# tia-lsp.nvim - Neovim Plugin for Siemens TIA Portal

A Neovim/LazyVim plugin that launches the [`tia-lsp`](https://gitea.l-tech.rs/lazar/tia-lsp) language server and adds editor-specific features for Siemens TIA Portal languages. Currently supports **SCL** (Structured Control Language), with planned support for **STL/AWL**, **LAD**, and **FBD**.

## Features

| Feature | Description |
|---------|-------------|
| **Auto-Prefix** | Automatically adds `#` prefix to local variables (like TIA Portal) |
| **Multiline Parameters** | Fill FB/Function call parameters across multiple lines with `<Space>mp` or `:SCLMultilineParams` |
| **Tab Navigation** | Jump between parameters with `<Tab>` in insert mode |
| **Workspace UDT Scanner** | Scans project for user-defined types (.udt files) |
| **Workspace Global DB Scanner** | Scans project for global data blocks (.db files) |
| **blink.cmp Integration** | Smart completion source for blink.cmp — DB members, FB parameters, built-in types (IEC_TIMER IN/PT/Q/ET), nested UDT/array-of-UDT path resolution |
| **Attribute Block Toggle** | Interactive expand/collapse of `{...}` blocks with `<Leader>xa` |
| **Tree-sitter Highlighting** | Syntax highlighting via tree-sitter queries |

## Architecture

This plugin is part of a three-repo ecosystem:

```
tia-lsp.nvim       ← Neovim plugin (you are here) — launches the LSP client,
│                     adds editor features (auto-# prefix, blink.cmp source,
│                     attribute toggle, workspace scanning, ...)
▼
tia-lsp            ← Standalone LSP server — reads JSON-RPC over stdio,
│                     provides hover, completion, diagnostics, formatting
│                     Requires: lua src/main.lua + compiled parser.so
▲
tia-mason-registry ← mason.nvim recipe — tells mason how to download tia-lsp,
                      compile parser.so, and create the tia-lsp executable
```

- **tia-lsp** ([repo](https://gitea.l-tech.rs/lazar/tia-lsp)) — the actual language server, editor-agnostic
- **tia-mason-registry** ([repo](https://gitea.l-tech.rs/lazar/tia-mason-registry)) — a single `package.yaml` for mason
- **tia-lsp.nvim** (this repo) — the Neovim-specific integration

## Installation

The plugin auto-detects the mason-installed `tia-lsp` executable via `vim.fn.exepath("tia-lsp")`. If not found, it falls back to running `lua <server_path>` (configurable).

### LazyVim + Mason (Recommended)

Mason downloads and builds the `tia-lsp` server; this plugin configures the LSP client.

**Step 1: Add the mason registry as a lazy.nvim plugin**

mason needs a local copy of the registry to read the install recipe. Adding it as a lazy.nvim plugin gets it cloned automatically:

```lua
-- ~/.config/nvim/lua/plugins/tia-mason-registry.lua
return {
  url = "https://gitea.l-tech.rs/lazar/tia-mason-registry.git",
  name = "tia-mason-registry",
}
```

**Step 2: Register the registry with mason**

```lua
-- ~/.config/nvim/lua/plugins/mason.lua
return {
  "mason-org/mason.nvim",
  opts = {
    registries = {
      "file:" .. vim.fn.expand("~/.local/share/nvim/lazy/tia-mason-registry"),
      "github:mason-org/mason-registry",
    },
  },
}
```

> **Why this works:** lazy.nvim clones `tia-mason-registry` to `~/.local/share/nvim/lazy/tia-mason-registry`. The `file:` registry path points mason to that directory, where it finds `packages/tia-lsp/package.yaml`. Mason needs [`yq`](https://github.com/mikefarah/yq) to parse YAML custom registries — install it once: `:MasonInstall yq`

**Step 3: Install the LSP server**

```
:MasonInstall tia-lsp
```

This clones `tia-lsp` from the source repo, compiles `parser.so` (tree-sitter), and places the `tia-lsp` executable on PATH.

