(local cmp (require :cmp))

(fn has-words-before []
  (let [(line col) (unpack (vim.api.nvim_win_get_cursor 0))
        cur-line (. (vim.api.nvim_buf_get_lines 0
                                          (- line 1)
                                          line
                                          true
                      1))]
    (and (not= col 0)
         (= (: (: cur-line :sub col col) :match "%s")
            nil))))

(fn tab [fallback]
  (let [cmp (require :cmp)
        luasnip (require :luasnip)]
    (if (cmp.visible)
        (cmp.select_next_item)
        (let [available (luasnip.expand_or_jumpable)]
          (if (= (available) true)
              (luasnip.expand_or_jump)
              (if (has-words-before)
                  (cmp.complete)
                  (fallback)))))))

(fn stab [fallback]
  (let [cmp (require :cmp)
        luasnip (require :luasnip)]
    (if (cmp.visible)
        (cmp.select_prev_item)
        (let [available (luasnip.jumpable -1)]
          (if (= (available) true)
              (luasnip.jump -1)
              (if (has-words-before)
                  (cmp.complete)
                  (fallback)))))))

(let [lspkind (require :lspkind)
      luasnip_loaders (require :luasnip.loaders.from_vscode)]
  (luasnip_loaders.lazy_load)
  (cmp.setup {:formatting {:format lspkind.cmp_format}
              :snippet {:expand (fn [args]
                                  (let [luasnip (require :luasnip)]
                                    (luasnip.lsp_expand args.body)))}
              :sources [{:name "buffer"}      {:name "nvim_lsp"} 
                        {:name "look"}        {:name "path"}
                        {:name "calc"}        {:name "spell"}
                        {:name "cmp-conjure"} {:name "luasnip"}
                        {:name "tags"}]
              :mapping {"<C-d>" (cmp.mapping.scroll_docs -4)
                        "<C-u>" (cmp.mapping.scroll_docs 4)
                        "<Up>" (cmp.mapping (cmp.mapping.select_prev_item) [:i :c])
                        "<Down>" (cmp.mapping (cmp.mapping.select_next_item) [:i :c]) 
                        "<C-g>" (cmp.mapping.close)
                        "<CR>" (cmp.mapping.confirm {:select true})
                        "<Tab>" (cmp.mapping tab [:i :s])
                        "<S-Tab>" (cmp.mapping stab [:i :s])}}))