feat: support shared-workspace file flow for matrix

adapter/matrix/files.py

@@ -0,0 +1,103 @@
+from __future__ import annotations
+
+import mimetypes
+import re
+from datetime import UTC, datetime
+from pathlib import Path
+
+from core.protocol import Attachment
+
+
+def _sanitize_component(value: str) -> str:
+    cleaned = re.sub(r"[^A-Za-z0-9._-]+", "_", value)
+    cleaned = cleaned.strip("._-")
+    return cleaned or "unknown"
+
+
+def _default_filename(attachment: Attachment) -> str:
+    if attachment.filename:
+        return attachment.filename
+
+    extension = mimetypes.guess_extension(attachment.mime_type or "") or ""
+    base = {
+        "image": "image",
+        "audio": "audio",
+        "video": "video",
+        "document": "attachment",
+    }.get(attachment.type, "attachment")
+    return f"{base}{extension}"
+
+
+def build_workspace_attachment_path(
+    *,
+    workspace_root: Path,
+    matrix_user_id: str,
+    room_id: str,
+    filename: str,
+    timestamp: str | None = None,
+) -> tuple[str, Path]:
+    stamp = timestamp or datetime.now(UTC).strftime("%Y%m%d-%H%M%S")
+    safe_user = _sanitize_component(matrix_user_id.lstrip("@"))
+    safe_room = _sanitize_component(room_id.lstrip("!"))
+    safe_name = _sanitize_component(filename) or "attachment.bin"
+    relative_path = (
+        Path("surfaces")
+        / "matrix"
+        / safe_user
+        / safe_room
+        / "inbox"
+        / f"{stamp}-{safe_name}"
+    )
+    return relative_path.as_posix(), workspace_root / relative_path
+
+
+async def download_matrix_attachment(
+    *,
+    client,
+    workspace_root: Path,
+    matrix_user_id: str,
+    room_id: str,
+    attachment: Attachment,
+    timestamp: str | None = None,
+) -> Attachment:
+    if not attachment.url:
+        return attachment
+
+    filename = _default_filename(attachment)
+    relative_path, absolute_path = build_workspace_attachment_path(
+        workspace_root=workspace_root,
+        matrix_user_id=matrix_user_id,
+        room_id=room_id,
+        filename=filename,
+        timestamp=timestamp,
+    )
+    absolute_path.parent.mkdir(parents=True, exist_ok=True)
+
+    response = await client.download(attachment.url)
+    body = getattr(response, "body", None)
+    if body is None:
+        raise RuntimeError(f"Matrix download response for {attachment.url} has no body")
+    absolute_path.write_bytes(body)
+
+    return Attachment(
+        type=attachment.type,
+        url=attachment.url,
+        filename=filename,
+        mime_type=attachment.mime_type,
+        workspace_path=relative_path,
+    )
+
+
+def resolve_workspace_attachment_path(workspace_root: Path, workspace_path: str) -> Path:
+    path = Path(workspace_path)
+    if path.is_absolute():
+        return path
+    return workspace_root / path
+
+
+def matrix_msgtype_for_attachment(attachment: Attachment) -> str:
+    return {
+        "image": "m.image",
+        "audio": "m.audio",
+        "video": "m.video",
+    }.get(attachment.type, "m.file")