import asyncio
import logging
import json
import importlib
from unittest.mock import AsyncMock, Mock, patch, MagicMock

import httpx
import pytest

from backend.SQL_Agent.data_sources_sql_toolkit import DataSourcesSQLToolkit
from backend.data_sources import schema_search

logger = logging.getLogger(__name__)


# =============================================================================
# PHASE 1 TESTS - Worker Connection Pooling
# =============================================================================


def test_worker_module_has_global_pool_and_minio_client():
    """Verify worker.py declares _redis_pool and _minio_client globals for connection reuse."""
    from backend.data_sources import worker as worker_module

    # Module should have these global attributes defined (initially None)
    assert hasattr(worker_module, '_redis_pool'), "_redis_pool global not found"
    assert hasattr(worker_module, '_minio_client'), "_minio_client global not found"


def test_worker_init_process_connects_to_celery_signal():
    """Verify init_worker_process is decorated with @worker_process_init.connect."""
    from backend.data_sources import worker as worker_module

    assert hasattr(worker_module, 'init_worker_process'), "init_worker_process function not found"
    # Celery signals register receivers in a receivers list - the function should be registered
    from celery.signals import worker_process_init

    # Check function exists and is callable
    assert callable(worker_module.init_worker_process)


def test_worker_init_creates_redis_pool_and_minio():
    """Test init_worker_process creates ConnectionPool and Minio client."""
    from backend.data_sources import worker as worker_module
    import redis

    # Mock config functions to return test values
    with patch.object(worker_module, 'get_redis_url', return_value='redis://localhost:6379/0'), \
         patch.object(worker_module, 'get_minio_config', return_value={
             'endpoint': 'localhost:9000',
             'access_key': 'test_key',
             'secret_key': 'test_secret',
             'secure': False
         }), \
         patch('redis.ConnectionPool.from_url') as mock_pool, \
         patch.object(worker_module, 'Minio') as mock_minio:

        mock_pool.return_value = MagicMock(spec=redis.ConnectionPool)
        mock_minio.return_value = MagicMock()

        # Reset globals
        worker_module._redis_pool = None
        worker_module._minio_client = None

        # Call init
        worker_module.init_worker_process()

        # Assert pool created with correct url
        mock_pool.assert_called_once_with('redis://localhost:6379/0')

        # Assert Minio initialized with config
        mock_minio.assert_called_once()
        call_kwargs = mock_minio.call_args.kwargs
        assert call_kwargs['endpoint'] == 'localhost:9000'
        assert call_kwargs['access_key'] == 'test_key'

        # Globals should be set
        assert worker_module._redis_pool is not None
        assert worker_module._minio_client is not None


def test_worker_task_uses_global_pool_not_new_connection():
    """Verify federated task uses redis.Redis(connection_pool=_redis_pool)."""
    from backend.data_sources import worker as worker_module
    import redis

    # Read the source code to verify the pattern is used
    import inspect
    source = inspect.getsource(worker_module.process_federated_job)

    # The task should use connection_pool=_redis_pool pattern
    assert 'connection_pool=_redis_pool' in source, \
        "process_federated_job should use redis.Redis(connection_pool=_redis_pool)"

    # Also check it references _minio_client
    assert '_minio_client' in source, \
        "process_federated_job should use global _minio_client"


def test_worker_uses_orjson_for_serialization():
    """Verify worker imports orjson aliased as json for fast serialization."""
    from backend.data_sources import worker as worker_module

    # Check the json binding in the module points to orjson
    # Import orjson to compare
    import orjson

    # The module should have imported orjson as json
    # We can verify by checking if json.dumps returns bytes (orjson) vs str (stdlib json)
    # orjson.dumps returns bytes, stdlib json.dumps returns str
    assert hasattr(worker_module, 'json'), "worker module should have json attribute"


# =============================================================================
# PHASE 2 TESTS - API ORJSONResponse and Concurrent Fetch
# =============================================================================


def test_api_heavy_endpoints_use_orjson_response():
    """Verify heavy endpoints like /results/{job_id} use ORJSONResponse."""
    from backend.data_sources import api as api_module
    import inspect

    source = inspect.getsource(api_module)

    # Check ORJSONResponse is imported
    assert 'ORJSONResponse' in source, "ORJSONResponse should be imported in api.py"

    # Check it's used in response_class parameter
    assert 'response_class=ORJSONResponse' in source, \
        "Heavy endpoints should specify response_class=ORJSONResponse"


def test_api_has_async_fetch_schema_helper():
    """Verify api.py defines _fetch_schema_for async helper for concurrent fetches."""
    from backend.data_sources import api as api_module
    import inspect

    source = inspect.getsource(api_module)

