solorice/.config/nvim/lua/user/bufferline.lua

local status_ok, bufferline = pcall(require, 'bufferline')
if not status_ok then
    return
end

bufferline.setup {
    options = {
        numbers = 'none', -- | 'ordinal' | 'buffer_id' | 'both' | function({ ordinal, id, lower, raise }): string,
        close_command = 'Bdelete! %d', -- can be a string | function, see 'Mouse actions'
        right_mouse_command = 'Bdelete! %d', -- can be a string | function, see 'Mouse actions'
        left_mouse_command = 'buffer %d', -- can be a string | function, see 'Mouse actions'
        middle_mouse_command = nil, -- can be a string | function, see 'Mouse actions'
        -- NOTE: this plugin is designed with this icon in mind,
        -- and so changing this is NOT recommended, this is intended
        -- as an escape hatch for people who cannot bear it for whatever reason
        indicator_icon = '▎',
        buffer_close_icon = '',
        -- buffer_close_icon = '',
        modified_icon = '●',
        close_icon = '',
        -- close_icon = '',
        left_trunc_marker = '',
        right_trunc_marker = '',
        --- name_formatter can be used to change the buffer's label in the bufferline.
        --- Please note some names can/will break the
        --- bufferline so use this at your discretion knowing that it has
        --- some limitations that will *NOT* be fixed.
        -- name_formatter = function(buf)  -- buf contains a 'name', 'path' and 'bufnr'
        --   -- remove extension from markdown files for example
        --   if buf.name:match('%.md') then
        --     return vim.fn.fnamemodify(buf.name, ':t:r')
        --   end
        -- end,
        max_name_length = 30,
        max_prefix_length = 30, -- prefix used when a buffer is de-duplicated
        tab_size = 21,
        diagnostics = false, -- | 'nvim_lsp' | 'coc',
        diagnostics_update_in_insert = false,
        -- diagnostics_indicator = function(count, level, diagnostics_dict, context)
        --   return '('..count..')'
        -- end,
        -- NOTE: this will be called a lot so don't do any heavy processing here
        -- custom_filter = function(buf_number)
        --   -- filter out filetypes you don't want to see
        --   if vim.bo[buf_number].filetype ~= '<i-dont-want-to-see-this>' then
        --     return true
        --   end
        --   -- filter out by buffer name
        --   if vim.fn.bufname(buf_number) ~= '<buffer-name-I-dont-want>' then
        --     return true
        --   end
        --   -- filter out based on arbitrary rules
        --   -- e.g. filter out vim wiki buffer from tabline in your work repo
        --   if vim.fn.getcwd() == '<work-repo>' and vim.bo[buf_number].filetype ~= 'wiki' then
        --     return true
        --   end
        -- end,
        offsets = { { filetype = 'NvimTree', text = '', padding = 1 } },
        show_buffer_icons = true,
        show_buffer_close_icons = true,
        show_close_icon = true,
        show_tab_indicators = true,
        persist_buffer_sort = true, -- whether or not custom sorted buffers should persist
        -- can also be a table containing 2 custom separators
        -- [focused and unfocused]. eg: { '|', '|' }
        separator_style = 'thin', -- | 'thick' | 'thin' | { 'any', 'any' },
        enforce_regular_tabs = true,
        always_show_bufferline = true,
        -- sort_by = 'id' | 'extension' | 'relative_directory' | 'directory' | 'tabs' | function(buffer_a, buffer_b)
        --   -- add custom logic
        --   return buffer_a.modified > buffer_b.modified
        -- end
    },
    highlights = {
        fill = {
            guifg = { attribute = 'fg', highlight = '#ff0000' },
            guibg = { attribute = 'bg', highlight = 'TabLine' },
        },
        background = {
            guifg = { attribute = 'fg', highlight = 'TabLine' },
            guibg = { attribute = 'bg', highlight = 'TabLine' },
        },

        -- buffer_selected = {
        --   guifg = {attribute='fg',highlight='#ff0000'},
        --   guibg = {attribute='bg',highlight='#0000ff'},
        --   gui = 'none'
        --   },
        buffer_visible = {
            guifg = { attribute = 'fg', highlight = 'TabLine' },
            guibg = { attribute = 'bg', highlight = 'TabLine' },
        },

        close_button = {
            guifg = { attribute = 'fg', highlight = 'TabLine' },
            guibg = { attribute = 'bg', highlight = 'TabLine' },
        },
        close_button_visible = {
            guifg = { attribute = 'fg', highlight = 'TabLine' },
            guibg = { attribute = 'bg', highlight = 'TabLine' },
        },
        -- close_button_selected = {
        --   guifg = {attribute='fg',highlight='TabLineSel'},
        --   guibg ={attribute='bg',highlight='TabLineSel'}
        --   },

        tab_selected = {
            guifg = { attribute = 'fg', highlight = 'Normal' },
            guibg = { attribute = 'bg', highlight = 'Normal' },
        },
        tab = {
            guifg = { attribute = 'fg', highlight = 'TabLine' },
            guibg = { attribute = 'bg', highlight = 'TabLine' },
        },
        tab_close = {
            -- guifg = {attribute='fg',highlight='LspDiagnosticsDefaultError'},
            guifg = { attribute = 'fg', highlight = 'TabLineSel' },
            guibg = { attribute = 'bg', highlight = 'Normal' },
        },

        duplicate_selected = {
            guifg = { attribute = 'fg', highlight = 'TabLineSel' },
            guibg = { attribute = 'bg', highlight = 'TabLineSel' },
            gui = 'italic',
        },
        duplicate_visible = {
            guifg = { attribute = 'fg', highlight = 'TabLine' },
            guibg = { attribute = 'bg', highlight = 'TabLine' },
            gui = 'italic',
        },
        duplicate = {
            guifg = { attribute = 'fg', highlight = 'TabLine' },
            guibg = { attribute = 'bg', highlight = 'TabLine' },
            gui = 'italic',
        },

        modified = {
            guifg = { attribute = 'fg', highlight = 'TabLine' },
            guibg = { attribute = 'bg', highlight = 'TabLine' },
        },
        modified_selected = {
            guifg = { attribute = 'fg', highlight = 'Normal' },
            guibg = { attribute = 'bg', highlight = 'Normal' },
        },
        modified_visible = {
            guifg = { attribute = 'fg', highlight = 'TabLine' },
            guibg = { attribute = 'bg', highlight = 'TabLine' },
        },

        separator = {
            guifg = { attribute = 'bg', highlight = 'TabLine' },
            guibg = { attribute = 'bg', highlight = 'TabLine' },
        },
        separator_selected = {
            guifg = { attribute = 'bg', highlight = 'Normal' },
            guibg = { attribute = 'bg', highlight = 'Normal' },
        },
        -- separator_visible = {
        --   guifg = {attribute='bg',highlight='TabLine'},
        --   guibg = {attribute='bg',highlight='TabLine'}
        --   },
        indicator_selected = {
            guifg = { attribute = 'fg', highlight = 'LspDiagnosticsDefaultHint' },
            guibg = { attribute = 'bg', highlight = 'Normal' },
        },
    },
}