vim-settings/neovim/lua/plugins/lualine.lua

local M = {}

-- Only return interesting ffenc (not utf-8[unix])
function M.custom_ffenc()
    local enc = vim.bo.fenc
    local format = vim.bo.fileformat
    if enc ~= "utf-8" or format ~= "unix" then
        return enc .. "[" .. format .. "]"
    end

    return ""
end

function M.mixed_indent()
    local mixed = vim.fn.search([[\v^(\t+ | +\t)]], 'nw')
    if mixed > 0 then
        return "i:" .. mixed
    end
    local space_indent = vim.fn.search([[\v^ +]], 'nw')
    local tab_indent = vim.fn.search([[\v^\t+]], 'nw')
    if tab_indent > 0 and space_indent > 0 then
        return "i:" .. require("math").max(tab_indent, space_indent)
    end

    return ""
end

function M.trailing_whitespace()
    local line = vim.fn.search([[\s\+$]], 'nw')
    if line ~= 0 then
        return "tw:" .. line
    end

    return ""
end

-- Configure lualine witha  provided theme
function M.config_lualine(theme_name)
    -- Theme name transformations
    if theme_name == nil then
        theme_name = "auto"
    elseif theme_name:find("wombat") then
        theme_name = "wombat"
    elseif theme_name == "wombuddy" then
        theme_name = "wombat"
    end

    require("lualine").setup {
        options = {
            theme = theme_name,
            icons_enabled = false,
            component_separators = {left = "|", right = "|"},
            section_separators = {left = "", right = ""},
        },
        sections = {
            lualine_a = {{"mode", fmt = function(str) return str:sub(1, 1) end}},
            lualine_b = {"FugitiveHead", "diff"},
            lualine_c = {"filename"},
            lualine_x = {M.custom_ffenc, "filetype"},
            lualine_y = {"progress", "location"},
            lualine_z = {
                {"diagnostics", sources = {"nvim_lsp"}},
                {M.mixed_indent, color = {bg = "#de4f1f"}},
                {M.trailing_whitespace, color = {bg = "#de4f1f"}},
            },
        },
    }
end

return M