local helpers = require("test.unit.helpers")(after_each)
local itp = helpers.gen_itp(it)

local to_cstr = helpers.to_cstr
local get_str = helpers.ffi.string
local eq      = helpers.eq
local NULL    = helpers.NULL

local buffer = helpers.cimport("./src/nvim/buffer.h")
local globals = helpers.cimport("./src/nvim/globals.h")
local stl = helpers.cimport("./src/nvim/statusline.h")

describe('build_stl_str_hl', function()
  local buffer_byte_size = 100
  local STL_INITIAL_ITEMS = 20
  local output_buffer = ''

  -- This function builds the statusline
  --
  -- @param arg Optional arguments are:
  --    .pat The statusline format string
  --    .fillchar The fill character used in the statusline
  --    .maximum_cell_count The number of cells available in the statusline
  local function build_stl_str_hl(arg)
    output_buffer = to_cstr(string.rep(" ", buffer_byte_size))

    local pat = arg.pat or ''
    local fillchar = arg.fillchar or (' '):byte()
    local maximum_cell_count = arg.maximum_cell_count or buffer_byte_size

    return stl.build_stl_str_hl(globals.curwin,
                                   output_buffer,
                                   buffer_byte_size,
                                   to_cstr(pat),
                                   NULL,
                                   0,
                                   fillchar,
                                   maximum_cell_count,
                                   NULL,
                                   NULL,
                                   NULL)
  end

  -- Use this function to simplify testing the comparison between
  --  the format string and the resulting statusline.
  --
  -- @param description The description of what the test should be doing
  -- @param statusline_cell_count The number of cells available in the statusline
  -- @param input_stl The format string for the statusline
  -- @param expected_stl The expected result string for the statusline
  --
  -- @param arg Options can be placed in an optional dictionary as the last parameter
  --    .expected_cell_count The expected number of cells build_stl_str_hl will return
  --    .expected_byte_length The expected byte length of the string (defaults to byte length of expected_stl)
  --    .file_name The name of the file to be tested (useful in %f type tests)
  --    .fillchar The character that will be used to fill any 'extra' space in the stl
  local function statusline_test(description,
                                 statusline_cell_count,
                                 input_stl,
                                 expected_stl,
                                 arg)

    -- arg is the optional parameter
    -- so we either fill in option with arg or an empty dictionary
    local option = arg or {}

    local fillchar = option.fillchar or (' '):byte()
    local expected_cell_count = option.expected_cell_count or statusline_cell_count
    local expected_byte_length = option.expected_byte_length or #expected_stl

    itp(description, function()
      if option.file_name then
        buffer.setfname(globals.curbuf, to_cstr(option.file_name), NULL, 1)
      else
        buffer.setfname(globals.curbuf, nil, NULL, 1)
      end

      local result_cell_count = build_stl_str_hl{pat=input_stl,
                                                 maximum_cell_count=statusline_cell_count,
                                                 fillchar=fillchar}

      eq(expected_stl, get_str(output_buffer, expected_byte_length))
      eq(expected_cell_count, result_cell_count)
    end)
  end

  -- expression testing
  statusline_test('Should expand expression', 2,
   '%!expand(20+1)',       '21')
  statusline_test('Should expand broken expression to itself', 11,
   '%!expand(20+1',       'expand(20+1')

  -- file name testing
  statusline_test('should print no file name', 10,
    '%f',                  '[No Name]',
    {expected_cell_count=9})
  statusline_test('should print the relative file name', 30,
    '%f',                  'test/unit/buffer_spec.lua',
    {file_name='test/unit/buffer_spec.lua', expected_cell_count=25})
  statusline_test('should print the full file name', 40,
    '%F',                  '/test/unit/buffer_spec.lua',
    {file_name='/test/unit/buffer_spec.lua', expected_cell_count=26})

  -- fillchar testing
  statusline_test('should handle `!` as a fillchar', 10,
    'abcde%=',             'abcde!!!!!',
    {fillchar=('!'):byte()})
  statusline_test('should handle `~` as a fillchar', 10,
    '%=abcde',             '~~~~~abcde',
    {fillchar=('~'):byte()})
  statusline_test('should put fillchar `!` in between text', 10,
    'abc%=def',            'abc!!!!def',
    {fillchar=('!'):byte()})
  statusline_test('should put fillchar `~` in between text', 10,
    'abc%=def',            'abc~~~~def',
    {fillchar=('~'):byte()})
  statusline_test('should put fillchar `━` in between text', 10,
    'abc%=def',            'abc━━━━def',
    {fillchar=0x2501})
  statusline_test('should handle zero-fillchar as a space', 10,
    'abcde%=',             'abcde     ',
    {fillchar=0})
  statusline_test('should print the tail file name', 80,
    '%t',                  'buffer_spec.lua',
    {file_name='test/unit/buffer_spec.lua', expected_cell_count=15})

