2 files changed, 56 insertions, 0 deletions
diff --git a/lua/lvim/core/autocmds.lua b/lua/lvim/core/autocmds.lua
index 569622be..664c1662 100644
--- a/lua/lvim/core/autocmds.lua
+++ b/lua/lvim/core/autocmds.lua
@@ -1,4 +1,5 @@
 local M = {}
+local Log = require "lvim.core.log"
 
 --- Load the default set of autogroups and autocommands.
 function M.load_augroups()
@@ -58,6 +59,60 @@ function M.load_augroups()
   }
 end
 
+local get_format_on_save_opts = function()
+  local defaults = require("lvim.config.defaults").format_on_save
+  -- accept a basic boolean `lvim.format_on_save=true`
+  if type(lvim.format_on_save) ~= "table" then
+    return defaults
+  end
+
+  return {
+    pattern = lvim.format_on_save.pattern or defaults.pattern,
+    timeout = lvim.format_on_save.timeout or defaults.timeout,
+  }
+end
+
+function M.enable_format_on_save(opts)
+  local fmd_cmd = string.format(":silent lua vim.lsp.buf.formatting_sync({}, %s)", opts.timeout_ms)
+  M.define_augroups {
+    format_on_save = { { "BufWritePre", opts.pattern, fmd_cmd } },
+  }
+  Log:debug "enabled format-on-save"
+end
+
+function M.disable_format_on_save()
+  M.remove_augroup "format_on_save"
+  Log:debug "disabled format-on-save"
+end
+
+function M.configure_format_on_save()
+  if lvim.format_on_save then
+    if vim.fn.exists "#format_on_save#BufWritePre" == 1 then
+      M.remove_augroup "format_on_save"
+      Log:debug "reloading format-on-save configuration"
+    end
+    local opts = get_format_on_save_opts()
+    M.enable_format_on_save(opts)
+  else
+    M.disable_format_on_save()
+  end
+end
+
+function M.toggle_format_on_save()
+  if vim.fn.exists "#format_on_save#BufWritePre" == 0 then
+    local opts = get_format_on_save_opts()
+    M.enable_format_on_save(opts)
+  else
+    M.disable_format_on_save()
+  end
+end
+
+function M.remove_augroup(name)
+  if vim.fn.exists("#" .. name) == 1 then
+    vim.cmd("au! " .. name)
+  end
+end
+
 function M.define_augroups(definitions) -- {{{1
   -- Create autocommand groups based on the passed definitions
   --
diff --git a/lua/lvim/core/commands.lua b/lua/lvim/core/commands.lua
index 61148889..a9dd51c0 100644
--- a/lua/lvim/core/commands.lua
+++ b/lua/lvim/core/commands.lua
@@ -16,6 +16,7 @@ M.defaults = {
   [[ command! LvimUpdate lua require('lvim.bootstrap').update() ]],
   [[ command! LvimSyncCorePlugins lua require('lvim.plugin-loader'):sync_core_plugins() ]],
   [[ command! LvimReload lua require('lvim.config'):reload() ]],
+  [[ command! LvimToggleFormatOnSave lua require('lvim.core.autocmds').toggle_format_on_save() ]],
 }
 
 M.load = function(commands)