import os
from kubernetes import client, config
from kubernetes.client.exceptions import ApiException
from mcp.server.fastmcp import FastMCP

mcp = FastMCP("k8s-cluster", host="0.0.0.0", port=8012)


def _load_kube() -> None:
    kubeconfig = os.getenv("KUBECONFIG")
    try:
        if kubeconfig and os.path.exists(kubeconfig):
            config.load_kube_config(config_file=kubeconfig)
        else:
            config.load_incluster_config()
    except Exception as exc:
        raise RuntimeError(f"Failed to load Kubernetes config: {exc}")


@mcp.tool()
def list_namespaces() -> list[str]:
    """List all Kubernetes namespaces visible to this server."""
    _load_kube()
    api = client.CoreV1Api()
    return [item.metadata.name for item in api.list_namespace().items]


@mcp.tool()
def list_pods(namespace: str | None = None, limit: int = 100) -> list[dict]:
    """List pods in a namespace with status and node placement."""
    _load_kube()
    api = client.CoreV1Api()
    ns = namespace or os.getenv("K8S_DEFAULT_NAMESPACE", "default")

    pods = api.list_namespaced_pod(ns, limit=limit).items
    return [
        {
            "name": pod.metadata.name,
            "phase": pod.status.phase,
            "node": pod.spec.node_name,
            "created": pod.metadata.creation_timestamp.isoformat() if pod.metadata.creation_timestamp else None,
        }
        for pod in pods
    ]


@mcp.tool()
def get_pod_logs(namespace: str, pod_name: str, tail_lines: int = 200) -> str:
    """Get recent logs from a specific pod."""
    _load_kube()
    api = client.CoreV1Api()
    return api.read_namespaced_pod_log(name=pod_name, namespace=namespace, tail_lines=tail_lines)


@mcp.tool()
def list_deployments(namespace: str | None = None) -> list[dict]:
    """List deployments in the namespace with availability details."""
    _load_kube()
    api = client.AppsV1Api()
    ns = namespace or os.getenv("K8S_DEFAULT_NAMESPACE", "default")

    try:
        deps = api.list_namespaced_deployment(ns).items
    except ApiException as exc:
        raise RuntimeError(f"Kubernetes API error: {exc}")

    return [
        {
            "name": dep.metadata.name,
            "ready_replicas": dep.status.ready_replicas or 0,
            "replicas": dep.status.replicas or 0,
        }
        for dep in deps
    ]


if __name__ == "__main__":
    mcp.run(transport="sse")