  -- standard text testing
  statusline_test('should copy plain text', 80,
    'this is a test',      'this is a test',
    {expected_cell_count=14})

  -- line number testing
  statusline_test('should print the buffer number', 80,
    '%n',                  '1',
    {expected_cell_count=1})
  statusline_test('should print the current line number in the buffer', 80,
    '%l',                  '0',
    {expected_cell_count=1})
  statusline_test('should print the number of lines in the buffer', 80,
    '%L',                  '1',
    {expected_cell_count=1})

  -- truncation testing
  statusline_test('should truncate when standard text pattern is too long', 10,
    '0123456789abcde',     '<6789abcde')
  statusline_test('should truncate when using =', 10,
    'abcdef%=ghijkl',      'abcdef<jkl')
  statusline_test('should truncate centered text when using ==', 10,
    'abcde%=gone%=fghij',  'abcde<ghij')
  statusline_test('should respect the `<` marker', 10,
    'abc%<defghijkl',      'abc<ghijkl')
  statusline_test('should truncate at `<` with one `=`, test 1', 10,
    'abc%<def%=ghijklmno', 'abc<jklmno')
  statusline_test('should truncate at `<` with one `=`, test 2', 10,
    'abcdef%=ghijkl%<mno', 'abcdefghi>')
  statusline_test('should truncate at `<` with one `=`, test 3', 10,
    'abc%<def%=ghijklmno', 'abc<jklmno')
  statusline_test('should truncate at `<` with one `=`, test 4', 10,
    'abc%<def%=ghij',     'abcdefghij')
  statusline_test('should truncate at `<` with one `=`, test 4', 10,
    'abc%<def%=ghijk',     'abc<fghijk')

  statusline_test('should truncate at `<` with many `=`, test 4', 10,
    'ab%<cdef%=g%=h%=ijk', 'ab<efghijk')

  statusline_test('should truncate at the first `<`', 10,
    'abc%<def%<ghijklm',   'abc<hijklm')

  statusline_test('should ignore trailing %', 3, 'abc%', 'abc')

  -- alignment testing with fillchar
  local function statusline_test_align(description,
                                       statusline_cell_count,
                                       input_stl,
                                       expected_stl,
                                       arg)
    arg = arg or {}
    statusline_test(description .. ' without fillchar',
      statusline_cell_count, input_stl, expected_stl:gsub('%~', ' '), arg)
    arg.fillchar = ('!'):byte()
    statusline_test(description .. ' with fillchar `!`',
      statusline_cell_count, input_stl, expected_stl:gsub('%~', '!'), arg)
    arg.fillchar = 0x2501
    statusline_test(description .. ' with fillchar `━`',
      statusline_cell_count, input_stl, expected_stl:gsub('%~', '━'), arg)
  end

  statusline_test_align('should right align when using =', 20,
    'neo%=vim',            'neo~~~~~~~~~~~~~~vim')
  statusline_test_align('should, when possible, center text when using %=text%=', 20,
    'abc%=neovim%=def',    'abc~~~~neovim~~~~def')
  statusline_test_align('should handle uneven spacing in the buffer when using %=text%=', 20,
    'abc%=neo_vim%=def',   'abc~~~neo_vim~~~~def')
  statusline_test_align('should have equal spaces even with non-equal sides when using =', 20,
    'foobar%=test%=baz',   'foobar~~~test~~~~baz')
  statusline_test_align('should have equal spaces even with longer right side when using =', 20,
    'a%=test%=longtext',   'a~~~test~~~~longtext')
  statusline_test_align('should handle an empty left side when using ==', 20,
    '%=test%=baz',         '~~~~~~test~~~~~~~baz')
  statusline_test_align('should handle an empty right side when using ==', 20,
    'foobar%=test%=',      'foobar~~~~~test~~~~~')
  statusline_test_align('should handle consecutive empty ==', 20,
    '%=%=test%=',          '~~~~~~~~~~test~~~~~~')
  statusline_test_align('should handle an = alone', 20,
    '%=',                  '~~~~~~~~~~~~~~~~~~~~')
  statusline_test_align('should right align text when it is alone with =', 20,
    '%=foo',               '~~~~~~~~~~~~~~~~~foo')
  statusline_test_align('should left align text when it is alone with =', 20,
    'foo%=',               'foo~~~~~~~~~~~~~~~~~')

