feat: handler for lazy-loading colorschemes

lua/lz/n/handler/colorscheme.lua

@@ -0,0 +1,53 @@
+local loader = require("lz.n.loader")
+
+---@class lz.n.ColorschemeHandler: lz.n.Handler
+---@field augroup? integer
+
+---@type lz.n.ColorschemeHandler
+local M = {
+    pending = {},
+    type = "colorscheme",
+    augroup = nil,
+}
+
+---@param plugin lz.n.Plugin
+function M.del(plugin)
+    for _, plugins in pairs(M.pending) do
+        plugins[plugin.name] = nil
+    end
+end
+
+---@param name string
+local function on_colorscheme(name)
+    if vim.tbl_contains(vim.fn.getcompletion("", "color"), name) then
+        return
+    end
+    loader.load(vim.tbl_values(M.pending[name]))
+end
+
+local function init()
+    if M.augroup then
+        return
+    end
+    M.augroup = vim.api.nvim_create_augroup("lz_n_handler_colorscheme", { clear = true })
+    vim.api.nvim_create_autocmd("ColorSchemePre", {
+        callback = function(event)
+            on_colorscheme(event.match)
+        end,
+        group = M.augroup,
+    })
+end
+
+---@param plugin lz.n.Plugin
+function M.add(plugin)
+    if not plugin.colorscheme then
+        return
+    end
+    init()
+    for _, colorscheme in pairs(plugin.colorscheme) do
+        M.pending[colorscheme] = M.pending[colorscheme] or {}
+        M.pending[colorscheme][plugin.name] = plugin.name
+    end
+end
+
+return M

lua/lz/n/handler/init.lua

@@ -12,6 +12,7 @@ M.types = {
     event = "event",
     ft = "ft",
     keys = "keys",
+    colorscheme = "colorscheme",
 }
 
 local handlers = {
@@ -19,6 +20,7 @@ local handlers = {
     event = require("lz.n.handler.event"),
     ft = require("lz.n.handler.ft"),
     keys = require("lz.n.handler.keys"),
+    colorscheme = require("lz.n.handler.colorscheme"),
 }
 
 ---@param plugin lz.n.Plugin