(nvim) better configure conform to conditionally select formatters based on config

nvim/lua/juancwu/plugins/conform.lua

@@ -1,12 +1,83 @@
+local formatters_by_ft = {
+	lua = { "stylua" },
+	javascript = { "prettier", "biome" },
+	typescript = { "prettier", "biome" },
+	javascriptreact = { "prettier", "biome" },
+	typescriptreact = { "prettier", "biome" },
+	css = { "prettier", "biome" },
+	markdown = { "prettier", "biome" },
+	go = { "gofmt" },
+	python = { "autopep8" },
+	yaml = { "yamlfmt" },
+}
+
+-- Function to find the first config file by walking up the directory tree
+local function find_first_config()
+	local current_dir = vim.fn.expand("%:p:h")
+	local home_dir = vim.fn.expand("$HOME")
+
+	local config_files = {
+		prettier = { ".prettierrc", ".prettierrc.json", ".prettierrc.js" },
+		biome = { "biome.json" },
+	}
+
+	while current_dir ~= home_dir and current_dir ~= "/" do
+		for formatter, patterns in pairs(config_files) do
+			for _, pattern in ipairs(patterns) do
+				local config_file = current_dir .. "/" .. pattern
+				if vim.fn.filereadable(config_file) == 1 then
+					return formatter
+				end
+			end
+		end
+		current_dir = vim.fn.fnamemodify(current_dir, ":h")
+	end
+	return nil
+end
+
+-- Function to determine the formatter based on config files and file type
+local function get_formatter()
+	local filetype = vim.bo.filetype
+	local available_formatters = formatters_by_ft[filetype] or {}
+	local formatter = find_first_config()
+
+	if formatter then
+		if formatter == "prettier" and vim.tbl_contains(available_formatters, "prettier") then
+			vim.g.current_formatter = "prettier"
+			return { "prettier" }
+		elseif formatter == "biome" and vim.tbl_contains(available_formatters, "biome") then
+			vim.g.current_formatter = "biome"
+			return { "biome" }
+		end
+	end
+
+	-- Default to the first available formatter for the file type, or prettier if none specified
+	vim.g.current_formatter = available_formatters[1] or "prettier"
+	return { vim.g.current_formatter }
+end
+
+local function format_on_save(bufnr)
+	if vim.g.disable_autoformat or vim.b[bufnr].disable_autoformat then
+		return
+	end
+	local formatters = get_formatter()
+	return {
+		timeout_ms = 500,
+		lsp_format = "fallback",
+		formatters = formatters,
+	}
+end
+
 return {
 	"stevearc/conform.nvim",
-	event = { "BufWritePre" },
+	event = { "BufWritePre", "BufEnter" },
 	cmd = { "ConformInfo" },
 	keys = {
 		{
 			"<leader>ff",
 			function()
-				require("conform").format({ async = true, lsp_format = "fallback" })
+				local formatters = get_formatter()
+				require("conform").format({ async = true, lsp_format = "fallback", formatters = formatters })
 			end,
 			mode = "",
 			desc = "[F]ormat buffer",
@@ -15,24 +86,8 @@ return {
 	config = function()
 		require("conform").setup({
 			notify_on_error = false,
-			formatters_by_ft = {
-				lua = { "stylua" },
-				javascript = { "prettier" },
-				typescript = { "prettier" },
-				javascriptreact = { "prettier" },
-				typescriptreact = { "prettier" },
-				css = { "prettier" },
-				markdown = { "prettier" },
-				go = { "gopls" },
-				python = { "autopep8" },
-				yaml = { "yamlfmt" },
-			},
-			format_on_save = function(bufnr)
-				if vim.g.disable_autoformat or vim.b[bufnr].disable_autoformat then
-					return
-				end
-				return { timeout_ms = 500, lsp_format = "fallback" }
-			end,
+			formatters_by_ft = formatters_by_ft,
+			format_on_save = format_on_save,
 		})
 
 		vim.api.nvim_create_user_command("FormatDisable", function()
@@ -46,5 +101,11 @@ return {
 		end, {
 			desc = "Enable autoformat on save",
 		})
+
+		vim.api.nvim_create_user_command("Formatter", function()
+			print("Current formatter: " .. (vim.g.current_formatter or "none"))
+		end, {
+			desc = "Show current formatter being used",
+		})
 	end,
 }