nvf/modules/plugins/languages/julia.nix

{
  lib,
  pkgs,
  config,
  ...
}: let
  inherit (builtins) attrNames;
  inherit (lib.options) mkEnableOption mkOption;
  inherit (lib.types) enum;
  inherit (lib.modules) mkIf mkMerge;
  inherit (lib.meta) getExe;
  inherit (lib.nvim.types) mkGrammarOption singleOrListOf;
  inherit (lib.generators) mkLuaInline;
  inherit (lib.nvim.attrsets) mapListToAttrs;
  inherit (lib.nvim.dag) entryBefore;

  defaultServers = ["julials"];
  servers = {
    julials = {
      enable = true;
      cmd =
        mkLuaInline
        /*
        lua
        */
        ''
          {
            '${getExe (pkgs.julia.withPackages ["LanguageServer"])}',
            '--startup-file=no',
            '--history-file=no',
            '-e',
            [[
              # Load LanguageServer.jl: attempt to load from ~/.julia/environments/nvim-lspconfig
              # with the regular load path as a fallback
              ls_install_path = joinpath(
                  get(DEPOT_PATH, 1, joinpath(homedir(), ".julia")),
                  "environments", "nvim-lspconfig"
              )
              pushfirst!(LOAD_PATH, ls_install_path)
              using LanguageServer
              popfirst!(LOAD_PATH)
              depot_path = get(ENV, "JULIA_DEPOT_PATH", "")
              project_path = let
                  dirname(something(
                      ## 1. Finds an explicitly set project (JULIA_PROJECT)
                      Base.load_path_expand((
                          p = get(ENV, "JULIA_PROJECT", nothing);
                          p === nothing ? nothing : isempty(p) ? nothing : p
                      )),
                      ## 2. Look for a Project.toml file in the current working directory,
                      ##    or parent directories, with $HOME as an upper boundary
                      Base.current_project(),
                      ## 3. First entry in the load path
                      get(Base.load_path(), 1, nothing),
                      ## 4. Fallback to default global environment,
                      ##    this is more or less unreachable
                      Base.load_path_expand("@v#.#"),
                  ))
              end
              @info "Running language server" VERSION pwd() project_path depot_path
              server = LanguageServer.LanguageServerInstance(stdin, stdout, project_path, depot_path)
              server.runlinter = true
              run(server)
            ]],
          }
        '';
      filetypes = ["julia"];
      root_markers = ["Project.toml" "JuliaProject.toml"];
      on_attach =
        mkLuaInline
        /*
        lua
        */
        ''
          function(_, bufnr)
              vim.api.nvim_buf_create_user_command(bufnr, 'LspJuliaActivateEnv', activate_julia_env, {
                desc = 'Activate a Julia environment',
                nargs = '?',
                complete = 'file',
              })
          end
        '';
    };
  };

  cfg = config.vim.languages.julia;
in {
  options = {
    vim.languages.julia = {
      enable = mkEnableOption "Julia language support";

      treesitter = {
        enable = mkEnableOption "Julia treesitter" // {default = config.vim.languages.enableTreesitter;};
        package = mkGrammarOption pkgs "julia";
      };

      lsp = {
        enable = mkEnableOption "Julia LSP support" // {default = config.vim.lsp.enable;};
        servers = mkOption {
          type = singleOrListOf (enum (attrNames servers));
          default = defaultServers;
          description = ''
            Julia LSP Server to Use

            ::: {.note}
            The entirety of Julia is bundled with nvf, if you enable this
            option, since there is no way to provide only the LSP server.

            If you want to avoid that, you have to change
            [vim.lsp.servers.julials.cmd](#opt-vim.lsp.servers._name_.cmd) to use
            the Julia binary in {env}`PATH`, and add the `LanguageServer`
            package to Julia in your devshells.

            Check the source file of this option for the full `cmd`.
            :::
          '';
        };
      };
    };
  };

  config = mkIf cfg.enable (mkMerge [
    (mkIf cfg.treesitter.enable {
      vim.treesitter.enable = true;
      vim.treesitter.grammars = [cfg.treesitter.package];
    })

    (mkIf cfg.lsp.enable {
      vim.luaConfigRC.julia-util =
        entryBefore ["lsp-servers"]
        /*
        lua
        */
        ''
          local function activate_julia_env(path)
            assert(vim.fn.has 'nvim-0.10' == 1, 'requires Nvim 0.10 or newer')
            local bufnr = vim.api.nvim_get_current_buf()
            local julials_clients = vim.lsp.get_clients { bufnr = bufnr, name = 'julials' }
            assert(
              #julials_clients > 0,
              'method julia/activateenvironment is not supported by any servers active on the current buffer'
            )
            local function _activate_env(environment)
              if environment then
                for _, julials_client in ipairs(julials_clients) do
                  julials_client:notify('julia/activateenvironment', { envPath = environment })
                end
                vim.notify('Julia environment activated: \n`' .. environment .. '`', vim.log.levels.INFO)
              end
            end
            if path then
              path = vim.fs.normalize(vim.fn.fnamemodify(vim.fn.expand(path), ':p'))
              local found_env = false
              for _, project_file in ipairs(root_files) do
                local file = vim.uv.fs_stat(vim.fs.joinpath(path, project_file))
                if file and file.type then
                  found_env = true
                  break
                end
              end
              if not found_env then
                vim.notify('Path is not a julia environment: \n`' .. path .. '`', vim.log.levels.WARN)
                return
              end
              _activate_env(path)
            else
              local depot_paths = vim.env.JULIA_DEPOT_PATH
                  and vim.split(vim.env.JULIA_DEPOT_PATH, vim.fn.has 'win32' == 1 and ';' or ':')
                or { vim.fn.expand '~/.julia' }
              local environments = {}
              vim.list_extend(environments, vim.fs.find(root_files, { type = 'file', upward = true, limit = math.huge }))
              for _, depot_path in ipairs(depot_paths) do
                local depot_env = vim.fs.joinpath(vim.fs.normalize(depot_path), 'environments')
                vim.list_extend(
                  environments,
                  vim.fs.find(function(name, env_path)
                    return vim.tbl_contains(root_files, name) and string.sub(env_path, #depot_env + 1):match '^/[^/]*$'
                  end, { path = depot_env, type = 'file', limit = math.huge })
                )
              end
              environments = vim.tbl_map(vim.fs.dirname, environments)
              vim.ui.select(environments, { prompt = 'Select a Julia environment' }, _activate_env)
            end
          end
        '';

      vim.lsp.servers =
        mapListToAttrs (n: {
          name = n;
          value = servers.${n};
        })
        cfg.lsp.servers;
    })
  ]);
}