refactor: Rename module ui -> highlight

lua/outline/highlight.lua

@@ -0,0 +1,72 @@
+local M = {}
+
+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)
+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)
+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,
+    }
+  end
+end
+
+function M.setup_highlights()
+  -- 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
+    local cline_hl = get_hl_by_name('CursorLine')
+    local string_hl = get_hl_by_name('String')
+
+    vim.api.nvim_set_hl(0, 'OutlineCurrent', {
+      bg = cline_hl.bg,
+      fg = string_hl.fg,
+      ctermbg = cline_hl.ctermbg,
+      ctermfg = string_hl.ctermfg,
+    })
+  end
+
+  -- Only inherit fg for these highlights because we do not want the other
+  -- stylings messing up the alignment, nor the background so that cursorline
+  -- can look normal when on top of it. This can be customized by setting these
+  -- highlights before outline.setup() is called, or using winhl.
+  for name, link in pairs({ Guides = 'Comment', FoldMarker = 'Normal' }) do
+    if vim.fn.hlexists('Outline' .. name) == 0 then
+      local h = get_hl_by_name(link)
+      vim.api.nvim_set_hl(0, 'Outline' .. name, { fg = h.fg, ctermfg = h.fg })
+    end
+  end
+
+  for name, link in pairs({
+    Details = 'Comment',
+    Lineno = 'LineNr',
+    JumpHighlight = 'Visual',
+  }) do
+    if vim.fn.hlexists('Outline' .. name) == 0 then
+      vim.api.nvim_set_hl(0, 'Outline' .. name, { link = link })
+    end
+  end
+end
+
+return M