package k8s

import (
	"fmt"

	corev1 "k8s.io/api/core/v1"

	"tower/internal/model"
)

// IssuesFromNodes applies the PLAN.md node rules.
//
// Pure rule function: does not talk to the API server.
func IssuesFromNodes(nodes []*corev1.Node) []model.Issue {
	out := make([]model.Issue, 0, 8)
	for _, n := range nodes {
		if n == nil {
			continue
		}

		// Ready / NotReady
		if cond := findNodeCondition(n, corev1.NodeReady); cond != nil {
			if cond.Status != corev1.ConditionTrue {
				out = append(out, model.Issue{
					ID:       fmt.Sprintf("k8s:node:%s:NotReady", n.Name),
					Category: model.CategoryKubernetes,
					Priority: model.PriorityP0,
					Title:    fmt.Sprintf("Node NotReady: %s", n.Name),
					Details:  cond.Message,
					Evidence: map[string]string{
						"kind":      "Node",
						"reason":    "NotReady",
						"namespace": "",
						"node":      n.Name,
						"status":    string(cond.Status),
					},
					SuggestedFix: "kubectl describe node " + n.Name,
				})
			}
		}

		// Pressure conditions.
		for _, ctype := range []corev1.NodeConditionType{corev1.NodeMemoryPressure, corev1.NodeDiskPressure, corev1.NodePIDPressure} {
			if cond := findNodeCondition(n, ctype); cond != nil {
				if cond.Status == corev1.ConditionTrue {
					out = append(out, model.Issue{
						ID:       fmt.Sprintf("k8s:node:%s:%s", n.Name, string(ctype)),
						Category: model.CategoryKubernetes,
						Priority: model.PriorityP1,
						Title:    fmt.Sprintf("Node %s: %s", ctype, n.Name),
						Details:  cond.Message,
						Evidence: map[string]string{
							"kind":      "Node",
							"reason":    string(ctype),
							"namespace": "",
							"node":      n.Name,
							"status":    string(cond.Status),
						},
						SuggestedFix: "kubectl describe node " + n.Name,
					})
				}
			}
		}
	}
	return out
}

func findNodeCondition(n *corev1.Node, t corev1.NodeConditionType) *corev1.NodeCondition {
	if n == nil {
		return nil
	}
	for i := range n.Status.Conditions {
		c := &n.Status.Conditions[i]
		if c.Type == t {
			return c
		}
	}
	return nil
}