"""简化季度盈利驱动模型：实际替换和有证据的未来假设分别形成桥。"""
import copy
import json
from decimal import Decimal as D, InvalidOperation


def finite(value):
    try:
        number = D(str(value))
    except (InvalidOperation, ValueError, TypeError) as exc:
        raise ValueError("invalid_numeric_input") from exc
    if not number.is_finite():
        raise ValueError("nonfinite_model_driver")
    return number


def profit(row):
    if any(row.get(key) is None for key in ["revenue", "margin", "finance", "tax"]):
        return None
    rev, margin, finance, tax = [finite(row[key]) for key in ["revenue", "margin", "finance", "tax"]]
    if rev < 0 or not (0 <= margin <= 1 and 0 <= tax <= 1):
        raise ValueError("driver_out_of_domain")
    return (rev*margin-finance)*(1-tax)


def eps(model, shares="100"):
    denominator = finite(shares)
    if denominator <= 0:
        raise ValueError("invalid_share_assumption")
    profits = [profit(model[q]) for q in [1, 2, 3, 4]]
    return None if any(p is None for p in profits) else sum(profits)/denominator


def update(model, actual, revisions):
    if actual.get("source_id") is None or actual.get("quarter") != 1:
        raise ValueError("unverified_actual_scope")
    after_actual = copy.deepcopy(model)
    after_actual[1] = {key: actual.get(key) for key in ["revenue", "margin", "finance", "tax"]}
    after_actual[1].update(status="actual", source_id=actual["source_id"])
    profit(after_actual[1])
    revised = copy.deepcopy(after_actual)
    changes, rejected = [], []
    for change in revisions:
        quarter, field = change["quarter"], change["field"]
        if quarter not in [2, 3, 4] or field not in ["revenue", "margin", "finance", "tax"]:
            raise ValueError("unsupported_revision")
        if not change.get("source_id"):
            rejected.append({"quarter": quarter, "field": field, "reason": "missing_revision_evidence"})
            continue
        new = finite(change["value"])
        changes.append({**change, "before": str(revised[quarter][field])})
        revised[quarter][field] = str(new)
        revised[quarter].setdefault("driver_sources", {})[field] = change["source_id"]
        profit(revised[quarter])
    before, replaced, after = eps(model), eps(after_actual), eps(revised)
    return {"old_eps": before, "actual_only_eps": replaced, "new_eps": after,
            "actual_effect": None if replaced is None or before is None else replaced-before,
            "assumption_effect": None if after is None or replaced is None else after-replaced,
            "changes": changes, "rejected": rejected, "model": revised}


old = {q: {"revenue": "100", "margin": "0.20", "finance": "0", "tax": "0.25", "status": "assumed"} for q in [1, 2, 3, 4]}
snapshot = copy.deepcopy(old)
actual = {"quarter": 1, "revenue": "120", "margin": "0.18", "finance": "0", "tax": "0.25", "source_id": "filing:AAA:Q1"}
revisions = [{"quarter": 2, "field": "revenue", "value": "110", "source_id": "orders:AAA:review-1"},
             {"quarter": 2, "field": "margin", "value": "0.19", "source_id": "costs:AAA:review-1"},
             {"quarter": 3, "field": "margin", "value": "0.30", "source_id": None}]
result = update(old, actual, revisions)
assert [result[k] for k in ["old_eps", "actual_only_eps", "new_eps", "actual_effect", "assumption_effect"]] == list(map(D, ["0.60", "0.612", "0.61875", "0.012", "0.00675"]))
assert result["model"][3]["margin"] == "0.20" and old == snapshot
assert len(result["rejected"]) == 1 and len(result["changes"]) == 2
unknown = update(old, {**actual, "tax": None}, revisions)
assert unknown["new_eps"] is None and unknown["actual_effect"] is None
for token in ["NaN", "Infinity", "-Infinity"]:
    try:
        update(old, {**actual, "revenue": token}, revisions)
    except ValueError:
        assert old == snapshot
    else:
        raise AssertionError("非有限驱动必须拒绝")
print(json.dumps({"bridge": {k: v for k, v in result.items() if k != "model"},
                  "missing_actual_tax_eps": unknown["new_eps"], "unchanged_q3": result["model"][3]}, default=str, sort_keys=True))