import importlib.util
import json
import subprocess
import sys
import types
import unittest
from pathlib import Path
from typing import cast
from unittest import mock

MODULE_PATH = Path(__file__).resolve().parents[1] / "scripts" / "obsidian-reindex-server.py"


def load_module():
    spec = importlib.util.spec_from_file_location("obsidian_reindex_server", MODULE_PATH)
    assert spec is not None and spec.loader is not None
    module = importlib.util.module_from_spec(spec)
    sys.modules[spec.name] = module
    spec.loader.exec_module(module)
    return cast(types.ModuleType, module)


class SemanticSearchRerankTests(unittest.TestCase):
    def setUp(self):
        self.server = load_module()
        self.results = [
            {"id": "a", "text": "alpha doc", "path": "a.md", "score": 0.1},
            {"id": "b", "text": "beta doc", "path": "b.md", "score": 0.2},
            {"id": "c", "text": "gamma doc", "path": "c.md", "score": 0.3},
        ]

    def _mock_search_run(self, expected_top_k=None):
        def fake_run(cmd, capture_output, text, timeout, env):
            if expected_top_k is not None:
                self.assertEqual(cmd[cmd.index("--top-k") + 1], str(expected_top_k))
            return subprocess.CompletedProcess(
                cmd,
                0,
                stdout=json.dumps({"index": "obsidian_bge_npu", "results": self.results}),
                stderr="",
            )

        return fake_run

    def test_disabled_rerank_preserves_vector_order(self):
        setattr(self.server, "RAG_RERANK_ENABLED", False)
        with mock.patch.object(self.server.subprocess, "run", self._mock_search_run(expected_top_k=2)):
            payload = self.server.run_semantic_search("npu smoke", top_k=2)
        self.assertTrue(payload["ok"])
        self.assertEqual(payload["search_k"], 2)
        self.assertEqual([item["id"] for item in payload["results"]], ["a", "b"])
        self.assertEqual(payload["rerank"]["reason"], "disabled")
        self.assertFalse(payload["rerank"]["attempted"])

    def test_enabled_rerank_reorders_matching_results(self):
        setattr(self.server, "RAG_RERANK_ENABLED", True)
        setattr(self.server, "RAG_RERANK_INITIAL_K", 3)
        setattr(self.server, "RAG_RERANK_TOP_K", 2)

        class FakeResponse:
            def __enter__(self):
                return self

            def __exit__(self, *args):
                return False

            def read(self):
                return json.dumps(
                    {
                        "ok": True,
                        "model": "synthetic-reranker",
                        "device": "NPU",
                        "npu_busy_delta_us": 123,
                        "results": [
                            {"id": "c", "score": 9.0},
                            {"id": "a", "score": 7.0},
                        ],
                    }
                ).encode()

        with mock.patch.object(self.server.subprocess, "run", self._mock_search_run(expected_top_k=3)), mock.patch.object(
            self.server.request, "urlopen", return_value=FakeResponse()
        ):
            payload = self.server.run_semantic_search("npu smoke", top_k=2)
        self.assertEqual([item["id"] for item in payload["results"]], ["c", "a"])
        self.assertTrue(payload["rerank"]["attempted"])
        self.assertTrue(payload["rerank"]["ok"])
        self.assertEqual(payload["rerank"]["npu_busy_delta_us"], 123)
        self.assertEqual(payload["results"][0]["rerank_rank"], 1)

    def test_enabled_rerank_error_falls_back_to_vector_order(self):
        setattr(self.server, "RAG_RERANK_ENABLED", True)
        setattr(self.server, "RAG_RERANK_INITIAL_K", 3)
        setattr(self.server, "RAG_RERANK_TOP_K", 2)
        with mock.patch.object(self.server.subprocess, "run", self._mock_search_run(expected_top_k=3)), mock.patch.object(
            self.server.request, "urlopen", side_effect=OSError("reranker unavailable")
        ):
            payload = self.server.run_semantic_search("npu smoke", top_k=2)
        self.assertEqual([item["id"] for item in payload["results"]], ["a", "b"])
        self.assertTrue(payload["rerank"]["attempted"])
        self.assertFalse(payload["rerank"]["ok"])
        self.assertIn("reranker unavailable", payload["rerank"]["error"])

    def test_enabled_rerank_requires_positive_npu_proof(self):
        setattr(self.server, "RAG_RERANK_ENABLED", True)
        setattr(self.server, "RAG_RERANK_INITIAL_K", 3)
        setattr(self.server, "RAG_RERANK_TOP_K", 2)
        setattr(self.server, "RAG_RERANK_REQUIRE_NPU_PROOF", True)

        class FakeResponse:
            def __enter__(self):
                return self

            def __exit__(self, *args):
                return False

            def read(self):
                return json.dumps(
                    {
                        "ok": True,
                        "device": "NPU",
                        "npu_busy_delta_us": 0,
                        "results": [{"id": "c", "score": 9.0}],
                    }
                ).encode()

        with mock.patch.object(self.server.subprocess, "run", self._mock_search_run(expected_top_k=3)), mock.patch.object(
            self.server.request, "urlopen", return_value=FakeResponse()
        ):
            payload = self.server.run_semantic_search("npu smoke", top_k=2)
        self.assertEqual([item["id"] for item in payload["results"]], ["a", "b"])
        self.assertTrue(payload["rerank"]["attempted"])
        self.assertFalse(payload["rerank"]["ok"])
        self.assertIn("positive npu_busy_delta_us", payload["rerank"]["error"])


if __name__ == "__main__":
    unittest.main()