"""按证据顺序定位零成交首个失效阶段。"""
import json


def diagnose(rows, key, window, threshold, cash, price, allowed):
    if not rows:
        return 'data:no_rows'
    if key != 'US:ALFA':
        return 'signal:symbol_key'
    if len(rows) < window:
        return 'signal:warmup'
    signal = int(rows[-1] > threshold)
    if not signal:
        return 'signal:zero'
    quantity = int((cash - 1) // price)
    if quantity <= 0:
        return 'target:zero_quantity'
    if not allowed:
        return 'execution:blocked'
    return f'fill:{quantity}'


base = dict(rows=[10, 11, 12], key='US:ALFA', window=3, threshold=11,
            cash=101, price=10, allowed=True)
cases = {'no_rows': {'rows': []}, 'wrong_key': {'key': 'ALFA'},
         'warmup': {'window': 120}, 'zero_signal': {'threshold': 13},
         'zero_quantity': {'cash': 5}, 'blocked': {'allowed': False}, 'fixed': {}}
report = {label: diagnose(**dict(base, **change)) for label, change in cases.items()}
assert list(report.values()) == ['data:no_rows', 'signal:symbol_key', 'signal:warmup',
                                'signal:zero', 'target:zero_quantity',
                                'execution:blocked', 'fill:10']
assert diagnose(**dict(base, rows=[], allowed=False)) == 'data:no_rows'
print(json.dumps(report))