refactor(highlights): use custom highlight groups (#44)

* fix: allow highlights without style

The issue shouldn't be possible, but there seems to be some optimization
going on that sometimes removes empty tables.

* refactor(highlights): use custom highlight groups

* remove empty comment

lua/mellifluous/color.lua

@@ -70,6 +70,10 @@ function color_meta:with_lightness(val)
     return M.new(oklch_to_hex(oklch))
 end
 
+function color_meta:get_hsl()
+    return hex_to_okhsl(self.hex)
+end
+
 function color_meta:saturated(val)
     local okhsl = hex_to_okhsl(self.hex)
     okhsl.s = clip(okhsl.s + val, 0, 100)

lua/mellifluous/highlights/custom_groups.lua

@@ -0,0 +1,62 @@
+local M = {}
+
+-- Any shared highlight groups that cannot be found in general highlights or
+-- treesitter highlights are created here.
+
+function M.get(colors)
+    local config = require('mellifluous.config').config
+    local shader = require('mellifluous.utils.shader')
+
+    return {
+        MainKeyword = { fg = colors.main_keywords, style = config.styles.keywords },
+
+        IndentLine = function(bg)
+            return { fg = shader.replicate_shade(colors.bg, colors.fg4, bg) }
+        end,
+        IndentLineActive = function(bg)
+            return { fg = shader.replicate_shade(colors.bg, colors.fg5, bg) }
+        end,
+        IndentLineInactive = function(bg)
+            return {
+                fg = config.is_bg_dark
+                    and shader.replicate_shade(colors.bg, colors.bg4, bg)
+                    or shader.replicate_shade(colors.bg, colors.dark_bg2, bg)
+            }
+        end,
+
+        MenuButton = { fg = colors.ui_blue },
+        MenuButtonSelected = function(bg)
+            local applied_bg = config.is_bg_dark
+                and shader.replicate_shade(colors.bg, colors.bg4, bg)
+                or shader.replicate_shade(colors.bg, colors.dark_bg2, bg)
+            return {
+                fg = shader.replicate_shade(colors.bg, applied_bg, colors.ui_blue),
+                bg = applied_bg,
+            }
+        end,
+
+        FileTree = {
+                fg = colors.fg2,
+                bg = (config.transparent_background.file_tree
+                        and 'NONE')
+                    or config.flat_background.file_tree
+                        and colors.bg
+                        or colors.dark_bg
+        },
+        FileTreeWinSeparator = function(bg)
+            return {
+                fg = config.flat_background.line_numbers ~= config.flat_background.file_tree
+                        and bg -- no separator if LineNr bg differs from this bg
+                    or config.flat_background.line_numbers and config.flat_background.file_tree
+                        and colors.fg5 -- stronger separator if both bg are flat
+                    or config.is_bg_dark
+                        and colors.bg3
+                        or colors.dark_bg2,
+
+                bg = bg,
+            }
+        end,
+    }
+end
+
+return M

lua/mellifluous/highlights/general.lua

@@ -3,6 +3,7 @@ local M = {}
 function M.set(hl, colors)
     local shader = require('mellifluous.utils.shader')
     local config = require('mellifluous.config').config
+    local groups = require('mellifluous.highlights.custom_groups').get(colors)
 
