feat: modernize the plugin

lua/cp/config.lua

@@ -1,5 +1,21 @@
+---@class cp.ContestConfig
+---@field cpp_version number
+---@field compile_flags string[]
+---@field debug_flags string[]
+---@field timeout_ms number
+
+---@class cp.HooksConfig
+---@field before_run? function
+---@field before_debug? function
+
+---@class cp.Config
+---@field contests table<string, cp.ContestConfig>
+---@field snippets table<string, any>
+---@field hooks cp.HooksConfig
+
 local M = {}
 
+---@type cp.Config
 M.defaults = {
 	contests = {
 		default = {
@@ -25,6 +41,9 @@ M.defaults = {
 	},
 }
 
+---@param base_config cp.ContestConfig
+---@param contest_config cp.ContestConfig
+---@return cp.ContestConfig
 local function extend_contest_config(base_config, contest_config)
 	local result = vim.tbl_deep_extend("force", base_config, contest_config)
 
@@ -35,23 +54,69 @@ local function extend_contest_config(base_config, contest_config)
 	return result
 end
 
+---@param path string
+---@param tbl table
+---@return boolean is_valid
+---@return string|nil error_message
+local function validate_path(path, tbl)
+	local ok, err = pcall(vim.validate, tbl)
+	return ok, err and path .. "." .. err
+end
+
+---@param path string
+---@param contest_config table|nil
+---@return boolean is_valid
+---@return string|nil error_message
+local function validate_contest_config(path, contest_config)
+	if not contest_config then
+		return true, nil
+	end
+
+	return validate_path(path, {
+		cpp_version = { contest_config.cpp_version, "number", true },
+		compile_flags = { contest_config.compile_flags, "table", true },
+		debug_flags = { contest_config.debug_flags, "table", true },
+		timeout_ms = { contest_config.timeout_ms, "number", true },
+	})
+end
+
+---@param user_config cp.Config|nil
+---@return cp.Config
 function M.setup(user_config)
-	vim.validate({
+	local ok, err = validate_path("config", {
 		user_config = { user_config, { "table", "nil" }, true },
 	})
+	if not ok then
+		error(err)
+	end
 
 	if user_config then
-		vim.validate({
+		ok, err = validate_path("config", {
 			contests = { user_config.contests, { "table", "nil" }, true },
 			snippets = { user_config.snippets, { "table", "nil" }, true },
 			hooks = { user_config.hooks, { "table", "nil" }, true },
 		})
+		if not ok then
+			error(err)
+		end
 
 		if user_config.hooks then
-			vim.validate({
+			ok, err = validate_path("config.hooks", {
 				before_run = { user_config.hooks.before_run, { "function", "nil" }, true },
 				before_debug = { user_config.hooks.before_debug, { "function", "nil" }, true },
 			})
+			if not ok then
+				error(err)
+			end
+		end
+
+		if user_config.contests then
+			for contest_name, contest_config in pairs(user_config.contests) do
+				ok, err = validate_contest_config("config.contests." .. contest_name, contest_config)
+				if not ok then
+					error(err)
+				end
+			end
 		end
 	end