config/.config/nvim/lua/user/cmp.lua

local cmp_status_ok, cmp = pcall(require, "cmp")
if not cmp_status_ok then
  return
end

local snip_status_ok, luasnip = pcall(require, "luasnip")
if not snip_status_ok then
  return
end

local buffer_fts = {
  "markdown",
  "toml",
  "yaml",
  "json",
}

local function contains(t, value)
  for _, v in pairs(t) do
    if v == value then
      return true
    end
  end
  return false
end

local compare = require "cmp.config.compare"

require("luasnip/loaders/from_vscode").lazy_load()

local check_backspace = 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 icons = require "user.icons"

local kind_icons = icons.kind

-- I don't have most of the following but they can serve as future examples
vim.api.nvim_set_hl(0, "CmpItemKindCopilot", { fg = "#6CC644" })
vim.api.nvim_set_hl(0, "CmpItemKindTabnine", { fg = "#CA42F0" })
vim.api.nvim_set_hl(0, "CmpItemKindEmoji", { fg = "#FDE030" })
vim.api.nvim_set_hl(0, "CmpItemKindCrate", { fg = "#F64D00" })

vim.g.cmp_active = true

cmp.setup {
  enabled = function()
    local buftype = vim.api.nvim_buf_get_option(0, "buftype")
    if buftype == "prompt" then
      return false
    end
    return vim.g.cmp_active
  end,
  preselect = cmp.PreselectMode.None,
  snippet = {
    expand = function(args)
      luasnip.lsp_expand(args.body) -- For `luasnip` users.
    end,
  },
  mapping = cmp.mapping.preset.insert {
    ["<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(-1), { "i", "c" }),
    ["<C-f>"] = cmp.mapping(cmp.mapping.scroll_docs(1), { "i", "c" }),
    ["<C-Space>"] = cmp.mapping(cmp.mapping.complete(), { "i", "c" }),
    -- ["<C-y>"] = cmp.config.disable, -- Specify `cmp.config.disable` if you want to remove the default `<C-y>` mapping.
    ["<C-c>"] = cmp.mapping {
      i = cmp.mapping.abort(),
      c = cmp.mapping.close(),
    },
    ["<m-j>"] = cmp.mapping {
      i = cmp.mapping.abort(),
      c = cmp.mapping.close(),
    },
    ["<m-k>"] = cmp.mapping {
      i = cmp.mapping.abort(),
      c = cmp.mapping.close(),
    },
    ["<m-c>"] = cmp.mapping {
      i = cmp.mapping.abort(),
      c = cmp.mapping.close(),
    },
    ["<S-CR>"] = cmp.mapping {
      i = cmp.mapping.abort(),
      c = cmp.mapping.close(),
    },
    -- Accept currently selected item. If none selected, `select` first item.
    -- Set `select` to `false` to only confirm explicitly selected items.
    ["<CR>"] = cmp.mapping.confirm { select = false },
    ["<Right>"] = cmp.mapping.confirm { select = true },
    ["<Tab>"] = cmp.mapping(function(fallback)
      if cmp.visible() then
        cmp.select_next_item()
      elseif luasnip.jumpable(1) then
        luasnip.jump(1)
      elseif luasnip.expand_or_jumpable() then
        luasnip.expand_or_jump()
      elseif luasnip.expandable() then
        luasnip.expand()
      elseif check_backspace() then
        -- cmp.complete()
        fallback()
      else
        fallback()
      end
    end, {
      "i",
      "s",
    }),
    ["<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",
    }),
  },
  formatting = {
    fields = { "kind", "abbr", "menu" },
    format = function(entry, vim_item)
      -- Kind icons
      vim_item.kind = kind_icons[vim_item.kind]

      if entry.source.name == "cmp_tabnine" then
        vim_item.kind = icons.misc.Robot
        vim_item.kind_hl_group = "CmpItemKindTabnine"
      end
      if entry.source.name == "copilot" then
        vim_item.kind = icons.git.Octoface
        vim_item.kind_hl_group = "CmpItemKindCopilot"
      end

      if entry.source.name == "emoji" then
        vim_item.kind = icons.misc.Smiley
        vim_item.kind_hl_group = "CmpItemKindEmoji"
      end

      if entry.source.name == "crates" then
        vim_item.kind = icons.misc.Package
        vim_item.kind_hl_group = "CmpItemKindCrate"
      end

      if entry.source.name == "lab.quick_data" then
        vim_item.kind = icons.misc.CircuitBoard
        vim_item.kind_hl_group = "CmpItemKindConstant"
      end

      -- NOTE: order matters
      vim_item.menu = ({
        nvim_lsp = "",
        nvim_lua = "",
        luasnip = "",
        buffer = "",
        path = "",
        emoji = "",
      })[entry.source.name]
      return vim_item
    end,
  },
  sources = {
    {
      name = "crates", group_index = 1 },
    {
      name = "copilot",
      max_item_count = 3,
      group_index = 2,
    },
    {
      name = "nvim_lsp",
      filter = function(entry, ctx)
        local kind = require("cmp.types.lsp").CompletionItemKind[entry:get_kind()]
        if kind == "Snippet" and ctx.prev_context.filetype == "java" then
          return true
        end

        if kind == "Text" then
          return true
        end
      end,
      group_index = 2,
    },
    { name = "nvim_lua", group_index = 2 },
    { name = "luasnip", group_index = 2 },
    {
      name = "buffer",
      group_index = 2,
      filter = function(entry, ctx)
        if not contains(buffer_fts, ctx.prev_context.filetype) then
          return true
        end
      end,
    },
    { name = "path", group_index = 2 },
    { name = "emoji", group_index = 2 },
    { name = "lab.quick_data", keyword_length = 4, group_index = 2 },
  },
  sorting = {
    priority_weight = 2,
    comparators = {
      compare.offset,
      compare.exact,
      -- compare.scopes,
      compare.score,
      compare.recently_used,
      compare.locality,
      -- compare.kind,
      compare.sort_text,
      compare.length,
      compare.order,
    },
  },
  confirm_opts = {
    behavior = cmp.ConfirmBehavior.Replace,
    select = false,
  },
  window = {
    documentation = false,
    completion = {
      border = "rounded",
      winhighlight = "NormalFloat:Pmenu,NormalFloat:Pmenu,CursorLine:PmenuSel,Search:None",
    },
  },
  experimental = {
    ghost_text = true,
  },
}