refactor(nvim): rewrite highlight (now color) plugin

2 files changed, 105 insertions, 114 deletions

diff --git a/plugin/50-highlight.lua b/plugin/50-color.lua
index 3a68146..c525866 100644
--- a/plugin/50-highlight.lua
+++ b/plugin/50-color.lua
@@ -1,23 +1,34 @@
 --
--- 50-highlight.lua
+-- 50-color.lua
 --
--- * Creates a function to adjust highlight groups for the solarized colorscheme. It also sets popup
---   menu width and border style.
--- * Creates a function that outputs a 'tabline' compatible strings that sets the tabline
---   format and style.
--- * Creates an autocommand to trigger these functions when the background or color scheme changes.
+-- * Highlight tweaks for the solarized colorscheme, plus popup-menu and tabpage-title styling.
+-- * The lualine statusline (https://github.com/nvim-lualine/lualine.nvim), themed to match.
+-- * Registers both into dotfiles.color, which re-applies them on colorscheme / 'background' changes
+--   and once after startup.
 -- * Sets the default colorscheme (solarized) and background (dark).
 --
 -- User commands:
 --   `ColorsBgToggle`: toggle light/dark background
 --   `TabRename`: rename current tab
---   `TabRenameFileName`: rename current tab with current active buffer file name
+--   `TabRenameFileName`: rename current tab to the active buffer's file name
+--   `LualineConfig`: show the resolved lualine configuration
 --
 
+local color = require("dotfiles.color")
+local lualine = require("lualine")
+
 local solarized = { blue = "#268bd2" }
 
--- Adjust highlights (for the solarized theme) to fit my personal tastes.
-local function adjust_solarized_highlights()
+----------------------------------------------------------------------------------------------------
+-- Highlights
+----------------------------------------------------------------------------------------------------
+
+-- Highlight applier: adjust the solarized groups to fit my personal tastes. No-ops unless solarized
+-- is the active colorscheme.
+local function apply_solarized_highlights()
+	if vim.g.colors_name ~= "solarized" then
+		return
+	end
 	-- Window bar style
 	vim.api.nvim_set_hl(0, "WinBarCwd", { fg = solarized.blue, italic = true })
 	vim.api.nvim_set_hl(0, "WinBarFilePath", { italic = true })
@@ -41,15 +52,10 @@ local function adjust_solarized_highlights()
 	vim.api.nvim_set_hl(0, "Folded", { bg = normal_bg, underline = true, update = true })
 end
 
-local function toggle_theme()
-	vim.opt.background = vim.o.background == "light" and "dark" or "light"
-	vim.notify("Color theme set to " .. vim.o.background)
-end
-
--- Creates custom highlight groups for styling the tabpage title bars:
+-- Highlight applier: create custom highlight groups for styling the tabpage title bars:
 -- * TabLineWinCount: number of open windows in the tabpage
 -- * TabLineSelWinCount: number of open windows in the currently active tabpage
-local function create_tabpage_title_hl()
+local function apply_tabpage_title_highlights()
 	local normal = vim.api.nvim_get_hl(0, { name = "Normal", link = false })
 	local tabline = vim.api.nvim_get_hl(0, { name = "TabLine", link = false })
 	local tablinesel = vim.api.nvim_get_hl(0, { name = "TabLineSel", link = false })
@@ -62,6 +68,66 @@ local function create_tabpage_title_hl()
 	)
 end
 
