"""
Session deletion (cascade) and the three opening-balance modes.

Both were user-reported issues:
  * deleting a closing failed with a FOREIGN KEY error because child rows blocked it
  * the opening balance auto-seeded, with no way to choose zero / carry-forward / manual
"""
from __future__ import annotations

import os
import tempfile

_TMP = tempfile.mkdtemp(prefix="ar_lifecycle_test_")
os.environ["AR_DATA_DIR"] = _TMP

from fastapi.testclient import TestClient  # noqa: E402

from app.api.main import app  # noqa: E402
from app.db import models  # noqa: E402
from app.db.database import SessionLocal, init_db  # noqa: E402
from tests.test_excel_export import make_amazon_xlsx  # noqa: E402


def _new(c, name: str, month_end: str, **kw) -> int:
    body = {"name": name, "month_end_date": month_end, "clearing_lag_days": 2, **kw}
    r = c.post("/api/sessions", json=body)
    assert r.status_code == 200, r.text
    return r.json()["id"]


def _processed_session(c, name: str, month_end: str, **kw) -> int:
    sid = _new(c, name, month_end, **kw)
    path = os.path.join(_TMP, f"USA {name}.xlsx")
    make_amazon_xlsx(path, order_rows=6)
    with open(path, "rb") as fh:
        assert c.post(f"/api/sessions/{sid}/files",
                      files={"files": (os.path.basename(path), fh)}).status_code == 200
    assert c.post(f"/api/sessions/{sid}/process").status_code == 200
    assert c.get(f"/api/sessions/{sid}/status").json()["status"] == "processed"
    return sid


# --------------------------------------------------------------------- deletion
def test_delete_removes_session_and_all_children():
    init_db()
    with TestClient(app) as c:
        sid = _processed_session(c, "to delete", "2026-01-31")

        db = SessionLocal()
        assert db.query(models.Transaction).filter_by(session_id=sid).count() > 0
        db.close()

        r = c.delete(f"/api/sessions/{sid}")
        assert r.status_code == 200, r.text
        assert r.json()["deleted"] == sid
        assert r.json()["rows_deleted"]          # reported what it removed

        assert c.get(f"/api/sessions/{sid}").status_code == 404
        db = SessionLocal()
        for model in (models.Transaction, models.Settlement, models.ReceivableResultRow,
                      models.ReconciliationRow, models.MarketPayout, models.Exception_,
                      models.OpeningBalance, models.FxRate, models.Reserve,
                      models.JournalEntry, models.SessionFile):
            assert db.query(model).filter_by(session_id=sid).count() == 0, model.__tablename__
        db.close()


def test_delete_blocked_while_processing():
    init_db()
    with TestClient(app) as c:
        sid = _new(c, "busy", "2026-01-31")
        db = SessionLocal()
        db.get(models.Session, sid).status = "processing"
        db.commit()
        db.close()

        assert c.delete(f"/api/sessions/{sid}").status_code == 409

        db = SessionLocal()                       # tidy up
        db.get(models.Session, sid).status = "draft"
        db.commit()
        db.close()
        assert c.delete(f"/api/sessions/{sid}").status_code == 200


# --------------------------------------------------------- opening-balance modes
def test_opening_mode_zero_is_the_default():
    init_db()
    with TestClient(app) as c:
        prior = _processed_session(c, "prior for zero", "2026-01-31")
        c.put(f"/api/sessions/{prior}/opening-balances",
              json=[{"marketplace": "USA", "amount": 5000.0, "reason": "x", "source": "manual"}])

        sid = _new(c, "zero month", "2026-02-28")          # no opening_mode passed
        assert c.get(f"/api/sessions/{sid}").json()["opening_mode"] == "zero"
        assert all(o["amount"] == 0.0 for o in c.get(f"/api/sessions/{sid}/opening-balances").json())


def test_opening_mode_carry_forward_at_creation():
    init_db()
    with TestClient(app) as c:
        prior = _processed_session(c, "prior carry", "2026-03-31")
        closing = c.get(f"/api/sessions/{prior}/ar-movement").json()["closing"]
        assert closing != 0

        sid = _new(c, "carry month", "2026-04-30",
                   opening_mode="carry_forward", opening_source_session_id=prior)
        s = c.get(f"/api/sessions/{sid}").json()
        assert s["opening_mode"] == "carry_forward"
        usa = [o for o in c.get(f"/api/sessions/{sid}/opening-balances").json()
               if o["marketplace"] == "USA"][0]
        assert usa["amount"] == closing
        assert usa["source"] == "carried_forward"


def test_carry_forward_and_reset_endpoints():
    init_db()
    with TestClient(app) as c:
        prior = _processed_session(c, "prior endpoints", "2026-05-31")
        closing = c.get(f"/api/sessions/{prior}/ar-movement").json()["closing"]

        sid = _processed_session(c, "target endpoints", "2026-06-30")   # starts at zero
        assert c.get(f"/api/sessions/{sid}/ar-movement").json()["opening"] == 0.0

        cands = c.get(f"/api/sessions/{sid}/opening-candidates").json()
        assert any(x["session_id"] == prior for x in cands["candidates"])

        r = c.post(f"/api/sessions/{sid}/opening-balances/carry-forward",
                   json={"from_session_id": prior})
        assert r.status_code == 200, r.text
        assert r.json()["applied"] >= 1
        mv = c.get(f"/api/sessions/{sid}/ar-movement").json()
        assert mv["opening"] == closing
        # the roll-forward must move with the new opening
        assert round(mv["closing"], 2) == round(
            closing + mv["net_revenue"] + mv["received_payouts"], 2)

        assert c.post(f"/api/sessions/{sid}/opening-balances/reset").status_code == 200
        assert c.get(f"/api/sessions/{sid}/ar-movement").json()["opening"] == 0.0
        assert c.get(f"/api/sessions/{sid}").json()["opening_mode"] == "zero"


def test_carry_forward_with_no_prior_falls_back_to_zero():
    """A first-ever closing that asks to carry forward must still be creatable."""
    init_db()
    with TestClient(app) as c:
        # a month earlier than every processed closing -> no candidates
        sid = _new(c, "earliest", "2020-01-31", opening_mode="carry_forward")
        s = c.get(f"/api/sessions/{sid}").json()
        assert s["opening_mode"] == "zero"
        assert c.delete(f"/api/sessions/{sid}").status_code == 200