**Step 4: Add this plugin**

```lua
-- ~/.config/nvim/lua/plugins/tia-lsp.lua
return {
  "https://gitea.l-tech.rs/lazar/tia-lsp.nvim",
  ft = "scl",
  lazy = true,
  dependencies = {
    "neovim/nvim-lspconfig",
    "nvim-treesitter/nvim-treesitter",
    "saghen/blink.cmp",            -- optional, for completion
  },
  opts = {
    lsp = {
      -- on_attach = function(client, bufnr) ... end,
    },
    cmp = true,              -- enable blink.cmp integration
    workspace_types = true,  -- scan project for UDTs and DBs
    auto_prefix = true,      -- auto-# prefix for local variables
  },
}
```

**Step 5: Configure blink.cmp defaults**

The `scl` completion source must be listed in blink.cmp's `sources.default` with the corresponding provider definition. Create or update your blink.cmp config:

```lua
-- ~/.config/nvim/lua/plugins/blink.lua (or extend your existing blink.cmp spec)
return {
  "saghen/blink.cmp",
  optional = true,
  opts = {
    sources = {
      default = { "lsp", "path", "snippets", "buffer", "scl" },
      providers = {
        scl = {
          name = "scl",
          module = "tia.blink_cmp_source",
          score_offset = 100,
        },
      },
    },
  },
}
```

> **Why this is needed:** blink.cmp only queries sources listed in `sources.default`. Without `"scl"` there, the DB member and built-in type completions (e.g., `"MyDB".myField` or `#myTimer.IN`) will not appear.

**Step 6: Verify**

Open a `.scl` file and run `:LspInfo`. `tia_lsp` should be attached. Run `:checkhealth` for detailed diagnostics.

---

### Manual Setup (without Mason)

Clone and build the server manually, then point the plugin at it.

```bash
# 1. Clone the LSP server
git clone --depth 1 https://gitea.l-tech.rs/lazar/tia-lsp.git ~/tia-lsp

# 2. Compile the tree-sitter parser (required for parsing SCL)
cc -fPIC -I ~/tia-lsp/src/tree_sitter -c ~/tia-lsp/src/parser.c -o ~/tia-lsp/parser.o
cc -shared ~/tia-lsp/parser.o -o ~/tia-lsp/parser.so
```

Then configure the plugin. The plugin first looks for `tia-lsp` on PATH; if not found, it falls back to running `lua <server_path>`. The tree-sitter parser is loaded from `parser.so` adjacent to the server.

```lua
require("tia_lsp").setup({
  server_path = "~/tia-lsp/src/main.lua",  -- fallback if tia-lsp not on PATH
  ts_parser_url = "https://gitea.l-tech.rs/lazar/tia-lsp.git",
  cmp = true,
  workspace_types = true,
  auto_prefix = true,
})
```

## Configuration Options

| Option | Type | Default | Description |
|--------|------|---------|-------------|
| `server_path` | string | `~/dev/tia-lsp/src/main.lua` | Path to LSP server (fallback when `tia-lsp` not on PATH; change for manual installs) |
| `ts_parser_url` | string | `file://~/dev/tia-lsp` | URL passed to nvim-treesitter for the SCL parser source |
| `lsp.on_attach` | function | `nil` | Custom LSP attach callback |
| `lsp.formatting` | boolean | `false` | Enable format command |
| `cmp` | boolean | `true` | Enable blink.cmp integration |
| `workspace_types` | boolean | `true` | Enable workspace UDT scanning |
| `auto_prefix` | boolean | `true` | Enable auto-# prefixing |
| `project_root` | string | `nil` | Custom project root |
| `library_paths` | table | `{}` | Additional library paths |
| `debug` | boolean | `false` | Enable debug logging |

## Commands

| Command | Description |
|---------|-------------|
| `:SCLShowVariables` | Show local variables in current file |
| `:SCLShowWorkspaceTypes` | Show workspace UDTs, FBs, and Global DBs count |
| `:SCLRescanWorkspaceTypes` | Rescan workspace for types and DBs |
| `:SCLPrefixWord` | Manually prefix current word with `#` |
| `:SCLMultilineParams` | Fill multiline parameters for FB/Function call |
| `:SCLFormat` | Format current SCL file |
| `:SCLToggleAttrBlock` | Toggle attribute block under cursor |
| `:SCLExpandAllAttrBlocks` | Expand all `{...}` blocks in buffer |
| `:SCLCollapseAllAttrBlocks` | Collapse all matching attribute blocks |

