import click


@click.group("db")
def commands():
    """
    Commands for managing an MLflow tracking database.
    """


@commands.command()
@click.argument("url")
def upgrade(url):
    """
    Upgrade the schema of an MLflow tracking database to the latest supported version.

    **IMPORTANT**: Schema migrations can be slow and are not guaranteed to be transactional -
    **always take a backup of your database before running migrations**. The migrations README,
    which is located at
    https://github.com/mlflow/mlflow/blob/master/mlflow/store/db_migrations/README.md, describes
    large migrations and includes information about how to estimate their performance and
    recover from failures.
    """
    import mlflow.store.db.utils

    engine = mlflow.store.db.utils.create_sqlalchemy_engine_with_retry(url)
    if mlflow.store.db.utils._is_empty_database(engine):
        mlflow.store.db.utils._initialize_tables(engine)
    else:
        mlflow.store.db.utils._upgrade_db(engine)


@commands.command("migrate-to-default-workspace")
@click.argument("url")
@click.option(
    "--dry-run/--no-dry-run",
    default=False,
    show_default=True,
    help="Check for conflicts and report how many rows would be moved.",
)
@click.option(
    "--verbose",
    "-v",
    is_flag=True,
    default=False,
    help="List all conflicts instead of truncating the output.",
)
@click.option(
    "--yes",
    "-y",
    is_flag=True,
    default=False,
    help="Skip the confirmation prompt.",
)
def migrate_to_default_workspace(url, dry_run, verbose, yes):
    """
    Move workspace-scoped resources into the default workspace.

    **IMPORTANT**: This operation runs in a single transaction, but can still be long-running.
    Always take a backup of your database before running this command.
    """
    import sqlalchemy.exc

    import mlflow.store.db.utils
    from mlflow.store.db.workspace_migration import migrate_to_default_workspace as migrate

    engine = None
    try:
        engine = mlflow.store.db.utils.create_sqlalchemy_engine_with_retry(url)
        counts = migrate(engine, dry_run=True, verbose=verbose)

        total = sum(counts.values())
        if dry_run:
            click.echo("Dry run completed. Rows that would be moved to the default workspace:")
            for table_name, count in counts.items():
                click.echo(f"  {table_name}: {count}")
            click.echo(f"Total rows: {total}")
            return

        if total == 0:
            click.echo("No rows need to be moved.")
            return

        click.echo("Rows to be moved to the default workspace:")
        for table_name, count in counts.items():
            click.echo(f"  {table_name}: {count}")
        click.echo(f"Total rows: {total}")

        if not yes:
            click.confirm("Proceed with migration?", default=False, abort=True)

        migrate(engine, dry_run=False, verbose=verbose)
        click.echo(f"Moved {total} rows to the default workspace.")
    except RuntimeError as e:
        raise click.ClickException(str(e)) from e
    except sqlalchemy.exc.SQLAlchemyError as e:
        raise click.ClickException(f"Database error: {e}") from e
    finally:
        if engine is not None:
            engine.dispose()


def _parse_tag(value: str) -> tuple[str, str]:
    if "=" not in value:
        raise click.BadParameter(
            f"Tag {value!r} must be in key=value format (e.g. --tag team=team-a)."
        )
    key, _, val = value.partition("=")
    if not key:
        raise click.BadParameter(f"Tag {value!r} has an empty key. Use key=value format.")
    return key, val


@commands.command("move-resources")
@click.argument("url")
@click.option(
    "--from",
    "source_workspace",
    required=True,
    help="Source workspace name.",
)
@click.option(
    "--to",
    "target_workspace",
    required=True,
    help="Target workspace name.",
)
@click.option(
    "--resource-type",
    required=True,
    help="Table name of the resource type to move (e.g. experiments, registered_models).",
)
@click.option(
    "--name",
    multiple=True,
    help="Resource name(s) to move. Repeatable.",
)
@click.option(
    "--tag",
    multiple=True,
    help=(
        "Tag filter as key=value. Repeatable. "
        "When multiple tags are given, only resources matching ALL tags are included."
    ),
)
@click.option(
    "--dry-run/--no-dry-run",
    default=False,
    show_default=True,
    help="Show what would be moved without making changes.",
)
@click.option(
    "--verbose",
    "-v",
    is_flag=True,
    default=False,
    help="List all conflicts instead of truncating the output.",
)
@click.option(
    "--yes",
    "-y",
    is_flag=True,
    default=False,
    help="Skip the confirmation prompt.",
)
def move_resources(
    url, source_workspace, target_workspace, resource_type, name, tag, dry_run, verbose, yes
):
    """
    Move resources from one workspace to another.

