neovim-flake/modules/utility/venn.nix

{
  pkgs,
  config,
  lib,
  ...
}:
with lib;
with builtins; let
  cfg = config.vim.utility.venn-nvim;
in {
  options.vim.utility.venn-nvim = {
    enable = mkEnableOption "draw ASCII diagrams in Neovim";
  };

  config = mkIf (cfg.enable) {
    vim.startPlugins = [
      "venn-nvim"
    ];

    # TODO: https://github.com/jbyuki/venn.nvim#using-toggle-command
    # add keybindings for drawing diagrams
    vim.luaConfigRC.venn-nvim = nvim.dag.entryAnywhere ''
      local venn = require('venn')
      -- venn.nvim: enable or disable keymappings
      function _G.Toggle_venn()
          local venn_enabled = vim.inspect(vim.b.venn_enabled)
          if venn_enabled == "nil" then
              vim.b.venn_enabled = true
              vim.cmd[[setlocal ve=all]]
              -- draw a line on HJKL keystokes
              vim.api.nvim_buf_set_keymap(0, "n", "J", "<C-v>j:VBox<CR>", {noremap = true})
              vim.api.nvim_buf_set_keymap(0, "n", "K", "<C-v>k:VBox<CR>", {noremap = true})
              vim.api.nvim_buf_set_keymap(0, "n", "L", "<C-v>l:VBox<CR>", {noremap = true})
              vim.api.nvim_buf_set_keymap(0, "n", "H", "<C-v>h:VBox<CR>", {noremap = true})
              -- draw a box by pressing "f" with visual selection
              vim.api.nvim_buf_set_keymap(0, "v", "f", ":VBox<CR>", {noremap = true})
          else
              vim.cmd[[setlocal ve=]]
              vim.cmd[[mapclear <buffer>]]
              vim.b.venn_enabled = nil
          end
      end
      -- toggle keymappings for venn using <leader>v
      vim.api.nvim_set_keymap('n', '<leader>v', ":lua Toggle_venn()<CR>", { noremap = true})
    '';
  };
}