## Keybindings

| Key | Action |
|-----|--------|
| `K` | Hover (show variable info) |
| `gd` | Go to Definition |
| `<leader>s` | Document Symbols |
| `<leader>w` | Workspace Symbols |
| `<Space>mp` | Fill multiline FB/Function parameters (insert mode) |
| `<Tab>` | Jump to next parameter (insert mode) |
| `<Leader>xa` | Toggle attribute block under cursor |
| `<Leader>xae` | Expand all attribute blocks |
| `<Leader>xac` | Collapse all attribute blocks |
| `<leader>fw` | Workspace Symbols (Telescope) |
| `<leader>ca` | Code Actions |

## Attribute Block Toggle

Interactive expand/collapse of SCL variable attribute blocks:

```scl
-- Before: Verbose attributes
statCounter{EXTERNALACCESSIBLE := 'false'; EXTERNALVISIBLE := 'false'} : Int;

-- After: Collapsed
statCounter{...} : Int;
```

**Usage:**
- Place cursor inside any `{...}` block
- Press `<Leader>xa` to toggle expand/collapse
- Use `<Leader>xae` to expand all blocks in buffer
- Use `<Leader>xac` to collapse all blocks

**Note:** Collapsed blocks are automatically expanded before saving to preserve full content on disk.

## Filetype Detection

The plugin includes `ftdetect/scl.vim` which registers the following file extensions as `scl` filetype:
- `*.scl` — SCL source files
- `*.udt` — User-defined type files
- `*.db` — Data block files

## Project Structure

```
tia-lsp.nvim/
├── lua/
│   ├── tia_lsp/                 # Plugin entry point
│   │   ├── init.lua             # Main setup (vim.lsp.start, exepath detection)
│   │   └── plugins/
│   │       └── scl.lua          # LazyVim plugin spec (SCL filetype)
│   └── tia/                     # Language modules (shared across TIA languages)
│       ├── auto_prefix.lua      # Auto-# prefixing
│       ├── attr_toggle.lua      # Attribute block expand/collapse
│       ├── blink_cmp_source.lua # blink.cmp completion source
│       ├── builtin_instructions.lua
│       ├── db_parser.lua        # Global DB parser
│       ├── fb_parser.lua        # Function Block parser
│       ├── multiline_params.lua # Multiline parameter filling
│       ├── udt_parser.lua       # UDT parser
│       ├── variables.lua        # Variable extraction
│       └── workspace_types.lua  # Workspace scanning
├── queries/
│   └── scl/                     # Tree-sitter queries (per-language)
│       ├── highlights.scm       # Syntax highlighting
│       ├── indents.scm          # Indentation
│       ├── folds.scm            # Code folding
│       ├── locals.scm           # Variable scoping
│       └── tags.scm             # Navigation tags
├── ftdetect/
│   └── scl.vim                  # Filetype detection
└── test/                        # Plugin tests
    ├── run_tests.lua
    ├── test_harness.lua
    ├── test_udt.lua
    ├── test_db.lua
    ├── test_fb.lua
    └── test_integration.lua
```

## Requirements

- **Neovim 0.11+** (uses `vim.lsp.start()`)
- **tia-lsp** — the LSP server (install via mason or manually)
- **nvim-treesitter** — Syntax highlighting
- **blink.cmp** — Optional, for completion
- **Lua 5.1+** — LSP server runtime

## Troubleshooting

| Symptom | Likely Cause | Fix |
|---------|-------------|-----|
| `:MasonInstall tia-lsp` fails with "unknown package" | Custom registry not registered with mason | Check the `registries` list in your mason config includes the `file:` path to the cloned registry |
| `:MasonInstall tia-lsp` fails with "yq: command not found" | Mason needs `yq` to parse the YAML registry | Run `:MasonInstall yq` to install it, then retry `:MasonInstall tia-lsp` |
| `tia_lsp` not attached after opening `.scl` | Server not on PATH or `server_path` points to wrong location | Run `:LspInfo` to see what server is configured. Check `vim.fn.exepath("tia-lsp")` returns a path |
| LSP starts but no syntax highlighting | Tree-sitter parser (`parser.so`) not found | mason install generates it automatically. For manual setups, run the `cc` commands in the Manual Setup section |
| `parser.so` load error at startup | Compiled for wrong architecture or Lua version | Recompile: clean the old `.so` and run the `cc` build commands again |
| LSP starts but no completions/hover | Server can't find its modules | Mason installs to a managed directory. If using manual setup, ensure `src/` contents are present next to `main.lua` |

## Testing

```bash
lua test/run_tests.lua
```

Tests use files from a reference project (override with `SCL_REF_PROJECT=/path/to/ref lua test/run_tests.lua`).