add a function to get a platform-specific home directory

src/windy/platforms/emscripten/platform.nim

@@ -788,6 +788,9 @@ proc `onDownloadProgress=`*(handle: HttpRequestHandle, callback: HttpProgressCal
   if state == nil: return
   state.onDownloadProgress = callback
 
+proc getConfigHome*(appName: string): string =
+  raise newException(Exception, "getConfigHome is not supported on emscripten")
+
 proc openTempTextFile*(title, text: string) =
   ## Open a new tab in the browser.
   open_temp_text_file(title.cstring, text.cstring)

src/windy/platforms/linux/x11.nim

@@ -1,5 +1,5 @@
 import
-  std/[os, sequtils, sets, strformat, strutils, times, unicode, uri],
+  std/[os, sequtils, sets, strformat, strutils, times, unicode, uri, pathnorm],
   ../../[common, internal],
   vmath, pixie,
   x11/[glx, keysym, x, xevent, xlib, xcursor]
@@ -1327,6 +1327,15 @@ proc url*(window: Window): string =
   ## Url cannot be gotten on linux.
   warn "Url cannot be gotten on linux"
 
+proc getConfigHome*(appName: string): string =
+  ## Returns the platform-appropriate user config directory for the given app name.
+  ## For Linux: Honors XDG_CONFIG_HOME, defaults to ~/.config/<appName>.
+  let xdgConfigHome = getEnv("XDG_CONFIG_HOME")
+  if xdgConfigHome != "":
+    result = (xdgConfigHome / appName).normalizePath
+  else:
+    result = (getHomeDir() / ".config" / appName).normalizePath
+
 proc openUrl*(url: string) =
   ## Open a URL in the default browser.
   discard execShellCmd("xdg-open " & url)

src/windy/platforms/macos/platform.nim

@@ -1,5 +1,5 @@
 import
-  std/[os, times, unicode],
+  std/[os, times, unicode, pathnorm],
   opengl, pixie/fileformats/png, pixie/images, utils, vmath,
   ../../[common, internal], macdefs
 
@@ -1094,6 +1094,11 @@ proc getScreens*(): seq[Screen] =
         primary: i == 0
       )
 
+proc getConfigHome*(appName: string): string =
+  ## Returns the platform-appropriate user config directory for the given app name.
+  ## For macOS: Returns ~/Library/Application Support/<appName>.
+  result = (getHomeDir() / "Library" / "Application Support" / appName).normalizePath
+
 proc openTempTextFile*(title, text: string) =
   ## Open a text file in the default text editor.
   if not dirExists("tmp"):

src/windy/platforms/win32/platform.nim

@@ -1,5 +1,5 @@
 import
-  std/[os, times, unicode, strutils, tables],
+  std/[os, times, unicode, strutils, tables, pathnorm],
   ../../[common, internal], flatty/binny, pixie/fileformats/png,
   pixie/fileformats/bmp, pixie/images,
   urlly, utils, vmath, windefs, zippy
@@ -2492,6 +2492,11 @@ proc forceButtonReleased*(window: Window, button: Button) =
   ## This is used for simulating UI tests.
   window.handleButtonRelease(button)
 
+proc getConfigHome*(appName: string): string =
+  ## Returns the platform-appropriate user config directory for the given app name.
+  ## For Windows: Returns %APPDATA%\<appName>.
+  result = (getEnv("APPDATA") / appName).normalizePath
+
 proc openTempTextFile*(title, text: string) =
   ## Open a text file in the default text editor.
   if not dirExists("tmp"):