From 4199252d6b7d11964b5435c90ffbb28b6552c686 Mon Sep 17 00:00:00 2001
From: Jiahe Jiang <61075605+Isrothy@users.noreply.github.com>
Date: Tue, 3 Dec 2024 14:23:30 -0500
Subject: [PATCH] perf: Cache highlights to improve performance

---
 lua/nord/init.lua       | 40 +++++++++++++-------------
 lua/nord/utils/init.lua | 62 +++++++++++++++++++++++++++++++++++++++--
 2 files changed, 80 insertions(+), 22 deletions(-)

diff --git a/lua/nord/init.lua b/lua/nord/init.lua
index 63fe159..08dfa42 100644
--- a/lua/nord/init.lua
+++ b/lua/nord/init.lua
@@ -22,26 +22,26 @@ function nord.load(opts)
     require("nord.terminal").apply()
   end
 
-  utils.load(
-    require("nord.defaults").highlights(),
-    require("nord.lsp").highlights(),
-    require("nord.syntax").highlights(),
-    require("nord.terminal").highlights(),
-    require("nord.treesitter").highlights(),
-    require("nord.plugins.bufferline").highlights(),
-    require("nord.plugins.completion").highlights(),
-    require("nord.plugins.filetree").highlights(),
-    require("nord.plugins.git").highlights(),
-    require("nord.plugins.motion").highlights(),
-    require("nord.plugins.notify").highlights(),
-    require("nord.plugins.picker").highlights(),
-    require("nord.plugins.ui").highlights(),
-    require("nord.plugins.diffview").highlights(),
-    require("nord.plugins.neogit").highlights(),
-    require("nord.plugins.glance").highlights(),
-    require("nord.plugins.mini").highlights(),
-    require("nord.plugins.markview").highlights()
-  )
+  utils.load(function()
+    return require("nord.defaults").highlights(),
+      require("nord.lsp").highlights(),
+      require("nord.syntax").highlights(),
+      require("nord.terminal").highlights(),
+      require("nord.treesitter").highlights(),
+      require("nord.plugins.bufferline").highlights(),
+      require("nord.plugins.completion").highlights(),
+      require("nord.plugins.filetree").highlights(),
+      require("nord.plugins.git").highlights(),
+      require("nord.plugins.motion").highlights(),
+      require("nord.plugins.notify").highlights(),
+      require("nord.plugins.picker").highlights(),
+      require("nord.plugins.ui").highlights(),
+      require("nord.plugins.diffview").highlights(),
+      require("nord.plugins.neogit").highlights(),
+      require("nord.plugins.glance").highlights(),
+      require("nord.plugins.mini").highlights(),
+      require("nord.plugins.markview").highlights()
+  end)
 
   vim.g.colors_name = "nord"
 end
diff --git a/lua/nord/utils/init.lua b/lua/nord/utils/init.lua
index e7b375c..367140f 100644
--- a/lua/nord/utils/init.lua
+++ b/lua/nord/utils/init.lua
@@ -1,9 +1,31 @@
 local utils = {}
 local c = require("nord.colors").palette
 
-function utils.load(...)
-  local highlights = vim.tbl_extend("force", ...)
+local function get_cachable_config()
   local options = require("nord.config").options
+  local cached_options = vim.deepcopy(options)
+  cached_options.on_highlights = nil
+  cached_options.on_colors = nil
+  return {
+    opts = cached_options,
+    colors = c,
+  }
+end
+
+function utils.load(func)
+  local options = require("nord.config").options
+  local cacheable_config = get_cachable_config()
+  local ok, tbl = pcall(utils.load_from_file, "config")
+  local highlights = nil
+  if ok and tbl and vim.deep_equal(tbl.config, cacheable_config) then
+    highlights = tbl.highlights
+  else
+    highlights = vim.tbl_extend("force", func())
+    local ok, err = pcall(utils.save_to_file, "config", { config = cacheable_config, highlights = highlights })
+    if not ok then
+      vim.notify("Failed to save cache: " .. err, vim.log.levels.WARN)
+    end
+  end
   options.on_highlights(highlights, c)
   for group, hl in pairs(highlights) do
     vim.api.nvim_set_hl(0, group, hl)
@@ -70,4 +92,40 @@ function utils.make_global_bg(transparent)
   return c.polar_night.origin
 end
 
+local function cache_filename(filename)
+  return vim.fn.stdpath("cache") .. "/nord-" .. filename .. ".json"
+end
+
+function utils.save_to_file(filename, object)
+  filename = cache_filename(filename)
+  local file, err = io.open(filename, "w")
+  if not file then
+    error("Failed to open file for writing: " .. err)
+  end
+  local success, encoded = pcall(vim.json.encode, object)
+  if not success then
+    error("Failed to encode cache: " .. encoded)
+  end
+  file:write(encoded)
+  file:close()
+end
+
+function utils.load_from_file(filename)
+  filename = cache_filename(filename)
+  local file, err = io.open(filename, "r")
+  if not file then
+    error("Failed to open file for reading: " .. err)
+  end
+  local content = file:read("*a")
+  file:close()
+  local success, decoded = pcall(vim.json.decode, content, {
+    object = true,
+    array = true,
+  })
+  if not success then
+    error("Failed to decode file content: " .. decoded)
+  end
+  return decoded
+end
+
 return utils