oil: now support gitignored files

lua/plugins/oil.lua

@@ -1,6 +1,56 @@
 return {
     "stevearc/oil.nvim",
-    opts = {
+    opts = function()
+        -- helper function to parse output
+        local function parse_output(proc)
+            local result = proc:wait()
+            local ret = {}
+            if result.code == 0 then
+                for line in vim.gsplit(result.stdout, "\n", { plain = true, trimempty = true }) do
+                    -- Remove trailing slash
+                    line = line:gsub("/$", "")
+                    ret[line] = true
+                end
+            end
+            return ret
+        end
+
+        -- build git status cache
+        local function new_git_status()
+            return setmetatable({}, {
+                __index = function(self, key)
+                    local ignore_proc = vim.system(
+                        { "git", "ls-files", "--ignored", "--exclude-standard", "--others", "--directory" },
+                        {
+                            cwd = key,
+                            text = true,
+                        }
+                    )
+                    local tracked_proc = vim.system({ "git", "ls-tree", "HEAD", "--name-only" }, {
+                        cwd = key,
+                        text = true,
+                    })
+                    local ret = {
+                        ignored = parse_output(ignore_proc),
+                        tracked = parse_output(tracked_proc),
+                    }
+
+                    rawset(self, key, ret)
+                    return ret
+                end,
+            })
+        end
+        local git_status = new_git_status()
+
+        -- Clear git status cache on refresh
+        local refresh = require("oil.actions").refresh
+        local orig_refresh = refresh.callback
+        refresh.callback = function(...)
+            git_status = new_git_status()
+            orig_refresh(...)
+        end
+
+        return {
             keymaps = {
                 ["q"] = "actions.close",
                 ["<bs>"] = "actions.parent",
@@ -23,7 +73,28 @@ return {
                     nowait = true,
                 },
             },
+            view_options = {
+                is_hidden_file = function(name, bufnr)
+                    if vim.startswith(name, ".env") then
+                        return false
+                    end
+                    local dir = require("oil").get_current_dir(bufnr)
+                    local is_dotfile = vim.startswith(name, ".") and name ~= ".."
+                    -- if no local directory (e.g. for ssh connections), just hide dotfiles
+                    if not dir then
+                        return is_dotfile
+                    end
+                    -- dotfiles are considered hidden unless tracked
+                    if is_dotfile then
+                        return not git_status[dir].tracked[name]
+                    else
+                        -- Check if file is gitignored
+                        return git_status[dir].ignored[name]
+                    end
+                end,
             },
+        }
+    end,
     dependencies = { "nvim-tree/nvim-web-devicons" },
     cmd = { "Oil" },
     keys = {