import os
import io
import uuid
from datetime import date

import pytest
from fastapi.testclient import TestClient

# Ensure required env vars for app import/config
os.environ.setdefault("SECRET_KEY", "x" * 32)
os.environ.setdefault("DATABASE_URL", "sqlite:////tmp/delphi_test.sqlite")

from app.main import app  # noqa: E402
from app.auth.security import get_current_user  # noqa: E402
from tests.helpers import assert_http_error, assert_validation_error  # noqa: E402


class _User:
    def __init__(self):
        self.id = 1
        self.username = "uploader"
        self.is_admin = True
        self.is_active = True


@pytest.fixture()
def client():
    app.dependency_overrides[get_current_user] = lambda: _User()
    try:
        yield TestClient(app)
    finally:
        app.dependency_overrides.pop(get_current_user, None)


def _create_customer_and_file(client: TestClient):
    customer_id = f"UP-{uuid.uuid4().hex[:8]}"
    resp = client.post(
        "/api/customers/",
        json={"id": customer_id, "last": "Upload", "email": "u@example.com"},
    )
    assert resp.status_code == 200

    file_no = f"U-{uuid.uuid4().hex[:6]}"
    file_payload = {
        "file_no": file_no,
        "id": customer_id,
        "regarding": "Upload doc test",
        "empl_num": "E01",
        "file_type": "CIVIL",
        "opened": date.today().isoformat(),
        "status": "ACTIVE",
        "rate_per_hour": 100.0,
    }
    resp = client.post("/api/files/", json=file_payload)
    assert resp.status_code == 200
    return file_no


def test_upload_invalid_file_type_returns_400_envelope_and_correlation_header(client: TestClient):
    file_no = _create_customer_and_file(client)

    files = {
        "file": ("bad.txt", b"hello", "text/plain"),
    }
    resp = client.post(f"/api/documents/upload/{file_no}", files=files)

    assert_http_error(resp, 400, "Invalid file type")


def test_upload_oversize_file_returns_400_envelope_and_correlation_header(client: TestClient):
    file_no = _create_customer_and_file(client)

    # 10MB + 1 byte
    big_bytes = b"x" * (10 * 1024 * 1024 + 1)
    files = {
        "file": ("large.pdf", big_bytes, "application/pdf"),
    }
    resp = client.post(f"/api/documents/upload/{file_no}", files=files)

    assert_http_error(resp, 400, "File too large")


def test_upload_uses_incoming_correlation_id_when_provided(client: TestClient):
    file_no = _create_customer_and_file(client)

    cid = f"cid-{uuid.uuid4().hex[:8]}"
    files = {
        "file": ("bad.txt", b"hello", "text/plain"),
    }
    resp = client.post(
        f"/api/documents/upload/{file_no}",
        files=files,
        headers={"X-Correlation-ID": cid},
    )

    # Envelope shape and message
    assert_http_error(resp, 400, "Invalid file type")
    # Echoes our provided correlation id
    body = resp.json()
    assert resp.headers.get("X-Correlation-ID") == cid
    assert body.get("correlation_id") == cid


def test_upload_without_file_returns_400_no_file_uploaded(client: TestClient):
    file_no = _create_customer_and_file(client)

    # Provide an empty filename to trigger the explicit 400 in route logic
    files = {
        # Use a valid filename but zero-byte payload to hit the 400 "No file uploaded" branch
        "file": ("empty.pdf", io.BytesIO(b""), "application/pdf"),
    }
    resp = client.post(f"/api/documents/upload/{file_no}", files=files)

    assert_http_error(resp, 400, "No file uploaded")


def test_upload_missing_file_field_returns_422_validation_envelope(client: TestClient):
    file_no = _create_customer_and_file(client)

    # Submit without the required `file` field
    resp = client.post(
        f"/api/documents/upload/{file_no}",
        data={"description": "missing file"},
        headers={"X-Correlation-ID": f"cid-{uuid.uuid4().hex[:8]}"},
    )

    # Ensure 422 envelope and correlation header; details should mention `file`
    assert_validation_error(resp, "file")