"""Tests for the FastAPI surface in ``cyclone.api`` for the 835 ERA endpoint."""
from __future__ import annotations

import json
from pathlib import Path

import pytest
from fastapi.testclient import TestClient

from cyclone.api import app


FIXTURE = Path(__file__).parent / "fixtures" / "co_medicaid_835.txt"
UNBALANCED = Path(__file__).parent / "fixtures" / "unbalanced_835.txt"


@pytest.fixture
def client() -> TestClient:
    return TestClient(app)


# --------------------------------------------------------------------------- #
# JSON response path
# --------------------------------------------------------------------------- #


def test_parse_835_endpoint_returns_json(client: TestClient):
    text = FIXTURE.read_text()
    resp = client.post(
        "/api/parse-835",
        files={"file": ("co_medicaid_835.txt", text, "text/plain")},
        headers={"Accept": "application/json"},
    )
    assert resp.status_code == 200, resp.text
    body = resp.json()
    assert "envelope" in body
    assert "financial_info" in body
    assert "trace" in body
    assert "payer" in body
    assert "payee" in body
    assert "claims" in body and len(body["claims"]) == 2
    assert "summary" in body
    assert body["summary"]["total_claims"] == 2
    assert body["summary"]["passed"] == 2
    assert body["summary"]["failed"] == 0


# --------------------------------------------------------------------------- #
# NDJSON streaming path
# --------------------------------------------------------------------------- #


def test_parse_835_endpoint_streams_ndjson(client: TestClient):
    text = FIXTURE.read_text()
    resp = client.post(
        "/api/parse-835",
        files={"file": ("co_medicaid_835.txt", text, "text/plain")},
    )
    assert resp.status_code == 200, resp.text
    assert resp.headers["content-type"].startswith("application/x-ndjson")

    lines = list(resp.iter_lines())
    # 1 envelope + 1 financial_info + 1 trace + 1 payer + 1 payee + 2 claims + 1 summary = 8
    assert len(lines) == 8

    parsed = [json.loads(line) for line in lines]
    assert parsed[0]["type"] == "envelope"
    assert parsed[1]["type"] == "financial_info"
    assert parsed[2]["type"] == "trace"
    assert parsed[3]["type"] == "payer"
    assert parsed[4]["type"] == "payee"
    assert parsed[5]["type"] == "claim_payment"
    assert parsed[6]["type"] == "claim_payment"
    assert parsed[7]["type"] == "summary"

    # When include_raw_segments defaults to True, each claim carries raw segments.
    for obj in parsed[5:7]:
        assert "raw_segments" in obj["data"]
        assert isinstance(obj["data"]["raw_segments"], list)

    # Summary numbers match the JSON path.
    assert parsed[7]["data"]["total_claims"] == 2
    assert parsed[7]["data"]["passed"] == 2


def test_parse_835_endpoint_streams_ndjson_without_raw_segments(client: TestClient):
    text = FIXTURE.read_text()
    resp = client.post(
        "/api/parse-835?include_raw_segments=false",
        files={"file": ("co_medicaid_835.txt", text, "text/plain")},
    )
    assert resp.status_code == 200
    assert resp.headers["content-type"].startswith("application/x-ndjson")

    claims = [
        json.loads(line)
        for line in resp.iter_lines()
        if json.loads(line)["type"] == "claim_payment"
    ]
    assert len(claims) == 2
    for c in claims:
        assert c["data"]["raw_segments"] == []


# --------------------------------------------------------------------------- #
# Validation / error paths
# --------------------------------------------------------------------------- #


def test_parse_835_endpoint_rejects_missing_file(client: TestClient):
    # FastAPI's `File(...)` (no default) → 422 Unprocessable Entity.
    resp = client.post("/api/parse-835")
    assert resp.status_code == 422


def test_parse_835_endpoint_handles_payer_query_param(client: TestClient):
    text = FIXTURE.read_text()
    for payer in ("co_medicaid_835", "generic_835"):
        resp = client.post(
            f"/api/parse-835?payer={payer}",
            files={"file": ("co_medicaid_835.txt", text, "text/plain")},
            headers={"Accept": "application/json"},
        )
        assert resp.status_code == 200, (payer, resp.text)
        body = resp.json()
        assert body["summary"]["total_claims"] == 2
        assert body["summary"]["passed"] == 2


def test_parse_835_endpoint_rejects_unknown_payer(client: TestClient):
    text = FIXTURE.read_text()
    resp = client.post(
        "/api/parse-835?payer=does_not_exist",
        files={"file": ("co_medicaid_835.txt", text, "text/plain")},
    )
    assert resp.status_code == 400


def test_parse_835_endpoint_unbalanced_returns_422(client: TestClient):
    text = UNBALANCED.read_text()
    resp = client.post(
        "/api/parse-835",
        files={"file": ("unbalanced_835.txt", text, "text/plain")},
        headers={"Accept": "application/json"},
    )
    assert resp.status_code == 422, resp.text
    body = resp.json()
    assert body["summary"]["failed"] == 1
    # The R835_BAL_BPR_vs_CLP04 rule should have fired.
    assert any(
        issue["rule"] == "R835_BAL_BPR_vs_CLP04"
        for issue in body["validation"]["errors"]
    )


# --------------------------------------------------------------------------- #
# CORS
# --------------------------------------------------------------------------- #


def test_cors_headers_present_for_835(client: TestClient):
    resp = client.options(
        "/api/parse-835",
        headers={
            "Origin": "http://localhost:5173",
            "Access-Control-Request-Method": "POST",
            "Access-Control-Request-Headers": "content-type",
        },
    )
    assert resp.headers.get("access-control-allow-origin") == "http://localhost:5173"
    assert "POST" in resp.headers.get("access-control-allow-methods", "").upper()