     hl.set('Normal', {
         bg = (config.transparent_background.enabled and 'NONE')
@@ -131,33 +132,32 @@ function M.set(hl, colors)
     hl.set('Float', { link = 'Constant', style = config.styles.numbers or {} })                    --   A floating point constant: 2.3e10
     hl.set('Identifier', { fg = colors.fg, style = config.styles.variables or {} })                -- (*) Any variable name
     hl.set('Function', { fg = colors.functions, style = config.styles.functions or {} })           --   Function name (also: methods for classes)
-    hl.set('Statement', { link = 'Keyword' })                                            -- (*) Any statement
+    hl.set('Statement', { link = 'Keyword' })                                                      -- (*) Any statement
     hl.set('Conditional', { fg = colors.main_keywords, style = config.styles.conditionals or {} }) --   if, then, else, endif, switch, etc.
     hl.set('Repeat', { fg = colors.main_keywords, style = config.styles.loops or {} })             --   for, do, while, etc.
     hl.set('Label', { fg = colors.other_keywords })
     hl.set('Operator', {
         fg = config.is_bg_dark and colors.operators or colors.fg3,
         style = config.styles.operators or {}
-    })                                                                                   --   'sizeof', '+', '*', etc.
-    hl.set('Keyword', { fg = colors.other_keywords, style = config.styles.keywords })    --   any other keyword
-    hl.set('MellifluousMainKeyword', { fg = colors.main_keywords, style = config.styles.keywords }) -- Mainly keywords related to control flow
-    hl.set('Exception', { link = 'MellifluousMainKeyword' })                                        --   try, catch, throw
-    hl.set('PreProc', { fg = colors.functions })                                         -- (*) Generic Preprocessor
-    hl.set('Include', { link = 'PreProc' })                                              --   Preprocessor #include
-    hl.set('Define', { link = 'PreProc' })                                               --   Preprocessor #define
-    hl.set('Macro', { link = 'PreProc' })                                                --   Same as Define
-    hl.set('PreCondit', { link = 'PreProc' })                                            --   Preprocessor #if, #else, #endif, etc.
-    hl.set('Type', { fg = colors.types, style = config.styles.types or {} })             -- (*) int, long, char, etc.
-    hl.set('StorageClass', { link = 'Type' })                                            --   static, register, volatile, etc.
-    hl.set('Structure', { link = 'Type' })                                               --   struct, union, enum, etc.
-    hl.set('Typedef', { link = 'Type' })                                                 --   A typedef
-    hl.set('Special', { fg = colors.other_keywords })                                    -- (*) Any special symbol
-    hl.set('SpecialChar', { link = 'Special' })                                          --   Special character in a constant
-    hl.set('Tag', { link = 'Special' })                                                  --   You can use CTRL-] on this
-    hl.set('Delimiter', { link = 'Operator' })                                           --   Character that needs attention
-    hl.set('SpecialComment', { link = 'Special' })                                       --   Special things inside a comment (e.g. '\n')
-    hl.set('Debug', { link = 'Special' })                                                --   Debugging statements
-    hl.set('Underlined', { underline = true, fg = colors.fg3 })                          -- Text that stands out, HTML links
+    })                                                                                --   'sizeof', '+', '*', etc.
+    hl.set('Keyword', { fg = colors.other_keywords, style = config.styles.keywords }) --   any other keyword
+    hl.set('Exception', groups.MainKeyword)                                           --   try, catch, throw
+    hl.set('PreProc', { fg = colors.functions })                                      -- (*) Generic Preprocessor
+    hl.set('Include', { link = 'PreProc' })                                           --   Preprocessor #include
+    hl.set('Define', { link = 'PreProc' })                                            --   Preprocessor #define
+    hl.set('Macro', { link = 'PreProc' })                                             --   Same as Define
+    hl.set('PreCondit', { link = 'PreProc' })                                         --   Preprocessor #if, #else, #endif, etc.
+    hl.set('Type', { fg = colors.types, style = config.styles.types or {} })          -- (*) int, long, char, etc.
+    hl.set('StorageClass', { link = 'Type' })                                         --   static, register, volatile, etc.
+    hl.set('Structure', { link = 'Type' })                                            --   struct, union, enum, etc.
+    hl.set('Typedef', { link = 'Type' })                                              --   A typedef
+    hl.set('Special', { fg = colors.other_keywords })                                 -- (*) Any special symbol
+    hl.set('SpecialChar', { link = 'Special' })                                       --   Special character in a constant
+    hl.set('Tag', { link = 'Special' })                                               --   You can use CTRL-] on this
+    hl.set('Delimiter', { link = 'Operator' })                                        --   Character that needs attention
+    hl.set('SpecialComment', { link = 'Special' })                                    --   Special things inside a comment (e.g. '\n')
+    hl.set('Debug', { link = 'Special' })                                             --   Debugging statements
+    hl.set('Underlined', { underline = true, fg = colors.fg3 })                       -- Text that stands out, HTML links
     hl.set('Bold', { bold = config.bold })
     hl.set('Italic', { italic = config.italic })
     hl.set('Ignore', { fg = colors.fg5 })                                                      -- Left blank, hidden |hl-Ignore| (NOTE: May be invisible here in template)
@@ -173,7 +173,7 @@ function M.set(hl, colors)
     hl.set('LspCodeLens', { bg = colors.bg2 })                 -- Used to color the virtual text of the codelens. See |nvim_buf_set_extmark()|.
     hl.set('LspCodeLensSeparator', { fg = colors.fg5 })        -- Used to color the seperator between two or more code lens.
     hl.set('LspSignatureActiveParameter', { bg = colors.bg4 }) -- Used to highlight the active parameter in the signature help. See |vim.lsp.handlers.signature_help()|.
-    ---
+
     hl.set('DiagnosticError', { fg = colors.ui_red })          -- Used as the base highlight group. Other Diagnostic highlights link to this by default (except Underline)
     hl.set('DiagnosticWarn', { fg = colors.ui_orange })        -- Used as the base highlight group. Other Diagnostic highlights link to this by default (except Underline)
     hl.set('DiagnosticInfo', { fg = colors.ui_blue })          -- Used as the base highlight group. Other Diagnostic highlights link to this by default (except Underline)

