package cluster

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"sort"
	"strings"
	"time"
)

type imagePullCredentialDeploymentList struct {
	Items []struct {
		Metadata struct {
			Name   string            `json:"name"`
			Labels map[string]string `json:"labels"`
		} `json:"metadata"`
	} `json:"items"`
}

// imagePullCredentialBlockerReasons classifies image pull failures caused by
// registry auth or missing imagePullSecret material.
// Signature: (o *Orchestrator) imagePullCredentialBlockerReasons(ctx context.Context) (map[string]string, error).
// Why: deleting a pod with bad registry credentials does not refresh Vault/CSI
// secret material; the secret sync path needs a direct repair signal.
func (o *Orchestrator) imagePullCredentialBlockerReasons(ctx context.Context) (map[string]string, error) {
	eventsOut, err := o.kubectl(ctx, 30*time.Second, "get", "events", "-A", "-o", "json")
	if err != nil {
		return nil, fmt.Errorf("query events for image-pull credential scan: %w", err)
	}
	reasons := map[string]string{}
	if strings.TrimSpace(eventsOut) == "" {
		return reasons, nil
	}
	var events eventList
	if err := json.Unmarshal([]byte(eventsOut), &events); err != nil {
		return nil, fmt.Errorf("decode events for image-pull credential scan: %w", err)
	}
	for _, event := range events.Items {
		if !strings.EqualFold(strings.TrimSpace(event.Type), "Warning") {
			continue
		}
		if !strings.EqualFold(strings.TrimSpace(event.InvolvedObject.Kind), "Pod") {
			continue
		}
		reason := strings.TrimSpace(event.Reason)
		message := strings.TrimSpace(event.Message)
		if !imagePullCredentialEvent(reason, message) {
			continue
		}
		namespace := strings.TrimSpace(event.InvolvedObject.Namespace)
		if namespace == "" {
			namespace = strings.TrimSpace(event.Metadata.Namespace)
		}
		name := strings.TrimSpace(event.InvolvedObject.Name)
		if namespace == "" || name == "" {
			continue
		}
		reasons[namespace+"/"+name] = "ImagePullCredentialBlocker:" + imagePullCredentialFailureClass(reason, message)
	}
	return reasons, nil
}

// healImagePullCredentialSync restarts namespace-local Vault sync deployments
// when pods are blocked on registry credentials.
// Signature: (o *Orchestrator) healImagePullCredentialSync(ctx context.Context) ([]string, error).
// Why: Secrets Store CSI secretObjects are materialized by mounted workloads; a
// restarted vault-sync deployment is the bounded repair that refreshes pull
// secrets such as harbor-regcred without mutating application deployments.
func (o *Orchestrator) healImagePullCredentialSync(ctx context.Context) ([]string, error) {
	if o.runner.DryRun {
		return nil, nil
	}
	blockers, err := o.imagePullCredentialBlockerReasons(ctx)
	if err != nil {
		return nil, err
	}
	if len(blockers) == 0 {
		return nil, nil
	}

	namespaces := map[string]struct{}{}
	for key := range blockers {
		namespace, _, ok := strings.Cut(key, "/")
		if ok && strings.TrimSpace(namespace) != "" {
			namespaces[namespace] = struct{}{}
		}
	}
	orderedNamespaces := make([]string, 0, len(namespaces))
	for namespace := range namespaces {
		orderedNamespaces = append(orderedNamespaces, namespace)
	}
	sort.Strings(orderedNamespaces)

	repaired := []string{}
	errs := []string{}
	for _, namespace := range orderedNamespaces {
		namespaceRepairs, restartErr := o.restartVaultSyncDeployments(ctx, namespace)
		repaired = append(repaired, namespaceRepairs...)
		if restartErr != nil {
			errs = append(errs, restartErr.Error())
		}
	}
	sort.Strings(repaired)
	if len(errs) > 0 {
		return repaired, errors.New(strings.Join(errs, "; "))
	}
	return repaired, nil
}

// restartVaultSyncDeployments runs one orchestration or CLI step.
// Signature: (o *Orchestrator) restartVaultSyncDeployments(ctx context.Context, namespace string) ([]string, error).
// Why: namespaces using Vault/CSI secret material have tiny sync deployments
// named or labeled vault-sync; restarting those nudges secretObject rotation.
func (o *Orchestrator) restartVaultSyncDeployments(ctx context.Context, namespace string) ([]string, error) {
	out, err := o.kubectl(ctx, 20*time.Second, "-n", namespace, "get", "deployment", "-o", "json")
	if err != nil {
		return nil, fmt.Errorf("query deployments in %s for image-pull credential repair: %w", namespace, err)
	}
	var deployments imagePullCredentialDeploymentList
	if err := json.Unmarshal([]byte(out), &deployments); err != nil {
		return nil, fmt.Errorf("decode deployments in %s for image-pull credential repair: %w", namespace, err)
	}

	repaired := []string{}
	for _, deployment := range deployments.Items {
		name := strings.TrimSpace(deployment.Metadata.Name)
		if name == "" || !vaultSyncDeployment(name, deployment.Metadata.Labels) {
			continue
		}
		if _, err := o.kubectl(ctx, 25*time.Second, "-n", namespace, "rollout", "restart", "deployment", name); err != nil {
			return repaired, fmt.Errorf("restart %s/deployment/%s for image-pull credential repair: %w", namespace, name, err)
		}
		if _, err := o.kubectl(ctx, 75*time.Second, "-n", namespace, "rollout", "status", "deployment/"+name, "--timeout=60s"); err != nil {
			return repaired, fmt.Errorf("wait for %s/deployment/%s after image-pull credential repair: %w", namespace, name, err)
		}
		repaired = append(repaired, namespace+"/deployment/"+name)
	}
	if len(repaired) == 0 {
		return nil, fmt.Errorf("image-pull credential blocker in namespace %s but no vault-sync deployment was found", namespace)
	}
	return repaired, nil
}

