Reduce complexity of Joins query / Validity

[ahuang11]

[ahuang11]

    async def find_join_tables(self, messages: list | str, join_tables: list[str] | None = None):
        if join_tables:
            multi_source = any('//' in jt for jt in join_tables)
        else:
            multi_source = len(memory['available_sources']) > 1
            if multi_source:
                available_tables = ", ".join(f"//{a_source}//{a_table}" for a_source in memory["available_sources"] for a_table in a_source.get_tables())
            else:
                available_tables = memory['current_source'].get_tables()

            with self.interface.add_step(title="Determining tables required for join") as step:
                output = await self.llm.invoke(
                    messages,
                    system=f"List the tables that need to be joined; be sure to include both `//`: {available_tables}",
                    response_model=TableJoins,
                )
                join_tables = output.tables
                step.stream(f'\nJoin requires following tables: {join_tables}', replace=True)
                step.success_title = 'Found tables required for join'

        sources = {}
        for source_table in join_tables:
            if multi_source:
                try:
                    _, a_source_name, a_table = source_table.split("//", maxsplit=2)
                except ValueError:
                    a_source_name, a_table = source_table.split("//", maxsplit=1)
                a_source = next((source for source in memory["available_sources"] if a_source_name == source.name), None)
            else:
                a_source = memory['current_source']
                a_table = source_table
            sources[a_source_name] = (a_source, a_table)
        return sources

I think this needs context of the column schemas.