"""已核实的独立业务从源快照进入正式单据；预览、指纹、执行分别留痕。"""

import copy
from collections import Counter
from datetime import date, datetime
from decimal import Decimal
from types import SimpleNamespace

from sqlalchemy import select

from app.models import (
    Business,
    BusinessItem,
    PayrollInput,
    Personnel,
    Product,
    Receipt,
    Shipment,
    ShipmentItem,
    TPlusSourceLink,
    TPlusWorkLine,
    User,
)
from app.services import payroll_months
from app.services.authorization_service import require_permission
from app.services.no_generator import next_no
from app.services.tplus.calculation_preview import execute_preview
from app.services.tplus.fifo import money
from app.services.tplus.workbench import WorkbenchError, digest, get_run


def _link(session, source, entity, source_id):
    return session.scalar(
        select(TPlusSourceLink).where(
            TPlusSourceLink.source_database == source,
            TPlusSourceLink.entity_type == entity,
            TPlusSourceLink.source_id == str(source_id),
        )
    )


def _latest_input(session, business_id):
    return session.scalar(
        select(PayrollInput)
        .where(PayrollInput.business_id == business_id)
        .order_by(PayrollInput.version.desc())
        .limit(1)
    )


def _append_compatible(old, new):
    """只能新增单据、补充事实；既有单据金额、日期与原发货归属变化进入差异处理。"""
    for entity, fields, identity in (
        (
            "shipments",
            (
                "date",
                "amount",
                "quantity",
                "product_id",
                "unit",
                "personnel_id",
                "business_key",
                "performance_excluded",
                "correction_pair_key",
            ),
            lambda r: (r["source_id"], r["line_id"]),
        ),
        (
            "receipts",
            ("date", "amount", "voucher_confirmed", "exclusion", "redirect_business_key"),
            lambda r: r["source_id"],
        ),
    ):
        current = {identity(r): r for r in new[entity]}
        for previous in old[entity]:
            candidate = current.get(identity(previous))
            if candidate is None or any(
                str(previous.get(f)) != str(candidate.get(f)) for f in fields
            ):
                return False
    return all(
        old["group"].get(k) == new["group"].get(k)
        for k in ("opening_balance", "excluded_receipt_ids", "customer_id")
    )


def _target_state(session, link):
    if link is None:
        return None
    business = session.get(Business, link.target_id)
    if business is None:
        raise WorkbenchError("BUSINESS_TARGET_MISSING")
    tables = (
        (Business, Business.id == business.id),
        (BusinessItem, BusinessItem.business_id == business.id),
        (Shipment, Shipment.business_id == business.id),
        (Receipt, Receipt.business_id == business.id),
    )
    result = {}
    for model, condition in tables:
        result[model.__tablename__] = [
            {c.name: str(getattr(r, c.name)) for c in model.__table__.columns}
            for r in session.scalars(select(model).where(condition).order_by(model.id))
        ]
    return result


def _build(session, run):
    preview = SimpleNamespace(input_json=run.input_json, source_database=run.source_database)
    execute_preview(session, preview, save_lines=False, customer_scope=True)
    frozen = preview.snapshot_json
    rows = []
    targets = {}
    seen_customers = set()
    for key, values in frozen["calculation_inputs"].items():
        summary = preview.summary_json["groups"][key]
        row = {"entity_type": "businesses", "source_id": key, "action": "PENDING", "reason": None}
        rows.append(row)
        if summary["status"] not in ("READY", "SUCCEEDED"):
            row["reason"] = ",".join(summary.get("reasons", [])) or "BUSINESS_DATA_PENDING"
            continue
        customer_id = values["group"]["customer_id"]
        if customer_id in seen_customers:
            row["action"], row["reason"] = "SKIP", "CUSTOMER_SCOPE_ALREADY_SELECTED"
            continue
        seen_customers.add(customer_id)
        active_ships = [s for s in values["shipments"] if not s.get("performance_excluded")]
        if not active_ships:
            row["action"], row["reason"] = "SKIP", "CORRECTION_EXCLUDED"
            continue
        if any(not ship.get("guidance_finalized") for ship in active_ships):
            row["reason"] = "GUIDANCE_FINALIZATION_REQUIRED"
            continue
        business_key = "customer:" + customer_id
        row["business_key"] = business_key
        row["input_hash"] = digest(values)
        link = _link(session, run.source_database, "businesses", business_key)
        targets[key] = _target_state(session, link)
        if link:
            current = _latest_input(session, link.target_id)
            row["target_id"] = link.target_id
            if current and current.fingerprint == row["input_hash"]:
                row["action"] = "SKIP"
            elif current and _append_compatible(current.data_json, values):
                row["action"] = "UPDATE"
            else:
                row["action"], row["reason"] = "CONFLICT", "FORMAL_SOURCE_CHANGED"
        else:
            row["action"] = "CREATE"
        for entity, ids in (
            ("shipments", values["group"]["shipment_ids"]),
            ("receipts", values["group"]["receipt_ids"]),
        ):
            for source_id in ids:
                linked = _link(session, run.source_database, entity, source_id)
                source_rows = values[entity]
                excluded = all(r.get("exclusion") or r.get("performance_excluded")
                               for r in source_rows if r["source_id"] == source_id)
                if linked and not excluded and (
                    not link
                    or not current
                    or source_id not in current.data_json["maps"].get(entity, {})
                ):
                    row["action"], row["reason"] = "CONFLICT", "SOURCE_ALREADY_IMPORTED"
        if not _link(session, run.source_database, "customers", values["group"]["customer_id"]):
            row["action"], row["reason"] = "PENDING", "CUSTOMER_IMPORT_REQUIRED"
        for ship in active_ships:
            if not _link(session, run.source_database, "products", ship["product_id"]):
                row["action"], row["reason"] = "PENDING", "PRODUCT_IMPORT_REQUIRED"
    frozen = {"calculation": frozen, "plan": rows, "targets": targets}
    return rows, frozen, digest(frozen)


