neovim-flake/modules/languages/rust.nix

{
  pkgs,
  config,
  lib,
  ...
}:
with lib;
with builtins; let
  cfg = config.vim.languages.rust;
in {
  options.vim.languages.rust = {
    enable = mkEnableOption "Rust language support";

    treesitter = {
      enable = mkOption {
        description = "Enable Rust treesitter";
        type = types.bool;
        default = config.vim.languages.enableTreesitter;
      };
      package = nvim.types.mkGrammarOption pkgs "rust";
    };

    crates = {
      enable = mkEnableOption "crates-nvim, tools for managing dependencies";
      codeActions = mkOption {
        description = "Enable code actions through null-ls";
        type = types.bool;
        default = true;
      };
    };

    lsp = {
      enable = mkOption {
        description = "Rust LSP support (rust-analyzer with extra tools)";
        type = types.bool;
        default = config.vim.languages.enableLSP;
      };
      package = mkOption {
        description = "rust-analyzer package";
        type = types.package;
        default = pkgs.rust-analyzer;
      };
      opts = mkOption {
        description = "Options to pass to rust analyzer";
        type = types.str;
        default = "";
      };
    };
  };

  config = mkIf cfg.enable (mkMerge [
    (mkIf cfg.crates.enable {
      vim.lsp.null-ls.enable = mkIf cfg.crates.codeActions true;

      vim.startPlugins = ["crates-nvim"];

      vim.autocomplete.sources = ["crates"];
      vim.luaConfigRC.rust-crates = nvim.dag.entryAnywhere ''
        require('crates').setup {
          null_ls = {
            enabled = ${boolToString cfg.crates.codeActions},
            name = "crates.nvim",
          }
        }
      '';
    })
    (mkIf cfg.treesitter.enable {
      vim.treesitter.enable = true;
      vim.treesitter.grammars = [cfg.treesitter.package];
    })
    (mkIf cfg.lsp.enable {
      vim.startPlugins = ["rust-tools"];

      vim.lsp.lspconfig.enable = true;
      vim.lsp.lspconfig.sources.rust-lsp = ''
        local rt = require('rust-tools')
        rust_on_attach = function(client, bufnr)
          default_on_attach(client, bufnr)
          local opts = { noremap=true, silent=true, buffer = bufnr }
          vim.keymap.set("n", "<leader>ris", rt.inlay_hints.set, opts)
          vim.keymap.set("n", "<leader>riu", rt.inlay_hints.unset, opts)
          vim.keymap.set("n", "<leader>rr", rt.runnables.runnables, opts)
          vim.keymap.set("n", "<leader>rp", rt.parent_module.parent_module, opts)
          vim.keymap.set("n", "<leader>rm", rt.expand_macro.expand_macro, opts)
          vim.keymap.set("n", "<leader>rc", rt.open_cargo_toml.open_cargo_toml, opts)
          vim.keymap.set("n", "<leader>rg", function() rt.crate_graph.view_crate_graph("x11", nil) end, opts)
        end
        local rustopts = {
          tools = {
            autoSetHints = true,
            hover_with_actions = false,
            inlay_hints = {
              only_current_line = false,
            }
          },
          server = {
            capabilities = capabilities,
            on_attach = rust_on_attach,
            cmd = {"${cfg.lsp.package}/bin/rust-analyzer"},
            settings = {
              ${cfg.lsp.opts}
            }
          }
        }
        rt.setup(rustopts)
      '';
    })
  ]);
}