lua/mellifluous/highlights/plugins/indent_blankline.lua

@@ -1,10 +1,10 @@
 local M = {}
 
 function M.set(hl, colors)
-    local config = require('mellifluous.config').config
+    local groups = require('mellifluous.highlights.custom_groups').get(colors)
 
-    hl.set('IblIndent', { fg = (config.is_bg_dark and colors.bg4) or colors.dark_bg2 })
-    hl.set('IblScope', { fg = colors.fg5 })
+    hl.set('IblIndent', groups.IndentLineInactive(colors.bg))
+    hl.set('IblScope', groups.IndentLineActive(colors.bg))
     hl.set('IblWhitespace', { link = 'Whitespace' })
 end
 

lua/mellifluous/highlights/plugins/lazy.lua

@@ -2,10 +2,12 @@ local M = {}
 
 function M.set(hl, colors)
     local config = require('mellifluous.config').config
+    local groups = require('mellifluous.highlights.custom_groups').get(colors)
+    local bg = hl.get('NormalFloat').bg
 
     hl.set('LazyNormal', { bg = colors.bg2 })
-    hl.set('LazyButton', { fg = colors.fg2, bg = colors.bg })
-    hl.set('LazyButtonActive', { fg = colors.fg, bg = config.is_bg_dark and colors.bg5 or colors.bg4 })
+    hl.set('LazyButton', groups.MenuButton)
+    hl.set('LazyButtonActive', groups.MenuButtonSelected(bg))
     hl.set('LazyH1', { link = 'LazyButtonActive' })
 
     hl.set('LazyProgressTodo', { fg = config.is_bg_dark and colors.fg5 or colors.dark_bg })

lua/mellifluous/highlights/plugins/mason.lua

@@ -1,14 +1,15 @@
 local M = {}
 
 function M.set(hl, colors)
-    local config = require('mellifluous.config').config
+    local groups = require('mellifluous.highlights.custom_groups').get(colors)
+    local bg = hl.get('NormalFloat').bg
 
     hl.set('MasonHeader', { fg = colors.dark_bg, bg = colors.ui_orange, bold = true })
     hl.set('MasonHeaderSecondary', { fg = colors.dark_bg, bg = colors.ui_blue, bold = true })
-    hl.set('MasonHighlightBlockBold', { fg = colors.fg, bg = config.is_bg_dark and colors.bg5 or colors.bg4, bold = true })
+    hl.set('MasonHighlightBlockBold', groups.MenuButtonSelected(bg))
     hl.set('MasonHighlightBlockBoldSecondary', { link = 'MasonHighlightBlockBold' })
     hl.set('MasonHighlightBlock', { fg = colors.dark_bg, bg = colors.ui_green })
-    hl.set('MasonMutedBlock', { fg = colors.fg2, bg = colors.bg })
+    hl.set('MasonMutedBlock', groups.MenuButton)
     hl.set('MasonHighlight', { fg = colors.ui_yellow })
     hl.set('MasonHighlightSecondary', { fg = colors.ui_purple })
     hl.set('MasonMuted', { fg = colors.fg3 })

