#!/usr/bin/env python3
"""Tests for Apple Silicon DFlash benchmark planning helpers (issue #152, #154)."""

import os
import sys
from unittest.mock import patch

sys.path.insert(0, os.path.dirname(os.path.dirname(__file__)))

from benchmarks.dflash_apple_silicon import (  # noqa: E402
    build_mlx_benchmark_command,
    detect_total_memory_gb,
    render_report_template,
    select_pair,
)


class TestPairSelection:
    def test_prefers_qwen35_9b_on_36gb_mac(self):
        pair = select_pair(total_memory_gb=36)
        assert pair.slug == "qwen35-9b"
        assert pair.base_model == "Qwen/Qwen3.5-9B"
        assert pair.draft_model == "z-lab/Qwen3.5-9B-DFlash"

    def test_falls_back_to_4b_when_memory_is_tight(self):
        pair = select_pair(total_memory_gb=20)
        assert pair.slug == "qwen35-4b"
        assert pair.base_model == "Qwen/Qwen3.5-4B"


class TestCommandGeneration:
    def test_builds_upstream_mlx_benchmark_command(self):
        pair = select_pair(total_memory_gb=36)
        command = build_mlx_benchmark_command(pair, dataset="gsm8k", max_samples=64)
        assert "python -m dflash.benchmark --backend mlx" in command
        assert "--model Qwen/Qwen3.5-9B" in command
        assert "--draft-model z-lab/Qwen3.5-9B-DFlash" in command
        assert "--dataset gsm8k" in command
        assert "--max-samples 64" in command

    def test_9b_pair_uses_mitigated_window_size(self):
        """Issue #154: 9B model should use window size 2048 to avoid Metal GPU timeout."""
        pair = select_pair(total_memory_gb=36)
        assert pair.draft_sliding_window_size == 2048, \
            "9B pair must use window size 2048 to avoid Metal GPU timeout (issue #154)"

    def test_4b_pair_can_use_full_window_size(self):
        """4B model can safely use the full 4096 sliding window."""
        pair = select_pair(total_memory_gb=20)
        assert pair.draft_sliding_window_size == 4096, \
            "4B pair should use full window size; no timeout risk"


class TestReportTemplate:
    def test_report_template_mentions_baseline_and_verdict(self):
        pair = select_pair(total_memory_gb=36)
        report = render_report_template(machine_label="M3 Max 36GB", pair=pair)
        assert "DFlash Apple Silicon Benchmark Report" in report
        assert "M3 Max 36GB" in report
        assert "Qwen/Qwen3.5-9B" in report
        assert "plain MLX or llama.cpp speculative decoding" in report
        assert "Worth operationalizing locally?" in report

    def test_9b_report_includes_mitigation_note(self):
        """Issue #154: report for 9B must document the window size mitigation."""
        pair = select_pair(total_memory_gb=36)
        report = render_report_template(machine_label="M3 Max 36GB", pair=pair)
        assert "Issue #154 mitigation" in report
        assert "2048" in report
        assert "Metal GPU timeout" in report
        assert "kIOGPUCommandBufferCallbackErrorTimeout" in report


class TestMemoryDetection:
    @patch("benchmarks.dflash_apple_silicon.platform.system", return_value="Darwin")
    @patch("benchmarks.dflash_apple_silicon.subprocess.check_output", return_value=b"38654705664\n")
    def test_detect_total_memory_gb_on_macos(self, _mock_sysctl, _mock_system):
        assert detect_total_memory_gb() == 36.0