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')
local grid = helpers.cimport('./src/nvim/grid.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 ' '
    local maximum_cell_count = arg.maximum_cell_count or buffer_byte_size
    if type(fillchar) == type('') then
      fillchar = grid.schar_from_str(fillchar)
    end

    return stl.build_stl_str_hl(
      globals.curwin,
      output_buffer,
      buffer_byte_size,
      to_cstr(pat),
      -1,
      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 ' '
    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 = '!' }
  )
  statusline_test(
    'should handle `~` as a fillchar',
    10,
    '%=abcde',
    '~~~~~abcde',
    { fillchar = '~' }
  )
  statusline_test(
    'should put fillchar `!` in between text',
    10,
    'abc%=def',
    'abc!!!!def',
    { fillchar = '!' }
  )
  statusline_test(
    'should put fillchar `~` in between text',
    10,
    'abc%=def',
    'abc~~~~def',
    { fillchar = '~' }
  )
  statusline_test(
    'should put fillchar `━` in between text',
    10,
    'abc%=def',
    'abc━━━━def',
    { fillchar = '━' }
  )
  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 = '!'
    statusline_test(
      description .. ' with fillchar `!`',
      statusline_cell_count,
      input_stl,
      expected_stl:gsub('%~', '!'),
      arg
    )
    arg.fillchar = '━'
    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 = '@' }
  )

  -- 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)