(local faith (require :faith))
(local utils (require :fennel-ls.utils))

(fn position [line character]
  {: line : character})

(fn range [start-line start-col end-line end-col]
  {:start (position start-line start-col) :end (position end-line   end-col)})

;; "a" U+0061  is in  U+0000 to  U+007F, and therefore is 1 byte  in UTF-8, and 1 codepoint  in UTF-16
;; "λ" U+03BB  is in  U+0080 to  U+07FF, and therefore is 2 bytes in UTF-8, and 1 codepoint  in UTF-16
;; "ｾ" U+FF7E  is in  U+0800 to  U+FFFF, and therefore is 3 bytes in UTF-8, and 1 codepoint  in UTF-16
;; "𐐀" U+10400 is in U+10000 to U+10FFFF,and therefore is 4 bytes in UTF-8, and 2 codepoints in UTF-16
;; These symbols cover each of the four cases of byte/codepoint widths
;; they should be sufficient for testing

(fn test-position->byte []
  (faith.= 1 (utils.position->byte "a𐐀λ\nbλ𐐀" (position 0 0) :utf-8))
  (faith.= 2 (utils.position->byte "a𐐀λ\nbλ𐐀" (position 0 1) :utf-8))
  (faith.= 6 (utils.position->byte "a𐐀λ\nbλ𐐀" (position 0 5) :utf-8))
  (faith.= 8 (utils.position->byte "a𐐀λ\nbλ𐐀" (position 0 7) :utf-8))
  (faith.= 9 (utils.position->byte "a𐐀λ\nbλ𐐀" (position 1 0) :utf-8))
  (faith.= 10 (utils.position->byte "a𐐀λ\nbλ𐐀" (position 1 1) :utf-8))
  (faith.= 12 (utils.position->byte "a𐐀λ\nbλ𐐀" (position 1 3) :utf-8))
  (faith.= 16 (utils.position->byte "a𐐀λ\nbλ𐐀" (position 1 7) :utf-8))
  (faith.= 1 (utils.position->byte "a𐐀λ\nbλ𐐀" (position 0 0) :utf-16))
  (faith.= 2 (utils.position->byte "a𐐀λ\nbλ𐐀" (position 0 1) :utf-16))
  (faith.= 6 (utils.position->byte "a𐐀λ\nbλ𐐀" (position 0 3) :utf-16))
  (faith.= 8 (utils.position->byte "a𐐀λ\nbλ𐐀" (position 0 4) :utf-16))
  (faith.= 9 (utils.position->byte "a𐐀λ\nbλ𐐀" (position 1 0) :utf-16))
  (faith.= 10 (utils.position->byte "a𐐀λ\nbλ𐐀" (position 1 1) :utf-16))
  (faith.= 12 (utils.position->byte "a𐐀λ\nbλ𐐀" (position 1 2) :utf-16))
  (faith.= 16 (utils.position->byte "a𐐀λ\nbλ𐐀" (position 1 4) :utf-16))
  (faith.= 19 (utils.position->byte "a𐐀ｾλ\nbλ𐐀" (position 1 4) :utf-16))
  (faith.= 19 (utils.position->byte "a𐐀ｾλ\nbλ𐐀" (position 1 4) :utf-16))
  (faith.= 7 (utils.position->byte "ｾｾ" (position 0 2) :utf-16))
  nil)

(fn test-byte->position []
  (faith.= (position 0 0) (utils.byte->position "a𐐀λ\nbλ𐐀" 1 :utf-8))
  (faith.= (position 0 1) (utils.byte->position "a𐐀λ\nbλ𐐀" 2 :utf-8))
  (faith.= (position 0 5) (utils.byte->position "a𐐀λ\nbλ𐐀" 6 :utf-8))
  (faith.= (position 0 7) (utils.byte->position "a𐐀λ\nbλ𐐀" 8 :utf-8))
  (faith.= (position 1 0) (utils.byte->position "a𐐀λ\nbλ𐐀" 9 :utf-8))
  (faith.= (position 1 1) (utils.byte->position "a𐐀λ\nbλ𐐀" 10 :utf-8))
  (faith.= (position 1 3) (utils.byte->position "a𐐀λ\nbλ𐐀" 12 :utf-8))
  (faith.= (position 1 7) (utils.byte->position "a𐐀λ\nbλ𐐀" 16 :utf-8))
  (faith.= (position 0 0) (utils.byte->position "a𐐀λ\nbλ𐐀" 1 :utf-16))
  (faith.= (position 0 1) (utils.byte->position "a𐐀λ\nbλ𐐀" 2 :utf-16))
  (faith.= (position 0 3) (utils.byte->position "a𐐀λ\nbλ𐐀" 6 :utf-16))
  (faith.= (position 0 4) (utils.byte->position "a𐐀λ\nbλ𐐀" 8 :utf-16))
  (faith.= (position 1 0) (utils.byte->position "a𐐀λ\nbλ𐐀" 9 :utf-16))
  (faith.= (position 1 1) (utils.byte->position "a𐐀λ\nbλ𐐀" 10 :utf-16))
  (faith.= (position 1 2) (utils.byte->position "a𐐀λ\nbλ𐐀" 12 :utf-16))
  (faith.= (position 1 4) (utils.byte->position "a𐐀λ\nbλ𐐀" 16 :utf-16))
  (faith.= (position 1 4) (utils.byte->position "a𐐀ｾλ\nbλ𐐀" 19 :utf-16))
  (faith.= (position 1 4) (utils.byte->position "a𐐀ｾλ\nbλ𐐀" 19 :utf-16))
  (faith.= (position 0 2) (utils.byte->position "ｾｾ" 7 :utf-16))
  nil)

(fn test-apply-changes []
  (faith.= "the beginning"
    (utils.apply-changes
      "replace beginning"
      [{:range (range 0 0 0 7) :text "the"}]
      :utf-8))

  (faith.= "first line\nsecond line\nreplacement"
    (utils.apply-changes
      "first line\nsecond line\nreplace end"
      [{:range (range 2 7 2 11) :text "ment"}]
      :utf-8))

  (faith.= "new string"
    (utils.apply-changes
      "replace all"
      [{:range (range 0 0 0 11) :text "new string"}]
      :utf-8))

  (faith.=
    (utils.apply-changes
      "this is the\nold file"
      [{:text "And this is the\nnew file"}]
      :utf-8)
    "And this is the\nnew file"))
  ;; TODO test substitute multiple ranges

{: test-position->byte
 : test-byte->position
 : test-apply-changes}