local M = {}

function M.setup()
  local has_words_before = function()
    local line, col = unpack(vim.api.nvim_win_get_cursor(0))
    return col ~= 0 and vim.api.nvim_buf_get_lines(0, line - 1, line, true)[1]:sub(col, col):match "%s" == nil
  end

  local luasnip = require("luasnip")
  local cmp = require("cmp")

  cmp.setup {
    completion = { completeopt = "menu,menuone,noinsert", keyword_length = 1 },
    experimental = { native_menu = false, ghost_text = false },
    snippet = {
      expand = function(args)
        require("luasnip").lsp_expand(args.body)
      end,
    },
    formatting = {
      format = function(entry, vim_item)
        vim_item.menu = ({
          nvim_lsp = "[LSP]",
          buffer = "[Buffer]",
          luasnip = "[Snip]",
          nvim_lua = "[Lua]",
          treesitter = "[Treesitter]",
          path = "[Path]",
        })[entry.source.name]
        return vim_item
      end,
  },
  mapping = {
      ["<C-k>"] = cmp.mapping(cmp.mapping.select_prev_item(), { "i", "c" }),
      ["<C-j>"] = cmp.mapping(cmp.mapping.select_next_item(), { "i", "c" }),
      ["<C-b>"] = cmp.mapping(cmp.mapping.scroll_docs(-4), { "i", "c" }),
      ["<C-f>"] = cmp.mapping(cmp.mapping.scroll_docs(4), { "i", "c" }),
      ["<C-Space>"] = cmp.mapping(cmp.mapping.complete(), { "i", "c" }),
      ["<C-e>"] = cmp.mapping { i = cmp.mapping.close(), c = cmp.mapping.close() },
      ["<CR>"] = cmp.mapping {
          i = cmp.mapping.confirm { behavior = cmp.ConfirmBehavior.Replace, select = false },
          c = function(fallback)
              if cmp.visible() then
                  cmp.confirm { behavior = cmp.ConfirmBehavior.Replace, select = false }
              else
                  fallback()
              end
          end,
      },
      ["<Tab>"] = cmp.mapping(
          function(fallback)
              if cmp.visible() then
                  cmp.select_next_item()
              elseif luasnip.expand_or_jumpable() then
                  luasnip.expand_or_jump()
              elseif has_words_before() then
                  cmp.complete()
              else
                  fallback()
              end
          end, {
          "i",
          "s",
          "c",
      }),
      ["<S-Tab>"] = cmp.mapping(function(fallback)
          if cmp.visible() then
              cmp.select_prev_item()
          elseif luasnip.jumpable(-1) then
              luasnip.jump(-1)
          else
              fallback()
          end
      end, {
      "i",
      "s",
      "c",
      }),

  },
  sources = {
      { name = "nvim_lsp" },
      { name = "treesitter" },
      { name = "buffer" },
      { name = "luasnip" },
      { name = "nvim_lua" },
      { name = "path" },
      -- { name = "spell" },
      -- { name = "emoji" },
      -- { name = "calc" },
  },
  window = {
      documentation = {
          border = { "╭", "─", "╮", "│", "╯", "─", "╰", "│" },
          winhighlight = "NormalFloat:NormalFloat,FloatBorder:TelescopeBorder",
      },
  },
  }

  -- Use buffer source for `/`
  cmp.setup.cmdline("/", {
    mapping = cmp.mapping.preset.cmdline(),
    sources = {
      { name = "buffer" },
    },
  })

  -- Use cmdline & path source for ':' (if you enabled `native_menu`, this won't work anymore).
  cmp.setup.cmdline(':', {
    mapping = cmp.mapping.preset.cmdline(),
    sources = cmp.config.sources({
      { name = 'path' }
    }, {
      { name = 'cmdline' }
    })
  })

end

return M