fix: Better highlights (#344)

* scratch: easy reproduce for buffers

* fix: Many highlight fixes

lua/telescope/pickers/highlights.lua

@@ -0,0 +1,76 @@
+local a = vim.api
+
+local highlights = {}
+
+local ns_telescope_selection = a.nvim_create_namespace('telescope_selection')
+local ns_telescope_entry = a.nvim_create_namespace('telescope_entry')
+
+local Highlighter = {}
+Highlighter.__index = Highlighter
+
+function Highlighter:new(picker)
+  return setmetatable({
+    picker = picker,
+  }, self)
+end
+
+function Highlighter:hi_display(row, prefix, display_highlights)
+  local results_bufnr = assert(self.picker.results_bufnr, "Must have a results bufnr")
+
+  a.nvim_buf_clear_namespace(results_bufnr, ns_telescope_entry, row, row + 1)
+  local len_prefix = #prefix
+
+  for _, hl_block in ipairs(display_highlights) do
+    a.nvim_buf_add_highlight(
+      results_bufnr,
+      ns_telescope_entry,
+      hl_block[2],
+      row,
+      len_prefix + hl_block[1][1],
+      len_prefix + hl_block[1][2]
+    )
+  end
+end
+
+function Highlighter:clear_display()
+  a.nvim_buf_clear_namespace(self.picker.results_bufnr, ns_telescope_entry, 0, -1)
+end
+
+function Highlighter:hi_sorter(row, prompt, display)
+  local picker = self.picker
+  if not picker.sorter or not picker.sorter.highlighter then
+    return
+  end
+
+  local results_bufnr = assert(self.picker.results_bufnr, "Must have a results bufnr")
+  picker:highlight_one_row(results_bufnr, prompt, display, row)
+end
+
+function Highlighter:hi_selection(row, caret)
+  local results_bufnr = assert(self.picker.results_bufnr, "Must have a results bufnr")
+
+  a.nvim_buf_clear_namespace(results_bufnr, ns_telescope_selection, 0, -1)
+  a.nvim_buf_add_highlight(
+    results_bufnr,
+    ns_telescope_selection,
+    'TelescopeSelectionCaret',
+    row,
+    0,
+    #caret
+  )
+
+  a.nvim_buf_add_highlight(
+    results_bufnr,
+    ns_telescope_selection,
+    'TelescopeSelection',
+    row,
+    #caret,
+    -1
+  )
+end
+
+highlights.new = function(...)
+  return Highlighter:new(...)
+end
+
+return highlights