+----------------------------------------------------------------------------------------------------
+-- Statusline
+----------------------------------------------------------------------------------------------------
+
+-- Spell flag: which spell languages are enabled, or nil when 'spelllang' matches none of these.
+local function spell_status()
+	if vim.o.spelllang == "fr" then
+		return "+S(fr)"
+	elseif vim.o.spelllang == "en_us" then
+		return "+S(en)"
+	elseif vim.o.spelllang == "en_us,fr" then
+		return "+S(en,fr)"
+	end
+end
+
+-- Custom status flags: "+F" when formatting is on for the buffer, followed by the spell flag.
+local function statuses()
+	return (vim.b.format and "+F" or "") .. (vim.o.spell and spell_status() or "")
+end
+
+-- lualine builds its own section-b-backed highlights for the diff/diagnostics components
+-- (lualine_b_diff_added_normal, lualine_b_diagnostics_error_normal, ...). Stamp bold onto them with
+-- update=true so only the bold attribute changes — fg and section b's background are left untouched.
+-- Must run after lualine (re)creates the groups: initial setup, theme switch, colorscheme.
+local function bold_diff_diag()
+	for name in pairs(vim.api.nvim_get_hl(0, {})) do
+		if name:find("^lualine_b_diff") or name:find("^lualine_b_diagnostics") then
+			vim.api.nvim_set_hl(0, name, { bold = true, update = true })
+		end
+	end
+end
+
+local lualine_sections = {
+	lualine_c = { statuses, "filename" },
+	lualine_x = { "encoding", "fileformat", "filetype", "lsp_status" },
+}
+
+local lualine_options = {
+	disabled_filetypes = { "netrw", "qf" },
+	component_separators = { left = "|", right = "|" },
+	section_separators = { left = "", right = "" },
+}
+
+-- Pick the lualine theme from 'background' and (re)apply the configuration.
+local function setup()
+	lualine_options.theme = vim.o.background == "light" and "solarized_light" or "solarized_dark"
+	lualine.setup({ options = lualine_options, sections = lualine_sections })
+end
+
+-- Statusline applier: re-pick the lualine theme for the current 'background', then re-bold the
+-- diff/diagnostics groups once lualine has rebuilt them.
+local function apply_statusline_highlights()
+	setup()
+	vim.schedule(bold_diff_diag)
+end
+
+----------------------------------------------------------------------------------------------------
+-- Tabline
+----------------------------------------------------------------------------------------------------
+
 -- Builds the window-count segment of a tabpage label, e.g. ` (2)[+] ` (no styling).
 -- `is_modified` appends the `[+]` marker when any window in the tab has pending changes.
 local function make_tab_info_label(win_count, is_modified)
@@ -87,8 +153,7 @@ local function make_tab_label(id, is_current, width)
 	end
 	tab_label = tab_label_prefix .. tab_label
 	local display_width = vim.fn.strdisplaywidth(tab_label)
-	return (display_width > width)
-			and (vim.fn.strcharpart(tab_label, 0, width - 1) .. "…")
+	return (display_width > width) and (vim.fn.strcharpart(tab_label, 0, width - 1) .. "…")
 		or (tab_label .. string.rep(" ", width - display_width))
 end
 
@@ -122,48 +187,49 @@ function GetTabLine()
 	return s .. "%#TabLineFill#"
 end
 
+-- Name the current tab from the command argument.
 local function rename_tab(opts)
 	vim.t.tabname = opts.args
 	vim.cmd.redrawtabline()
 end
 
+-- Name the current tab after the active buffer's file name (without extension).
 local function rename_tab_to_cur_filename()
 	vim.t.tabname = vim.fn.expand("%:t:r")
 	vim.cmd.redrawtabline()
 end
 
--- Adjust highlights to fit my personal tastes.
-local function adjust_highlights()
-	if vim.g.colors_name == "solarized" then
-		adjust_solarized_highlights()
-	end
-	create_tabpage_title_hl()
-end
-
+----------------------------------------------------------------------------------------------------
+-- Commands & init
 ----------------------------------------------------------------------------------------------------
 
-vim.api.nvim_create_autocmd("ColorScheme", {
-	desc = "Adjust custom highlights",
-	group = vim.g.dotfiles.augroup,
-	callback = adjust_highlights,
-})
+-- Flip between the light and dark backgrounds (the colorscheme reloads, OptionSet re-themes).
+local function toggle_theme()
+	vim.opt.background = vim.o.background == "light" and "dark" or "light"
+	vim.notify("Color theme set to " .. vim.o.background)
+end
 
