! ev-ic-fail (+ ev-ic-fail 1))
        (append!
          ev-ic-failures
          (str name "\n    expected: " expected "\n    got:      " got))))))

;; Find the value of a "KEY:value" line in a VEVENT line list (or nil).
(define
  ev-ic-line
  (fn
    (lines key)
    (cond
      ((empty? lines) nil)
      ((ev-ic-prefix? (first lines) (str key ":")) (first lines))
      (else (ev-ic-line (rest lines) key)))))

(define
  ev-ic-prefix?
  (fn
    (s p)
    (and (>= (len s) (len p)) (= (substring s 0 (len p)) p))))

(define
  ev-ic-run-all!
  (fn
    ()
    (do
      (let
        ((lines (ev/event->ical-lines (ev-event (quote one) (ev-dt 2026 6 10 14 0) 60 nil 1))))
        (do
          (ev-ic-check! "VEVENT opens" (first lines) "BEGIN:VEVENT")
          (ev-ic-check! "VEVENT closes" (ev-ic-line lines "END") "END:VEVENT")
          (ev-ic-check!
            "UID is the event id"
            (ev-ic-line lines "UID")
            "UID:one")
          (ev-ic-check!
            "DTSTART is a UTC basic-format stamp"
            (ev-ic-line lines "DTSTART")
            "DTSTART:20260610T140000Z")
          (ev-ic-check!
            "DURATION of 60m is PT1H"
            (ev-ic-line lines "DURATION")
            "DURATION:PT1H")
          (ev-ic-check!
            "a one-off event has no RRULE"
            (ev-ic-line lines "RRULE")
            nil)))
      (ev-ic-check!
        "30m duration is PT30M"
        (ev-ic-line
          (ev/event->ical-lines
            (ev-event
              (quote e)
              (ev-dt 2026 1 1 9 0)
              30
              nil
              1))
          "DURATION")
        "DURATION:PT30M")
      (ev-ic-check!
        "90m duration is PT1H30M"
        (ev-ic-line
          (ev/event->ical-lines
            (ev-event
              (quote e)
              (ev-dt 2026 1 1 9 0)
              90
              nil
              1))
          "DURATION")
        "DURATION:PT1H30M")
      (let
        ((lines (ev/event->ical-lines (ev-event-full (quote yoga) (ev-dt 2026 6 1 18 0) 90 {:interval 2 :freq :weekly :until (ev-dt 2026 6 30 23 0) :byday (list 0 2)} 20 (list (ev-dt 2026 6 8 18 0)) (list (ev-dt 2026 6 20 18 0))))))
        (do
          (ev-ic-check!
            "weekly RRULE serializes interval/until/byday in order"
            (ev-ic-line lines "RRULE")
            "RRULE:FREQ=WEEKLY;INTERVAL=2;UNTIL=20260630T230000Z;BYDAY=MO,WE")
          (ev-ic-check!
            "EXDATE line"
            (ev-ic-line lines "EXDATE")
            "EXDATE:20260608T180000Z")
          (ev-ic-check!
            "RDATE line"
            (ev-ic-line lines "RDATE")
            "RDATE:20260620T180000Z")))
      (ev-ic-check!
        "daily COUNT RRULE"
        (ev-ic-line
          (ev/event->ical-lines
            (ev-event
              (quote d)
              (ev-dt 2026 6 1 9 0)
              30
              {:freq :daily :count 5}
              1))
          "RRULE")
        "RRULE:FREQ=DAILY;COUNT=5")
      (ev-ic-check!
        "monthly nth-weekday BYDAY (2nd Tuesday)"
        (ev-ic-line
          (ev/event->ical-lines
            (ev-event
              (quote b)
              (ev-dt 2026 1 13 9 0)
              60
              {:freq :monthly :byday (list {:ord 2 :wd 1})}
              5))
          "RRULE")
        "RRULE:FREQ=MONTHLY;BYDAY=2TU")
      (ev-ic-check!
        "monthly last-Friday BYDAY"
        (ev-ic-line
          (ev/event->ical-lines
            (ev-event
              (quote b)
              (ev-dt 2026 1 30 9 0)
              60
              {:freq :monthly :byday (list {:ord -1 :wd 4})}
              5))
          "RRULE")
        "RRULE:FREQ=MONTHLY;BYDAY=-1FR")
      (ev-ic-check!
        "monthly BYMONTHDAY (incl. negative)"
        (ev-ic-line
          (ev/event->ical-lines
            (ev-event
              (quote b)
              (ev-dt 2026 1 15 9 0)
              60
              {:bymonthday (list 15 -1) :freq :monthly}
              5))
          "RRULE")
        "RRULE:FREQ=MONTHLY;BYMONTHDAY=15,-1")
      (ev-ic-check!
        "all seven weekday tokens map correctly"
        (ev-ic-line
          (ev/event->ical-lines
            (ev-event
              (quote w)
              (ev-dt 2026 6 1 9 0)
              30
              {:freq :weekly :byday (list 0 1 2 3 4 5 6)}
              1))
          "RRULE")
        "RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR,SA,SU")
      (let
        ((cal (ev/events->ical-lines (list (ev-event (quote a) (ev-dt 2026 6 1 9 0) 30 nil 1) (ev-event (quote b) (ev-dt 2026 6 2 9 0) 30 nil 1)))))
        (do
          (ev-ic-check! "VCALENDAR opens" (first cal) "BEGIN:VCALENDAR")
          (ev-ic-check!
            "VCALENDAR declares VERSION"
            (ev-ic-line cal "VERSION")
            "VERSION:2.0")
          (ev-ic-check!
            "two events -> two VEVENT blocks"
            (len (filter (fn (l) (= l "BEGIN:VEVENT")) cal))
            2)
          (ev-ic-check!
            "VCALENDAR has exactly one closing line"
            (len (filter (fn (l) (= l "END:VCALENDAR")) cal))
            1)))
      (ev-ic-check!
        "render joins lines with CRLF"
        (ev/ical-render
          (list "BEGIN:VCALENDAR" "VERSION:2.0" "END:VCALENDAR"))
        "BEGIN:VCALENDAR\r\nVERSION:2.0\r\nEND:VCALENDAR"))))

