local lsp = require("core.lsp.functions")

return { "hrsh7th/nvim-cmp",
  requires = {
    "nvim-treesitter/nvim-treesitter",
    "lukas-reineke/cmp-under-comparator", -- better results
    "xzbdmw/colorful-menu.nvim" -- fancy colors
  },

  -- suppliers for completions (they require nvim-cmp to be loaded before they are)
  deps = {
    "hrsh7th/cmp-buffer", -- buffers
    "FelipeLema/cmp-async-path", -- path
    { "hrsh7th/cmp-nvim-lsp",
      function()
        -- add lsp capabilities
        lsp.add_capabilities(require("cmp_nvim_lsp").default_capabilities())
      end
    }, -- lsp
    "hrsh7th/cmp-nvim-lsp-signature-help", -- completion information
    { "L3MON4D3/cmp-luasnip-choice", -- luasnip
      requires = "L3MON4D3/LuaSnip"
    }
  },

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

    -- setup cmp
    cmp.setup {
      -- disable when in comments
      enabled = function()
        local context = require("cmp.config.context")
        if vim.api.nvim_get_mode().mode == "c" then
          return true
        else
          return not context.in_treesitter_capture("comment")
            and not context.in_syntax_group("Comment")
        end
      end,

      -- completion sources
      sources = cmp.config.sources {
        { name = "nvim_lsp", priority = 999 },
        { name = "luasnip_choice", priority = 750 },
        { name = "buffer", max_item_count = 3 },
        { name = "async_path", max_item_count = 5 },
        { name = "neorg" },
        { name = "nvim_lsp_signature_help" }
      },

      -- how to sort results
      sorting = {
        comparators = {
          cmp.config.compare.exact,
          cmp.config.compare.offset,
          cmp.config.compare.score,
          require("cmp-under-comparator").under,
          cmp.config.compare.kind,
          cmp.config.compare.sort_text,
          cmp.config.compare.length,
          cmp.config.compare.order,
        }
      },

      -- appearance of window
      window = {
        completion = {
          scrollbar = false,
          border = vim.g.border_style,
          winhighlight = "Normal:WinBarNC,FloatBorder:WinBarNC,Search:WinBarNC",
        },
        documentation = {
          border = vim.g.border_style,
          winhighlight = "Normal:WinBarNC,FloatBorder:WinBarNC,Search:WinBarNC",
        }
      },

      -- position of window
      view = {
        entries = {
          name = "custom",
          selection_order = "near_cursor"
        }
      },

      -- formatting of content
      formatting = {
        fields = { "menu", "abbr", "kind" },
        format = function(entry, item)
          local hl_info = require("colorful-menu").cmp_highlights(entry)
          local menu_icon = {
            nvim_lsp = "λ",
            luasnip = "%",
            buffer = "@",
            path = "#",
            async_path = "#"
          }

          -- add a little icon
          item.menu = menu_icon[entry.source.name]

          -- add highlights
          if hl_info ~= nil then
            item.abbr_hl_group = hl_info.highlights
            item.abbr = hl_info.text
          end

          return item
        end
      },

      experimental = {
        ghost_text = true
      },

      -- snippet integration
      snippet = {
        expand = function(args)
          luasnip.lsp_expand(args.body)
        end
      },

      -- mappings
      mapping = cmp.mapping.preset.insert {
        ["<C-y>"] = cmp.mapping.confirm {
          select = true
        },
        ["<C-n>"] = cmp.mapping.select_next_item(),
        ["<C-p>"] = cmp.mapping.select_prev_item(),
        ["<C-u>"] = cmp.mapping.scroll_docs(-4),
        ["<C-d>"] = cmp.mapping.scroll_docs(4),
        ["<ESC>"] = cmp.mapping.close()
      }
    }
  end
}