nvim.nix/nvim/lua/plugins/completion.lua

return {
  {
    'hrsh7th/nvim-cmp',
    event = 'VeryLazy',
    dependencies = {
      'hrsh7th/cmp-buffer',
      'hrsh7th/cmp-cmdline',
      'hrsh7th/cmp-path',
      'hrsh7th/cmp-nvim-lsp',
      'ray-x/cmp-treesitter',
      'L3MON4D3/luasnip',
      'saadparwaiz1/cmp_luasnip',
    },
    config = function()
      local cmp = require('cmp')
      cmp.setup {
        snippet = {
          expand = function(args)
            require('luasnip').lsp_expand(args.body)
          end,
        },
        mapping = cmp.mapping.preset.insert {
          ['<C-u>'] = cmp.mapping.scroll_docs(-4),
          ['<C-d>'] = cmp.mapping.scroll_docs(4),
          ['<C-n>'] = cmp.mapping.select_next_item { behavior = cmp.SelectBehavior.Insert },
          ['<C-p>'] = cmp.mapping.select_prev_item { behavior = cmp.SelectBehavior.Insert },
          ['<C-Space>'] = cmp.mapping.confirm {
            select = true,
            behavior = cmp.SelectBehavior.Insert
          },
        },
        sources = cmp.config.sources({
          { name = 'nvim_lsp',   keyword_length = 1 },
          { name = 'luasnip' },
          { name = 'buffer' },
          { name = 'path' },
          { name = 'treesitter', keyword_length = 3 },
        }),
      }

      cmp.setup.cmdline({ '/', '?' }, {
        mapping = cmp.mapping.preset.cmdline(),
        sources = {
          { name = 'buffer' },
        },
      })

      cmp.setup.cmdline(':', {
        mapping = cmp.mapping.preset.cmdline(),
        sources = cmp.config.sources({
          { name = 'path' },
          { name = 'buffer' },
          { name = 'cmdline' },
        }),
        matching = { disallow_symbol_nonprefix_matching = false },
      })
    end,
  },
  {
    'L3MON4D3/luasnip',
    event = 'VeryLazy',
    dependencies = { 'rafamadriz/friendly-snippets' },
    config = function()
      local ls = require('luasnip')
      ls.config.set_config {
        history = true,
        updateevents = 'TextChanged, TextChangedI',
      }
      require('luasnip.loaders.from_vscode').lazy_load()

      vim.keymap.set({ 'i', 's' }, '<C-J>', function()
        if ls.expand_or_jumpable() then
          ls.expand_or_jump()
        end
      end, { silent = true })

      vim.keymap.set({ 'i', 's' }, '<C-K>', function()
        if ls.jumpable(-1) then
          ls.jump(-1)
        end
      end, { silent = true })

      vim.keymap.set({ 'i', 's' }, '<C-L>', function()
        if ls.choice_active() then
          ls.change_choice(1)
        end
      end, { silent = true })
    end,
  },
}