;; ---- import + round-trip ----

;; The occurrence starts an event expands to over a fixed window.
(define
  ev-ic-starts
  (fn
    (ev)
    (map (fn (o) (get o :start)) (ev-expand ev (ev-date 2026 1 1) (ev-date 2027 1 1)))))

;; Round-trip an event through export then import; true if both expand alike.
(define
  ev-ic-roundtrips?
  (fn
    (ev)
    (= (ev-ic-starts ev) (ev-ic-starts (ev/ical-lines->event (ev/event->ical-lines ev))))))

(define
  ev-ic-rt-run-all!
  (fn
    ()
    (do
      ;; ---- field parsers ----
      (ev-ic-check! "parse DTSTART" (ev-ical-parse-dt "20260601T180000Z") (ev-dt 2026 6 1 18 0))
      (ev-ic-check! "parse DURATION PT1H30M" (ev-ical-parse-duration "PT1H30M") 90)
      (ev-ic-check! "parse DURATION PT1H" (ev-ical-parse-duration "PT1H") 60)
      (ev-ic-check! "parse DURATION PT30M" (ev-ical-parse-duration "PT30M") 30)
      (ev-ic-check! "parse plain BYDAY token" (ev-ical-parse-byday-token "MO") 0)
      (ev-ic-check! "parse ordinal BYDAY token" (ev-ical-parse-byday-token "2TU") {:ord 2 :wd 1})
      (ev-ic-check! "parse last-weekday BYDAY token" (ev-ical-parse-byday-token "-1FR") {:ord -1 :wd 4})

      ;; ---- imported event basic fields ----
      (let
        ((ev (ev/ical-lines->event (ev/event->ical-lines (ev-event (quote yoga) (ev-dt 2026 6 1 18 0) 90 nil 1)))))
        (do
          (ev-ic-check! "imported id is a symbol" (get ev :id) (quote yoga))
          (ev-ic-check! "imported dtstart" (get ev :dtstart) (ev-dt 2026 6 1 18 0))
          (ev-ic-check! "imported duration" (get ev :duration) 90)))

      ;; ---- round-trips preserve the occurrence set ----
      (ev-ic-check!
        "round-trip: one-off event"
        (ev-ic-roundtrips? (ev-event (quote a) (ev-dt 2026 6 10 14 0) 60 nil 1))
        true)
      (ev-ic-check!
        "round-trip: daily COUNT"
        (ev-ic-roundtrips? (ev-event (quote a) (ev-dt 2026 6 1 9 0) 30 {:freq :daily :count 5} 1))
        true)
      (ev-ic-check!
        "round-trip: weekly interval/until/byday + exdate + rdate"
        (ev-ic-roundtrips?
          (ev-event-full
            (quote a)
            (ev-dt 2026 6 1 18 0)
            90
            {:freq :weekly :interval 2 :byday (list 0 2) :until (ev-dt 2026 6 30 23 0)}
            20
            (list (ev-dt 2026 6 8 18 0))
            (list (ev-dt 2026 6 20 18 0))))
        true)
      (ev-ic-check!
        "round-trip: monthly nth-weekday"
        (ev-ic-roundtrips? (ev-event (quote a) (ev-dt 2026 1 13 9 0) 60 {:freq :monthly :byday (list {:ord 2 :wd 1})} 1))
        true)
      (ev-ic-check!
        "round-trip: monthly bymonthday"
        (ev-ic-roundtrips? (ev-event (quote a) (ev-dt 2026 1 15 9 0) 60 {:freq :monthly :bymonthday (list 15 -1)} 1))
        true)

