"""转客户更正：成对确认、原始单据保留，同一回款只归一个业务。"""

from decimal import Decimal

from sqlalchemy import select

from app.core.exceptions import BadRequestError
from app.core.tplus_lock import TPlusBusyError, sync_lock
from app.models import TPlusFact, TPlusSourceLink
from app.services.tplus.fifo import money
from app.services.tplus.snapshots import source_records
from app.services.tplus.workbench import (
    WorkbenchError,
    _work_source_database,
    digest,
    fact_out,
    latest_facts,
)


def correction_fact(facts, entity, source_id):
    """实体前缀避免发货ID与收款ID相同相互覆盖；旧事实只供核对。"""
    found = facts.get(("CORRECTION", f"{entity}:{source_id}")) or facts.get(
        ("CORRECTION", str(source_id))
    )
    return found if found and found.data_json.get("entity") == entity else None


def verified_correction(session, source, facts, entity, record):
    fact = correction_fact(facts, entity, record.source_id)
    if fact is None:
        return {}
    data = fact.data_json
    if data.get("source_hash") != record.row_hash:
        raise WorkbenchError("CORRECTION_RECONFIRM_REQUIRED")
    if entity == "SHIPMENT":
        if data.get("details_hash") != _details_hash(session, source, record):
            raise WorkbenchError("CORRECTION_RECONFIRM_REQUIRED")
        other = correction_fact(facts, entity, data.get("paired_source_id"))
        if not other or (
            other.data_json.get("paired_source_id") != record.source_id
            or other.data_json.get("pair_key") != data["pair_key"]
            or other.data_json.get("source_hash") != data.get("paired_hash")
        ):
            raise WorkbenchError("CORRECTION_PAIR_REQUIRED")
        peers = source_records(session, source, "shipments", ids=[data["paired_source_id"]])
        if len(peers) != 1 or peers[0].row_hash != data["paired_hash"]:
            raise WorkbenchError("CORRECTION_RECONFIRM_REQUIRED")
        if other.data_json.get("details_hash") != _details_hash(session, source, peers[0]):
            raise WorkbenchError("CORRECTION_RECONFIRM_REQUIRED")
        neg, pos = _amount(session, source, record), _amount(session, source, peers[0])
        if neg + pos != 0 or neg * pos >= 0:
            raise WorkbenchError("CORRECTION_RECONFIRM_REQUIRED")
    return data


def _records(session, source, entity, ids):
    rows = source_records(session, source, entity, ids=ids)
    if {r.source_id for r in rows} != set(ids):
        raise BadRequestError("所选更正单或实际回款不在当前完整源快照中")
    return {r.source_id: r for r in rows}


def _amount(session, source, head):
    lines = source_records(session, source, "shipment_items", parent_ids=[head.source_id])
    if not lines or any(r.payload_json.get("taxAmount") is None for r in lines):
        raise BadRequestError("更正单缺少完整含税金额明细，不能成对排除")
    return sum((money(r.payload_json["taxAmount"]) for r in lines), Decimal(0))


def _details_hash(session, source, head):
    return digest(
        [
            (r.source_id, r.row_hash)
            for r in source_records(session, source, "shipment_items", parent_ids=[head.source_id])
        ]
    )


def save_pair(session, payload, actor_id):
    """沿用源级互斥锁，全部事实同事务追加；同一提交幂等。"""
    source = _work_source_database(session)
    try:
        with sync_lock(session):
            session.rollback()
            facts = latest_facts(session, source)
            heads = _records(
                session,
                source,
                "shipments",
                [
                    payload.negative_shipment_id,
                    payload.positive_shipment_id,
                ],
            )
            negative, positive = (
                heads[payload.negative_shipment_id],
                heads[payload.positive_shipment_id],
            )
            if negative.payload_json.get("idcustomer") == positive.payload_json.get("idcustomer"):
                raise BadRequestError("转客户更正对必须分别属于原客户和新客户")
            if any(h.payload_json.get("voucherState") != 189 for h in heads.values()):
                raise BadRequestError("更正销货单尚未生效")
            neg, pos = _amount(session, source, negative), _amount(session, source, positive)
            if not (neg < 0 < pos and neg + pos == 0):
                raise BadRequestError("必须选择金额相抵的一张负数及一张正数更正单")
            target = facts.get(("GROUP", payload.target_group_key))
            if not target or str(target.data_json["customer_id"]) != str(
                negative.payload_json["idcustomer"]
            ):
                raise BadRequestError("目标平账组必须属于负数更正单的原客户")
            cash = _records(session, source, "receipts", payload.receipt_ids)
            if any(
                str(r.payload_json.get("idpartner")) != str(positive.payload_json["idcustomer"])
                or r.payload_json.get("isReceiveFlag") != 1
                or money(r.payload_json.get("amount", "0")) <= 0
                for r in cash.values()
            ):
                raise BadRequestError("实际回款须为新客户名下的正数收款单")
            pair_key = digest([source, negative.source_id, positive.source_id])
            proposed = []
            for head, peer in ((negative, positive), (positive, negative)):
                proposed.append(
                    (
                        f"SHIPMENT:{head.source_id}",
                        {
                            "entity": "SHIPMENT",
                            "pair_key": pair_key,
                            "exclude_performance": True,
                            "paired_source_id": peer.source_id,
                            "source_hash": head.row_hash,
                            "paired_hash": peer.row_hash,
                            "details_hash": _details_hash(session, source, head),
                        },
                    )
                )
            for row in cash.values():
                proposed.append(
                    (
                        f"RECEIPT:{row.source_id}",
                        {
                            "entity": "RECEIPT",
                            "pair_key": pair_key,
                            "exclude_performance": False,
                            "redirect_business_key": payload.target_group_key,
                            "source_hash": row.row_hash,
                        },
                    )
                )
            result = []
            for key, data in proposed:
                entity, source_id = key.split(":", 1)
                current = correction_fact(facts, entity, source_id)
                if current and current.data_json.get("pair_key") != pair_key:
                    raise BadRequestError("该源单据已有其他更正配对，不能重复处理")
                # 已导入单据只能重放同一事实；修改需来源差异及当月调整处理。
                linked = session.scalar(
                    select(TPlusSourceLink).where(
                        TPlusSourceLink.source_database == source,
                        TPlusSourceLink.entity_type
                        == ("shipments" if entity == "SHIPMENT" else "receipts"),
                        TPlusSourceLink.source_id == source_id,
                    )
                )
                same = bool(current and all(current.data_json.get(k) == v for k, v in data.items()))
                if linked and not same:
                    raise BadRequestError(
                        "该单据已正式导入，请核对来源差异；已生成工资的差额使用当月调整单"
                    )
                if same:
                    result.append(current)
                    continue
                fact = TPlusFact(
                    source_database=source,
                    kind="CORRECTION",
                    fact_key=key,
                    version=(current.version if current else 0) + 1,
                    data_json=data,
                    evidence=payload.evidence,
                    requested_by=actor_id,
                )
                session.add(fact)
                result.append(fact)
            session.flush()
            session.commit()
            return {"pair_key": pair_key, "facts": [fact_out(f) for f in result]}
    except TPlusBusyError:
        session.rollback()
        raise BadRequestError("资料或任务正在更新，请稍后重试") from None
    except WorkbenchError:
        session.rollback()
        raise BadRequestError("请先完整采集更正发货、发货明细及收款数据") from None
    except Exception:
        session.rollback()
        raise