Updated theme switcher function

Signed-off-by: Taken <taken@mairimashita.org>

lua/taken/functions/themes.lua

@@ -1,9 +1,6 @@
 local M = {}
 
 function M.themeselector()
-    local configDir = vim.fn.stdpath("config")
-    local prefsFile = configDir .. "/lua/taken/prefs.lua"
-
     local themes = {
         "rose-pine-main",
         "rose-pine-moon",
@@ -31,12 +28,29 @@ function M.themeselector()
         "kanagawa-wave",
     }
 
+    local configDir = vim.fn.stdpath("config")
+    local prefsFile = configDir .. "/lua/taken/prefs.lua"
+    local oldstring = 'M.colorscheme = .*"'
+
     local opts = {
         prompt = "Select a theme",
     }
 
+    local function change_theme(old, new)
+        -- function from nvchad
+        local file = io.open(prefsFile, "r")
+        local added_pattern = string.gsub(old, "-", "%%-")
+        local new_content = file:read("*all"):gsub(added_pattern, new)
+
+        file = io.open(prefsFile, "w")
+        file:write(new_content)
+        file:close()
+    end
+
     local exec = function(choice)
         vim.cmd("colorscheme " .. choice)
+        local newstring = 'M.colorscheme = "' .. choice .. '"'
+        change_theme(oldstring, newstring)
     end
 
     vim.ui.select(themes, opts, exec)