      ;; ---- parse a VCALENDAR with several events ----
      (let
        ((cal
           (ev/events->ical-lines
             (list
               (ev-event (quote a) (ev-dt 2026 6 1 9 0) 30 {:freq :daily :count 3} 1)
               (ev-event (quote b) (ev-dt 2026 6 2 10 0) 60 nil 1)))))
        (let
          ((events (ev/parse-vcalendar cal)))
          (do
            (ev-ic-check! "VCALENDAR parses both events" (len events) 2)
            (ev-ic-check! "first event id" (get (first events) :id) (quote a))
            (ev-ic-check! "second event id" (get (first (rest events)) :id) (quote b))
            (ev-ic-check!
              "parsed events expand correctly"
              (ev-ic-starts (first events))
              (ev-ic-starts (ev-event (quote a) (ev-dt 2026 6 1 9 0) 30 {:freq :daily :count 3} 1)))))))))

;; ---- timezone-aware export (TZID + VTIMEZONE) ----
(define
  ev-ic-find
  (fn
    (lines pfx)
    (cond
      ((empty? lines) nil)
      ((ev-ic-prefix? (first lines) pfx) (first lines))
      (else (ev-ic-find (rest lines) pfx)))))

(define ev-ic-count (fn (lines x) (len (filter (fn (l) (= l x)) lines))))

(define
  ev-ic-index
  (fn
    (lines x)
    (cond
      ((empty? lines) -1)
      ((= (first lines) x) 0)
      (else
        (let ((r (ev-ic-index (rest lines) x))) (if (< r 0) -1 (+ 1 r)))))))

(define
  ev-ic-tz-run-all!
  (fn
    ()
    (do
      ;; a tz event's DTSTART is local wall-clock with a TZID parameter
      (ev-ic-check!
        "tz event DTSTART uses TZID + local wall-clock (not UTC)"
        (ev-ic-find (ev/event->ical-lines (ev-event-tz (quote w) (ev-dt 2026 7 15 18 0) 60 nil 1 ev-tz-london)) "DTSTART")
        "DTSTART;TZID=Europe/London:20260715T180000")
      (ev-ic-check!
        "a non-tz event still uses a UTC Z stamp"
        (ev-ic-find (ev/event->ical-lines (ev-event (quote n) (ev-dt 2026 7 15 18 0) 60 nil 1)) "DTSTART")
        "DTSTART:20260715T180000Z")
      ;; UNTIL stays UTC even for a TZID event (RFC 5545)
      (ev-ic-check!
        "tz event RRULE UNTIL is still UTC"
        (ev-ic-find
          (ev/event->ical-lines
            (ev-event-tz (quote s) (ev-dt 2026 6 1 18 0) 60 {:freq :weekly :byday (list 0) :until (ev-dt 2026 6 30 23 0)} 1 ev-tz-london))
          "RRULE")
        "RRULE:FREQ=WEEKLY;UNTIL=20260630T220000Z;BYDAY=MO")
      ;; EXDATE matches the DTSTART form (TZID + local)
      (ev-ic-check!
        "tz event EXDATE uses TZID + local"
        (ev-ic-find
          (ev/event->ical-lines
            (assoc
              (ev-event-tz (quote s) (ev-dt 2026 7 1 18 0) 60 {:freq :daily :count 3} 1 ev-tz-london)
              :exdate
              (list (ev-dt 2026 7 2 18 0))))
          "EXDATE")
        "EXDATE;TZID=Europe/London:20260702T180000")

