"""PR-C — cost-centre authority + expense governance."""
from __future__ import annotations

from decimal import Decimal

import pytest
import pytest_asyncio

from app.domains.finance import read_service
from app.domains.finance.models import (
    FinanceCostCenter,
    FinanceExternalStatement,
    FinanceSpendFact,
)

PERIOD = "2026-05"


@pytest_asyncio.fixture
async def seeded(db_session):
    db = db_session
    # Authoritative master. CC-MKT + CC-FIN have no spend → TWO unused
    # codes, which would crash the old sorted(generator-of-dicts) path.
    db.add(FinanceCostCenter(source="huilianyi", code="CC-RD", name="研发", active=True))
    db.add(FinanceCostCenter(source="huilianyi", code="CC-MKT", name="市场", active=True))
    db.add(FinanceCostCenter(source="huilianyi", code="CC-FIN", name="财务", active=True))
    # Internal spend: $500 on CC-RD (in master) + $100 on CC-GHOST (orphan).
    for i, (cc, usd) in enumerate([("CC-RD", "500"), ("CC-GHOST", "100")]):
        db.add(FinanceSpendFact(
            fact_key=f"f-{i}", period=PERIOD, cost_type="cloud", basis="consumption",
            sub_category="EC2", vendor="aws", cost_center=cc, allocation_source="scope_owner",
            amount_native=Decimal(usd), currency_native="USD", amount_usd=Decimal(usd),
            fx_basis="native_usd", is_provisional=True, source_domain="cmdb",
            rollup_fingerprint="x",
        ))

    def stmt(doc, line, **kw):
        base = dict(
            statement_key=f"k-{doc}-{line}", source="huilianyi", external_doc_no=doc,
            line_no=line, period=PERIOD, amount_native=Decimal("10"), currency="USD",
            amount_usd=Decimal("10"), fx_basis="native_usd", cost_center="CC-RD",
        )
        base.update(kw)
        return FinanceExternalStatement(**base)

    # Duplicate invoice INV-1 across two docs; one PAID-but-unverified.
    db.add_all([
        stmt("D1", 0, invoice_no="INV-1", invoice_verified=True, payment_status="PAID"),
        stmt("D2", 0, invoice_no="INV-1", invoice_verified=True, payment_status="PAID"),
        stmt("D3", 0, invoice_no="INV-9", invoice_verified=False, payment_status="PAID", vendor="X"),
    ])
    await db.flush()
    return db


@pytest.mark.asyncio
async def test_cost_center_coverage_counts_consumption_basis_only(db_session):
    """Regression (2026-07-08): cost_center_coverage must count the
    consumption basis ONLY. consumption / procurement / cash are three
    lenses on the SAME money; summing them (the old bug) double-counts a
    hardware asset (cash purchase + monthly depreciation) and a cloud PO
    (procurement commitment + its consumption bill) on the same cost centre,
    inflating total_spend_usd and skewing coverage_pct.
    """
    db = db_session
    db.add(FinanceCostCenter(source="huilianyi", code="CC-RD", name="研发", active=True))

    def _fact(key, basis, usd, cost_type):
        return FinanceSpendFact(
            fact_key=key, period=PERIOD, cost_type=cost_type, basis=basis,
            sub_category="x", vendor="v", cost_center="CC-RD",
            allocation_source="scope_owner",
            amount_native=Decimal(usd), currency_native="USD",
            amount_usd=Decimal(usd), fx_basis="native_usd",
            is_provisional=True, source_domain="cmdb", rollup_fingerprint="x",
        )

    # Same cost centre, three bases: only the $100 consumption row is spend.
    db.add_all([
        _fact("c-cons", "consumption", "100", "cloud"),
        _fact("c-proc", "procurement", "5000", "procurement"),
        _fact("c-cash", "cash", "12000", "hardware"),
    ])
    await db.flush()

    r = await read_service.cost_center_coverage(db, PERIOD)
    # Total spend reflects ONLY the consumption lens — not 100+5000+12000.
    assert r["total_spend_usd"] == "100.00"
    assert r["coverage_pct"] == 100.0  # CC-RD is in master → fully covered


@pytest.mark.asyncio
async def test_cost_center_coverage_flags_orphan(seeded):
    r = await read_service.cost_center_coverage(seeded, PERIOD)
    assert r["master_count"] == 3
    orphan_codes = {o["code"] for o in r["orphans"]}
    assert "CC-GHOST" in orphan_codes        # spend on a non-master code
    assert "CC-RD" not in orphan_codes
    assert r["coverage_pct"] < 100.0
    # Two master codes with no spend — exercises the unused sort (no crash).
    unused_codes = {u["code"] for u in r["unused"]}
    assert {"CC-MKT", "CC-FIN"} <= unused_codes


@pytest.mark.asyncio
async def test_expense_governance_duplicate_and_unverified(seeded):
    r = await read_service.expense_governance(seeded, PERIOD)
    dups = {d["invoice_no"]: d for d in r["duplicate_invoices"]}
    assert "INV-1" in dups
    assert dups["INV-1"]["doc_count"] == 2
    paid_unverified = {p["external_doc_no"] for p in r["paid_unverified"]}
    assert "D3" in paid_unverified           # PAID but invoice_verified=False
    assert "D1" not in paid_unverified        # verified → not flagged