# tests/plugins/host_agent/test_agent_docker.py
"""Unit tests for the agent's stdlib Docker collector.

No socket / no network — the UDS request layer is monkeypatched so we exercise
the cpu/mem math, chunked-body decoding, sample assembly, and the silent-skip
contract in isolation.
"""
from plugins.host_agent import agent as a


# ── chunked transfer decoding ─────────────────────────────────────────────────

def test_dechunk_reassembles_body():
    chunked = b"4\r\nWiki\r\n5\r\npedia\r\n0\r\n\r\n"
    assert a._dechunk(chunked) == b"Wikipedia"


def test_dechunk_ignores_chunk_extensions():
    assert a._dechunk(b"3;name=v\r\nabc\r\n0\r\n\r\n") == b"abc"


# ── cpu / mem math (ported from the old central scraper) ──────────────────────

def test_docker_cpu_pct():
    stats = {
        "cpu_stats": {
            "cpu_usage": {"total_usage": 200_000_000},
            "system_cpu_usage": 2_000_000_000,
            "online_cpus": 4,
        },
        "precpu_stats": {
            "cpu_usage": {"total_usage": 100_000_000},
            "system_cpu_usage": 1_000_000_000,
        },
    }
    # cpu_delta=1e8, sys_delta=1e9 → 0.1 * 4 cpus * 100 = 40.0%
    assert a._docker_cpu_pct(stats) == 40.0


def test_docker_cpu_pct_guards_bad_stats():
    assert a._docker_cpu_pct({}) == 0.0
    # No forward progress in system time → 0, never a divide error.
    assert a._docker_cpu_pct({
        "cpu_stats": {"cpu_usage": {"total_usage": 5}, "system_cpu_usage": 10},
        "precpu_stats": {"cpu_usage": {"total_usage": 5}, "system_cpu_usage": 10},
    }) == 0.0


def test_docker_mem_subtracts_cache():
    stats = {"memory_stats": {
        "usage": 200 * 1024 * 1024,
        "limit": 1000 * 1024 * 1024,
        "stats": {"cache": 50 * 1024 * 1024},
    }}
    usage, limit, pct = a._docker_mem(stats)
    assert usage == 150 * 1024 * 1024          # working set = usage − cache
    assert limit == 1000 * 1024 * 1024
    assert pct == 15.0


def test_docker_ports_keeps_only_published():
    ports = [
        {"PublicPort": 8080, "PrivatePort": 80, "Type": "tcp"},
        {"PrivatePort": 5432, "Type": "tcp"},  # unpublished → dropped
    ]
    assert a._docker_ports(ports) == [
        {"host_port": 8080, "container_port": 80, "protocol": "tcp"},
    ]


# ── collect_docker assembly + silent skip ─────────────────────────────────────

def test_collect_docker_silent_skip_when_no_socket():
    # Absent socket path must degrade to [] (zero-config on Docker-less hosts).
    assert a.collect_docker("/nonexistent/does-not-exist.sock") == []


def test_collect_docker_assembles_container(monkeypatch):
    container = {
        "Id": "abc123def4567890",
        "Names": ["/web"],
        "Image": "nginx:latest",
        "State": "running",
        "Created": 1_700_000_000,
        "Ports": [{"PublicPort": 8080, "PrivatePort": 80, "Type": "tcp"}],
    }
    stats = {
        "cpu_stats": {"cpu_usage": {"total_usage": 200_000_000},
                      "system_cpu_usage": 2_000_000_000, "online_cpus": 4},
        "precpu_stats": {"cpu_usage": {"total_usage": 100_000_000},
                         "system_cpu_usage": 1_000_000_000},
        "memory_stats": {"usage": 200 * 1024 * 1024, "limit": 1000 * 1024 * 1024,
                         "stats": {"cache": 50 * 1024 * 1024}},
    }

    def fake_request(socket_path, path, timeout=a.DOCKER_API_TIMEOUT):
        return [container] if path.startswith("/containers/json") else stats

    monkeypatch.setattr(a, "_docker_request", fake_request)
    out = a.collect_docker("/var/run/docker.sock")
    assert len(out) == 1
    c = out[0]
    assert c["name"] == "web"
    assert c["container_id"] == "abc123def456"   # 12-char short id
    assert c["image"] == "nginx:latest"
    assert c["status"] == "running"
    assert c["cpu_pct"] == 40.0
    assert c["mem_pct"] == 15.0
    assert c["ports"] == [{"host_port": 8080, "container_port": 80, "protocol": "tcp"}]
    assert c["started_at"].startswith("2023-11-14T")  # epoch → ISO-8601


def test_collect_docker_skips_stats_for_stopped(monkeypatch):
    container = {"Id": "x" * 16, "Names": ["/db"], "Image": "pg", "State": "exited",
                 "Created": None, "Ports": []}

    def fake_request(socket_path, path, timeout=a.DOCKER_API_TIMEOUT):
        if path.startswith("/containers/json"):
            return [container]
        raise AssertionError("stats must not be fetched for a stopped container")

    monkeypatch.setattr(a, "_docker_request", fake_request)
    out = a.collect_docker("/var/run/docker.sock")
    assert out[0]["status"] == "exited"
    assert out[0]["cpu_pct"] is None and out[0]["started_at"] is None


# ── build_sample wiring ───────────────────────────────────────────────────────

def test_build_sample_includes_docker_when_present(monkeypatch):
    monkeypatch.setattr(a, "collect_docker", lambda _s: [{"name": "web", "status": "running"}])
    sample = a.build_sample(["/"], {}, "/var/run/docker.sock")
    assert sample["docker"] == [{"name": "web", "status": "running"}]


def test_build_sample_omits_docker_when_empty(monkeypatch):
    monkeypatch.setattr(a, "collect_docker", lambda _s: [])
    sample = a.build_sample(["/"], {}, "/var/run/docker.sock")
    assert "docker" not in sample


# ── config ────────────────────────────────────────────────────────────────────

def test_read_config_defaults_docker_socket(tmp_path):
    cfg_file = tmp_path / "agent.conf"
    cfg_file.write_text("url = https://steward.example\ntoken = abc\n")
    cfg = a.read_config(str(cfg_file))
    assert cfg["docker_socket"] == a.DEFAULT_DOCKER_SOCKET


def test_read_config_honours_explicit_docker_socket(tmp_path):
    cfg_file = tmp_path / "agent.conf"
    cfg_file.write_text(
        "url = https://steward.example\ntoken = abc\n"
        "docker_socket = /run/user/1000/docker.sock\n")
    cfg = a.read_config(str(cfg_file))
    assert cfg["docker_socket"] == "/run/user/1000/docker.sock"