      ;; ---- VTIMEZONE block ----
      (let
        ((vtz (ev-ical-vtimezone ev-tz-london)))
        (do
          (ev-ic-check! "VTIMEZONE names the zone" (ev-ic-find vtz "TZID") "TZID:Europe/London")
          (ev-ic-check! "DAYLIGHT transitions GMT->BST" (ev-ic-find vtz "TZOFFSETTO:+0100") "TZOFFSETTO:+0100")
          (ev-ic-check! "DAYLIGHT rule is last Sunday of March" (ev-ic-find vtz "RRULE:FREQ=YEARLY;BYMONTH=3") "RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=-1SU")
          (ev-ic-check! "STANDARD rule is last Sunday of October" (ev-ic-find vtz "RRULE:FREQ=YEARLY;BYMONTH=10") "RRULE:FREQ=YEARLY;BYMONTH=10;BYDAY=-1SU")))
      (let
        ((vtz (ev-ical-vtimezone ev-tz-paris)))
        (do
          (ev-ic-check! "Paris DAYLIGHT goes to +0200 (CEST)" (ev-ic-find vtz "TZOFFSETTO:+0200") "TZOFFSETTO:+0200")
          (ev-ic-check! "Paris STANDARD goes to +0100 (CET)" (ev-ic-find vtz "TZOFFSETTO:+0100") "TZOFFSETTO:+0100")))
      ;; southern hemisphere exports a valid VTIMEZONE too: reversed offsets,
      ;; first-Sunday rules, and the -480 rule time folds back to local 02:00/03:00
      (let
        ((vtz (ev-ical-vtimezone ev-tz-sydney)))
        (do
          (ev-ic-check! "Sydney VTIMEZONE names the zone" (ev-ic-find vtz "TZID") "TZID:Australia/Sydney")
          (ev-ic-check! "Sydney DAYLIGHT goes to +1100 (AEDT)" (ev-ic-find vtz "TZOFFSETTO:+1100") "TZOFFSETTO:+1100")
          (ev-ic-check! "Sydney STANDARD goes to +1000 (AEST)" (ev-ic-find vtz "TZOFFSETTO:+1000") "TZOFFSETTO:+1000")
          (ev-ic-check! "Sydney DAYLIGHT rule is first Sunday of October" (ev-ic-find vtz "RRULE:FREQ=YEARLY;BYMONTH=10") "RRULE:FREQ=YEARLY;BYMONTH=10;BYDAY=1SU")
          (ev-ic-check! "Sydney STANDARD rule is first Sunday of April" (ev-ic-find vtz "RRULE:FREQ=YEARLY;BYMONTH=4") "RRULE:FREQ=YEARLY;BYMONTH=4;BYDAY=1SU")
          (ev-ic-check! "Sydney DAYLIGHT begins 02:00 local (AEST std, -480 folded)" (ev-ic-find vtz "DTSTART") "DTSTART:19701004T020000")))

      ;; ---- VCALENDAR carries one VTIMEZONE per distinct zone ----
      (let
        ((cal (ev/events->ical-lines (list (ev-event-tz (quote a) (ev-dt 2026 6 1 9 0) 60 nil 1 ev-tz-london)))))
        (do
          (ev-ic-check! "VCALENDAR includes the referenced VTIMEZONE" (ev-ic-count cal "BEGIN:VTIMEZONE") 1)
          (ev-ic-check! "VTIMEZONE precedes the VEVENT" (< (ev-ic-index cal "BEGIN:VTIMEZONE") (ev-ic-index cal "BEGIN:VEVENT")) true)))
      (ev-ic-check!
        "two events in the same zone share one VTIMEZONE"
        (ev-ic-count
          (ev/events->ical-lines
            (list
              (ev-event-tz (quote a) (ev-dt 2026 6 1 9 0) 60 nil 1 ev-tz-london)
              (ev-event-tz (quote b) (ev-dt 2026 6 2 9 0) 60 nil 1 ev-tz-london)))
          "BEGIN:VTIMEZONE")
        1)
      (ev-ic-check!
        "events in two zones get two VTIMEZONEs"
        (ev-ic-count
          (ev/events->ical-lines
            (list
              (ev-event-tz (quote a) (ev-dt 2026 6 1 9 0) 60 nil 1 ev-tz-london)
              (ev-event-tz (quote b) (ev-dt 2026 6 2 9 0) 60 nil 1 ev-tz-paris)))
          "BEGIN:VTIMEZONE")
        2)
      (ev-ic-check!
        "a non-tz-only calendar has no VTIMEZONE"
        (ev-ic-count (ev/events->ical-lines (list (ev-event (quote a) (ev-dt 2026 6 1 9 0) 60 nil 1))) "BEGIN:VTIMEZONE")
        0)

      ;; ---- import tolerates the TZID parameter ----
      (ev-ic-check!
        "import parses DTSTART;TZID local time"
        (get
          (ev/ical-lines->event (ev/event->ical-lines (ev-event-tz (quote a) (ev-dt 2026 7 15 18 0) 60 nil 1 ev-tz-london)))
          :dtstart)
        (ev-dt 2026 7 15 18 0))
      (ev-ic-check!
        "import parses a southern-zone DTSTART;TZID local time"
        (get
          (ev/ical-lines->event (ev/event->ical-lines (ev-event-tz (quote a) (ev-dt 2026 1 15 18 0) 60 nil 1 ev-tz-sydney)))
          :dtstart)
        (ev-dt 2026 1 15 18 0)))))

(define
  ev-ical-tests-run!
  (fn
    ()
    (do
      (set! ev-ic-pass 0)
      (set! ev-ic-fail 0)
      (set! ev-ic-failures (list))
      (ev-ic-run-all!)
      (ev-ic-rt-run-all!)
      (ev-ic-tz-run-all!)
      {:failures ev-ic-failures :total (+ ev-ic-pass ev-ic-fail) :passed ev-ic-pass :failed ev-ic-fail})))