"""Tests for the pure reconciliation functions.

These tests use lightweight stand-in objects (namedtuples) rather than
SQLAlchemy ORM instances, so the reconcile module has zero DB dependency.
"""

from __future__ import annotations

from dataclasses import dataclass
from datetime import date
from typing import Optional

import pytest

from cyclone import reconcile


# --- Stand-in types -----------------------------------------------------------


@dataclass
class FakeClaim:
    id: str
    patient_control_number: str
    service_date_from: Optional[date]
    state: str = "submitted"
    matched_remittance_id: Optional[str] = None


@dataclass
class FakeRemit:
    id: str
    payer_claim_control_number: str
    service_date: Optional[date]
    is_reversal: bool = False


# --- match() ------------------------------------------------------------------


def test_match_same_pcn_within_window_matches():
    claims = [FakeClaim("CLM-1", "PCN-A", date(2026, 6, 1))]
    remits = [FakeRemit("CLP-1", "PCN-A", date(2026, 6, 2))]
    matches = reconcile.match(claims, remits, window_days=7)
    assert len(matches) == 1
    assert matches[0].claim.id == "CLM-1"
    assert matches[0].remittance.id == "CLP-1"
    assert matches[0].strategy == "auto"


def test_match_dates_outside_window_unmatched():
    claims = [FakeClaim("CLM-1", "PCN-A", date(2026, 6, 1))]
    remits = [FakeRemit("CLP-1", "PCN-A", date(2026, 7, 1))]  # 30d apart
    matches = reconcile.match(claims, remits, window_days=7)
    assert matches == []


def test_match_different_pcn_unmatched():
    claims = [FakeClaim("CLM-1", "PCN-A", date(2026, 6, 1))]
    remits = [FakeRemit("CLP-1", "PCN-B", date(2026, 6, 1))]
    matches = reconcile.match(claims, remits)
    assert matches == []


def test_match_multiple_claims_same_pcn_picks_closest_date():
    claims = [
        FakeClaim("CLM-1", "PCN-A", date(2026, 5, 1)),
        FakeClaim("CLM-2", "PCN-A", date(2026, 6, 1)),  # closer
    ]
    remits = [FakeRemit("CLP-1", "PCN-A", date(2026, 6, 2))]
    matches = reconcile.match(claims, remits)
    assert len(matches) == 1
    assert matches[0].claim.id == "CLM-2"


def test_match_multiple_remits_same_pcn_each_gets_own_claim():
    claims = [
        FakeClaim("CLM-1", "PCN-A", date(2026, 6, 1)),
        FakeClaim("CLM-2", "PCN-A", date(2026, 6, 15)),
    ]
    remits = [
        FakeRemit("CLP-1", "PCN-A", date(2026, 6, 2)),
        FakeRemit("CLP-2", "PCN-A", date(2026, 6, 16)),
    ]
    matches = reconcile.match(claims, remits)
    assert len(matches) == 2
    claim_ids = {m.claim.id for m in matches}
    assert claim_ids == {"CLM-1", "CLM-2"}


def test_match_skips_already_matched_claims():
    claims = [FakeClaim("CLM-1", "PCN-A", date(2026, 6, 1), matched_remittance_id="OLD")]
    remits = [FakeRemit("CLP-1", "PCN-A", date(2026, 6, 1))]
    matches = reconcile.match(claims, remits)
    assert matches == []


def test_match_falls_back_to_first_claim_when_no_service_date():
    """When the remit has no service_date, match the first claim for that PCN."""
    claims = [
        FakeClaim("CLM-1", "PCN-A", None),
        FakeClaim("CLM-2", "PCN-A", None),
    ]
    remits = [FakeRemit("CLP-1", "PCN-A", None)]
    matches = reconcile.match(claims, remits)
    assert len(matches) == 1
    assert matches[0].claim.id == "CLM-1"


def test_match_reversal_flag_propagates():
    claims = [FakeClaim("CLM-1", "PCN-A", date(2026, 6, 1))]
    remits = [FakeRemit("CLP-1", "PCN-A", date(2026, 6, 1), is_reversal=True)]
    matches = reconcile.match(claims, remits)
    assert matches[0].is_reversal is True