def _add_link(session, source, entity, source_id, target):
    session.add(
        TPlusSourceLink(
            source_database=source,
            entity_type=entity,
            source_id=str(source_id),
            target_id=target.id,
        )
    )


def _new_no(session, model, column, prefix):
    return next_no(session, model=model, column_name=column, prefix=prefix)


def _create(session, run, row, frozen):
    values = copy.deepcopy(frozen["calculation"]["calculation_inputs"][row["source_id"]])
    people = {}
    for code in values["facts"]["personnel"]:
        candidates = list(
            session.scalars(
                select(Personnel)
                .join(TPlusSourceLink, TPlusSourceLink.target_id == Personnel.id)
                .where(
                    TPlusSourceLink.source_database == run.source_database,
                    TPlusSourceLink.entity_type == "personnel",
                    Personnel.source_no == code,
                )
            )
        )
        if len(candidates) == 1:
            people[code] = candidates[0]
    active_ships = [s for s in values["shipments"] if not s.get("performance_excluded")]
    needed = {str(s["personnel_id"]) for s in active_ships}
    needed.update(str(s["manager_id"]) for s in active_ships if s.get("manager_id"))
    for handover in values["facts"]["handovers"]:
        needed.update((str(handover["from_personnel_id"]), str(handover["to_personnel_id"])))
    if needed - people.keys():
        raise WorkbenchError("PERSONNEL_IMPORT_REQUIRED")
    customer = _link(session, run.source_database, "customers", values["group"]["customer_id"])
    old_input = _latest_input(session, row["target_id"]) if row.get("target_id") else None
    business = (
        session.get(Business, row["target_id"], with_for_update=True)
        if row.get("target_id")
        else Business(
            business_no=_new_no(session, Business, "business_no", "YW"),
            customer_id=customer.target_id,
            owner_personnel_id=people[str(active_ships[0]["personnel_id"])].id,
            business_date=min(date.fromisoformat(s["date"]) for s in active_ships),
            status=1,
            is_special=0,
            t_plus_id=row["business_key"],
            source_no=row["business_key"],
            sync_batch_no=run.run_no,
            synced_at=datetime.now(),
        )
    )
    session.add(business)
    session.flush()
    if old_input is None:
        _add_link(session, run.source_database, "businesses", row["business_key"], business)
    maps = (
        copy.deepcopy(old_input.data_json["maps"])
        if old_input
        else {"shipments": {}, "shipment_items": {}, "receipts": {}, "personnel": {}}
    )
    maps["personnel"].update({code: p.id for code, p in people.items()})
    freight_total, sales_total, cost_total = Decimal(0), Decimal(0), Decimal(0)
    for source_id in values["group"]["shipment_ids"]:
        lines = [s for s in values["shipments"] if s["source_id"] == source_id]
        if not lines:
            continue
        if any(s.get("performance_excluded") for s in lines):
            values.setdefault("excluded_corrections", []).append(
                {"shipment_id": source_id, "lines": lines}
            )
            continue
        head = lines[0]
        freight = sum((money(s.get("freight_amount") or "0") for s in lines), Decimal(0))
        if source_id in maps["shipments"]:
            existing = session.get(Shipment, maps["shipments"][source_id], with_for_update=True)
            if (
                existing is None
                or existing.total_amount != sum((money(s["amount"]) for s in lines), Decimal(0))
                or existing.ship_date.isoformat() != head["date"]
            ):
                raise WorkbenchError("FORMAL_TARGET_CHANGED")
            sales_total += existing.total_amount
            freight_total += existing.freight_amount
            cost_total += sum(
                (money(s["cost_total"]) for s in lines if s.get("cost_total") is not None),
                Decimal(0),
            )
            continue
        shipment = Shipment(
            business_id=business.id,
            shipment_no=_new_no(session, Shipment, "shipment_no", "SH"),
            ship_date=date.fromisoformat(head["date"]),
            total_amount=sum((money(s["amount"]) for s in lines), Decimal(0)),
            freight_amount=freight,
            source_no=head["source_no"],
            t_plus_id=source_id,
            sync_batch_no=run.run_no,
            synced_at=datetime.now(),
        )
        session.add(shipment)
        session.flush()
        maps["shipments"][source_id] = shipment.id
        _add_link(session, run.source_database, "shipments", source_id, shipment)
        for ship in lines:
            product = session.get(
                Product,
                _link(session, run.source_database, "products", ship["product_id"]).target_id,
            )
            quantity = money(ship["quantity"])
            amount = money(ship["amount"])
            cost = money(ship["cost_total"]) if ship.get("cost_total") is not None else None
            item = ShipmentItem(
                shipment_id=shipment.id,
                product_id=product.id,
                product_name=product.product_name,
                spec_model=product.spec_model or "",
                unit=ship["unit"],
                quantity=quantity,
                sale_price=(amount / quantity).quantize(Decimal("0.0001")),
                amount=amount,
            )
            session.add(item)
            session.flush()
            maps["shipment_items"][ship["line_id"]] = item.id
            session.add(
                BusinessItem(
                    business_id=business.id,
                    product_id=product.id,
                    product_name=product.product_name,
                    spec_model=product.spec_model or "",
                    unit=ship["unit"],
                    quantity=quantity,
                    sale_price=item.sale_price,
                    sale_amount=amount,
                    cost_amount=cost,
                    product_category=ship["category"],
                )
            )
            sales_total += amount
            cost_total += cost or Decimal(0)
        freight_total += freight
    received = Decimal(0)
    for cash in values["receipts"]:
        if cash.get("exclusion"):
            continue
        if cash["source_id"] in maps["receipts"]:
            existing = session.get(
                Receipt, maps["receipts"][cash["source_id"]], with_for_update=True
            )
            if (
                existing is None
                or existing.amount != money(cash["amount"])
                or existing.receipt_date.isoformat() != cash["date"]
            ):
                raise WorkbenchError("FORMAL_TARGET_CHANGED")
            received += existing.amount
            continue
        receipt = Receipt(
            business_id=business.id,
            receipt_batch_no=_new_no(session, Receipt, "receipt_batch_no", "HK"),
            receipt_date=date.fromisoformat(cash["date"]),
            amount=money(cash["amount"]),
            is_barter=0,
            settlement_status=0,
            source_no=cash["source_no"],
            t_plus_id=cash["source_id"],
            sync_batch_no=run.run_no,
            synced_at=datetime.now(),
        )
        session.add(receipt)
        session.flush()
        maps["receipts"][cash["source_id"]] = receipt.id
        _add_link(session, run.source_database, "receipts", cash["source_id"], receipt)
        received += receipt.amount
    business.total_sale_amount = sales_total
    business.total_ship_amount = sales_total
    business.total_cost_amount = cost_total
    business.total_received_amount = received
    business.total_freight_amount = freight_total
    values["maps"] = maps
    values["source_facts"] = frozen["calculation"]["facts"]
    session.add(
        PayrollInput(
            business_id=business.id,
            version=old_input.version + 1 if old_input else 1,
            source_database=run.source_database,
            group_key=row["source_id"],
            fingerprint=row["input_hash"],
            data_json=values,
            requested_by=run.requested_by,
        )
    )
    row["target_id"] = business.id