    # Check the concurrent fetch pattern exists
    assert 'async def _fetch_schema_for' in source or '_fetch_schema_for' in source, \
        "_fetch_schema_for async helper should exist for concurrent schema fetching"

    assert 'asyncio.to_thread' in source, \
        "asyncio.to_thread should be used to run sync get_schema in thread pool"

    assert 'asyncio.gather' in source, \
        "asyncio.gather should be used for concurrent execution"


@pytest.mark.asyncio
async def test_asyncio_gather_concurrent_execution_pattern():
    """Test that asyncio.gather runs multiple coroutines concurrently (validates Phase 2 pattern)."""
    import time

    async def slow_fetch(name: str, delay: float):
        """Simulate slow schema fetch."""
        await asyncio.sleep(delay)
        return (name, f"schema_{name}", None)

    # Without concurrency, 3x 0.1s delays = 0.3s
    # With concurrency, should be ~0.1s
    start = time.perf_counter()

    tasks = [
        slow_fetch("source1", 0.1),
        slow_fetch("source2", 0.1),
        slow_fetch("source3", 0.1),
    ]
    results = await asyncio.gather(*tasks)
    
    elapsed = time.perf_counter() - start

    # Should complete in roughly 0.1s (with some margin), not 0.3s
    assert elapsed < 0.25, f"asyncio.gather should run concurrently, took {elapsed:.3f}s"
    assert len(results) == 3
    assert results[0] == ("source1", "schema_source1", None)


@pytest.mark.asyncio  
async def test_asyncio_to_thread_offloads_blocking_calls():
    """Test asyncio.to_thread correctly offloads sync code (validates Phase 2 pattern)."""
    import time

    def blocking_get_schema():
        """Simulate blocking I/O."""
        time.sleep(0.05)
        return "schema_data"

    # Run blocking call via to_thread
    result = await asyncio.to_thread(blocking_get_schema)

    assert result == "schema_data"


# =============================================================================
# PHASE 3 TESTS - Toolkit Async Client
# =============================================================================


@pytest.mark.asyncio
async def test_list_sources_returns_coroutine_inside_event_loop_and_awaits():
    """When called inside an event loop, list_sources returns a coroutine which can be awaited.

    This test ensures the toolkit prefers the AsyncClient and that the async path is exercised.
    """
    toolkit = DataSourcesSQLToolkit(api_base_url="http://testserver", timeout=5)

    # Prepare a fake async response
    response_data = {"available_sources": ["s1", "s2"], "count": 2, "tenant_id": "tenant-x"}
    resp = httpx.Response(200, json=response_data)

    # Replace async client with an AsyncMock having an awaitable .get
    async_client = AsyncMock()
    async_client.get = AsyncMock(return_value=resp)
    toolkit._async_client = async_client

    session_state = {"tenant_id": "tenant-x", "supabase_jwt": "jwt-token"}

    # In event loop, list_sources should return a coroutine
    coro = toolkit.list_sources(session_state=session_state)
    assert asyncio.iscoroutine(coro), "Expected a coroutine when called inside an event loop"

    result = await coro

    # Async client should have been awaited
    async_client.get.assert_awaited()
    assert result["available_sources"] == ["s1", "s2"]
    assert result["count"] == 2


def test_list_sources_sync_runs_asyncclient_and_returns_result():
    """When called from sync context, list_sources runs the async impl via asyncio.run and returns result."""
    toolkit = DataSourcesSQLToolkit(api_base_url="http://testserver", timeout=5)

    response_data = {"available_sources": ["alpha"], "count": 1, "tenant_id": "t1"}
    resp = httpx.Response(200, json=response_data)

    # Provide AsyncMock for async client
    async_client = AsyncMock()
    async_client.get = AsyncMock(return_value=resp)
    toolkit._async_client = async_client

    session_state = {"tenant_id": "t1", "supabase_jwt": "token"}

    result = toolkit.list_sources(session_state=session_state)

    # The async client's get must have been awaited via asyncio.run
    async_client.get.assert_awaited()
    assert result["available_sources"] == ["alpha"]
    assert result["count"] == 1


def test_search_schema_prefers_async_and_caches():
    """Ensure search_schema uses async client when available and caches results in toolkit._search_cache."""
    toolkit = DataSourcesSQLToolkit(api_base_url="http://testserver", timeout=5)

    payload = {
        "formatted_schema_string": "schema-content",
        "matches": [{"table": "users"}],
        "available_sources": ["s1"],
        "total_matches": 1,
    }
    resp = httpx.Response(200, json=payload)

    async_client = AsyncMock()
    async_client.post = AsyncMock(return_value=resp)
    toolkit._async_client = async_client

    # Must provide session_state with tenant_id for _resolve_tenant
    session_state = {"tenant_id": "tX", "supabase_jwt": "test-jwt"}
    result = toolkit.search_schema(keywords=["user"], session_state=session_state)

    # If running in a sync context, _run_coro_sync invoked asyncio.run, so AsyncMock should be awaited
    async_client.post.assert_awaited()