lua/mellifluous/highlights/plugins/neo_tree.lua

@@ -2,7 +2,8 @@ local M = {}
 
 function M.set(hl, colors)
     local root_fg = colors.fg3
-    local config = require('mellifluous.config').config
+    local groups = require('mellifluous.highlights.custom_groups').get(colors)
+    local normal_group = groups.FileTree
 
     hl.set('NeoTreeGitConflict', { fg = colors.ui_purple })
     hl.set('NeoTreeGitDeleted', { fg = colors.red })
@@ -12,33 +13,18 @@ function M.set(hl, colors)
     hl.set('NeoTreeGitRenamed', { fg = colors.ui_orange })
     hl.set('NeoTreeGitUntracked', { fg = colors.ui_orange })
 
-    hl.set('NeoTreeNormal', {
-        bg = (config.transparent_background.file_tree and 'NONE') or (config.flat_background.file_tree and hl.get(
-            'Normal'
-        ).bg) or colors.dark_bg,
-        fg = colors.fg2,
-    })
-    hl.set('NeoTreeNormalNC', { link = 'NeoTreeNormal' })
-    hl.set('NeoTreePopup', { link = 'NeoTreeNormal' })
-    hl.set('NeoTreeWinSeparator', {
-        bg = hl.get('NeoTreeNormal').bg,
-        fg = (config.flat_background.line_numbers ~= config.flat_background.file_tree
-                and hl.get('NeoTreeNormal').bg) -- no separator if LineNr bg differs from this bg
-            or (config.flat_background.line_numbers
-                and config.flat_background.file_tree
-                and (config.is_bg_dark and colors.bg4)
-                or colors.dark_bg2) -- stronger separator if both bg are flat
-            or (config.is_bg_dark and colors.bg3)
-            or colors.dark_bg2,
-    })
-    hl.set('NeoTreeIndentMarker', { fg = colors.fg5 })
-    hl.set('NeoTreeEndOfBuffer', { bg = hl.get('NeoTreeNormal').bg, fg = hl.get('EndOfBuffer').fg })
+    hl.set('NeoTreeNormal', normal_group)
+    hl.set('NeoTreeNormalNC', normal_group)
+    hl.set('NeoTreePopup', normal_group)
+    hl.set('NeoTreeWinSeparator', groups.FileTreeWinSeparator(normal_group.bg))
+    hl.set('NeoTreeIndentMarker', groups.IndentLine(normal_group.bg))
+    hl.set('NeoTreeEndOfBuffer', { bg = normal_group.bg, fg = hl.get('EndOfBuffer').fg })
     hl.set('NeoTreeFolderIcon', { fg = hl.get('Directory').fg })
     hl.set('NeoTreeRootName', { fg = root_fg })
-    hl.set('NeoTreeStatusLine', { link = 'NeoTreeNormal' })
+    hl.set('NeoTreeStatusLine', normal_group)
     hl.set('NeoTreeCursorLine', { link = 'CursorLine' })
     hl.set('NeoTreeCursorLineSign', { bg = hl.get('CursorLine').bg })
-    hl.set('NeoTreeSignColumn', { link = 'NeoTreeNormal' })
+    hl.set('NeoTreeSignColumn', normal_group)
     hl.set('NeoTreeFloatTitle', { fg = colors.fg2 })
     hl.set('NeoTreeTitleBar', { link = 'NeoTreeFloatTitle' })
 end

lua/mellifluous/highlights/plugins/neotest.lua

@@ -2,11 +2,12 @@ local M = {}
 
 function M.set(hl, colors)
 	local config = require("mellifluous.config").config
+    local groups = require('mellifluous.highlights.custom_groups').get(colors)
 
 	hl.set("NeotestAdapterName", { fg = colors.fg3 })
 	hl.set("NeotestFocused", { fg = hl.get("Normal").fg, bold = true })
 	hl.set("NeotestTarget", { style = { underline = true } })
-	hl.set("NeotestIndent", { fg = colors.fg4 })
+    hl.set("NeotestIndent", groups.IndentLine(colors.bg))
 	hl.set("NeotestExpandMarker", { link = "NeotestIndent" })
 
