-- Tests for undo tree and :earlier and :later.
local helpers = require('test.functional.helpers')(after_each)

local feed_command = helpers.feed_command
local write_file = helpers.write_file
local command = helpers.command
local source = helpers.source
local expect = helpers.expect
local clear = helpers.clear
local feed = helpers.feed
local eval = helpers.eval
local eq = helpers.eq

local function expect_empty_buffer()
  -- The space will be removed by helpers.dedent but is needed because dedent
  -- will fail if it can not find the common indent of the given lines.
  return expect(' ')
end
local function expect_line(line)
  return eq(line, eval('getline(".")'))
end

describe('undo tree:', function()
  before_each(clear)
  local fname = 'Xtest_functional_legacy_undotree'
  teardown(function()
    os.remove(fname .. '.source')
  end)

  describe(':earlier and :later', function()
    before_each(function()
      os.remove(fname)
    end)
    teardown(function()
      os.remove(fname)
    end)

    it('time specifications, g- g+', function()
      -- We write the test text to a file in order to prevent nvim to record
      -- the inserting of the text into the undo history.
      write_file(fname, '\n123456789\n')

      -- `:earlier` and `:later` are (obviously) time-sensitive, so this test
      -- sometimes fails if the system is under load. It is wrapped in a local
      -- function to allow multiple attempts.
      local function test_earlier_later()
        clear()
        feed_command('e ' .. fname)
        -- Assert that no undo history is present.
        eq({}, eval('undotree().entries'))
        -- Delete three characters and undo.
        feed('Gxxx')
        expect_line('456789')
        feed('g-')
        expect_line('3456789')
        feed('g-')
        expect_line('23456789')
        feed('g-')
        expect_line('123456789')
        feed('g-')
        expect_line('123456789')

        -- Delete three other characters and go back in time step by step.
        feed('$xxx')
        expect_line('123456')
        command('sleep 1')
        feed('g-')
        expect_line('1234567')
        feed('g-')
        expect_line('12345678')
        feed('g-')
        expect_line('456789')
        feed('g-')
        expect_line('3456789')
        feed('g-')
        expect_line('23456789')
        feed('g-')
        expect_line('123456789')
        feed('g-')
        expect_line('123456789')
        feed('g-')
        expect_line('123456789')
        feed('10g+')
        expect_line('123456')

        -- Delay for two seconds and go some seconds forward and backward.
        command('sleep 2')
        feed('Aa<esc>')
        feed('Ab<esc>')
        feed('Ac<esc>')
        expect_line('123456abc')
        feed_command('earlier 1s')
        expect_line('123456')
        feed_command('earlier 3s')
        expect_line('123456789')
        feed_command('later 1s')
        expect_line('123456')
        feed_command('later 1h')
        expect_line('123456abc')
      end

      helpers.retry(2, nil, test_earlier_later)
    end)

    it('file-write specifications', function()
      feed('ione one one<esc>')
      feed_command('w ' .. fname)
      feed('otwo<esc>')
      feed('otwo<esc>')
      feed_command('w')
      feed('othree<esc>')
      feed_command('earlier 1f')
      expect([[
        one one one
        two
        two]])
      feed_command('earlier 1f')
      expect('one one one')
      feed_command('earlier 1f')
      expect_empty_buffer()
      feed_command('later 1f')
      expect('one one one')
      feed_command('later 1f')
      expect([[
        one one one
        two
        two]])
      feed_command('later 1f')
      expect([[
        one one one
        two
        two
        three]])
    end)
  end)

  it('scripts produce one undo-block for all changes by default', function()
    source([[
      normal Aaaaa
      normal obbbb
      normal occcc
    ]])
    expect([[
      aaaa
      bbbb
      cccc]])
    feed('u')
    expect_empty_buffer()
  end)

  it("setting 'undolevel' can break undo-blocks (inside scripts)", function()
    -- :source is required (because interactive changes are _not_ grouped,
    -- even with :undojoin).
    source([[
      normal Aaaaa
      set ul=100
      normal obbbb
      set ul=100
      normal occcc
    ]])
    expect([[
      aaaa
      bbbb
      cccc]])
    feed('u')
    expect([[
      aaaa
      bbbb]])
    feed('u')
    expect('aaaa')
    feed('u')
    expect_empty_buffer()
  end)

  it(':undojoin can join undo-blocks inside scripts', function()
    feed('Goaaaa<esc>')
    feed('obbbb<esc>u')
    expect_line('aaaa')
    source([[
      normal obbbb
      set ul=100
      undojoin
      normal occcc
    ]])
    feed('u')
    expect_line('aaaa')
  end)

  it('undo an expression-register', function()
    local normal_commands = 'o1\027a2\018=string(123)\n\027'
    write_file(fname .. '.source', normal_commands)

    feed('oa<esc>')
    feed('ob<esc>')
    feed([[o1<esc>a2<C-R>=setline('.','1234')<cr><esc>]])
    expect([[

      a
      b
      12034]])
    feed('uu')
    expect([[

      a
      b
      1]])
    feed('oc<esc>')
    feed([[o1<esc>a2<C-R>=setline('.','1234')<cr><esc>]])
    expect([[

      a
      b
      1
      c
      12034]])
    feed('u')
    expect([[

      a
      b
      1
      c
      12]])
    feed('od<esc>')
    feed_command('so! ' .. fname .. '.source')
    expect([[

      a
      b
      1
      c
      12
      d
      12123]])
    feed('u')
    expect([[

      a
      b
      1
      c
      12
      d]])

    -- The above behaviour was tested in the legacy Vim test because the
    -- legacy tests were executed with ':so!'.  The behavior differs for
    -- interactive use (even in Vim; see ":help :undojoin"):
    feed(normal_commands)
    expect([[

      a
      b
      1
      c
      12
      d
      12123]])
    feed('u')
    expect([[

      a
      b
      1
      c
      12
      d
      1]])
  end)
end)