(require-library lazy-lists)
(import lazy-lists)

;;; (run xpr0 xpr1 ...)
;;; -------------------
(define (run . xprs)
  (let loop ((xprs xprs))
    (if (null? xprs)
      (print "All tests passed!")
      (if (car xprs)
        (loop (cdr xprs))
        (error 'run "#### Some test failed! ####")))))

(define (cons-right var lst)
  (if (null? lst)
    (cons var lst)
    (cons (car lst) (cons-right var (cdr lst)))))

(define (Within eps seq)
  (let loop ((seq seq))
    (let ((a (Ref 0 seq)) (b (Ref 1 seq)))
      (if (< (abs (- a b)) eps)
        b
        (loop (Rest seq))))))

(define (Relative eps seq)
  (let loop ((seq seq))
    (let ((a (Ref 0 seq)) (b (Ref 1 seq)))
      (if (<= (abs (/ a b)) (* (abs b) eps))
        b
        (loop (Rest seq))))))

(define (Newton x) ; fixed point for square root
  (lambda (a) (/ (+ a (/ x a)) 2))) 

(define (Sums seq) ; List of sums
  (letrec ((sums (Cons 0 (Map + seq (Lazy (Length seq) sums)))))
    (Rest sums)))

(define (First-five) (List 0 1 2 3 4))
(define (Fibs)
  (Append (List 0 1) (Lazy #f (Map + (Rest (Fibs)) (Fibs)))))

;(define port (open-input-file "lazy-lists.scm"))
;(define input (input->List port read-line))