 	hl.set("NeotestDir", { fg = hl.get("Directory").fg })

lua/mellifluous/highlights/plugins/nvim_tree.lua

@@ -2,11 +2,9 @@ local M = {}
 
 function M.set(hl, colors)
     local config = require('mellifluous.config').config
-    local root_fg = colors.dark_bg
-
-    if config.plugins.nvim_tree.show_root == true then
-        root_fg = colors.fg3
-    end
+    local groups = require('mellifluous.highlights.custom_groups').get(colors)
+    local normal_group = groups.FileTree;
+    local root_fg = config.plugins.nvim_tree.show_root and colors.fg3 or colors.dark_bg
 
     hl.set('NvimTreeGitDeleted', { fg = colors.red })
     hl.set('NvimTreeGitDirty', { fg = colors.ui_orange })
@@ -15,28 +13,13 @@ function M.set(hl, colors)
     hl.set('NvimTreeGitNew', { fg = colors.ui_blue })
     hl.set('NvimTreeGitRenamed', { fg = colors.ui_orange })
     hl.set('NvimTreeGitStaged', { fg = colors.ui_green })
-    hl.set('NvimTreeNormal', {
-        bg = (config.transparent_background.file_tree and 'NONE')
-            or (config.flat_background.file_tree and hl.get('Normal').bg)
-            or colors.dark_bg,
-        fg = colors.fg2
-    })
-    hl.set('NvimTreeNormalNC', { link = 'NvimTreeNormal' })
-    hl.set('NvimTreePopup', { link = 'NvimTreeNormal' })
-    hl.set('NvimTreeSignColumn', { link = 'NvimTreeNormal' })
-    hl.set('NvimTreeWinSeparator', {
-        bg = hl.get('NvimTreeNormal').bg,
-        fg = (config.flat_background.line_numbers ~= config.flat_background.file_tree
-                and hl.get('NvimTreeNormal').bg) -- no separator if LineNr bg differs from this bg
-            or (config.flat_background.line_numbers
-                and config.flat_background.file_tree
-                and (config.is_bg_dark and colors.bg4)
-                or colors.dark_bg2) -- stronger separator if both bg are flat
-            or (config.is_bg_dark and colors.bg3)
-            or colors.dark_bg2
-    })
-    hl.set('NvimTreeIndentMarker', { fg = hl.get('Directory').fg })
-    hl.set('NvimTreeEndOfBuffer', { bg = hl.get('NvimTreeNormal').bg, fg = hl.get('EndOfBuffer').fg })
+    hl.set('NvimTreeNormal', normal_group)
+    hl.set('NvimTreeNormalNC', normal_group)
+    hl.set('NvimTreePopup', normal_group)
+    hl.set('NvimTreeSignColumn', normal_group)
+    hl.set('NvimTreeWinSeparator', groups.FileTreeWinSeparator(normal_group.bg))
+    hl.set('NvimTreeIndentMarker', groups.IndentLine(normal_group.bg))
+    hl.set('NvimTreeEndOfBuffer', { bg = normal_group.bg, fg = hl.get('EndOfBuffer').fg })
     hl.set('NvimTreeFolderIcon', { fg = hl.get('Directory').fg })
     hl.set('NvimTreeRootFolder', { fg = root_fg })
 end

lua/mellifluous/highlights/plugins/semantic_tokens.lua

@@ -1,6 +1,8 @@
 local M = {}
 
 function M.set(hl, colors)
+    local groups = require('mellifluous.highlights.custom_groups').get(colors)
+
     hl.set('@lsp.type.comment', {}) -- let treesitter handle those
     hl.set('@lsp.type.enum', { link = 'Type' })
     hl.set('@lsp.type.enumMember', { link = 'Constant' })
@@ -12,7 +14,7 @@ function M.set(hl, colors)
     hl.set('@lsp.type.property', { fg = colors.fg })
     hl.set('@lsp.type.variable', {})
     hl.set('@lsp.typemod.variable.constant', { link = 'Constant' })
-    hl.set('@lsp.typemod.keyword.controlFlow', { fg = colors.main_keywords })
+    hl.set('@lsp.typemod.keyword.controlFlow', groups.MainKeyword)
 end
 
 return M