# dq/expectations.py
# Great-Expectations-style suite for fct_bookings. Each expectation
# returns dict(success=bool, observed=...).

from typing import List, Dict, Any


def expect_column_values_to_be_unique(rows: List[Dict[str, Any]], column: str):
    seen, dups = set(), 0
    for r in rows:
        v = r.get(column)
        if v in seen:
            dups += 1
        seen.add(v)
    return {'success': dups == 0, 'observed_dups': dups}


def expect_column_values_to_not_be_null(rows: List[Dict[str, Any]], column: str):
    nulls = sum(1 for r in rows if r.get(column) is None)
    return {'success': nulls == 0, 'observed_nulls': nulls}


def expect_column_values_to_be_between(rows: List[Dict[str, Any]], column: str, low: float, high: float):
    bad = sum(1 for r in rows if not (low <= r.get(column, 0) <= high))
    return {'success': bad == 0, 'observed_out_of_range': bad}


def run_suite(rows: List[Dict[str, Any]]) -> Dict[str, Any]:
    return {
        'unique_booking_id': expect_column_values_to_be_unique(rows, 'booking_id'),
        'guest_id_not_null': expect_column_values_to_not_be_null(rows, 'guest_id'),
        'amount_in_range':   expect_column_values_to_be_between(rows, 'amount_cents', 100, 10_000_000),
    }