# 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        {"PrivatePort": 5432, "Type": "tcp"},  # unpublished → dropped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"},
    ]


# ── enrichment helpers ────────────────────────────────────────────────────────

def test_docker_grouping_from_labels():
    g = a._docker_grouping({
        "com.docker.compose.project": "myproj",
        "com.docker.swarm.service.name": "web",
        "com.docker.swarm.task.id": "t123",
        "com.docker.swarm.node.id": "n456",
    })
    assert g == {"compose_project": "myproj", "service_name": "web",
                 "task_id": "t123", "node_id": "n456"}


def test_docker_grouping_empty():
    assert a._docker_grouping(None) == {
        "compose_project": None, "service_name": None, "task_id": None, "node_id": None}


def test_docker_inspect_fields():
    insp = {"RestartCount": 3,
            "State": {"Health": {"Status": "unhealthy"}, "ExitCode": 137, "OOMKilled": True}}
    assert a._docker_inspect_fields(insp) == ("unhealthy", 3, 137, True)


def test_docker_inspect_fields_no_healthcheck():
    # Containers without a HEALTHCHECK have no State.Health → health is None.
    health, restarts, exit_code, oom = a._docker_inspect_fields(
        {"RestartCount": 0, "State": {"ExitCode": 0, "OOMKilled": False}})
    assert health is None and restarts == 0 and exit_code == 0 and oom is False


def test_docker_net_io_sums_counters():
    stats = {
        "networks": {"eth0": {"rx_bytes": 1000, "tx_bytes": 2000},
                     "eth1": {"rx_bytes": 5, "tx_bytes": 7}},
        "blkio_stats": {"io_service_bytes_recursive": [
            {"op": "Read", "value": 4096}, {"op": "Write", "value": 8192}]},
    }
    assert a._docker_net_io(stats) == (1005, 2007, 4096, 8192)


# ── 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"}],
        "Labels": {"com.docker.compose.project": "myproj",
                   "com.docker.swarm.service.name": "web"},
    }
    inspect = {"RestartCount": 2,
               "State": {"Health": {"Status": "healthy"}, "ExitCode": 0, "OOMKilled": False}}
    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}},
        "networks": {"eth0": {"rx_bytes": 1000, "tx_bytes": 2000}},
        "blkio_stats": {"io_service_bytes_recursive": [
            {"op": "Read", "value": 4096}, {"op": "Write", "value": 8192}]},
    }

    def fake_request(socket_path, path, timeout=a.DOCKER_API_TIMEOUT):
        if path.startswith("/containers/json"):
            return [container]
        if "/stats" in path:
            return stats
        if path.endswith("/json"):     # inspect
            return inspect
        raise AssertionError(f"unexpected path {path}")

    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
    # enrichment
    assert c["health"] == "healthy" and c["restart_count"] == 2
    assert c["exit_code"] == 0 and c["oom_killed"] is False
    assert c["net_rx_bytes"] == 1000 and c["net_tx_bytes"] == 2000
    assert c["blk_read_bytes"] == 4096 and c["blk_write_bytes"] == 8192
    assert c["compose_project"] == "myproj" and c["service_name"] == "web"


def test_collect_docker_skips_stats_for_stopped(monkeypatch):
    container = {"Id": "x" * 16, "Names": ["/db"], "Image": "pg", "State": "exited",
                 "Created": None, "Ports": [], "Labels": {}}
    inspect = {"RestartCount": 0,
               "State": {"ExitCode": 137, "OOMKilled": True}}  # no Health block

    def fake_request(socket_path, path, timeout=a.DOCKER_API_TIMEOUT):
        if path.startswith("/containers/json"):
            return [container]
        if path.endswith("/json"):     # inspect — fetched for stopped too (exit code)
            return inspect
        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
    # inspect still gives us why it died
    assert out[0]["exit_code"] == 137 and out[0]["oom_killed"] is True
    assert out[0]["health"] 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"