highlight.fnl

(local util (require "leap.util"))

(local {: inc : dec} util)
(local api vim.api)
(local map vim.tbl_map)


(local M {:ns (api.nvim_create_namespace "")
          :extmarks []
          :group {:label-primary "LeapLabelPrimary"
                  :label-secondary "LeapLabelSecondary"
                  :label-selected "LeapLabelSelected"
                  :match "LeapMatch"
                  :backdrop "LeapBackdrop"}
          :priority {:label 65535
                     :cursor 65534
                     :backdrop 65533}})


(fn M.cleanup [self affected-windows]
  ; Clear beacons & cursor.
  (each [_ [bufnr id] (ipairs self.extmarks)]
    (api.nvim_buf_del_extmark bufnr self.ns id))
  (set self.extmarks [])
  ; Clear backdrop.
  (when (pcall api.nvim_get_hl_by_name self.group.backdrop false)  ; group exists?
    (each [_ winid (ipairs affected-windows)]
      (local wininfo (. (vim.fn.getwininfo winid) 1))
      (api.nvim_buf_clear_namespace
        wininfo.bufnr self.ns (dec wininfo.topline) wininfo.botline))
    ; Safety measure for scrolloff > 0: we always clean up the current view too.
    (api.nvim_buf_clear_namespace 0 self.ns
                                  (dec (vim.fn.line "w0"))
                                  (vim.fn.line "w$"))))


(fn M.apply-backdrop [self ranges]
  (when (pcall api.nvim_get_hl_by_name self.group.backdrop false)  ; group exists?
    (each [_ range (ipairs ranges)]
      (vim.highlight.range range.bufnr self.ns self.group.backdrop
                           [range.startrow range.startcol]
                           [range.endrow range.endcol]
                           {:priority self.priority.backdrop}))))


(fn M.highlight-cursor [self ?pos]
  "The cursor is down on the command line during `getchar`,
so we set a temporary highlight on it to see where we are."
  (let [[line col &as pos] (or ?pos (util.get-cursor-pos))
        ; nil means the cursor is on an empty line.
        ch-at-curpos (or (util.get-char-at pos {}) " ")  ; get-char-at needs 1,1-idx
        ; (Ab)using extmarks even here, to be able to highlight the cursor on empty lines too.
        id (api.nvim_buf_set_extmark 0 self.ns (dec line) (dec col)
                                     {:virt_text [[ch-at-curpos :Cursor]]
                                      :virt_text_pos "overlay"
                                      :hl_mode "combine"
                                      :priority self.priority.cursor})]
    (table.insert self.extmarks [(api.nvim_get_current_buf) id])))


(fn M.init-highlight [self force?]
  (let [bg vim.o.background
        defaults {self.group.match {:fg (case bg
                                          :light "#222222"
                                          _ "#ccff88")
                                    :ctermfg "red"
                                    :underline true
                                    :nocombine true}
                  self.group.label-primary {:fg "black"
                                            :bg (case bg
                                                  :light "#ff8877"
                                                  _ "#ccff88")
                                            :ctermfg "black"
                                            :ctermbg "red"
                                            :nocombine true}
                  self.group.label-secondary {:fg "black"
                                              :bg (case bg
                                                    :light "#77aaff"
                                                    _ "#99ccff")
                                              :ctermfg "black"
                                              :ctermbg "blue"
                                              :nocombine true}
                  self.group.label-selected {:fg "black"
                                             :bg "magenta"
                                             :ctermfg "black"
                                             :ctermbg "magenta"
                                             :nocombine true}}]
    (each [group-name def-map (pairs defaults)]
      (when (not force?) (set def-map.default true))
      (api.nvim_set_hl 0 group-name def-map))))


M