" Tests for various corner cases of applying code changes from LSP.
"
" These can be verified against the reference vscode implementation using the
" following javascript program:
"
"   const { TextDocument } = require('vscode-languageserver-textdocument');
"   const { TextEdit, Position, Range } = require('vscode-languageserver-types');
"   function MkPos(line, offset) { return Position.create(line - 1, offset - 1); }
"   function MkInsert(pos, newText) { return TextEdit.insert(pos, newText); }
"   function MkDelete(start, end) { return TextEdit.del(Range.create(start, end)); }
"   function TestChanges(s, es) {
"     return TextDocument.applyEdits(TextDocument.create(null, null, null, s), es);
"   }
"
"   const fs = require("fs");
"   const assert = require('assert').strict;
"   const testRegex = /(?<!vscode skip.*)AssertEqual\s+("[^"]*"),\s*TestChanges\(("[^"]*"),\s*(\[[^\]]*\])/g;
"   const data = fs.readFileSync(0, "utf-8");
"   const tests = data.matchAll(testRegex);
"   for (const test of tests) {
"     console.log(test[0]);
"     assert.equal(eval(test[1]), TestChanges(eval(test[2]), eval(test[3])));
"   }
"
" Save it to test_code_action_corner_cases.js and invoke it using:
"
"   $ npm install vscode-languageserver-{textdocument,types}
"   $ node test_code_action_corner_cases.js <test_code_action_corner_cases.vader

Before:
  Save &fixeol
  set nofixeol

  Save &fileformats
  set fileformats=unix

  function! TestChanges(contents, changes) abort
    let l:file = tempname()

    try
      call writefile(split(a:contents, '\n', 1), l:file, 'bs')

      call ale#code_action#ApplyChanges(l:file, a:changes, {
      \ 'should_save': 1,
      \})

      let l:result = join(readfile(l:file, 'b'), "\n")
    finally
      if filereadable(l:file)
        call delete(l:file)
      endif
    endtry

    return l:result
  endfunction!

  function! MkPos(line, offset) abort
    return {'line': a:line, 'offset': a:offset}
  endfunction!

  function! MkInsert(pos, newText) abort
    return {'start': a:pos, 'end': a:pos, 'newText': a:newText}
  endfunction!

  function! MkDelete(start, end) abort
    return {'start': a:start, 'end': a:end, 'newText': ''}
  endfunction!

After:
  delfunction TestChanges
  delfunction MkPos
  delfunction MkInsert
  delfunction MkDelete

  Restore

Execute(Preserve (no)eol at eof):
  AssertEqual "noeol",    TestChanges("noeol",    [])
  AssertEqual "eol\n",    TestChanges("eol\n",    [])
  AssertEqual "eols\n\n", TestChanges("eols\n\n", [])

Execute(Respect fixeol):
  set fixeol

  silent echo "vscode skip" | AssertEqual "noeol\n", TestChanges("noeol", [])
  silent echo "vscode skip" | AssertEqual "eol\n",   TestChanges("eol\n", [])

Execute(Add/del eol at eof):
  AssertEqual "addeol\n", TestChanges("addeol",   [MkInsert(MkPos(1, 7), "\n")])
  AssertEqual "deleol",   TestChanges("deleol\n", [MkDelete(MkPos(1, 7), MkPos(1, 8))])

Execute(One character insertions to first line):
  AssertEqual "xabc\ndef1\nghi\n", TestChanges("abc\ndef1\nghi\n", [MkInsert(MkPos(1, 0), "x")])
  AssertEqual "xabc\ndef2\nghi\n", TestChanges("abc\ndef2\nghi\n", [MkInsert(MkPos(1, 1), "x")])
  AssertEqual "axbc\ndef3\nghi\n", TestChanges("abc\ndef3\nghi\n", [MkInsert(MkPos(1, 2), "x")])
  AssertEqual "abcx\ndef4\nghi\n", TestChanges("abc\ndef4\nghi\n", [MkInsert(MkPos(1, 4), "x")])
  AssertEqual "abc\nxdef5\nghi\n", TestChanges("abc\ndef5\nghi\n", [MkInsert(MkPos(1, 5), "x")])
  AssertEqual "abc\nxdef6\nghi\n", TestChanges("abc\ndef6\nghi\n", [MkInsert(MkPos(1, 6), "x")])

Execute(One character + newline insertions to first line):
  AssertEqual "x\nabc\ndef1\nghi\n", TestChanges("abc\ndef1\nghi\n", [MkInsert(MkPos(1, 0), "x\n")])
  AssertEqual "x\nabc\ndef2\nghi\n", TestChanges("abc\ndef2\nghi\n", [MkInsert(MkPos(1, 1), "x\n")])
  AssertEqual "ax\nbc\ndef3\nghi\n", TestChanges("abc\ndef3\nghi\n", [MkInsert(MkPos(1, 2), "x\n")])
  AssertEqual "abcx\n\ndef4\nghi\n", TestChanges("abc\ndef4\nghi\n", [MkInsert(MkPos(1, 4), "x\n")])
  AssertEqual "abc\nx\ndef5\nghi\n", TestChanges("abc\ndef5\nghi\n", [MkInsert(MkPos(1, 5), "x\n")])
  AssertEqual "abc\nx\ndef6\nghi\n", TestChanges("abc\ndef6\nghi\n", [MkInsert(MkPos(1, 6), "x\n")])

