flake-nvim/flake.nix

# flake.nix
{
  description = "My own Neovim flake";
  inputs = {
    nixpkgs = {
      url = "github:NixOS/nixpkgs";
    };
    neovim = {
      url = "github:nix-community/neovim-nightly-overlay";
      inputs.nixpkgs.follows = "nixpkgs";
    };
    plugin-dracula = {
    	url = "github:Mofiqul/dracula.nvim";
    	flake = false;
    };
    plugin-gruvbox = {
      url = "github:ellisonleao/gruvbox.nvim";
	    flake = false;
    };
    plugin-lsp = {
      url = "https://github.com/neovim/nvim-lspconfig";
      flake = false;
    };
    plugin-cmp = {
      url = "https://github.com/hrsh7th/nvim-cmp";
      flake = false;
    };
    plugin-cmp-vsnip = {
      url = "https://github.com/hrsh7th/cmp-vsnip";
      flake = false;
    };
    plugin-cmp-lsp = {
      url = "https://github.com/hrsh7th/cmp-nvim-lsp";
      flake = false;
    };
    plugin-cmp-buffer = {
      url = "https://github.com/hrsh7th/cmp-buffer";
      flake = false;
    };
    plugin-cmp-path = {
      url = "https://github.com/hrsh7th/cmp-path";
      flake = false;
    };
    plugin-cmp-cmd = {
      url = "https://github.com/hrsh7th/cmp-cmdline";
      flake = false;
    };
    plugin-vim-vsnip = {
      url = "https://github.com/hrsh7th/vim-vsnip";
      flake = false;
    };
  };
  
  outputs = { self, nixpkgs, neovim, ... }@inputs: {
	  nixosModules.neovim = {config, pkgs, ...} :
	  {
	    environment.systemPackages = with pkgs; [
	      inputs.neovim.packages.${pkgs.system}.neovim 
	    ];
	    programs.neovim = {
        enable = true;
        configure = {
          packages.myTetspkg = {
          start =  with pkgs.vimPlugins; [
        # Use pre-packaged plugins from nixpkgs
        dracula-nvim  # or the closest match available
        nvim-lspconfig
        nvim-cmp
        cmp-nvim-lsp
        cmp-buffer
        cmp-path
        cmp-cmdline
        vim-vsnip
        cmp-vsnip
      ];};
        customRC = ''
          set runtimepath+=${inputs.plugin-dracula}
          set runtimepath+=${inputs.plugin-lsp}
          set runtimepath+=${inputs.plugin-cmp}
          set runtimepath+=${inputs.plugin-cmp-vsnip}
          set runtimepath+=${inputs.plugin-cmp-buffer}
          set runtimepath+=${inputs.plugin-cmp-path}
          set runtimepath+=${inputs.plugin-cmp-lsp}
          set runtimepath+=${inputs.plugin-cmp-cmd}
          set runtimepath+=${inputs.plugin-vim-vsnip}

	        colorscheme dracula
	        autocmd BufEnter * :setlocal tabstop=2 shiftwidth=2 expandtab
          autocmd BufEnter *.nix :setlocal tabstop=2 shiftwidth=2 expandtab
          autocmd BufEnter *.py :setlocal tabstop=4 shiftwidth=4 expandtab

          lua <<EOF
  -- Set up nvim-cmp.
  --local cmp = require'cmp'

  cmp.setup({
    snippet = {
      -- REQUIRED - you must specify a snippet engine
      expand = function(args)
        vim.fn["vsnip#anonymous"](args.body) -- For `vsnip` users.
        -- require('luasnip').lsp_expand(args.body) -- For `luasnip` users.
        -- require('snippy').expand_snippet(args.body) -- For `snippy` users.
        -- vim.fn["UltiSnips#Anon"](args.body) -- For `ultisnips` users.
        -- vim.snippet.expand(args.body) -- For native neovim snippets (Neovim v0.10+)

        -- For `mini.snippets` users:
        -- local insert = MiniSnippets.config.expand.insert or MiniSnippets.default_insert
        -- insert({ body = args.body }) -- Insert at cursor
        -- cmp.resubscribe({ "TextChangedI", "TextChangedP" })
        -- require("cmp.config").set_onetime({ sources = {} })
      end,
    },
    window = {
      -- completion = cmp.config.window.bordered(),
      -- documentation = cmp.config.window.bordered(),
    },
    mapping = cmp.mapping.preset.insert({
      ['<C-b>'] = cmp.mapping.scroll_docs(-4),
      ['<C-f>'] = cmp.mapping.scroll_docs(4),
      ['<C-Space>'] = cmp.mapping.complete(),
      ['<C-e>'] = cmp.mapping.abort(),
      ['<CR>'] = cmp.mapping.confirm({ select = true }), -- Accept currently selected item. Set `select` to `false` to only confirm explicitly selected items.
    }),
    sources = cmp.config.sources({
      { name = 'nvim_lsp' },
      { name = 'vsnip' }, -- For vsnip users.
      -- { name = 'luasnip' }, -- For luasnip users.
      -- { name = 'ultisnips' }, -- For ultisnips users.
      -- { name = 'snippy' }, -- For snippy users.
    }, {
      { name = 'buffer' },
    })
  })

  -- To use git you need to install the plugin petertriho/cmp-git and uncomment lines below
  -- Set configuration for specific filetype.
  --[[ cmp.setup.filetype('gitcommit', {
    sources = cmp.config.sources({
      { name = 'git' },
    }, {
      { name = 'buffer' },
    })
 })
 require("cmp_git").setup() ]]-- 

  -- Use buffer source for `/` and `?` (if you enabled `native_menu`, this won't work anymore).
  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' }
    }),
    matching = { disallow_symbol_nonprefix_matching = false }
  })

  -- Set up lspconfig.
  local capabilities = require('cmp_nvim_lsp').default_capabilities()
  -- Replace <YOUR_LSP_SERVER> with each lsp server you've enabled.
  require('lspconfig')['rust_analyzer'].setup {
    capabilities = capabilities
  }
EOF
        '';
        };
	    };
    };  
  };
}