From 6c6b7673af1314dd7c8254a95eb8d331f6b76ac6 Mon Sep 17 00:00:00 2001
From: Steven Arcangeli <stevearc@stevearc.com>
Date: Sat, 21 Jan 2023 18:46:30 -0800
Subject: [PATCH] feat: update preview window when cursor is moved (#42)

---
 lua/oil/actions.lua | 17 ++++-----------
 lua/oil/util.lua    |  9 ++++++++
 lua/oil/view.lua    | 50 ++++++++++++++++++++++++++++++++++++++++-----
 3 files changed, 58 insertions(+), 18 deletions(-)

diff --git a/lua/oil/actions.lua b/lua/oil/actions.lua
index 32b7bac..9b7b860 100644
--- a/lua/oil/actions.lua
+++ b/lua/oil/actions.lua
@@ -1,4 +1,5 @@
 local oil = require("oil")
+local util = require("oil.util")
 
 local M = {}
 
@@ -29,15 +30,6 @@ M.select_split = {
   end,
 }
 
----@return nil|integer
-local function get_preview_win()
-  for _, winid in ipairs(vim.api.nvim_tabpage_list_wins(0)) do
-    if vim.api.nvim_win_is_valid(winid) and vim.api.nvim_win_get_option(winid, "previewwindow") then
-      return winid
-    end
-  end
-end
-
 M.preview = {
   desc = "Open the entry under the cursor in a preview window, or close the preview window if already open",
   callback = function()
@@ -46,7 +38,7 @@ M.preview = {
       vim.notify("Could not find entry under cursor", vim.log.levels.ERROR)
       return
     end
-    local winid = get_preview_win()
+    local winid = util.get_preview_win()
     if winid then
       local cur_id = vim.w[winid].oil_entry_id
       if entry.id == cur_id then
@@ -61,7 +53,7 @@ M.preview = {
 M.preview_scroll_down = {
   desc = "Scroll down in the preview window",
   callback = function()
-    local winid = get_preview_win()
+    local winid = util.get_preview_win()
     if winid then
       vim.api.nvim_win_call(winid, function()
         vim.cmd.normal({
@@ -76,7 +68,7 @@ M.preview_scroll_down = {
 M.preview_scroll_up = {
   desc = "Scroll up in the preview window",
   callback = function()
-    local winid = get_preview_win()
+    local winid = util.get_preview_win()
     if winid then
       vim.api.nvim_win_call(winid, function()
         vim.cmd.normal({
@@ -174,7 +166,6 @@ M.open_cmdline = {
   callback = function()
     local config = require("oil.config")
     local fs = require("oil.fs")
-    local util = require("oil.util")
     local entry = oil.get_cursor_entry()
     if not entry then
       return
diff --git a/lua/oil/util.lua b/lua/oil/util.lua
index 97cacf9..5aae2cb 100644
--- a/lua/oil/util.lua
+++ b/lua/oil/util.lua
@@ -516,4 +516,13 @@ M.hack_around_termopen_autocmd = function(prev_mode)
   end, 10)
 end
 
+---@return nil|integer
+M.get_preview_win = function()
+  for _, winid in ipairs(vim.api.nvim_tabpage_list_wins(0)) do
+    if vim.api.nvim_win_is_valid(winid) and vim.api.nvim_win_get_option(winid, "previewwindow") then
+      return winid
+    end
+  end
+end
+
 return M
diff --git a/lua/oil/view.lua b/lua/oil/view.lua
index b5978cb..5695f00 100644
--- a/lua/oil/view.lua
+++ b/lua/oil/view.lua
@@ -189,20 +189,60 @@ M.initialize = function(bufnr)
     vim.api.nvim_buf_set_option(bufnr, k, v)
   end
   M.set_win_options()
+  vim.api.nvim_clear_autocmds({
+    buffer = bufnr,
+    group = "Oil",
+  })
   vim.api.nvim_create_autocmd("BufHidden", {
+    desc = "Delete oil buffers when no longer in use",
+    group = "Oil",
+    nested = true,
+    buffer = bufnr,
     callback = function()
       vim.defer_fn(M.cleanup, 2000)
     end,
-    nested = true,
-    buffer = bufnr,
   })
   vim.api.nvim_create_autocmd("BufDelete", {
-    callback = function()
-      session[bufnr] = nil
-    end,
+    group = "Oil",
     nested = true,
     once = true,
     buffer = bufnr,
+    callback = function()
+      session[bufnr] = nil
+    end,
+  })
+  local timer
+  vim.api.nvim_create_autocmd("CursorMoved", {
+    desc = "Update oil preview window",
+    group = "Oil",
+    buffer = bufnr,
+    callback = function()
+      if timer then
+        timer:again()
+        return
+      end
+      timer = vim.loop.new_timer()
+      timer:start(10, 100, function()
+        timer:stop()
+        timer:close()
+        timer = nil
+        vim.schedule(function()
+          if vim.api.nvim_get_current_buf() ~= bufnr then
+            return
+          end
+          local oil = require("oil")
+          local entry = oil.get_cursor_entry()
+          if entry then
+            local winid = util.get_preview_win()
+            if winid then
+              if entry.id ~= vim.w[winid].oil_entry_id then
+                oil.select({ preview = true })
+              end
+            end
+          end
+        end)
+      end)
+    end,
   })
   M.render_buffer_async(bufnr, {}, function(err)
     if err then