"""Tests for OpenAPI spec fetcher module.

RED phase: written before implementation.
"""

from __future__ import annotations

from unittest.mock import patch

import pytest

from app.openapi.ssrf import SSRFError

pytestmark = pytest.mark.unit

_SAMPLE_JSON = '{"openapi": "3.0.0", "info": {"title": "Test", "version": "1.0"}, "paths": {}}'
_SAMPLE_YAML = "openapi: '3.0.0'\ninfo:\n  title: Test\n  version: '1.0'\npaths: {}\n"
_PUBLIC_IP = "93.184.216.34"


@pytest.fixture
def _mock_public_dns():
    with patch("app.openapi.ssrf.resolve_hostname", return_value=[_PUBLIC_IP]):
        yield


class TestFetchSpec:
    """Tests for fetch_spec function."""

    @pytest.mark.usefixtures("_mock_public_dns")
    async def test_fetch_json_spec_succeeds(self, httpx_mock) -> None:
        """Fetch a JSON spec and return parsed dict."""
        from app.openapi.fetcher import fetch_spec

        httpx_mock.add_response(
            url="https://example.com/spec.json",
            text=_SAMPLE_JSON,
            headers={"content-type": "application/json"},
        )
        result = await fetch_spec("https://example.com/spec.json")
        assert isinstance(result, dict)
        assert result["openapi"] == "3.0.0"

    @pytest.mark.usefixtures("_mock_public_dns")
    async def test_fetch_yaml_spec_succeeds(self, httpx_mock) -> None:
        """Fetch a YAML spec and return parsed dict."""
        from app.openapi.fetcher import fetch_spec

        httpx_mock.add_response(
            url="https://example.com/spec.yaml",
            text=_SAMPLE_YAML,
            headers={"content-type": "application/x-yaml"},
        )
        result = await fetch_spec("https://example.com/spec.yaml")
        assert isinstance(result, dict)
        assert result["openapi"] == "3.0.0"

    @pytest.mark.usefixtures("_mock_public_dns")
    async def test_fetch_yaml_by_url_extension(self, httpx_mock) -> None:
        """Auto-detect YAML format from .yaml URL extension."""
        from app.openapi.fetcher import fetch_spec

        httpx_mock.add_response(
            url="https://example.com/api.yaml",
            text=_SAMPLE_YAML,
            headers={"content-type": "text/plain"},
        )
        result = await fetch_spec("https://example.com/api.yaml")
        assert isinstance(result, dict)
        assert result["openapi"] == "3.0.0"

    async def test_ssrf_blocked_url_raises(self) -> None:
        """SSRF-blocked URL raises SSRFError."""
        from app.openapi.fetcher import fetch_spec

        with (
            patch("app.openapi.ssrf.resolve_hostname", return_value=["10.0.0.1"]),
            pytest.raises(SSRFError),
        ):
            await fetch_spec("http://internal.corp/spec.json")

    @pytest.mark.usefixtures("_mock_public_dns")
    async def test_oversized_response_raises(self, httpx_mock) -> None:
        """Response exceeding 10MB raises ValueError."""
        from app.openapi.fetcher import fetch_spec

        big_content = "x" * (10 * 1024 * 1024 + 1)
        httpx_mock.add_response(
            url="https://example.com/huge.json",
            text=big_content,
            headers={"content-type": "application/json"},
        )
        with pytest.raises(ValueError, match="too large"):
            await fetch_spec("https://example.com/huge.json")

    @pytest.mark.usefixtures("_mock_public_dns")
    async def test_invalid_json_raises(self, httpx_mock) -> None:
        """Non-parseable JSON raises ValueError."""
        from app.openapi.fetcher import fetch_spec

        httpx_mock.add_response(
            url="https://example.com/bad.json",
            text="not valid json {{{",
            headers={"content-type": "application/json"},
        )
        with pytest.raises(ValueError, match="[Pp]arse|[Ii]nvalid|[Dd]ecode"):
            await fetch_spec("https://example.com/bad.json")

    @pytest.mark.usefixtures("_mock_public_dns")
    async def test_invalid_yaml_raises(self, httpx_mock) -> None:
        """Non-parseable YAML raises ValueError."""
        from app.openapi.fetcher import fetch_spec

        httpx_mock.add_response(
            url="https://example.com/bad.yaml",
            text=": invalid: yaml: {\n",
            headers={"content-type": "application/x-yaml"},
        )
        with pytest.raises(ValueError, match="[Pp]arse|[Ii]nvalid|[Yy]AML"):
            await fetch_spec("https://example.com/bad.yaml")