cleanup and rename provider to plugin

docs/plugin_authoring.md

@@ -0,0 +1,148 @@
+# Plugin authoring: ResultTable and plugin adapters
+
+This short guide explains how to write plugins that integrate with the strict
+ResultTable API: adapters yield `ResultModel` instances, and plugins register
+via `SYS.result_table_adapters.register_plugin` with columns and a
+`selection_fn`.
+
+The public terminology is plugin-first, even though some internal classes and
+metadata fields still use `Provider` naming.
+
+---
+
+## Quick summary
+- Plugins register a plugin adapter, a `columns` definition, and a `selection_fn`.
+- `selection_fn` returns CLI args for a selected row.
+- For HTML table or list scraping, prefer `TablePluginMixin` from `SYS.plugin_helpers`.
+
+## Runtime dependency policy
+- Treat required runtime dependencies such as Playwright as mandatory: import them unconditionally and let missing dependencies fail fast.
+- Use guarded imports only for truly optional dependencies such as `pandas`.
+- Keep plugin code minimal and explicit: fail early and document required runtime dependencies in README and installation notes.
+
+---
+
+## Minimal plugin template
+
+```py
+# plugins/my_plugin.py
+from typing import Any, Dict, Iterable, List
+
+from SYS.result_table_api import ResultModel, ColumnSpec, title_column
+from SYS.result_table_adapters import register_plugin
+
+SAMPLE_ITEMS = [
+    {
+        "name": "Example File.pdf",
+        "path": "https://example.com/x.pdf",
+        "ext": "pdf",
+        "size": 1024,
+        "source": "myplugin",
+    },
+]
+
+
+def adapter(items: Iterable[Dict[str, Any]]) -> Iterable[ResultModel]:
+    for it in items:
+        title = it.get("name") or it.get("title") or str(it.get("path") or "")
+        yield ResultModel(
+            title=str(title),
+            path=str(it.get("path")) if it.get("path") else None,
+            ext=str(it.get("ext")) if it.get("ext") else None,
+            size_bytes=int(it.get("size")) if it.get("size") is not None else None,
+            metadata=dict(it),
+            source=str(it.get("source")) if it.get("source") else "myplugin",
+        )
+
+
+def columns_factory(rows: List[ResultModel]) -> List[ColumnSpec]:
+    cols = [title_column()]
+    if any((row.metadata or {}).get("size") for row in rows):
+        cols.append(ColumnSpec("size", "Size", lambda row: row.size_bytes or ""))
+    return cols
+
+
+def selection_fn(row: ResultModel) -> List[str]:
+    if row.path:
+        return ["-path", row.path]
+    return ["-title", row.title or ""]
+
+
+register_plugin("myplugin", adapter, columns=columns_factory, selection_fn=selection_fn)
+```
+
+---
+
+## Table scraping with `TablePluginMixin`
+
+If your plugin scrapes HTML tables or list-like results, use `TablePluginMixin`:
+
+```py
+from PluginCore.base import Provider
+from SYS.plugin_helpers import TablePluginMixin
+
+
+class MyTablePlugin(TablePluginMixin, Provider):
+    URL = ("https://example.org/search",)
+
+    def validate(self) -> bool:
+        return True
+
+    def search(self, query: str, limit: int = 50, **kwargs):
+        url = f"{self.URL[0]}?q={quote_plus(query)}"
+        return self.search_table_from_url(url, limit=limit)
+```
+
+`TablePluginMixin.search_table_from_url` returns
+`PluginCore.base.SearchResult` entries. If you want to integrate the plugin
+with the strict `ResultTable` registry, add a small adapter that converts
+`SearchResult` to `ResultModel` and register it using `register_plugin`.
+
+---
+
+## Columns and selection
+- `columns` may be a static `List[ColumnSpec]` or a factory that inspects sample rows.
+- `selection_fn` must accept a `ResultModel` and return a `List[str]` representing CLI args.
+- For downloadable file rows, prefer explicit URL args such as `['-url', row.path]` so downstream downloaders interpret the row unambiguously.
+- Ensure `ResultModel.source` is set directly or falls back to the registered plugin name during serialization.
+
+---
+
+## Optional pandas support
+`SYS.html_table.extract_records` prefers a pure-lxml path but can fall back to
+`pandas.read_html` when pandas is installed and the helper detects it works for
+the input table. This is optional. Document whether your plugin requires
+`pandas` and emit a clear error or log message when it is missing.
+
+---
+
+## Testing and examples
+- Write `tests/test_plugin_<name>.py` or follow the repo's older naming conventions when extending existing tests.
+- Verify `plugin.build_table(...)` produces a `ResultTable` with rows and columns.
+- Verify `serialize_rows()` yields `_selection_args`, `_selection_action` when applicable, and `source`.
+- When you need an exact CLI stage sequence, call `table.set_row_selection_action(row_index, tokens)` so replay uses the row action verbatim.
+- For table-oriented plugins, test `search_table_from_url` with a local HTML fixture or a mocked `HTTPClient`.
+
+Example test skeleton:
+
+```py
+from SYS.result_table_adapters import get_plugin
+from plugins import example_plugin
+
+
+def test_example_plugin_registration():
+    plugin = get_plugin("example")
+    rows = list(plugin.adapter(example_plugin.SAMPLE_ITEMS))
+    assert rows and rows[0].title
+    cols = plugin.get_columns(rows)
+    assert any(col.name == "title" for col in cols)
+    table = plugin.build_table(example_plugin.SAMPLE_ITEMS)
+    assert table.provider == "example" and table.rows
+```
+
+---
+
+## References and examples
+- Read `plugins/example_plugin.py` for a compact example of a strict adapter and dynamic columns.
+- Read `plugins/vimm/__init__.py` for a table-oriented plugin that uses `TablePluginMixin` and converts `SearchResult` to `ResultModel` for registration.
+- See `docs/plugin_guide.md` for a broader plugin development checklist.