"""PR-B — promote non-IT expense into the ledger + external reconcile.

Verifies the no-double-count promotion (only promote_to_ledger rows become
cost_type='expense' in the unified ledger) and the internal-vs-external
reconciliation view.
"""
from __future__ import annotations

from decimal import Decimal

import pytest
import pytest_asyncio

from app.core.coordinators import finance_spend_coordinator as coord
from app.domains.finance import read_service
from app.domains.finance.models import FinanceExternalStatement, FinanceSpendFact

PERIOD = "2026-05"


@pytest_asyncio.fixture
async def seeded(db_session):
    db = db_session
    # collect_all_rows runs the AI collector, which requires the whitelist
    # platform setting (migration 149 seeds it in real envs).
    from app.integrations.models import PlatformSetting
    db.add(PlatformSetting(key="ai_spending.service_whitelist", value={"aws": ["Bedrock"]}))
    db.add(PlatformSetting(key="ai_spending.cny_to_usd_rate", value=0.14))

    def ext(doc, line, cat, usd, *, promote, cc="CC-RD", vendor="携程",
            invoice_verified=None, payment_status=None):
        return FinanceExternalStatement(
            statement_key=f"k-{doc}-{line}", source="huilianyi",
            external_doc_no=doc, line_no=line, period=PERIOD,
            expense_category=cat, mapped_cost_type=("expense" if promote else None),
            promote_to_ledger=promote, cost_center=cc, department="研发",
            vendor=vendor, amount_native=Decimal(usd), currency="USD",
            amount_usd=Decimal(usd), fx_basis="native_usd",
            invoice_verified=invoice_verified, payment_status=payment_status,
        )

    # Two promoted non-IT expense lines ($100 + $40) + one IT-overlap
    # line ($60, promote=False — reconciliation-only).
    db.add_all([
        ext("BX-1", 0, "差旅费", "100", promote=True, payment_status="PAID"),
        ext("BX-1", 1, "餐饮费", "40", promote=True),
        ext("BX-2", 0, "云服务费", "60", promote=False, vendor="AWS",
            invoice_verified=True, payment_status="PAID"),
    ])
    # Internal computed cloud spend in the same cost centre ($500).
    db.add(FinanceSpendFact(
        fact_key="f-cloud-ccrd", period=PERIOD, cost_type="cloud",
        basis="consumption", sub_category="EC2", vendor="aws",
        department="研发", cost_center="CC-RD", allocation_source="scope_owner",
        amount_native=Decimal("500"), currency_native="USD",
        amount_usd=Decimal("500"), fx_basis="native_usd",
        is_provisional=True, source_domain="cmdb", rollup_fingerprint="x",
    ))
    await db.flush()
    return db


@pytest.mark.asyncio
async def test_collect_expense_rows_only_promoted(seeded):
    rows = await coord.collect_expense_rows(seeded, PERIOD)
    # Only the two promote=True lines become ledger expense rows.
    assert len(rows) == 2
    assert all(r.cost_type == "expense" for r in rows)
    total = sum(r.amount_usd for r in rows)
    assert total == Decimal("140.000000")  # 100 + 40, NOT the $60 IT line
    cats = {r.sub_category for r in rows}
    assert cats == {"差旅费", "餐饮费"}


@pytest.mark.asyncio
async def test_collect_all_rows_includes_expense(seeded):
    # collect_all_rows recomputes the IT streams from SOURCE systems
    # (cmdb_cost_facts etc.), which this fixture doesn't seed — so we only
    # assert the expense stream is wired in (it reads the external ledger,
    # which IS seeded). The cloud finance_spend_facts row is the
    # materialised OUTPUT, not a collector input.
    rows = await coord.collect_all_rows(seeded, PERIOD)
    by_type = {}
    for r in rows:
        by_type[r.cost_type] = by_type.get(r.cost_type, Decimal("0")) + r.amount_usd
    assert by_type.get("expense") == Decimal("140.000000")


@pytest.mark.asyncio
async def test_external_reconcile_internal_vs_external(seeded):
    r = await read_service.external_reconcile(seeded, PERIOD, "cost_center")
    assert r["dim"] == "cost_center"
    row = next(x for x in r["rows"] if x["cost_center"] == "CC-RD")
    # Internal excludes the promoted 'expense' (would self-compare); only
    # the cloud $500 counts internal here.
    assert Decimal(row["internal_usd"]) == Decimal("500.00")
    # External = ALL statements (100 + 40 + 60).
    assert Decimal(row["external_usd"]) == Decimal("200.00")
    assert Decimal(row["diff_usd"]) == Decimal("300.00")
    assert row["ext_docs"] == 3
    assert row["ext_invoices_verified"] == 1
    assert row["ext_paid"] == 2


@pytest.mark.asyncio
async def test_external_statements_browse_filters_promoted(seeded):
    only_recon = await read_service.external_statements(seeded, PERIOD, promoted=False)
    assert only_recon["total"] == 1
    assert only_recon["rows"][0]["vendor"] == "AWS"
    promoted = await read_service.external_statements(seeded, PERIOD, promoted=True)
    assert promoted["total"] == 2