-vim.api.nvim_create_autocmd("OptionSet", {
-	desc = "Adjust custom highlights on theme change",
-	pattern = "background",
-	group = vim.g.dotfiles.augroup,
-	callback = adjust_highlights,
-})
+-- Show the resolved lualine configuration.
+local function show_lualine_config()
+	vim.notify(vim.inspect(lualine.get_config()))
+end
+
+color.register(apply_solarized_highlights)
+color.register(apply_tabpage_title_highlights)
+color.register(apply_statusline_highlights)
 
 vim.api.nvim_create_user_command(
 	"ColorsBgToggle",
 	toggle_theme,
 	{ desc = "Toggle light/dark theme" }
 )
-
 vim.api.nvim_create_user_command("TabRename", rename_tab, { nargs = 1 })
-
 vim.api.nvim_create_user_command("TabRenameFileName", rename_tab_to_cur_filename, { nargs = 0 })
+vim.api.nvim_create_user_command(
+	"LualineConfig",
+	show_lualine_config,
+	{ desc = "Show lualine configuration" }
+)
 
 -- See `:help stl-%!`
 vim.o.tabline = "%!v:lua.GetTabLine()"
diff --git a/plugin/50-statusline.lua b/plugin/50-statusline.lua
deleted file mode 100644
index e1d1687..0000000
--- a/plugin/50-statusline.lua
+++ /dev/null
@@ -1,75 +0,0 @@
---
--- Status line configuration plugin
---
--- I use lualine, see https://github.com/nvim-lualine/lualine.nvim#configuring-lualine-in-initvim
-
-local lualine = require("lualine")
-
-local function spell_status()
-	if vim.o.spelllang == "fr" then
-		return "+S(fr)"
-	elseif vim.o.spelllang == "en_us" then
-		return "+S(en)"
-	elseif vim.o.spelllang == "en_us,fr" then
-		return "+S(en,fr)"
-	end
-end
-
-local function statuses()
-	return (vim.b.autoformat and "+F" or "") .. (vim.o.spell and spell_status() or "")
-end
-
--- lualine builds its own section-b-backed highlights for the diff/diagnostics
--- components (lualine_b_diff_added_normal, lualine_b_diagnostics_error_normal,
--- ...). Stamp bold onto them with update=true so only the bold attribute
--- changes -- fg and section b's background are left untouched. Must run after
--- lualine (re)creates the groups: initial setup, theme switch, colorscheme.
-local function bold_diff_diag()
-	for name in pairs(vim.api.nvim_get_hl(0, {})) do
-		if name:find("^lualine_b_diff") or name:find("^lualine_b_diagnostics") then
-			vim.api.nvim_set_hl(0, name, { bold = true, update = true })
-		end
-	end
-end
-
-vim.api.nvim_create_autocmd("ColorScheme", {
-	desc = "Re-bold lualine diff/diagnostics after colorscheme rebuild",
-	group = vim.g.dotfiles.augroup,
-	callback = function()
-		vim.schedule(bold_diff_diag)
-	end,
-})
-
-local lualine_sections = {
-	lualine_c = { statuses, "filename" },
-	lualine_x = { "encoding", "fileformat", "filetype", "lsp_status" },
-}
-
-local lualine_options = {
-	disabled_filetypes = { "netrw", "qf" },
-	component_separators = { left = "|", right = "|" },
-	section_separators = { left = "", right = "" },
-}
-
-local function setup()
-	lualine_options.theme = vim.o.background == "light" and "solarized_light" or "solarized_dark"
-	lualine.setup({ options = lualine_options, sections = lualine_sections })
-end
-
--- Adjust colors when the theme (light/dark) changes
-vim.api.nvim_create_autocmd("OptionSet", {
-	desc = "Adjust color scheme",
-	pattern = "background",
-	group = vim.g.dotfiles.augroup,
-	callback = function()
-		setup()
-		vim.schedule(bold_diff_diag)
-	end,
-})
-
-setup()
-vim.schedule(bold_diff_diag)
-
-vim.api.nvim_create_user_command("LualineConfig", function()
-	vim.notify(vim.inspect(lualine.get_config()))
-end, { desc = "Show lualine configuration" })