# tests/plugins/host_agent/test_agent_collectors.py
"""Unit tests for per-resource collectors, driven by fixture /proc files."""
from unittest.mock import patch
import pytest
from plugins.host_agent import agent as a


PROC_STAT_SAMPLE_1 = "cpu  100 0 50 850 0 0 0 0 0 0\n"
PROC_STAT_SAMPLE_2 = "cpu  200 0 100 1700 0 0 0 0 0 0\n"

PROC_MEMINFO = (
    "MemTotal:       16000000 kB\n"
    "MemFree:         2000000 kB\n"
    "MemAvailable:    6000000 kB\n"
    "SwapTotal:       4000000 kB\n"
    "SwapFree:        3500000 kB\n"
)

PROC_LOADAVG = "0.42 0.55 0.61 1/234 5678\n"
PROC_UPTIME = "482934.12 1000000.00\n"
OS_RELEASE = 'PRETTY_NAME="Ubuntu 24.04 LTS"\nNAME="Ubuntu"\n'


def test_collect_memory_uses_available(tmp_path):
    p = tmp_path / "meminfo"
    p.write_text(PROC_MEMINFO)
    with patch.object(a, "MEMINFO_PATH", str(p)):
        mem = a.collect_memory()
    assert mem["total_bytes"] == 16000000 * 1024
    assert mem["available_bytes"] == 6000000 * 1024
    assert mem["used_bytes"] == (16000000 - 6000000) * 1024
    assert mem["swap_used_bytes"] == (4000000 - 3500000) * 1024


def test_collect_load(tmp_path):
    p = tmp_path / "loadavg"
    p.write_text(PROC_LOADAVG)
    with patch.object(a, "LOADAVG_PATH", str(p)):
        load = a.collect_load()
    assert load == {"1m": 0.42, "5m": 0.55, "15m": 0.61}


def test_collect_uptime(tmp_path):
    p = tmp_path / "uptime"
    p.write_text(PROC_UPTIME)
    with patch.object(a, "UPTIME_PATH", str(p)):
        assert a.collect_uptime() == 482934


def test_collect_cpu_reads_twice():
    # Two sequential _read_file calls return two stat snapshots.
    reads = iter([PROC_STAT_SAMPLE_1, PROC_STAT_SAMPLE_2])

    def _read(_path):
        return next(reads)

    with patch.object(a, "_read_file", _read), \
         patch.object(a.time, "sleep", lambda _s: None):
        pct, cores = a.collect_cpu(sample_window=0.0)
    # totals: 1000 → 2000 (delta 1000). idle+iowait: 850 → 1700 (delta 850).
    # busy = 150. pct = 15.0. No cpuN lines in the fixture → no per-core values.
    assert pct == pytest.approx(15.0, abs=0.1)
    assert cores == []


def test_collect_storage():
    fake = {"/": (1000, 400, 600), "/mnt/data": (2000, 500, 1500)}

    def _fake_usage(path):
        total, used, free = fake[path]

        class R:
            pass

        r = R()
        r.total = total
        r.used = used
        r.free = free
        return r

    # Inodes (#5745): "/" has 100 with 1 free; /mnt/data (btrfs-like) reports none.
    inodes = {"/": (100, 1), "/mnt/data": (0, 0)}

    def _fake_statvfs(path):
        files, ffree = inodes[path]
        return type("S", (), {"f_files": files, "f_ffree": ffree})()

    with patch.object(a.shutil, "disk_usage", side_effect=_fake_usage), \
            patch.object(a.os, "statvfs", side_effect=_fake_statvfs):
        out = a.collect_storage(["/", "/mnt/data"])
    assert out == [
        {"mount": "/",         "total_bytes": 1000, "used_bytes": 400,
         "inodes_total": 100, "inodes_used": 99},
        {"mount": "/mnt/data", "total_bytes": 2000, "used_bytes": 500},
    ]


def test_collect_metadata(tmp_path):
    p = tmp_path / "os-release"
    p.write_text(OS_RELEASE)

    class Uname:
        release = "6.8.0-45-generic"
        machine = "x86_64"

    with patch.object(a, "OS_RELEASE_PATH", str(p)), \
         patch.object(a.os, "uname", return_value=Uname()):
        meta = a.collect_metadata()
    assert meta["kernel"] == "6.8.0-45-generic"
    assert meta["arch"] == "x86_64"
    assert "Ubuntu 24.04" in meta["distro"]


def test_a_mount_that_does_not_answer_is_reported_stalled_and_not_probed_again():
    """#5760: statvfs on a stalled NFS share blocks with no timeout, and read
    inline that froze the whole agent. The sample goes on without it, and a
    probe still blocked isn't stacked on by the next sample."""
    import threading
    release = threading.Event()
    calls: list[str] = []

    def _usage(path):
        calls.append(path)
        if path == "/nfs/media":
            release.wait(5)
        return type("R", (), {"total": 1000, "used": 400, "free": 600})()

    a._stuck_mounts.clear()
    try:
        with patch.object(a.shutil, "disk_usage", side_effect=_usage), \
                patch.object(a.os, "statvfs", side_effect=OSError):
            first = a.collect_storage(["/", "/nfs/media"], deadline=0.2)
            second = a.collect_storage(["/", "/nfs/media"], deadline=0.2)
        assert first == second == [
            {"mount": "/", "total_bytes": 1000, "used_bytes": 400},
            {"mount": "/nfs/media", "stalled": True},
        ]
        assert calls.count("/nfs/media") == 1
    finally:
        release.set()
        a._stuck_mounts.clear()


def test_a_mount_that_errors_is_left_out_not_the_whole_list():
    def _usage(path):
        if path == "/nfs/gone":
            raise OSError(116, "Stale file handle")
        return type("R", (), {"total": 10, "used": 1, "free": 9})()

    with patch.object(a.shutil, "disk_usage", side_effect=_usage), \
            patch.object(a.os, "statvfs", side_effect=OSError):
        out = a.collect_storage(["/", "/nfs/gone"])
    assert out == [{"mount": "/", "total_bytes": 10, "used_bytes": 1}]