#| 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.
 |#
(import (mcgoron iterator string)
        (mcgoron iterator srfi 128))

(let* ((str "")
       (itr (string-iterator-start str)))
  (test-group "empty-string"
    (test-assert "iterator-at-start?" (iterator-at-start? itr))
    (test-assert "iterator-at-end?" (iterator-at-end? itr))
    (test-assert "iterator-next" (not (iterator-next itr)))
    (test-assert "iterator-prev" (not (iterator-next itr)))
    (test-assert "iterator-advance 0" (iterator=? itr
                                                  (iterator-advance itr 0)))
    (test "iterator->index" 0 (iterator->index itr))
    (test-assert "iterator=?" (iterator=? itr (string-iterator-end str)))
    (test-assert "iterator-ref" (with-exception-check ref-at-end
                                  (iterator-ref itr)))))

(let* ((str "a")
       (itr (string-iterator-start str))
       (itr-from-itr (string-iterator-start itr)))
  (test-group "non empty string"
    (test-assert "iterator-at-start?" (iterator-at-start? itr))
    (test-assert "iterator-at-end?" (not (iterator-at-end? itr)))
    (test-assert (iterator=? itr itr-from-itr))
    (test "iterator-ref 0" #\a (iterator-ref itr))
    (test-assert "iterator-advance start -1" (not (iterator-advance itr -1)))
    (let ((next-itr (iterator-advance itr 1)))
      (test-assert "iterator? advanced" (iterator? next-itr))
      (test-assert "iterator-at-end? advanced" (iterator-at-end? next-itr))
      (test-assert "iterator=? end advanced"
                   (iterator=? next-itr (string-iterator-end str)))
      (test-assert "iterator=? itr next-itr"
                   (not (iterator=? itr next-itr)))
      (test-assert "iterator<? itr next-itr"
                   (iterator<? itr next-itr))
      (test-assert "iterator=? itr previous"
                   (iterator=? itr (iterator-advance next-itr -1)))
      (test "iterator->index next-itr" 1
            (iterator->index next-itr))
      (test-assert "iterator-ref next-itr"
                   (with-exception-check ref-at-end
                     (iterator-ref next-itr))))))

(let* ((str "abcd")
       (itr1 (string-iterator-start str)))
  (test-group "multiple advance")
  (let ((itr2 (iterator-advance itr1 1))
        (itr3 (iterator-advance itr1 2))
        (itr4 (iterator-advance itr1 3)))
    (test-assert "itr4 status" (not (iterator-at-end? itr4)))
    (test "itr1 ref" #\a (iterator-ref itr1))
    (test "itr2 ref" #\b (iterator-ref itr2))
    (test "itr3 ref" #\c (iterator-ref itr3))
    (test "itr4 ref" #\d (iterator-ref itr4))
    (test-assert "itr2->itr3" (iterator=? itr3
                                          (iterator-next itr2)))
    (test-assert "itr2->itr4" (iterator=? itr4
                                          (iterator-advance itr2 2)))
    (test-assert "itr2 < itr4" (iterator<? itr2 itr4))
    (test-assert "itr4->itr2" (iterator=? itr2
                                          (iterator-advance itr4 -2)))))