fix(config): easier language default per-contest

lua/cp/config.lua

@@ -267,12 +267,7 @@ function M.setup(user_config)
         error('No language configurations found')
       end
 
-      if vim.tbl_contains(available_langs, 'cpp') then
-        contest_config.default_language = 'cpp'
-      else
-        table.sort(available_langs)
-        contest_config.default_language = available_langs[1]
-      end
+      contest_config.default_language = available_langs[1]
     end
   end
 

lua/cp/pickers/init.lua

@@ -159,8 +159,10 @@ end
 ---@param contest_id string Contest identifier
 ---@param problem_id string Problem identifier
 local function setup_problem(platform, contest_id, problem_id)
-  local cp = require('cp')
-  cp.handle_command({ fargs = { platform, contest_id, problem_id } })
+  vim.schedule(function()
+    local cp = require('cp')
+    cp.handle_command({ fargs = { platform, contest_id, problem_id } })
+  end)
 end
 
 M.get_platforms = get_platforms

spec/config_spec.lua

@@ -169,7 +169,7 @@ describe('cp.config', function()
         assert.equals('cpp', result.contests.test.default_language)
       end)
 
-      it('sets default_language to first available when cpp not present', function()
+      it('sets default_language to single available language when only one configured', function()
         local user_config = {
           contests = {
             test = {
@@ -183,6 +183,38 @@ describe('cp.config', function()
         assert.equals('python', result.contests.test.default_language)
       end)
 
+      it('sets default_language to single available language even when not cpp', function()
+        local user_config = {
+          contests = {
+            test = {
+              rust = {
+                test = { './target/release/solution' },
+                extension = 'rs'
+              },
+            },
+          },
+        }
+
+        local result = config.setup(user_config)
+
+        assert.equals('rust', result.contests.test.default_language)
+      end)
+
+      it('uses first available language when multiple configured', function()
+        local user_config = {
+          contests = {
+            test = {
+              python = { test = { 'python3' } },
+              cpp = { compile = { 'g++' } },
+            },
+          },
+        }
+
+        local result = config.setup(user_config)
+
+        assert.is_true(vim.tbl_contains({'cpp', 'python'}, result.contests.test.default_language))
+      end)
+
       it('preserves explicit default_language', function()
         local user_config = {
           contests = {