(run
  (= (Length (First-five)) 5)
  (= (Length (Rest (First-five))) 4)
  (eq? (Length (Rest (Cardinals))) #f)
  (= (Length (Take 5 (Cardinals))) 5)
  (eq? (Length (Cardinals)) #f)
  (eq? (Length (Drop 5 (Cardinals))) #f)
  (= (First (Drop 5 (Cardinals))) 5)
  (equal? (List->list (First-five)) '(0 1 2 3 4))
  (equal? (List->list (Take 5 (Cardinals))) '(0 1 2 3 4))
  (= (Length (Interval 2 10)) (- 10 2))
  (equal? (List->list (Interval 2 10)) '(2 3 4 5 6 7 8 9))
  (equal? (List->list (Interval 10 2)) '(10 9 8 7 6 5 4 3))
  (equal?
    (receive (head index tail) (Split-with (cut = <> 3) (First-five))
      (cons (First tail) (List->list head)))
    '(3 0 1 2))
  (equal?
    (receive (head index tail) (Split-with (cut = <> 5) (Take 10 (Cardinals)))
      (append (List->list tail) (List->list head)))
    '(5 6 7 8 9 0 1 2 3 4))
  (= (Index (cut = <> 2) (First-five)) 2)
  (= (Index (cut = <> 20) (First-five)) 5)
  (equal? (List->list (Take-upto (cut = <> 5) (Take 10 (Cardinals))))
       '(0 1 2 3 4))
  (= (Length (Take-upto (cut = <> 5) (Take 10 (Cardinals)))) 5)
  (= (Length (Drop-upto (cut = <> 5) (Take 10 (Cardinals)))) 5)
  (= (First (Drop-upto (cut = <> 5) (Take 10 (Cardinals)))) 5)
  (= (Length (Drop-upto (cut = <> 2) (First-five))) 3)
  (= (First (Drop-upto (cut = <> 2) (First-five))) 2)
  (equal? (List->list (Memp odd? (First-five))) '(1 2 3 4))
  (equal? (List->list (Memv 5 (Take 10 (Cardinals)))) '(5 6 7 8 9))
  (equal? (Assv 5 (Take 10 (Map (lambda (x) (list x x)) (Cardinals))))
    '(5 5))
  (eq? (Assv 10 (Map (lambda (x) (list x x)) (First-five))) #f)
  (eq? (Equal? (Cardinals) (Cardinals)) #f)
  (eq? (Equal? (Cardinals) (First-five)) #f)
  (eq? (Equal? (First-five) (First-five)) #t)
  (= (Length (Take 10 (Cardinals))) 10)
  (equal? (List->list (Take 5 (Filter odd? (Drop 1 (Cardinals)))))
    '(1 3 5 7 9))
  (eq? (Length (Cardinals)) #f)
  (equal? (List->list (Map add1 (First-five))) '(1 2 3 4 5))
  (equal? (List->list (Map + (First-five) (Take 5 (Cardinals))))
    '(0 2 4 6 8))
  (eq? (Length (Map + (Cardinals) (Cardinals))) #f)
  (= (Length (Filter odd? (First-five))) 2)
  (equal? (List->list (Filter odd? (First-five))) '(1 3))
  (eq? (Length (Filter odd? (Cardinals))) #f)
  (= (Ref 20 (Sieve = (Zip (Cardinals) (Cardinals)))) 20)
  (equal? (List->list (Sieve = (Zip (First-five) (First-five))))
    '(0 1 2 3 4))
  (= (Ref 25 (Cardinals)) 25)
  (= (Ref 2 (First-five)) 2)
  (equal? (List->list (Take 3 (Repeat #f))) '(#f #f #f))
  (equal? (List->list (Take 3 (Repeatedly (lambda () 1))))
    '(1 1 1))
  (equal? (List->list (Take 3 (Iterate add1 0))) '(0 1 2))
  (eq? (Length (Iterate add1 0)) #f)
  (= (Length (Append (First-five) (First-five))) 10)
  (equal? (List->list  (Append (First-five) (First-five)))
    '(0 1 2 3 4 0 1 2 3 4))
  (equal? (List->list (Take 12 (Append (First-five) (Cardinals))))
    '(0 1 2 3 4 0 1 2 3 4 5 6))
  (eq? (Length (Append (First-five) (Cardinals))) #f)
  (equal? (List->list (Reverse (First-five))) '(4 3 2 1 0))
  (equal? (List->list (Reverse (Take 5 (Cardinals)))) '(4 3 2 1 0))
  (= (Length (Reverse (First-five))) 5)
  (eq? (Length (Reverse* (Cardinals))) #f)
  (equal? (List->list (Ref 5 (Reverse* (Cardinals)))) '(5 4 3 2 1 0))
  (equal? (List->list (Take 10 (Cycle (First-five))))
    '(0 1 2 3 4 0 1 2 3 4))
  (eq? (Length (Cycle (First-five))) #f)
  (equal? (List->list (Sort < (First-five))) '(0 1 2 3 4))
  (= (Length (Sort < (First-five))) 5)
  (equal? (List->list (Sort < (List 3 1 0 2 4))) '(0 1 2 3 4))
  (equal?
    (receive (head tail) (Split-at 5 (Cardinals))
      (cons (First tail) (List->list head)))
    '(5 0 1 2 3 4))
  (equal?
    (receive (head tail) (Split-at 15 (Take 5 (Cardinals)))
      (append (List->list tail) (List->list head)))
    '(0 1 2 3 4))
  (= (Fold-left + 0 (Take 5 (Cardinals))) 10)
  (= (Fold-left + 0 (First-five) (First-five)) 20)
  (= (Fold-left * 1 (List 1 2 3 4)) 24)
  (equal? (Fold-left cons '() (Take 5 (Cardinals)))
    '(((((() . 0) . 1) . 2) . 3) . 4))
  (equal? (Ref 4 (Fold-left* cons '() (Cardinals)))
    '(((((() . 0) . 1) . 2) . 3) . 4))
  (= (Fold-right + 0 (Take 5 (Cardinals))) 10)
  (= (Fold-right + 0 (First-five) (First-five)) 20)
  (equal? (Fold-right cons '() (First-five))
    '(0 1 2 3 4)) ; list
  (equal? (Fold-right cons '(a b c) (First-five))
    '(0 1 2 3 4 a b c)) ; append
  (equal? (Ref 4 (Fold-right* cons '() (Cardinals)))
    '(4 3 2 1 0)) ; note changed order
  (equal? (Ref 4 (Fold-right* cons-right '() (Cardinals)))
    '(0 1 2 3 4))
  (equal? (Ref 4 (Fold-right* cons '(a b c) (Cardinals)))
    '(4 3 2 1 0 a b c)) ; note changed order
  (equal? (Ref 4 (Fold-right* cons-right '(a b c) (Cardinals)))
    '(a b c 0 1 2 3 4))
  (equal? (List->list (vector->List '#(0 1 2 3 4))) '(0 1 2 3 4))
  (Null? (vector->List '#()))
  (equal? (List->vector (Take 5 (Cardinals))) '#(0 1 2 3 4))
  (equal? (List->vector (First-five)) '#(0 1 2 3 4))
  (equal? (List->vector Nil) '#())
  (eq? (Every? odd? (Take 15 (Filter odd? (Cardinals)))) #t)
  (eq? (Every? odd? (Take 15 (Cardinals))) #f)
  (eq? (Every? odd? Nil) #t)
  (eq? (Some? odd? Nil) #f)
  (eq? (Some? odd? (Take 5 (Filter even? (Cardinals)))) #f)
  (eq? (Some? odd? (First-five)) #t)
  (eq? (Length (Zip (Cardinals) (First-five))) #f)
  (eq? (Length (Zip (First-five) (Cardinals))) #f)
  (eq? (Length (Zip (Cardinals) (Cardinals))) #f)
  (= (Length (Zip (First-five) (First-five))) 10)
  (Eqv? (Take 14 (Zip (Cardinals) (First-five)))
    (List 0 0 1 1 2 2 3 3 4 4 5 6 7 8))
  (Eqv? (Take 14 (Zip (Cardinals) (Cardinals)))
    (List 0 0 1 1 2 2 3 3 4 4 5 5 6 6))
  (Eqv? (Zip (First-five) (First-five))
    (List 0 0 1 1 2 2 3 3 4 4))
  (= (Ref 50 (Primes)) 233)
  (Eqv? (Take 5 (Primes)) (List 2 3 5 7 11))
  (Eqv? (Take 10 (Fibs)) (List  0 1 1 2 3 5 8 13 21 34))
  ;; compute square root
  (let ((eps 0.000001))
    (< (abs (- (sqrt 2) (Within eps (Iterate (Newton 2) 2)))) eps))
  (equal? (List->list (Sums (First-five))) '(0 1 3 6 10))
  )