def execute_business(session, run):
    operator = session.get(User, run.requested_by)
    require_permission(session, operator, "tplus:import" if run.kind == "BUSINESS_APPLY" else "tplus:preview")
    request = run
    if run.kind == "BUSINESS_APPLY":
        request = get_run(session, run.input_json["preview_no"], run.source_database)
        if request.kind != "BUSINESS_PREVIEW" or request.status not in ("SUCCEEDED", "PARTIAL"):
            raise WorkbenchError("PREVIEW_REQUIRED")
    payroll_months.ensure_allocation_editable(session, request.input_json["month"], operator, require_maker=False)
    rows, frozen, fingerprint = _build(session, request)
    if run.kind == "BUSINESS_APPLY" and request.snapshot_hash != fingerprint:
        raise WorkbenchError("PREVIEW_STALE")
    counts = Counter()
    for i, row in enumerate(rows, 1):
        if run.kind == "BUSINESS_APPLY" and row["action"] in ("CREATE", "UPDATE"):
            try:
                with session.begin_nested():
                    _create(session, run, row, frozen)
            except WorkbenchError as exc:
                row["action"], row["reason"] = "PENDING", str(exc)
        counts[row["action"]] += 1
        session.add(
            TPlusWorkLine(
                run_no=run.run_no,
                line_no=i,
                entity_type="businesses",
                source_id=row["source_id"],
                action=row["action"],
                reason=row.get("reason"),
                data_json=row,
            )
        )
    run.snapshot_json, run.snapshot_hash = frozen, fingerprint
    run.summary_json = {
        "counts": dict(counts),
        "total": len(rows),
        "formal_business_written": run.kind == "BUSINESS_APPLY",
        "formal_payroll_written": False,
    }
    run.status = "PARTIAL" if counts["PENDING"] or counts["CONFLICT"] else "SUCCEEDED"