"""Unit tests for vram_manager.py — VRAMManager flush/poll/prewarm logic."""

import asyncio
import pytest
from unittest.mock import AsyncMock, MagicMock, patch

from vram_manager import VRAMManager


BASE_URL = "http://localhost:11434"


def _make_manager() -> VRAMManager:
    return VRAMManager(base_url=BASE_URL)


def _mock_client(get_response=None, post_response=None):
    """Return a context-manager mock for httpx.AsyncClient."""
    client = AsyncMock()
    client.__aenter__ = AsyncMock(return_value=client)
    client.__aexit__ = AsyncMock(return_value=False)
    if get_response is not None:
        client.get = AsyncMock(return_value=get_response)
    if post_response is not None:
        client.post = AsyncMock(return_value=post_response)
    return client


# ── _flush ─────────────────────────────────────────────────────────────────────

class TestFlush:
    async def test_sends_keep_alive_zero(self):
        client = _mock_client(post_response=MagicMock())
        with patch("vram_manager.httpx.AsyncClient", return_value=client):
            mgr = _make_manager()
            await mgr._flush("qwen3:4b")
        client.post.assert_awaited_once()
        _, kwargs = client.post.await_args
        body = kwargs.get("json") or client.post.call_args[1].get("json") or client.post.call_args[0][1]
        assert body["model"] == "qwen3:4b"
        assert body["keep_alive"] == 0

    async def test_posts_to_correct_endpoint(self):
        client = _mock_client(post_response=MagicMock())
        with patch("vram_manager.httpx.AsyncClient", return_value=client):
            mgr = _make_manager()
            await mgr._flush("qwen3:8b")
        url = client.post.call_args[0][0]
        assert url == f"{BASE_URL}/api/generate"

    async def test_ignores_exceptions_silently(self):
        client = AsyncMock()
        client.__aenter__ = AsyncMock(return_value=client)
        client.__aexit__ = AsyncMock(return_value=False)
        client.post = AsyncMock(side_effect=Exception("connection refused"))
        with patch("vram_manager.httpx.AsyncClient", return_value=client):
            mgr = _make_manager()
            # Should not raise
            await mgr._flush("qwen3:4b")


# ── _prewarm ───────────────────────────────────────────────────────────────────

class TestPrewarm:
    async def test_sends_keep_alive_300(self):
        client = _mock_client(post_response=MagicMock())
        with patch("vram_manager.httpx.AsyncClient", return_value=client):
            mgr = _make_manager()
            await mgr._prewarm("qwen3:4b")
        _, kwargs = client.post.await_args
        body = kwargs.get("json") or client.post.call_args[1].get("json") or client.post.call_args[0][1]
        assert body["keep_alive"] == 300
        assert body["model"] == "qwen3:4b"

    async def test_ignores_exceptions_silently(self):
        client = AsyncMock()
        client.__aenter__ = AsyncMock(return_value=client)
        client.__aexit__ = AsyncMock(return_value=False)
        client.post = AsyncMock(side_effect=Exception("timeout"))
        with patch("vram_manager.httpx.AsyncClient", return_value=client):
            mgr = _make_manager()
            await mgr._prewarm("qwen3:4b")


# ── _poll_evicted ──────────────────────────────────────────────────────────────

class TestPollEvicted:
    async def test_returns_true_when_models_absent(self):
        resp = MagicMock()
        resp.json.return_value = {"models": [{"name": "some_other_model"}]}
        client = _mock_client(get_response=resp)
        with patch("vram_manager.httpx.AsyncClient", return_value=client):
            mgr = _make_manager()
            result = await mgr._poll_evicted(["qwen3:4b", "qwen2.5:1.5b"], timeout=5)
        assert result is True

    async def test_returns_false_on_timeout_when_model_still_loaded(self):
        resp = MagicMock()
        resp.json.return_value = {"models": [{"name": "qwen3:4b"}]}
        client = _mock_client(get_response=resp)
        with patch("vram_manager.httpx.AsyncClient", return_value=client):
            mgr = _make_manager()
            result = await mgr._poll_evicted(["qwen3:4b"], timeout=0.1)
        assert result is False

    async def test_returns_true_immediately_if_already_empty(self):
        resp = MagicMock()
        resp.json.return_value = {"models": []}
        client = _mock_client(get_response=resp)
        with patch("vram_manager.httpx.AsyncClient", return_value=client):
            mgr = _make_manager()
            result = await mgr._poll_evicted(["qwen3:4b"], timeout=5)
        assert result is True

    async def test_handles_poll_error_and_continues(self):
        """If /api/ps errors, polling continues until timeout."""
        client = AsyncMock()
        client.__aenter__ = AsyncMock(return_value=client)
        client.__aexit__ = AsyncMock(return_value=False)
        client.get = AsyncMock(side_effect=Exception("network error"))
        with patch("vram_manager.httpx.AsyncClient", return_value=client):
            mgr = _make_manager()
            result = await mgr._poll_evicted(["qwen3:4b"], timeout=0.2)
        assert result is False


# ── enter_complex_mode / exit_complex_mode ─────────────────────────────────────

class TestComplexMode:
    async def test_enter_complex_mode_returns_true_on_success(self):
        mgr = _make_manager()
        mgr._flush = AsyncMock()
        mgr._poll_evicted = AsyncMock(return_value=True)
        result = await mgr.enter_complex_mode()
        assert result is True

    async def test_enter_complex_mode_flushes_medium_models(self):
        mgr = _make_manager()
        mgr._flush = AsyncMock()
        mgr._poll_evicted = AsyncMock(return_value=True)
        await mgr.enter_complex_mode()
        flushed = {call.args[0] for call in mgr._flush.call_args_list}
        assert "qwen3:4b" in flushed
        assert "qwen2.5:1.5b" in flushed

    async def test_enter_complex_mode_returns_false_on_eviction_timeout(self):
        mgr = _make_manager()
        mgr._flush = AsyncMock()
        mgr._poll_evicted = AsyncMock(return_value=False)
        result = await mgr.enter_complex_mode()
        assert result is False

    async def test_exit_complex_mode_flushes_complex_and_prewarms_medium(self):
        mgr = _make_manager()
        mgr._flush = AsyncMock()
        mgr._prewarm = AsyncMock()
        await mgr.exit_complex_mode()
        # Must flush 8b
        flushed = {call.args[0] for call in mgr._flush.call_args_list}
        assert "qwen3:8b" in flushed
        # Must prewarm medium models
        prewarmed = {call.args[0] for call in mgr._prewarm.call_args_list}
        assert "qwen3:4b" in prewarmed
        assert "qwen2.5:1.5b" in prewarmed