Get mode at time of event instead of at time of render

resolves: #36

# Details

Since all rendering and clearing of `extmarks` happens through a call to
`vim.schedule` it is possible that a mode change occurred between a
triggering event and the response to that event.

In most cases this is not really a problem, however some plugins will
programmatically cause several mode changes in quick succession which
can cause this plugin to be out of sync, i.e. thinking that a render is
not necessary since the last mode was already rendered, however when
rendering the last mode, the mode had changed and a render did not occur.

An example of this is `fzf-lua` which uses `terminal` mode to perform
certain actions.

This can cause the plugin to fall behind the current user state, however
rendering should be fast enough for this not to be a problem. Can revisit
this approach if it proves to be a problem.

Author: MeanderingProgrammer

lua/render-markdown/init.lua

@@ -226,22 +226,19 @@ function M.setup(opts)
     state.inline_query = vim.treesitter.query.parse('markdown_inline', state.config.inline_query)
 
     -- Call immediately to re-render on LazyReload
-    vim.schedule(function()
-        ui.refresh(vim.api.nvim_get_current_buf())
-    end)
+    ui.schedule_refresh(vim.api.nvim_get_current_buf())
 
     local group = vim.api.nvim_create_augroup('RenderMarkdown', { clear = true })
     vim.api.nvim_create_autocmd({ 'ModeChanged' }, {
         group = group,
         callback = function(event)
-            local was_rendered = vim.tbl_contains(state.config.render_modes, vim.v.event.old_mode)
-            local should_render = vim.tbl_contains(state.config.render_modes, vim.v.event.new_mode)
+            local render_modes = state.config.render_modes
+            local prev_rendered = vim.tbl_contains(render_modes, string.sub(vim.v.event.old_mode, 1, 1))
+            local should_render = vim.tbl_contains(render_modes, string.sub(vim.v.event.new_mode, 1, 1))
             -- Only need to re-render if render state is changing. I.e. going from normal mode to
             -- command mode with the default config, both are rendered, so no point re-rendering
-            if was_rendered ~= should_render then
-                vim.schedule(function()
-                    ui.refresh(event.buf)
-                end)
+            if prev_rendered ~= should_render then
+                ui.schedule_refresh(event.buf)
             end
         end,
     })
@@ -250,18 +247,14 @@ function M.setup(opts)
         callback = function()
             for _, win in ipairs(vim.v.event.windows) do
                 local buf = util.win_to_buf(win)
-                vim.schedule(function()
-                    ui.refresh(buf)
-                end)
+                ui.schedule_refresh(buf)
             end
         end,
     })
     vim.api.nvim_create_autocmd({ 'FileChangedShellPost', 'FileType', 'TextChanged' }, {
         group = group,
         callback = function(event)
-            vim.schedule(function()
-                ui.refresh(event.buf)
-            end)
+            ui.schedule_refresh(event.buf)
         end,
     })
 
@@ -272,13 +265,11 @@ end
 M.toggle = function()
     state.enabled = not state.enabled
     for _, buf in ipairs(vim.api.nvim_list_bufs()) do
-        vim.schedule(function()
-            if state.enabled then
-                ui.refresh(buf)
-            else
-                ui.clear_valid(buf)
-            end
-        end)
+        if state.enabled then
+            ui.schedule_refresh(buf)
+        else
+            ui.schedule_clear(buf)
+        end
     end
 end
 

lua/render-markdown/ui.lua

@@ -5,19 +5,37 @@ local markdown_inline = require('render-markdown.handler.markdown_inline')
 local state = require('render-markdown.state')
 local util = require('render-markdown.util')
 
+---@class render.md.Ui
 local M = {}
 
 M.namespace = vim.api.nvim_create_namespace('render-markdown.nvim')
 
 ---@param buf integer
-M.refresh = function(buf)
+M.schedule_refresh = function(buf)
+    local mode = vim.fn.mode()
+    vim.schedule(function()
+        M.refresh(buf, mode)
+    end)
+end
+
+---@param buf integer
+M.schedule_clear = function(buf)
+    vim.schedule(function()
+        M.clear_valid(buf)
+    end)
+end
+
+---@private
+---@param buf integer
+---@param mode string
+M.refresh = function(buf, mode)
     if not state.enabled then
         return
     end
     if not M.clear_valid(buf) then
         return
     end
-    if not vim.tbl_contains(state.config.render_modes, vim.fn.mode()) then
+    if not vim.tbl_contains(state.config.render_modes, mode) then
         return
     end
     if util.file_size_mb(buf) > state.config.max_file_size then
@@ -53,7 +71,8 @@ M.refresh = function(buf)
     logger.flush()
 end
 
---- Remove existing highlights / virtual text for valid buffers
+---Remove existing highlights / virtual text for valid buffers
+---@private
 ---@param buf integer
 ---@return boolean
 M.clear_valid = function(buf)