refactor: Reorganize modules

Primarily:
- Utils
- Sidebar (removed the need of writer.lua)
- Resolve keymaps shortcut in config eraly
- Put highlight functions into highlight.lua
- Put functions that do stuff on outline window into view.lua

lua/outline/highlight.lua

@@ -1,38 +1,102 @@
-local M = {}
+local M = {
+  ns = {
+    hover = vim.api.nvim_create_namespace('outline-current'),
+    items = vim.api.nvim_create_namespace('outline-items-highlight'),
+    vt = vim.api.nvim_create_namespace('outline-virt-text'),
+  },
+}
 
-M.hovered_hl_ns = vim.api.nvim_create_namespace('hovered_item')
-
-function M.clear_hover_highlight(bufnr)
-  vim.api.nvim_buf_clear_namespace(bufnr, M.hovered_hl_ns, 0, -1)
+---Clear all highlights in buffer
+---@param bufnr integer
+function M.clear_all_ns(bufnr)
+  vim.api.nvim_buf_clear_namespace(bufnr, -1, 0, -1)
 end
 
-function M.add_hover_highlight(bufnr, line, col_start)
-  vim.api.nvim_buf_add_highlight(bufnr, M.hovered_hl_ns, 'OutlineCurrent', line, col_start, -1)
+---Clear hover highlights in buffer
+---@param bufnr integer
+function M.clear_hovers(bufnr)
+  vim.api.nvim_buf_clear_namespace(bufnr, M.ns.hover, 0, -1)
 end
 
-local get_hl_by_name
-
-if vim.fn.has('nvim-0.9') == 1 then
-  get_hl_by_name = function(name)
-    local hl = vim.api.nvim_get_hl(0, { name = name, link = false })
-    return { fg = hl.fg, bg = hl.bg, ctermfg = hl.ctermfg, ctermbg = hl.ctermbg }
-  end
-else
-  get_hl_by_name = function(name)
-    ---@diagnostic disable-next-line undefined-field
-    local hlrgb = vim.api.nvim_get_hl_by_name(name, true)
-    ---@diagnostic disable-next-line undefined-field
-    local hl = vim.api.nvim_get_hl_by_name(name, false)
-    return {
-      fg = hlrgb.foreground,
-      bg = hlrgb.background,
-      ctermfg = hl.foreground,
-      ctermbg = hl.background,
-    }
+---Add single hover highlights
+---@param bufnr integer
+---@param nodes outline.FlatSymbolNode[]
+function M.hovers(bufnr, nodes)
+  for line, node in ipairs(nodes) do
+    if node.hovered then
+      vim.api.nvim_buf_add_highlight(bufnr, M.ns.hover, 'OutlineCurrent', line - 1, node.prefix_length, -1)
+    end
   end
 end
 
-function M.setup_highlights()
+---Add list of highlights `hl` for outline items
+---@param bufnr integer
+---@param hl_list outline.HL[]
+function M.items(bufnr, hl_list)
+  for _, h in ipairs(hl_list) do
+    -- stylua: ignore start
+    vim.api.nvim_buf_add_highlight(
+      bufnr, M.ns.items,
+      h.name, h.line - 1, h.from, h.to
+    )
+    -- stylua: ignore end
+  end
+end
+
+---Add details virtual text
+---@param bufnr integer Outline buffer
+---@param details string[] Virtual text to add
+function M.details(bufnr, details)
+  for index, detail in ipairs(details) do
+    vim.api.nvim_buf_set_extmark(bufnr, M.ns.vt, index - 1, -1, {
+      virt_text = { { detail, 'OutlineDetails' } },
+      virt_text_pos = 'eol',
+      hl_mode = 'combine',
+    })
+  end
+end
+
+---Add linenos virtual text
+---@param bufnr integer Outline buffer
+---@param linenos string[] Must already be padded
+---@param hl_mode string Valid value for `buf_set_extmark` option `hl_mode`
+function M.linenos(bufnr, linenos, hl_mode)
+  -- TODO: Fix lineno not appearing if text in line is truncated on the right
+  -- due to narrow window, after nvim fixes virt_text_hide.
+  for index, lineno in ipairs(linenos) do
+    vim.api.nvim_buf_set_extmark(bufnr, M.ns.vt, index - 1, -1, {
+      virt_text = { { lineno, 'OutlineLineno' } },
+      virt_text_pos = 'overlay',
+      virt_text_win_col = 0,
+      hl_mode = hl_mode,
+    })
+  end
+end
+
+---Create Outline highlights with default values if they don't already exist
+function M.setup()
+  local get_hl_by_name
+
+  if _G._outline_nvim_has[9] then
+    get_hl_by_name = function(name)
+      local hl = vim.api.nvim_get_hl(0, { name = name, link = false })
+      return { fg = hl.fg, bg = hl.bg, ctermfg = hl.ctermfg, ctermbg = hl.ctermbg }
+    end
+  else
+    get_hl_by_name = function(name)
+      ---@diagnostic disable-next-line undefined-field
+      local hlrgb = vim.api.nvim_get_hl_by_name(name, true)
+      ---@diagnostic disable-next-line undefined-field
+      local hl = vim.api.nvim_get_hl_by_name(name, false)
+      return {
+        fg = hlrgb.foreground,
+        bg = hlrgb.background,
+        ctermfg = hl.foreground,
+        ctermbg = hl.background,
+      }
+    end
+  end
+
   -- Setup the OutlineCurrent highlight group if it hasn't been done already by
   -- a theme or manually set
   if vim.fn.hlexists('OutlineCurrent') == 0 then