feat: add grapple window highlight groups (#164)

* feat: add grapple window highlight groups

* docs: update grapple highlights table

Author: scottmckendry

README.md

@@ -936,6 +936,10 @@ require("grapple").open_loaded({ all = true })
 | `GrappleName`    | `DiagnosticHint`  | N/A        | Tags window for tag name        |
 | `GrappleNoExist` | `DiagnosticError` | N/A        | Tags window for tag status      |
 | `GrappleCurrent` | `SpecialChar`     | `gui=bold` | All windows for current status  |
+| `GrappleFloat`   | `NormalFloat`     | N/A        | All windows for background      |
+| `GrappleBorder`  | `FloatBorder`     | N/A        | All windows for border          |
+| `GrappleTitle`   | `FloatTitle`      | N/A        | All windows for title           |
+| `GrappleFooter`  | `FloatFooter`     | N/A        | All windows for footer          |
 
 ## Persistent State
 

lua/grapple/window.lua

@@ -128,6 +128,12 @@ function Window:open()
     local win_opts = self:window_options()
     self.win_id = vim.api.nvim_open_win(self.buf_id, true, win_opts)
 
+    -- Set window highlights
+    self:set_highlight("NormalFloat", "GrappleNormal")
+    self:set_highlight("FloatBorder", "GrappleBorder")
+    self:set_highlight("FloatTitle", "GrappleTitle")
+    self:set_highlight("FloatFooter", "GrappleFooter")
+
     -- Setup window to conceal line IDs
     vim.api.nvim_set_option_value("concealcursor", "nvic", { win = self.win_id })
     vim.api.nvim_set_option_value("conceallevel", 3, { win = self.win_id })
@@ -607,4 +613,20 @@ function Window:alternate_path()
     return Path.fs_absolute(alt_name)
 end
 
+--- Replaces a highlight group in the window
+--- @param new_from string
+--- @param new_to string
+function Window:set_highlight(new_from, new_to)
+    local new_entry = new_from .. ":" .. new_to
+    local replace_pattern = string.format("(%s:[^,]*)", vim.pesc(new_from))
+    local new_winhighlight, n_replace = vim.wo[self.win_id].winhighlight:gsub(replace_pattern, new_entry)
+    if n_replace == 0 then
+        new_winhighlight = new_winhighlight .. "," .. new_entry
+    end
+
+    pcall(function()
+        vim.wo[self.win_id].winhighlight = new_winhighlight
+    end)
+end
+
 return Window

plugin/grapple.lua

@@ -6,6 +6,10 @@ vim.cmd("highlight default GrappleBold gui=bold cterm=bold")
 vim.cmd("highlight default link GrappleHint Comment")
 vim.cmd("highlight default link GrappleName DiagnosticHint")
 vim.cmd("highlight default link GrappleNoExist DiagnosticError")
+vim.cmd("highlight default link GrappleNormal NormalFloat")
+vim.cmd("highlight default link GrappleBorder FloatBorder")
+vim.cmd("highlight default link GrappleTitle FloatTitle")
+vim.cmd("highlight default link GrappleFooter FloatFooter")
 
 vim.cmd("highlight default GrappleCurrent gui=bold cterm=bold")
 vim.cmd("highlight! link GrappleCurrent SpecialChar")