package k8s

import (
	"fmt"
	"strings"
	"time"

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

	"tower/internal/model"
)

var warningEventReasons = map[string]struct{}{
	"FailedScheduling": {},
	"FailedMount":      {},
	"BackOff":          {},
	"Unhealthy":        {},
	"OOMKilling":       {},
	"FailedPull":       {},
	"Forbidden":        {},
	"ErrImagePull":     {},
	"ImagePullBackOff": {},
}

// IssuesFromEvents applies the PLAN.md Event rules.
//
// Dedup by (object UID, reason). For v1 Events, this is approximated by
// (involvedObject.uid, reason).
func IssuesFromEvents(events []*corev1.Event, now time.Time) []model.Issue {
	_ = now
	out := make([]model.Issue, 0, 16)
	seen := map[string]struct{}{}

	for _, e := range events {
		if e == nil {
			continue
		}
		if strings.ToLower(e.Type) != strings.ToLower(string(corev1.EventTypeWarning)) {
			continue
		}
		if _, ok := warningEventReasons[e.Reason]; !ok {
			continue
		}

		uid := string(e.InvolvedObject.UID)
		k := uid + ":" + e.Reason
		if _, ok := seen[k]; ok {
			continue
		}
		seen[k] = struct{}{}

		ns := e.InvolvedObject.Namespace
		if ns == "" {
			ns = e.Namespace
		}

		objKey := e.InvolvedObject.Kind + "/" + e.InvolvedObject.Name
		title := fmt.Sprintf("K8s Event %s: %s (%s)", e.Reason, objKey, ns)
		if ns == "" {
			title = fmt.Sprintf("K8s Event %s: %s", e.Reason, objKey)
		}

		details := strings.TrimSpace(e.Message)
		if details == "" {
			details = "Warning event emitted by Kubernetes."
		}

		out = append(out, model.Issue{
			ID:       fmt.Sprintf("k8s:event:%s:%s", uid, e.Reason),
			Category: model.CategoryKubernetes,
			Priority: model.PriorityP2,
			Title:    title,
			Details:  details,
			Evidence: map[string]string{
				"kind":      e.InvolvedObject.Kind,
				"reason":    e.Reason,
				"namespace": ns,
				"name":      e.InvolvedObject.Name,
				"uid":       uid,
			},
			SuggestedFix: suggestedFixForEvent(ns, e.InvolvedObject.Kind, e.InvolvedObject.Name),
		})
	}

	return out
}

func suggestedFixForEvent(ns, kind, name string) string {
	kindLower := strings.ToLower(kind)
	if ns != "" {
		switch kindLower {
		case "pod":
			return fmt.Sprintf("kubectl -n %s describe pod %s", ns, name)
		case "node":
			return fmt.Sprintf("kubectl describe node %s", name)
		default:
			return fmt.Sprintf("kubectl -n %s describe %s %s", ns, kindLower, name)
		}
	}
	return fmt.Sprintf("kubectl describe %s %s", kindLower, name)
}