u.nvim bracket matcher

matcher.lua

local Range = require 'u.Range'

local M = {}

local highlights = {}
local last_bracket_range = nil

local function clear_highlights()
  for _, hl in ipairs(highlights) do
    if hl and hl.clear then
      hl:clear()
    end
  end
  highlights = {}
end

local function update()
  local mode = vim.fn.mode()
  if mode ~= 'n' and mode ~= 'i' and mode ~= 'v' and mode ~= 'V' and mode ~= '\22' then
    return
  end

  local bufnr = vim.api.nvim_get_current_buf()
  local buftype = vim.bo[bufnr].buftype
  if buftype ~= '' then
    return
  end

  local bracket_range = Range.find_nearest_brackets()

  if bracket_range and last_bracket_range
      and bracket_range.start == last_bracket_range.start
      and bracket_range.stop == last_bracket_range.stop then
    return
  end

  clear_highlights()
  last_bracket_range = bracket_range

  if bracket_range == nil then return end

  local opening = Range.new(bracket_range.start, bracket_range.start, 'v')
  local closing = Range.new(bracket_range.stop, bracket_range.stop, 'v')

  table.insert(highlights, opening:highlight('MatchParen', { priority = 999 }))
  table.insert(highlights, closing:highlight('MatchParen', { priority = 999 }))
end

function M.setup()
  local group = vim.api.nvim_create_augroup('Matcher', { clear = true })
  vim.api.nvim_create_autocmd({ 'CursorMoved' }, {
    group = group,
    callback = update,
  })
end

return M