lualine.nvim/lua/lualine/utils/utils.lua

-- Copyright (c) 2020-2021 shadmansaleh
-- MIT license, see LICENSE for more details.
local M = {}

-- Note for now only works for termguicolors scope can be bg or fg or any other
-- attr parameter like bold/italic/reverse
---@param color_group string hl_group name
---@param scope       string bg | fg | sp
---@return table|string returns #rrggbb formatted color when scope is specified
----                       or complete color table when scope isn't specified
function M.extract_highlight_colors(color_group, scope)
  local color = require('lualine.highlight').get_lualine_hl(color_group)
  if not color then
    if vim.fn.hlexists(color_group) == 0 then
      return nil
    end
    color = vim.api.nvim_get_hl_by_name(color_group, true)
    if color.background ~= nil then
      color.bg = string.format('#%06x', color.background)
      color.background = nil
    end
    if color.foreground ~= nil then
      color.fg = string.format('#%06x', color.foreground)
      color.foreground = nil
    end
    if color.special ~= nil then
      color.sp = string.format('#%06x', color.special)
      color.special = nil
    end
  end
  if scope then
    return color[scope]
  end
  return color
end

--- retrieves color value from highlight group name in syntax_list
--- first present highlight is returned
---@param scope string|table
---@param syntaxlist table
---@param default string
---@return string|nil
function M.extract_color_from_hllist(scope, syntaxlist, default)
  scope = type(scope) == 'string' and { scope } or scope
  for _, highlight_name in ipairs(syntaxlist) do
    if vim.fn.hlexists(highlight_name) ~= 0 then
      local color = M.extract_highlight_colors(highlight_name)
      for _, sc in ipairs(scope) do
        if color.reverse then
          if sc == 'bg' then
            sc = 'fg'
          else
            sc = 'bg'
          end
        end
        if color[sc] then
          return color[sc]
        end
      end
    end
  end
  return default
end

---remove empty strings from list
---@param list table
---@return table
function M.list_shrink(list)
  local new_list = {}
  for i = 1, #list do
    if list[i] and #list[i] > 0 then
      table.insert(new_list, list[i])
    end
  end
  return new_list
end

--- Check if a auto command is already defined
---@param event string
---@param pattern string
---@param command_str string
---@return boolean whether autocmd is already defined
local function autocmd_is_defined(event, pattern, command_str)
  return vim.api.nvim_exec(string.format('au lualine %s %s', event, pattern), true):find(command_str) ~= nil
end

--- Define a auto command if it's not already defined
---@param event  string event name
---@param pattern string event pattern
---@param cmd    string command to run on event
---@param group   string group name defaults to lualine
function M.define_autocmd(event, pattern, cmd, group)
  if not cmd then
    cmd = pattern
    pattern = '*'
  end
  if not autocmd_is_defined(event, pattern, cmd) then
    vim.cmd(string.format('autocmd %s %s %s %s', group or 'lualine', event, pattern, cmd))
  end
end

-- Check if statusline is on focused window or not
function M.is_focused()
  return tonumber(vim.g.actual_curwin) == vim.api.nvim_get_current_win()
end

--- Check what's the character at pos
---@param str string
---@param pos number
---@return string character at position pos in string str
function M.charAt(str, pos)
  return string.char(str:byte(pos))
end

-- deepcopy adapted from penlight
-- https://github.com/lunarmodules/Penlight/blob/0653cdb05591454a9804a7fee8c873b8f06b0b8f/lua/pl/tablex.lua#L98-L122
local function cycle_aware_copy(t, cache)
  if type(t) ~= 'table' then
    return t
  end
  if cache[t] then
    return cache[t]
  end
  local res = {}
  cache[t] = res
  local mt = getmetatable(t)
  for k, v in pairs(t) do
    k = cycle_aware_copy(k, cache)
    v = cycle_aware_copy(v, cache)
    res[k] = v
  end
  setmetatable(res, mt)
  return res
end

--- make a deep copy of a table, recursively copying all the keys and fields.
-- This supports cycles in tables; cycles will be reproduced in the copy.
-- This will also set the copied table's metatable to that of the original.
-- @within Copying
-- @tab t A table
-- @return new table
function M.deepcopy(t)
  return cycle_aware_copy(t, {})
end

--- Check if comp is a lualine component
--- @param comp any
--- @return boolean
function M.is_component(comp)
  if type(comp) ~= 'table' then
    return false
  end
  local mt = getmetatable(comp)
  return mt and mt.__is_lualine_component == true
end

--- Call function with args and return it's result.
--- If error occurs during fn retry times times.
---@param fn function Function to call.
---@param args table List of arguments used for calling function.
---@param times number Number of times to retry on error.
---@return any Result of fn.
function M.retry_call(fn, args, times)
  times = times or 3
  for _ = 0, times - 1 do
    local result = { pcall(fn, unpack(args)) }
    if result[1] == true then
      return unpack(result, 2)
    end
  end
  return fn(unpack(args))
end

--- Wrap a function in retry_call
---@param fn function Function to call.
---@param times number Number of times to retry on error.
---@return function retry call wrapped function
function M.retry_call_wrap(fn, times)
  return function(...)
    return M.retry_call(fn, { ... }, times)
  end
end

---Escape % in str so it doesn't get picked as stl item.
---@param str string
---@return string
function M.stl_escape(str)
  if type(str) ~= 'string' then
    return str
  end
  return str:gsub('%%', '%%%%')
end

---A safe call inside a timmer
---@param timer userdata
---@param augroup string|nil autocmd group to reset too on error.
---@param fn function
---@param max_err integer
---@param err_msg string
---@return function a wraped fn that can be called inside a timer and that
---stops the timer after max_err errors in calling fn
function M.timer_call(timer, augroup, fn, max_err, err_msg)
  local err_cnt, ret = 0, nil
  max_err = max_err or 3
  return vim.schedule_wrap(function(...)
    if err_cnt > max_err then
      vim.loop.timer_stop(timer)
      if augroup then
        vim.cmd(string.format([[augroup %s | exe "autocmd!" | augroup END]], augroup))
      end
      error(err_msg .. ':\n' .. tostring(ret))
    end
    local ok
    ok, ret = pcall(fn, ...)
    if ok then
      err_cnt = 0
    else
      err_cnt = err_cnt + 1
    end
    return ret
  end)
end

return M