feat: add provider-neutral tracker automation

tracker/detection.py

@@ -0,0 +1,53 @@
+import os
+import re
+
+from .errors import TrackerError  # type: ignore[reportMissingImports]
+
+SUPPORTED_PROVIDERS = ("github", "gitlab", "gitea")
+
+
+def _validate_provider(value):
+    provider = (value or "").strip().lower()
+    if provider not in SUPPORTED_PROVIDERS:
+        raise TrackerError(
+            "invalid_provider",
+            f"unsupported provider: {value}",
+            details={"supported": list(SUPPORTED_PROVIDERS)},
+        )
+    return provider
+
+
+def _providers_from_remote(remote):
+    host_match = re.search(r"(?:https?://|ssh://|git@)([^/:]+)", remote or "")
+    host = host_match.group(1).lower() if host_match else ""
+    found = []
+    if host == "github.com" or "github" in host:
+        found.append("github")
+    if host == "gitlab.com" or "gitlab" in host:
+        found.append("gitlab")
+    if "gitea" in host:
+        found.append("gitea")
+    return found
+
+
+def resolve_provider(explicit=None, *, env=None, remote=None):
+    """Resolve provider using CLI, environment, then remote precedence."""
+    if explicit is not None:
+        return _validate_provider(explicit)
+    values = os.environ if env is None else env
+    configured = values.get("TRACKER_PROVIDER")
+    if configured:
+        return _validate_provider(configured)
+    matches = _providers_from_remote(remote or "")
+    if len(matches) == 1:
+        return matches[0]
+    if not remote:
+        raise TrackerError(
+            "provider_detection_failed",
+            "provider was not specified and no Git remote was available",
+        )
+    if len(matches) > 1:
+        message = "Git remote matches multiple supported providers"
+    else:
+        message = f"unsupported or unrecognised Git remote: {remote}"
+    raise TrackerError("provider_detection_failed", message, details={"remote": remote})