from __future__ import annotations

from dataclasses import dataclass
from importlib.util import find_spec


CONNECTOR_PROVIDER_CAPABILITY = "files.connector.providers"


@dataclass(frozen=True, slots=True)
class ConnectorProviderDescriptor:
    provider: str
    label: str
    protocol: str
    implemented: bool
    browse_supported: bool
    import_supported: bool
    optional_dependency: str | None
    permission_model: str
    sync_strategy: str
    conflict_strategy: str
    preview_strategy: str
    audit_events: tuple[str, ...]
    notes: str | None = None

    def to_response(self) -> dict[str, object]:
        return {
            "provider": self.provider,
            "label": self.label,
            "protocol": self.protocol,
            "implemented": self.implemented,
            "installed": self.installed,
            "browse_supported": self.browse_supported,
            "import_supported": self.import_supported,
            "optional_dependency": self.optional_dependency,
            "permission_model": self.permission_model,
            "sync_strategy": self.sync_strategy,
            "conflict_strategy": self.conflict_strategy,
            "preview_strategy": self.preview_strategy,
            "audit_events": list(self.audit_events),
            "notes": self.notes,
        }

    @property
    def installed(self) -> bool:
        if self.optional_dependency is None:
            return self.implemented
        return find_spec(self.optional_dependency) is not None


def connector_provider_descriptors() -> tuple[ConnectorProviderDescriptor, ...]:
    freeze_model = "Imported or synced connector files become managed GovOPlaN files with frozen blob/version provenance."
    governed_permissions = "GovOPlaN profile scope and connector policy are enforced before browse/import/sync; remote ACLs are still evaluated by the upstream service."
    return (
        ConnectorProviderDescriptor(
            provider="seafile",
            label="Seafile",
            protocol="seafile-api",
            implemented=True,
            browse_supported=True,
            import_supported=True,
            optional_dependency=None,
            permission_model=governed_permissions,
            sync_strategy="On-demand browse/import/sync; sync updates the managed file version when source content changes and never mutates the remote source.",
            conflict_strategy="Managed import/sync uses existing files conflict_strategy handling: reject, overwrite, or rename.",
            preview_strategy="Previews are generated from the frozen managed file after import or sync.",
            audit_events=("files.connector.imported", "files.connector.synced", "files.connector.accessed"),
            notes="Native account-token API for libraries, directories, file detail, and download-link import; WebDAV opt-in remains available.",
        ),
        ConnectorProviderDescriptor(
            provider="nextcloud",
            label="Nextcloud",
            protocol="webdav",
            implemented=True,
            browse_supported=True,
            import_supported=True,
            optional_dependency=None,
            permission_model=governed_permissions,
            sync_strategy="On-demand WebDAV browse/import/sync; sync updates the managed file version when source content changes and never mutates the remote source.",
            conflict_strategy="Managed import/sync uses existing files conflict_strategy handling: reject, overwrite, or rename.",
            preview_strategy="Previews are generated from the frozen managed file after import or sync.",
            audit_events=("files.connector.imported", "files.connector.synced", "files.connector.accessed"),
            notes="Uses the configured Nextcloud WebDAV endpoint, basic auth, or bearer token profile credentials.",
        ),
        ConnectorProviderDescriptor(
            provider="webdav",
            label="WebDAV",
            protocol="webdav",
            implemented=True,
            browse_supported=True,
            import_supported=True,
            optional_dependency=None,
            permission_model=governed_permissions,
            sync_strategy="On-demand WebDAV browse/import/sync; sync updates the managed file version when source content changes and never mutates the remote source.",
            conflict_strategy="Managed import/sync uses existing files conflict_strategy handling: reject, overwrite, or rename.",
            preview_strategy="Previews are generated from the frozen managed file after import or sync.",
            audit_events=("files.connector.imported", "files.connector.synced", "files.connector.accessed"),
            notes="Generic WebDAV provider for standards-compatible stores.",
        ),
        ConnectorProviderDescriptor(
            provider="smb",
            label="SMB",
            protocol="smb",
            implemented=True,
            browse_supported=True,
            import_supported=True,
            optional_dependency="smbprotocol",
            permission_model=governed_permissions,
            sync_strategy="On-demand browse/import/sync over administrator-declared shares; sync updates managed versions and never mutates the remote share.",
            conflict_strategy="Managed import/sync uses existing files conflict_strategy handling after download.",
            preview_strategy="Previews are generated from the frozen managed file after import or sync, not directly from the share.",
            audit_events=("files.connector.imported", "files.connector.synced", "files.connector.accessed"),
            notes="Requires the optional smbprotocol dependency and an smb://server[:port]/share[/path] profile endpoint.",
        ),
        ConnectorProviderDescriptor(
            provider="nfs",
            label="NFS",
            protocol="nfs",
            implemented=False,
            browse_supported=False,
            import_supported=False,
            optional_dependency=None,
            permission_model=governed_permissions,
            sync_strategy="Planned optional provider over administrator-mounted paths or a sidecar service.",
            conflict_strategy="Will use managed import conflict_strategy handling after download.",
            preview_strategy="Will preview from frozen managed file after import, not directly from the mount.",
            audit_events=("files.connector.imported", "files.connector.synced", "files.connector.accessed"),
            notes="Kept optional because NFS availability is deployment and host-kernel dependent.",
        ),
        ConnectorProviderDescriptor(
            provider="local",
            label="Local filesystem",
            protocol="file",
            implemented=False,
            browse_supported=False,
            import_supported=False,
            optional_dependency=None,
            permission_model="Local connector access should be restricted to administrator-declared roots plus GovOPlaN profile and policy checks.",
            sync_strategy="Planned optional provider; managed storage local backend already exists separately.",
            conflict_strategy=freeze_model,
            preview_strategy="Will preview from frozen managed file after import or sync.",
            audit_events=("files.connector.imported", "files.connector.synced", "files.connector.accessed"),
            notes="Separate from the existing managed-file local storage backend.",
        ),
    )