"""Device Manager 단위 테스트 — 정밀도 결정, 능력 등급, override."""

from __future__ import annotations

import pytest

from luke_scribe.devices.manager import DeviceManager
from luke_scribe.devices.vram_probe import GpuInfo, SystemInfo
from luke_scribe.errors import DeviceUnavailable


def _sys(gpus: list[GpuInfo], ram_mb: int = 16384) -> SystemInfo:
    return SystemInfo(
        cpu_count=8, ram_total_mb=ram_mb, ram_free_mb=ram_mb // 2, disk_free_mb=50000, gpus=gpus
    )


def _gpu(name: str, cc: str, total_mb: int, free_mb: int, index: int = 0) -> GpuInfo:
    return GpuInfo(
        index=index,
        name=name,
        compute_capability=cc,
        vram_total_mb=total_mb,
        vram_free_mb=free_mb,
        driver_version="550",
        runtime_cuda=None,
    )


class TestPrecision:
    def test_cc_7_plus_12gb_free_float16(self):
        m = DeviceManager(_sys([_gpu("T4", "7.5", 15360, 14820)]))
        p = m.detect()
        assert p.selected_compute_type == "float16"
        assert p.selected_device == "cuda:0"

    def test_cc_7_plus_low_free_int8_float16(self):
        m = DeviceManager(_sys([_gpu("L4", "8.9", 24576, 8000)]))
        p = m.detect()
        assert p.selected_compute_type == "int8_float16"

    def test_pascal_1050_int8(self):
        m = DeviceManager(_sys([_gpu("GTX 1050", "6.1", 4096, 3584)]))
        p = m.detect()
        assert p.selected_compute_type == "int8"

    def test_no_gpu_cpu_int8(self):
        m = DeviceManager(_sys([]))
        p = m.detect()
        assert p.selected_device == "cpu"
        assert p.selected_compute_type == "int8"
        assert p.capability_tier == "T0"
        assert any("CPU" in w for w in p.warnings)


class TestCapabilityTier:
    def test_t3_both_models(self):
        m = DeviceManager(_sys([_gpu("A100", "9.0", 81920, 70000)]))
        p = m.detect()
        assert p.capability_tier == "T3"
        assert p.workers >= 1

    def test_t1_small_gpu(self):
        m = DeviceManager(_sys([_gpu("RTX 3060", "8.6", 12288, 10000)]))
        p = m.detect()
        assert p.capability_tier in ("T1", "T2", "T3")


class TestOverrides:
    def test_explicit_cuda_missing_fails(self):
        m = DeviceManager(_sys([]))
        with pytest.raises(DeviceUnavailable):
            m.detect(device="cuda:0")

    def test_explicit_cuda_ok(self):
        m = DeviceManager(_sys([_gpu("T4", "7.5", 15360, 14820)]))
        p = m.detect(device="cuda:0", compute_type="float16")
        assert p.selected_device == "cuda:0"
        assert p.selection_source == "explicit"
        assert p.selected_compute_type == "float16"

    def test_explicit_cpu(self):
        m = DeviceManager(_sys([_gpu("T4", "7.5", 15360, 14820)]))
        p = m.detect(device="cpu")
        assert p.selected_device == "cpu"

    def test_explicit_bad_device(self):
        m = DeviceManager(_sys([]))
        with pytest.raises(DeviceUnavailable):
            m.detect(device="tpu:0")