  statusline_test_align('should approximately center text when using %=text%=', 21,
    'abc%=neovim%=def',    'abc~~~~neovim~~~~~def')
  statusline_test_align('should completely fill the buffer when using %=text%=', 21,
    'abc%=neo_vim%=def',   'abc~~~~neo_vim~~~~def')
  statusline_test_align('should have equal spacing even with non-equal sides when using =', 21,
    'foobar%=test%=baz',   'foobar~~~~test~~~~baz')
  statusline_test_align('should have equal spacing even with longer right side when using =', 21,
    'a%=test%=longtext',   'a~~~~test~~~~longtext')
  statusline_test_align('should handle an empty left side when using ==', 21,
    '%=test%=baz',         '~~~~~~~test~~~~~~~baz')
  statusline_test_align('should handle an empty right side when using ==', 21,
    'foobar%=test%=',      'foobar~~~~~test~~~~~~')

  statusline_test_align('should quadrant the text when using 3 %=', 40,
    'abcd%=n%=eovim%=ef',  'abcd~~~~~~~~~n~~~~~~~~~eovim~~~~~~~~~~ef')
  statusline_test_align('should work well with %t', 40,
    '%t%=right_aligned',   'buffer_spec.lua~~~~~~~~~~~~right_aligned',
    {file_name='test/unit/buffer_spec.lua'})
  statusline_test_align('should work well with %t and regular text', 40,
    'l%=m_l %t m_r%=r',    'l~~~~~~~m_l buffer_spec.lua m_r~~~~~~~~r',
    {file_name='test/unit/buffer_spec.lua'})
  statusline_test_align('should work well with %=, %t, %L, and %l', 40,
    '%t %= %L %= %l',      'buffer_spec.lua ~~~~~~~~~ 1 ~~~~~~~~~~ 0',
    {file_name='test/unit/buffer_spec.lua'})

  statusline_test_align('should quadrant the text when using 3 %=', 41,
    'abcd%=n%=eovim%=ef',  'abcd~~~~~~~~~n~~~~~~~~~eovim~~~~~~~~~~~ef')
  statusline_test_align('should work well with %t', 41,
    '%t%=right_aligned',   'buffer_spec.lua~~~~~~~~~~~~~right_aligned',
    {file_name='test/unit/buffer_spec.lua'})
  statusline_test_align('should work well with %t and regular text', 41,
    'l%=m_l %t m_r%=r',    'l~~~~~~~~m_l buffer_spec.lua m_r~~~~~~~~r',
    {file_name='test/unit/buffer_spec.lua'})
  statusline_test_align('should work well with %=, %t, %L, and %l', 41,
    '%t %= %L %= %l',      'buffer_spec.lua ~~~~~~~~~~ 1 ~~~~~~~~~~ 0',
    {file_name='test/unit/buffer_spec.lua'})

  statusline_test_align('should work with 10 %=', 50,
    'aaaa%=b%=c%=d%=e%=fg%=hi%=jk%=lmnop%=qrstuv%=wxyz',
    'aaaa~~b~~c~~d~~e~~fg~~hi~~jk~~lmnop~~qrstuv~~~wxyz')

  -- stl item testing
  local tabline = ''
  for i = 1, 1000 do
    tabline = tabline .. (i % 2 == 0 and '%#TabLineSel#' or '%#TabLineFill#') .. tostring(i % 2)
  end
  statusline_test('should handle a large amount of any items', 20,
    tabline,
    '<1010101010101010101') -- Should not show any error
  statusline_test('should handle a larger amount of = than stl initial item', 20,
    ('%='):rep(STL_INITIAL_ITEMS * 5),
    '                    ') -- Should not show any error
  statusline_test('should handle many extra characters', 20,
    'a' .. ('a'):rep(STL_INITIAL_ITEMS * 5),
    '<aaaaaaaaaaaaaaaaaaa') -- Does not show any error
  statusline_test('should handle many extra characters and flags', 20,
    'a' .. ('%=a'):rep(STL_INITIAL_ITEMS * 2),
    'a<aaaaaaaaaaaaaaaaaa') -- Should not show any error

  -- multi-byte testing
  statusline_test('should handle multibyte characters', 10,
    'Ĉ%=x',                'Ĉ        x')
  statusline_test('should handle multibyte characters and different fillchars', 10,
    'Ą%=mid%=end',         'Ą@mid@@end',
    {fillchar=('@'):byte()})

  -- escaping % testing
  statusline_test('should handle escape of %', 4, 'abc%%', 'abc%')
  statusline_test('case where escaped % does not fit', 3, 'abc%%abcabc', '<bc')
  statusline_test('escaped % is first', 1, '%%', '%')

end)