feat(ui): add basic winbar config

lua/config/init.lua

@@ -2,3 +2,4 @@ require('config.keymaps')
 require('config.autocommands')
 require('config.lsp')
 require('config.options')
+require('config.winbar')

lua/config/winbar.lua

@@ -0,0 +1,76 @@
+local folder_icon = require('config.icons').kinds.Folder
+
+local M = {}
+
+--- Window bar that shows the current file path (in a fancy way).
+---@return string
+function M.render()
+    -- Get the path and expand variables.
+    local path = vim.fs.normalize(vim.fn.expand('%:p') --[[@as string]])
+
+    -- No special styling for diff views.
+    if vim.startswith(path, 'diffview') then
+        return string.format('%%#Winbar#%s', path)
+    end
+
+    -- Replace slashes by arrows.
+    local separator = ' %#WinbarSeparator# '
+    local prefix, prefix_path = '', ''
+
+    -- If the window gets too narrow, shorten the path and drop the prefix.
+    if vim.api.nvim_win_get_width(0) < math.floor(vim.o.columns / 3) then
+        path = vim.fn.pathshorten(path)
+    else
+        -- For some special folders, add a prefix instead of the full path (making
+        -- sure to pick the longest prefix).
+        ---@type table<string, string>
+        local special_dirs = {
+            DOTFILES = vim.env.XDG_CONFIG_HOME,
+            HOME = vim.env.HOME,
+            GIT = vim.g.git_dir,
+            WORK = vim.env.HOME .. '/Projects',
+        }
+        for dir_name, dir_path in pairs(special_dirs) do
+            if vim.startswith(path, vim.fs.normalize(dir_path)) and #dir_path > #prefix_path then
+                prefix, prefix_path = dir_name, dir_path
+            end
+        end
+        if prefix ~= '' then
+            path = path:gsub('^' .. vim.pesc(prefix_path), '')
+            prefix = string.format('%%#WinBarDir#%s %s%s', folder_icon, prefix, separator)
+        end
+    end
+
+    -- Remove leading slash.
+    path = path:gsub('^/', '')
+
+    return table.concat({
+        ' ',
+        prefix,
+        table.concat(
+            vim.iter(vim.split(path, '/'))
+                :map(function(segment)
+                    return string.format('%%#Winbar#%s', segment)
+                end)
+                :totable(),
+            separator
+        ),
+    })
+end
+
+vim.api.nvim_create_autocmd('BufWinEnter', {
+    group = vim.api.nvim_create_augroup('my.winbar', { clear = true }),
+    desc = 'Attach winbar',
+    callback = function(args)
+        if
+            not vim.api.nvim_win_get_config(0).zindex -- Not a floating window
+            and vim.bo[args.buf].buftype == '' -- Normal buffer
+            and vim.api.nvim_buf_get_name(args.buf) ~= '' -- Has a file name
+            and not vim.wo[0].diff -- Not in diff mode
+        then
+            vim.wo.winbar = "%{%v:lua.require'config.winbar'.render()%}"
+        end
+    end,
+})
+
+return M