refactor(utils.lua): simplify language detection by using quarto modu…

…le for code chunk parsing

closes #353

lua/r/utils.lua

@@ -1,4 +1,5 @@
 local warn = require("r.log").warn
+local quarto = require("r.quarto")
 local uv = vim.uv
 
 local M = {}
@@ -76,29 +77,18 @@ end
 --- Get language at current cursor position
 ---@return string
 function M.get_lang()
-    if vim.bo.filetype == "" then return "none" end
-    -- Treesitter for rnoweb always return "latex" or "rnoweb"
-    if vim.bo.filetype == "rnoweb" then return get_rnw_lang() end
-    -- No treesitter parser for rhelp
-    if vim.bo.filetype == "rhelp" then return get_rhelp_lang() end
-
-    local p
-    if vim.bo.filetype == "rmd" or vim.bo.filetype == "quarto" then
-        local cline = vim.api.nvim_get_current_line()
-        if cline:find("^```.*child *= *") then
-            return "chunk_child"
-        elseif cline:find("^```%{") then
-            return "chunk_header"
-        elseif cline:find("^```$") then
-            return "chunk_end"
-        end
-        p = vim.treesitter.get_parser(vim.api.nvim_get_current_buf(), "markdown")
-    else
-        p = vim.treesitter.get_parser()
-    end
-    local c = vim.api.nvim_win_get_cursor(0)
-    local lang = p:language_for_range({ c[1] - 1, c[2], c[1] - 1, c[2] }):lang()
-    return lang
+    local filetype = vim.bo.filetype
+    if filetype == "" then return "none" end
+    if filetype == "rnoweb" then return get_rnw_lang() end
+    if filetype == "rhelp" then return get_rhelp_lang() end
+
+    local current_chunk = quarto.get_current_code_chunk(vim.api.nvim_get_current_buf())
+    if current_chunk.lang then return current_chunk.lang end
+
+    local parser = vim.treesitter.get_parser(vim.api.nvim_get_current_buf(), "markdown")
+    if not parser then return "" end
+
+    return parser:language_for_range(vim.api.nvim_win_get_cursor(0)):lang()
 end
 
 --- Request the windows manager to focus a window.