"""声明的向后比例复权；拆股调价/调量，现金股利只调价。"""
import json
from decimal import Decimal as D

raw = [("2026-10-19", D("100"), D("100")), ("2026-10-20", D("50"), D("200")),
       ("2026-10-21", D("49"), D("220")), ("2026-10-22", D("50"), D("240"))]
events = [{"date": "2026-10-20", "split": D("2"), "dividend": D("0")},
          {"date": "2026-10-21", "split": D("1"), "dividend": D("1")}]

def factors(day):
    price_factor, volume_factor = D("1"), D("1")
    for event in events:
        if day >= event["date"]:
            continue
        split, dividend = event["split"], event["dividend"]
        if split <= 0:
            raise ValueError("invalid_split")
        price_factor /= split
        volume_factor *= split
        if dividend:
            previous = max((row for row in raw if row[0] < event["date"]), key=lambda row: row[0])[1]
            multiplier = (previous-dividend)/previous
            if not 0 < multiplier <= 1:
                raise ValueError("invalid_dividend_factor")
            price_factor *= multiplier
    return price_factor, volume_factor

expected = {day: (price*factors(day)[0], volume*factors(day)[1]) for day, price, volume in raw}
vendor = {"2026-10-19": (D("49"), D("200")), "2026-10-20": (D("49"), D("200")),
          "2026-10-21": (D("49"), D("220")), "2026-10-22": (D("50"), D("240"))}
assert expected == vendor
bad = {**vendor, "2026-10-19": (D("50"), D("200")), "2026-10-20": (D("49"), D("204"))}
def discrepancies(observed, reference, tolerance=D("0.0001")):
    errors = {}
    for day in reference:
        fields = [field for index, field in enumerate(["close", "volume"])
                  if abs(observed[day][index]-reference[day][index]) > tolerance]
        if fields:
            errors[day] = fields
    return errors

errors = discrepancies(bad, expected)
assert errors == {"2026-10-19": ["close"], "2026-10-20": ["volume"]}
assert discrepancies(vendor, expected) == {}
rounded = {**vendor, "2026-10-19": (D("49.00005"), D("200"))}
assert discrepancies(rounded, expected) == {}
assert factors("2026-10-19") == (D("0.49"), D("2"))
assert factors("2026-10-20") == (D("0.98"), D("1"))
assert expected["2026-10-21"][0]/expected["2026-10-20"][0]-1 == 0
double_count = (D("49")+D("1"))/D("49")-1
assert double_count > 0
print(json.dumps({"expected": {d: [str(p), str(v)] for d, (p, v) in expected.items()},
                  "injected_errors": errors, "quarantined_dates": sorted(errors),
                  "usable_bad_vendor_dates": sorted(set(expected)-set(errors)),
                  "dividend_adjusted_return": "0", "double_counted_return": str(double_count)}, sort_keys=True))