// imagePullCredentialEvent runs one orchestration or CLI step.
// Signature: imagePullCredentialEvent(reason string, message string) bool.
// Why: image-pull auth detection must include kubelet pull-secret events while
// staying separate from DNS and ordinary transient pull backoff.
func imagePullCredentialEvent(reason string, message string) bool {
	normalizedReason := strings.ToLower(strings.TrimSpace(reason))
	if normalizedReason == "failedtoretrieveimagepullsecret" {
		return true
	}
	if normalizedReason != "failed" &&
		normalizedReason != "failedpull" &&
		normalizedReason != "errimagepull" &&
		normalizedReason != "imagepullbackoff" {
		return false
	}
	return imagePullMessageHasCredentialFailure(message)
}

// imagePullMessageHasCredentialFailure runs one orchestration or CLI step.
// Signature: imagePullMessageHasCredentialFailure(message string) bool.
// Why: credential blockers need a tight predicate so missing images and registry
// DNS outages keep their own repair paths.
func imagePullMessageHasCredentialFailure(message string) bool {
	lower := strings.ToLower(strings.TrimSpace(message))
	if lower == "" || imagePullMessageHasDNSFailure(message) {
		return false
	}
	return strings.Contains(lower, "failed to retrieve image pull secret") ||
		strings.Contains(lower, "failedtoretrieveimagepullsecret") ||
		strings.Contains(lower, "unable to retrieve some image pull secrets") ||
		(strings.Contains(lower, "image pull secret") && strings.Contains(lower, "not found")) ||
		(strings.Contains(lower, "pull secret") && strings.Contains(lower, "not found")) ||
		(strings.Contains(lower, "secret ") && strings.Contains(lower, " not found") && strings.Contains(lower, "pull")) ||
		strings.Contains(lower, "no basic auth credentials") ||
		strings.Contains(lower, "unauthorized") ||
		strings.Contains(lower, "authentication required") ||
		strings.Contains(lower, "authorization failed") ||
		strings.Contains(lower, "failed to authorize") ||
		strings.Contains(lower, "invalid username/password") ||
		strings.Contains(lower, "401 unauthorized") ||
		strings.Contains(lower, "403 forbidden") ||
		strings.Contains(lower, "pull access denied") ||
		strings.Contains(lower, "requested access to the resource is denied") ||
		strings.Contains(lower, "failed to fetch anonymous token")
}

// imagePullCredentialFailureClass runs one orchestration or CLI step.
// Signature: imagePullCredentialFailureClass(reason string, message string) string.
// Why: compact blocker classes keep logs and status useful without copying long
// kubelet event messages.
func imagePullCredentialFailureClass(reason string, message string) string {
	lowerReason := strings.ToLower(strings.TrimSpace(reason))
	lower := strings.ToLower(strings.TrimSpace(message))
	switch {
	case lowerReason == "failedtoretrieveimagepullsecret",
		strings.Contains(lower, "failed to retrieve image pull secret"),
		strings.Contains(lower, "unable to retrieve some image pull secrets"),
		strings.Contains(lower, "image pull secret") && strings.Contains(lower, "not found"),
		strings.Contains(lower, "pull secret") && strings.Contains(lower, "not found"),
		strings.Contains(lower, "secret ") && strings.Contains(lower, " not found") && strings.Contains(lower, "pull"):
		return "missing-pull-secret"
	case strings.Contains(lower, "no basic auth credentials"):
		return "no-basic-auth"
	case strings.Contains(lower, "invalid username/password"):
		return "invalid-credentials"
	case strings.Contains(lower, "unauthorized") || strings.Contains(lower, "authentication required"):
		return "unauthorized"
	case strings.Contains(lower, "forbidden") || strings.Contains(lower, "authorization failed") || strings.Contains(lower, "failed to authorize") || strings.Contains(lower, "failed to fetch anonymous token"):
		return "authorization-failed"
	case strings.Contains(lower, "pull access denied") || strings.Contains(lower, "requested access to the resource is denied"):
		return "pull-access-denied"
	default:
		return "registry-credential-error"
	}
}

// vaultSyncDeployment runs one orchestration or CLI step.
// Signature: vaultSyncDeployment(name string, labels map[string]string) bool.
// Why: different apps may prefix their sync deployment names, but they consistently
// identify the narrow Vault sync helper with a vault-sync name or label.
func vaultSyncDeployment(name string, labels map[string]string) bool {
	if strings.Contains(strings.ToLower(strings.TrimSpace(name)), "vault-sync") {
		return true
	}
	for key, value := range labels {
		if strings.Contains(strings.ToLower(strings.TrimSpace(key)), "vault-sync") ||
			strings.Contains(strings.ToLower(strings.TrimSpace(value)), "vault-sync") {
			return true
		}
	}
	return false
}