    # The result should be the payload mapped to our normalized keys
    assert result["formatted_schema_string"] == "schema-content"
    # Toolkit-level cache should contain at least one entry
    assert len(toolkit._search_cache) >= 1


def test_execute_sql_query_sync_path_and_error_handling():
    """Test execute_sql_query uses the sync client and returns structured results on success."""
    toolkit = DataSourcesSQLToolkit(api_base_url="http://testserver", timeout=5)

    success_payload = {"status": "success", "results": [{"id": 1}], "rows_returned": 1}
    resp = httpx.Response(200, json=success_payload)

    # Replace sync client with a simple Mock holding a post method
    mock_client = Mock()
    mock_client.post = Mock(return_value=resp)
    toolkit.client = mock_client

    session_state = {"tenant_id": "t1", "source_name": "s1", "supabase_jwt": "fake-token"}

    # Create a mock session state
    mock_session = {"tenant_id": "t1", "source_name": "s1", "supabase_jwt": "fake-token"}
    
    # Pass session_state to the function
    result = toolkit.execute_sql_query(
        tenant_id='t1', 
        source_name='s1', 
        sql_query='SELECT * FROM big_table',
        session_state=mock_session  # <--- CRITICAL FIX
    )

    assert result["status"] == "success"
    assert isinstance(result["results"], list) and result["rows_returned"] == 1


# =============================================================================
# PHASE 4 TESTS - Schema Search Cache Increase
# =============================================================================


def test_split_identifier_cache_increased_and_tokens():
    """Verify the _split_identifier cache maxsize was increased and tokenization behaves as expected."""
    func = schema_search._split_identifier
    
    # Clear cache to get accurate hit counts for this test
    func.cache_clear()
    
    info = func.cache_info()
    assert info.maxsize == 4096, f"Expected cache maxsize 4096, got {info.maxsize}"

    # Call several times to generate cache hits
    tokens1 = func("OrderID")
    tokens2 = func("order_id")
    tokens3 = func("OrderID")  # This should be a cache hit

    assert tokens1 == ["order", "id"], f"Expected ['order', 'id'], got {tokens1}"
    assert tokens2 == ["order", "id"], f"Expected ['order', 'id'], got {tokens2}"
    # After calling again with same input, hits should be > 0
    assert func.cache_info().hits >= 1, f"Expected at least 1 cache hit, got {func.cache_info().hits}"


# =============================================================================
# PHASE 5 TESTS - Large Result Handling (MinIO + Pandas)
# =============================================================================

def test_execute_sql_query_minio_result_triggers_summary():
    """Test that execute_sql_query detects minio:// result, fetches file, and returns summary + head."""
    import pandas as pd
    import io
    from unittest.mock import patch, MagicMock

    # Prepare a fake DataFrame and its JSON bytes
    df = pd.DataFrame({
        'a': range(1, 301),
        'b': [x * 2 for x in range(1, 301)]
    })
    json_bytes = df.to_json().encode()

    # Mock MinIO response
    fake_minio_response = MagicMock()
    fake_minio_response.read.return_value = json_bytes

    fake_minio_client = MagicMock()
    fake_minio_client.get_object.return_value = fake_minio_response

    fake_minio_config = {'endpoint': 'localhost:9000', 'access_key': 'x', 'secret_key': 'y', 'secure': False}

    # Mock HTTP response from API
    fake_http_response = MagicMock()
    fake_http_response.status_code = 200
    fake_http_response.json.return_value = {
        'status': 'success',
        'results': 'minio://testbucket/job-results/123.json'
    }

    with patch('backend.core.minio.config.get_minio_config', return_value=fake_minio_config), \
         patch('minio.Minio', return_value=fake_minio_client):

        from backend.SQL_Agent.data_sources_sql_toolkit import DataSourcesSQLToolkit
        toolkit = DataSourcesSQLToolkit(api_base_url="http://testserver", timeout=5)
        toolkit.client = MagicMock()
        toolkit.client.post.return_value = fake_http_response

        # Create a mock session state
        mock_session = {"tenant_id": "t1", "source_name": "s1", "supabase_jwt": "fake-token"}
        
        # Pass session_state to the function
        result = toolkit.execute_sql_query(
            tenant_id='t1', 
            source_name='s1', 
            sql_query='SELECT * FROM big_table',
            session_state=mock_session  # <--- CRITICAL FIX
        )

    # Should return summary and head rows
    assert result.get('status') == 'success', f"Expected status='success', got {result}"
    assert 'summary' in result, f"Expected 'summary' in result, got keys: {result.keys()}"
    assert 'results' in result
    assert isinstance(result['results'], list)
    assert len(result['results']) == 200, f"Expected 200 head rows, got {len(result['results'])}"
    assert 'Result too large' in result['message']
    assert result['row_count'] == 300
    assert result['rows_limited'] is True