    Selectively move workspace-scoped resources between workspaces by name
    or tag filter (mutually exclusive). When neither --name nor --tag is
    specified, all resources of the given type in the source workspace are moved.

    The --resource-type value is the database table name (e.g. experiments,
    registered_models, evaluation_datasets, webhooks, jobs).

    Tag filtering (--tag) is supported for experiments and registered_models
    only. When multiple --tag flags are given, only resources matching ALL tags
    are included (AND logic).

    \b
    Examples:
      # Move specific experiments by name
      mlflow db move-resources sqlite:///mlflow.db \\
        --from default --to team-a --resource-type experiments \\
        --name training-v1 --name training-v2
      # Move experiments matching ALL specified tags
      mlflow db move-resources sqlite:///mlflow.db \\
        --from default --to team-a --resource-type experiments \\
        --tag team=team-a --tag env=prod
      # Move all registered models from one workspace to another
      mlflow db move-resources sqlite:///mlflow.db \\
        --from default --to team-a --resource-type registered_models

    **IMPORTANT**: Always take a backup of your database before running this command.
    """
    import sqlalchemy.exc

    import mlflow.store.db.utils
    from mlflow.store.db.workspace_move import RESOURCE_TYPE_CHOICES
    from mlflow.store.db.workspace_move import move_resources as move
    from mlflow.store.db.workspace_utils import format_truncated_list

    if resource_type not in RESOURCE_TYPE_CHOICES:
        raise click.ClickException(
            f"Unknown resource type {resource_type!r}. "
            f"Valid types: {', '.join(RESOURCE_TYPE_CHOICES)}"
        )

    parsed_tags = [_parse_tag(t) for t in tag] if tag else None
    parsed_names = list(name) if name else None

    engine = None
    try:
        engine = mlflow.store.db.utils.create_sqlalchemy_engine_with_retry(url)
        needs_confirmation = not dry_run and not yes

        result = move(
            engine,
            source_workspace=source_workspace,
            target_workspace=target_workspace,
            resource_type=resource_type,
            names=parsed_names,
            tags=parsed_tags,
            dry_run=dry_run or needs_confirmation,
            verbose=verbose,
        )

        if not result.names:
            click.echo(f"No {resource_type} to move.")
            return

        max_display = None if verbose else 20
        name_list = format_truncated_list(result.names, max_rows=max_display)

        extra_notes: list[str] = []
        if result.row_count > len(result.names):
            extra_notes.append(
                f"Note: {result.row_count} rows match {len(result.names)} distinct "
                f"name(s). All rows with a matching name will be moved."
            )

        if dry_run:
            click.echo(
                f"Dry run completed. {result.row_count} {resource_type} row(s) would be moved "
                f"from {source_workspace!r} to {target_workspace!r}:{name_list}"
            )
            for note in extra_notes:
                click.echo(note)
            return

        if needs_confirmation:
            click.echo(
                f"{result.row_count} {resource_type} row(s) to move from "
                f"{source_workspace!r} to {target_workspace!r}:{name_list}"
            )
            for note in extra_notes:
                click.echo(note)
            click.confirm("Proceed with move?", default=False, abort=True)
            # Re-run the full move (including conflict detection) in a new
            # transaction. The preview counts above may differ from the
            # actual move if another admin modified the data in between,
            # but the second call is self-consistent and safe.
            result = move(
                engine,
                source_workspace=source_workspace,
                target_workspace=target_workspace,
                resource_type=resource_type,
                names=parsed_names,
                tags=parsed_tags,
                dry_run=False,
                verbose=verbose,
            )

        click.echo(
            f"Moved {result.row_count} {resource_type} row(s) "
            f"from {source_workspace!r} to {target_workspace!r}."
        )
    except RuntimeError as e:
        raise click.ClickException(str(e)) from e
    except sqlalchemy.exc.SQLAlchemyError as e:
        raise click.ClickException(f"Database error: {e}") from e
    finally:
        if engine is not None:
            engine.dispose()