from sqlglot import exp

from tht.config import ExecutionConfig
from tht.execute import ExecResult, PlanSummary


def runtime_warnings(result: ExecResult, cfg: ExecutionConfig) -> list[str]:
    warnings: list[str] = []
    if not result.rows:
        warnings.append("risultato vuoto: verificare filtri e join")
    if result.truncated:
        warnings.append("righe = limit: risultato troncato dalla preview")
    if result.execution_ms > cfg.warn_execution_ms:
        warnings.append(
            f"tempo di esecuzione elevato: {result.execution_ms} ms "
            f"(soglia {cfg.warn_execution_ms} ms)"
        )
    return warnings


def plan_warnings(plan: PlanSummary, cfg: ExecutionConfig) -> list[str]:
    warnings: list[str] = []
    if plan.plan_rows > cfg.warn_plan_rows:
        warnings.append(
            f"righe stimate dal piano: {plan.plan_rows} (soglia {cfg.warn_plan_rows}) — "
            f"possibile join molto ampio o cardinalita' anomala"
        )
    return warnings


def static_warnings(ast: exp.Expression) -> list[str]:
    """Euristica cast sospetti: CAST su colonne dentro WHERE (non-sargable)."""
    warnings: list[str] = []
    for where in ast.find_all(exp.Where):
        for cast in where.find_all(exp.Cast):
            if cast.find(exp.Column) is not None:
                warnings.append(
                    f"cast su colonna nel WHERE (possibile non-sargable): {cast.sql()}"
                )
    return warnings