nvf/modules/plugins/completion/nvim-cmp/config.nix

{
  lib,
  config,
  ...
}: let
  inherit (lib.modules) mkIf;
  inherit (lib.strings) optionalString;
  inherit (lib.generators) mkLuaInline;
  inherit (lib.nvim.lua) toLuaObject;
  inherit (builtins) attrNames;

  cfg = config.vim.autocomplete.nvim-cmp;
  luasnipEnable = config.vim.snippets.luasnip.enable;
  inherit (cfg) mappings;
in {
  config = mkIf cfg.enable {
    vim = {
      startPlugins = ["rtp-nvim"];
      lazy.plugins = {
        # cmp sources are loaded via lzn-auto-require as long as it is defined
        # in cmp sources
        cmp-buffer = {
          package = "cmp-buffer";
          lazy = true;
          after = ''
            local path = vim.fn.globpath(vim.o.packpath, 'pack/*/opt/cmp-buffer')
            require("rtp_nvim").source_after_plugin_dir(path)
          '';
        };
        cmp-path = {
          package = "cmp-path";
          lazy = true;
          after = ''
            local path = vim.fn.globpath(vim.o.packpath, 'pack/*/opt/cmp-path')
            require("rtp_nvim").source_after_plugin_dir(path)
          '';
        };
        nvim-cmp = {
          package = "nvim-cmp";
          after = ''
            ${optionalString luasnipEnable "local luasnip = require('luasnip')"}
                require("lz.n").trigger_load("cmp-path")
            local cmp = require("cmp")
            cmp.setup(${toLuaObject cfg.setupOpts})

            ${
              optionalString config.vim.lazy.enable ''
                require("lz.n").trigger_load("cmp-buffer")
              ''
            }
          '';

          event = ["InsertEnter" "CmdlineEnter"];
          lazy = true;
        };
      };

      autocomplete.nvim-cmp = {
        sources = {
          nvim-cmp = null;
          buffer = "[Buffer]";
          path = "[Path]";
        };

        setupOpts = {
          sources = map (s: {name = s;}) (attrNames cfg.sources);

          # TODO: try to get nvim-cmp to follow global border style
          window = mkIf config.vim.ui.borders.enable {
            completion = mkLuaInline "cmp.config.window.bordered()";
            documentation = mkLuaInline "cmp.config.window.bordered()";
          };

          formatting.format = cfg.format;
        };

        # `cmp` and `luasnip` are defined above, in the `nvim-cmp` section
        setupOpts.mapping = {
          ${mappings.complete} = mkLuaInline "cmp.mapping.complete()";
          ${mappings.close} = mkLuaInline "cmp.mapping.abort()";
          ${mappings.scrollDocsUp} = mkLuaInline "cmp.mapping.scroll_docs(-4)";
          ${mappings.scrollDocsDown} = mkLuaInline "cmp.mapping.scroll_docs(4)";
          ${mappings.confirm} = mkLuaInline "cmp.mapping.confirm({ select = true })";

          ${mappings.next} = mkLuaInline ''
            cmp.mapping(function(fallback)
              local has_words_before = 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

              if cmp.visible() then
                cmp.select_next_item()
                ${optionalString luasnipEnable ''
              elseif luasnip.locally_jumpable(1) then
                luasnip.jump(1)
            ''}
              elseif has_words_before() then
                cmp.complete()
              else
                fallback()
              end
            end)
          '';

          ${mappings.previous} = mkLuaInline ''
            cmp.mapping(function(fallback)
              if cmp.visible() then
                cmp.select_prev_item()
                ${optionalString luasnipEnable ''
              elseif luasnip.locally_jumpable(-1) then
                luasnip.jump(-1)
            ''}
              else
                fallback()
              end
            end)
          '';
        };
      };
    };
  };
}