feat: color slots

README.md

@@ -1,32 +1,49 @@
 # 🎨 Last Color
 **Last Color** saves the name of the last (successful) colorscheme change to your filesystem and allows you to recall it whenever you desire. As such, you can automatically set your colorscheme between sessions based on what you last used! See the [usage](#usage) section for an example.
 
-## Why?
-I'm *extremely* indecisive when choosing my colorscheme. I considered setting up my colors in a `.gitignore`d file, but **telescope**'s colorscheme picker is way too convenient compared to editing a file 🐵
-
 ## Installation
 Ye olde plugin manager.
 ```lua
--- packer
-use({ 'raddari/last-color.nvim' })
+{ 'raddari/last-color.nvim' }
 ```
 
 ## Configuration
-None. It'll call `setup` itself when loaded.
+None.
 
 ## Usage
-Dead simple. I use the snippet below in my `init.lua` to automatically use the last theme. There's also an Ex command; `:LastColor`.
+### Simple
+Drop something like this in your `init.lua`:
 ```lua
 -- kanagawa as a backup, `recall()` can return `nil`.
 local theme = require('last-color').recall() or 'kanagawa'
 vim.cmd(('colorscheme %s'):format(theme))
 ```
-I personally don't lazy load my plugins, but I'm sure you could modify the snippet to account for that 😀
+### Different Colorscheme Slots
+If you use a plugin like [`f-person/auto-dark-mode.nvim`](https://github.com/f-person/auto-dark-mode.nvim), you can choose which 'slot' the colorscheme will save to/load from:
+```lua
+-- LazySpec
+return {
+  'f-person/auto-dark-mode.nvim',
+  config = {
+    set_dark_mode = function()
+      local last_color = require('last-color')
+      -- last-color will now write to `<cache_dir>/last-color.dark` for any subsequent `colorscheme` commands
+      last_color.slot('dark')
+      -- last-color will now read from `<cache_dir>/last-color.dark`
+      vim.cmd.colorscheme(last_color.recall())
+    end,
+    set_light_mode = function()
+      local last_color = require('last-color')
+      -- last-color will now write to `<cache_dir>/last-color.light` for any subsequent `colorscheme` commands
+      last_color.slot('light')
+      -- last-color will now read from `<cache_dir>/last-color.light`
+      vim.cmd.colorscheme(last_color.recall())
+    end,
+  },
+}
+```
 
 ## Showcase
-Using the lua snippet above:
+Using the simple lua snippet above:
 
 ![last-color](https://user-images.githubusercontent.com/25364469/189385514-563ca684-41c9-42db-a2a6-12921f4f3095.gif)
-
-## Issues
-Please open an issue for any problems you encounter, or suggestions for improving the code quality. This is my first plugin, so I'm still learning and looking to improve 😁

lua/last-color/init.lua

@@ -3,14 +3,18 @@ local cache_file = string.format('%s/last-color', vim.fn.stdpath('data'))
 
 local M = {}
 
-local open_cache_file = function(mode)
+---@param mode string
+---@param slot string|nil
+local open_cache_file = function(mode, slot)
+  local filename = slot and ('%s.%s'):format(cache_file, slot) or cache_file
   -- 438(10) == 666(8) [owner/group/others can read/write]
   local flags = 438
-  return uv.fs_open(cache_file, mode, flags)
+  return uv.fs_open(filename, mode, flags)
 end
 
-local read_cache_file = function()
-  local fd, err_name, err_msg = open_cache_file('r')
+---@param slot string|nil
+local read_cache_file = function(slot)
+  local fd, err_name, err_msg = open_cache_file('r', slot)
   if not fd then
     if err_name == 'ENOENT' then
       -- cache never written: ok, :colorscheme never executed
@@ -27,19 +31,32 @@ local read_cache_file = function()
   return colorscheme
 end
 
-local write_cache_file = function(colorscheme)
-  local fd = assert(open_cache_file('w'))
+---@param colorscheme string name of colorscheme
+---@param slot string|nil name of slot to use
+local write_cache_file = function(colorscheme, slot)
+  local fd = assert(open_cache_file('w', slot))
   assert(uv.fs_write(fd, string.format('%s\n', colorscheme), -1))
   assert(uv.fs_close(fd))
 end
 
+---@type string|nil name of slot in use
+M.current_slot = nil
+
 --- Read the cached colorscheme from disk.
 --- @return string|nil colorscheme
 M.recall = function()
-  local ok, result = pcall(read_cache_file)
+  local ok, result = pcall(read_cache_file, M.current_slot)
   return ok and result or nil
 end
 
+---Sets the current slot to read/write colorscheme to.
+---@return string|nil slot previous slot in use
+M.slot = function(name)
+  local old = M.current_slot
+  M.current_slot = name
+  return old
+end
+
 --- Creates the autocommand which saves the last ':colorscheme' to disk, along
 --- with the Ex command 'LastColor'. This is automatically called when the
 --- plugin is loaded.
@@ -56,7 +73,7 @@ M.setup = function()
         return nil
       end
 
-      local ok, result = pcall(write_cache_file, new_scheme)
+      local ok, result = pcall(write_cache_file, new_scheme, M.current_slot)
       if not ok then
         vim.api.nvim_err_writeln(string.format('cannot write to cache file: %s', result))
         -- delete the autocommand to prevent further error notifications