add cacher module that's more invisible

1 files changed, 52 insertions, 0 deletions

diff --git a/cacher.lua b/cacher.lua
new file mode 100644
index 0000000..486f238
--- /dev/null
+++ b/cacher.lua
@@ -0,0 +1,52 @@
+-- Copyright 2025 David Vazgenovich Shakaryan
+
+local util = require('util')
+
+local mp_utils = require('mp.utils')
+
+local cacher = {}
+
+local function wrap_func(obj, opts, func, func_name)
+	return function(_, ...)
+		local fn = table.concat({opts.prefix, func_name, ...}, '.')
+		local path = mp_utils.join_path(opts.directory, fn)
+		local f = mp_utils.file_info(path)
+		local data
+
+		if not f or os.time() - f.mtime > opts.time then
+			data = func(obj, ...)
+			if data then
+				util.write_json_file(path, data)
+			end
+		end
+
+		if f and not data then
+			print('using cached ' .. fn)
+			data = util.read_json_file(path)
+		end
+
+		return data
+	end
+end
+
+function cacher.wrap(obj, opts)
+	local proxy = {}
+
+	setmetatable(proxy, {
+		__index = function(t, k)
+			local v = obj[k]
+			if type(v) ~= 'function' or not opts.functions[k] then
+				return v
+			end
+
+			local fn = wrap_func(obj, opts, v, k)
+			t[k] = fn
+
+			return fn
+		end,
+	})
+
+	return proxy
+end
+
+return cacher