Execute(One character insertions near end):
  AssertEqual "abc\ndef1\nghxi\n", TestChanges("abc\ndef1\nghi\n", [MkInsert(MkPos(3, 3), "x")])
  AssertEqual "abc\ndef2\nghix\n", TestChanges("abc\ndef2\nghi\n", [MkInsert(MkPos(3, 4), "x")])
  AssertEqual "abc\ndef3\nghi\nx", TestChanges("abc\ndef3\nghi\n", [MkInsert(MkPos(3, 5), "x")])
  AssertEqual "abc\ndef4\nghi\nx", TestChanges("abc\ndef4\nghi\n", [MkInsert(MkPos(3, 6), "x")])
  AssertEqual "abc\ndef5\nghi\nx", TestChanges("abc\ndef5\nghi\n", [MkInsert(MkPos(4, 1), "x")])
  AssertEqual "abc\ndef6\nghi\nx", TestChanges("abc\ndef6\nghi\n", [MkInsert(MkPos(4, 2), "x")])
  AssertEqual "abc\ndef7\nghi\nx", TestChanges("abc\ndef7\nghi\n", [MkInsert(MkPos(5, 1), "x")])
  AssertEqual "abc\ndef8\nghi\nx", TestChanges("abc\ndef8\nghi\n", [MkInsert(MkPos(5, 2), "x")])

Execute(One character + newline insertions near end):
  AssertEqual "abc\ndef1\nghx\ni\n", TestChanges("abc\ndef1\nghi\n", [MkInsert(MkPos(3, 3), "x\n")])
  AssertEqual "abc\ndef2\nghix\n\n", TestChanges("abc\ndef2\nghi\n", [MkInsert(MkPos(3, 4), "x\n")])
  AssertEqual "abc\ndef3\nghi\nx\n", TestChanges("abc\ndef3\nghi\n", [MkInsert(MkPos(3, 5), "x\n")])
  AssertEqual "abc\ndef4\nghi\nx\n", TestChanges("abc\ndef4\nghi\n", [MkInsert(MkPos(3, 6), "x\n")])
  AssertEqual "abc\ndef5\nghi\nx\n", TestChanges("abc\ndef5\nghi\n", [MkInsert(MkPos(4, 1), "x\n")])
  AssertEqual "abc\ndef6\nghi\nx\n", TestChanges("abc\ndef6\nghi\n", [MkInsert(MkPos(4, 2), "x\n")])

Execute(Newline insertions near end):
  AssertEqual "abc\ndef1\ngh\ni\n", TestChanges("abc\ndef1\nghi\n", [MkInsert(MkPos(3, 3), "\n")])
  AssertEqual "abc\ndef2\nghi\n\n", TestChanges("abc\ndef2\nghi\n", [MkInsert(MkPos(3, 4), "\n")])
  AssertEqual "abc\ndef3\nghi\n\n", TestChanges("abc\ndef3\nghi\n", [MkInsert(MkPos(3, 5), "\n")])
  AssertEqual "abc\ndef4\nghi\n\n", TestChanges("abc\ndef4\nghi\n", [MkInsert(MkPos(3, 6), "\n")])
  AssertEqual "abc\ndef5\nghi\n\n", TestChanges("abc\ndef5\nghi\n", [MkInsert(MkPos(4, 1), "\n")])

Execute(Single char deletions):
  AssertEqual "bc\ndef1\nghi\n",  TestChanges("abc\ndef1\nghi\n", [MkDelete(MkPos(1, 1), MkPos(1, 2))])
  AssertEqual "ab\ndef2\nghi\n",  TestChanges("abc\ndef2\nghi\n", [MkDelete(MkPos(1, 3), MkPos(1, 4))])
  AssertEqual "abcdef3\nghi\n",   TestChanges("abc\ndef3\nghi\n", [MkDelete(MkPos(1, 4), MkPos(1, 5))])
  AssertEqual "abcdef4\nghi\n",   TestChanges("abc\ndef4\nghi\n", [MkDelete(MkPos(1, 4), MkPos(1, 6))])
  AssertEqual "abc\ndef5\ngh\n",  TestChanges("abc\ndef5\nghi\n", [MkDelete(MkPos(3, 3), MkPos(3, 4))])
  AssertEqual "abc\ndef6\nghi",   TestChanges("abc\ndef6\nghi\n", [MkDelete(MkPos(3, 4), MkPos(3, 5))])
  AssertEqual "abc\ndef7\nghi",   TestChanges("abc\ndef7\nghi\n", [MkDelete(MkPos(3, 4), MkPos(3, 6))])
  AssertEqual "abc\ndef8\nghi\n", TestChanges("abc\ndef8\nghi\n", [MkDelete(MkPos(4, 1), MkPos(4, 2))])