dotfiles/nvim/.config/nvim/after/plugin/statusline.lua

local fn  = vim.fn
local api = vim.api
local cmd = vim.cmd

local M = {}

local colors = {
  line_bg  = '#21242b',
  bg       = '#000000',
  fg       = '#dobfa1',
  yellow   = '#fabd2f',
  cyan     = '#008080',
  darkblue = '#081633',
  green    = '#afd700',
  orange   = '#FF8800',
  purple   = '#5d4d7a',
  magenta  = '#c678dd',
  blue     = '#51afef',
  red      = '#ec5f67'
}

local function highlight(group, fg, bg)
  api.nvim_set_hl(0, group, { fg = fg, bg = bg })
end

highlight("Window"      , colors.red    , colors.bg)
highlight("Mode"        , colors.green  , colors.bg)
highlight("Filename"    , colors.blue   , colors.bg)
highlight("Fileformat"  , colors.purple , colors.bg)

highlight("GitBranch"   , colors.orange , colors.bg)
highlight("DiffAdded"   , colors.green  , colors.bg)
highlight("DiffChanged" , colors.orange , colors.bg)
highlight("DiffRemoved" , colors.red    , colors.bg)

highlight("DiagnosticsE", colors.red    , colors.bg)
highlight("DiagnosticsW", colors.yellow , colors.bg)
highlight("DiagnosticsI", colors.cyan   , colors.bg)
highlight("DiagnosticsH", colors.orange , colors.bg)

highlight("Location"    , colors.yellow , colors.bg)
highlight("Progress"    , colors.magenta, colors.bg)

M.trunc_width = setmetatable({
  git_status = 90,
  filename   = 140,
}, {
  __index = function()
    return 80
  end,
})

M.is_truncated = function(_, width)
  return api.nvim_win_get_width(0) < width
end

M.get_window_number = function()
  return string.format(" %s%d", "%#Window#", api.nvim_win_get_number(0))
end

M.modes = setmetatable({
  ["n" ] = "N"  ,
  ["no"] = "N·P",
  ["v" ] = "V"  ,
  ["V" ] = "V·L",
  [""] = "V·B", -- this is not ^V, but it's , they're different
  ["s" ] = "S"  ,
  ["S" ] = "S·L",
  [""] = "S·B", -- same with this one, it's not ^S but it's 
  ["i" ] = "I"  ,
  ["ic"] = "I"  ,
  ["R" ] = "R"  ,
  ["Rv"] = "V·R",
  ["c" ] = "C"  ,
  ["cv"] = "V·E",
  ["ce"] = "E"  ,
  ["r" ] = "P"  ,
  ["rm"] = "RM" ,
  ["r?"] = "C"  ,
  ["!" ] = "S"  ,
  ["t" ] = "T"  ,
}, {
  __index = function()
    return "U"
  end,
})

M.get_current_mode = function(self)
  local current_mode = api.nvim_get_mode().mode
  return string.format(" %s%s", "%#Mode#", self.modes[current_mode])
end

M.get_git_branch = function(self)
  if self:is_truncated(self.trunc_width.git_status) then
    return ""
  end

  return string.format(" %s %s", "%#GitBranch#", fn.FugitiveHead())
end

M.get_git_status = function(self)
  local signs = vim.b.gitsigns_status_dict
    or { head = "", added = 0, changed = 0, removed = 0 }
  local is_head_empty = signs.head ~= ""

  return is_head_empty
    and string.format(
      " %s+%s %s~%s %s-%s",
      "%#DiffAdded#",
      signs.added or 0,
      "%#DiffChanged#",
      signs.changed or 0,
      "%#DiffRemoved#",
      signs.removed or 0
    )
    or ""
end

M.get_filename = function(self)
  local filetype = vim.bo.filetype

  if filetype == "qf" then
    return string.format(" %s%s", "%#Filename#", "QF")
  else
    return string.format(" %s%s", "%#Filename#", '%t%m%r')
  end
end

M.get_fileformat = function()
  return string.format("%s%s", "%#Fileformat#", vim.o.fileformat):lower()
end

M.diagnostic_status = function()
  local diagnostic = ''

  local num_errors = #vim.diagnostic.get(0, { severity = vim.diagnostic.severity.ERROR })
  if num_errors > 0 then
    diagnostic = string.format("%s%s%d", diagnostic, ' %#DiagnosticsE#E:', num_errors)
  end

  local num_warnings = #vim.diagnostic.get(0, { severity = vim.diagnostic.severity.WARN })
  if num_warnings > 0 then
    diagnostic = string.format("%s%s%d", diagnostic, ' %#DiagnosticsW#W:', num_warnings)
  end

  local num_infos = #vim.diagnostic.get(0, { severity = vim.diagnostic.severity.INFO })
  if num_infos > 0 then
    diagnostic = string.format("%s%s%d", diagnostic, ' %#DiagnosticsI#I:', num_infos)
  end

  local num_hints = #vim.diagnostic.get(0, { severity = vim.diagnostic.severity.HINT })
  if num_hints > 0 then
    diagnostic = string.format("%s%s%d", diagnostic, ' %#DiagnosticsH#H:', num_hints)
  end

  return diagnostic
end

M.get_line_col = function()
  return string.format(" %s%s", "%#Location#", "%l:%c")
end

M.progress = function()
  return string.format(" %s%s", "%#Progress#", "%3p%% ")
end

M.set_active = function(self)
  return table.concat {
    self:get_current_mode(),
    self:get_filename(),
    self:get_git_status(),
    "%=",
    self:diagnostic_status(),
    self:get_line_col(),
    self:progress(),
  }
end

M.set_inactive = function(self)
  return table.concat {
    "%#Window#",
    -- Putting this in a function like the others seems to not work. And takes
    -- the window number of the active window. Same for filename.
    " %{winnr()}",
    "%#Filename#",
    ' %t%m%r',
    self:get_git_branch(),
    "%=",
    self:get_fileformat(),
    self:get_line_col(),
    self:progress(),
  }
end

_G.Statusline = setmetatable(M, {
  __call = function(self, mode)
    return self["set_" .. mode](self)
  end,
})

cmd [[
  augroup Statusline
  au!
  au WinEnter,BufEnter * setlocal statusline=%!v:lua.Statusline('active')
  au WinLeave,BufLeave * setlocal statusline=%!v:lua.Statusline('inactive')
  augroup END
]]

cmd [[
  augroup HideStatusline
  au!
  au! FileType fzf,toggleterm
  au FileType fzf,toggleterm set laststatus=0 noshowmode noruler
    \| au BufLeave <buffer> set laststatus=2 showmode ruler
  augroup END
]]