#| Copyright 2024 Peter McGoron
 |
 | Licensed under the Apache License, Version 2.0 (the "License");
 | you may not use this file except in compliance with the License.
 | You may obtain a copy of the License at
 |
 |     http://www.apache.org/licenses/LICENSE-2.0
 |
 | Unless required by applicable law or agreed to in writing, software
 | distributed under the License is distributed on an "AS IS" BASIS,
 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 | See the License for the specific language governing permissions and
 | limitations under the License.
 |#

(define-library (mcgoron weight-balanced-trees test random-number-vector)
  (import (scheme base)
          (srfi 158) (srfi 197) (srfi 252) (srfi 133) (srfi 26) (srfi 132))
  (export in-order-vector-generator)
  (begin
    (define (random-number-vector of)
      ;; Generate a random vector of exact integers with at most `of` number
      ;; of elements.
      (vector-generator-of (exact-integer-generator) of))
    (define (filter-non-empty-vectors gen)
      ;; Filter out the empty vector.
      (gremove (lambda (vec) (zero? (vector-length vec))) gen))
    (define (remove-duplicates gen)
      ;; Filter out vectors with duplicate entries.
      (define (filter vec)
        (call/cc
         (lambda (return)
           (vector-fold (lambda (prev elem)
                          (cond
                            ((null? prev) elem)
                            ((= elem prev) (return #f))
                            (else elem)))
                        '()
                        vec)
           #t)))
      (gfilter filter gen))
    (define (make-in-order gen)
      ;; Sort all vectors to be in-order.
      (gmap (cut vector-sort < <>) gen))
    (define (in-order-vector-generator of)
      (chain (random-number-vector of)
             (filter-non-empty-vectors _)
             (make-in-order _)
             (remove-duplicates _)))))