package cluster

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

type nodeReadyList struct {
	Items []nodeReadyItem `json:"items"`
}

type nodeReadyItem struct {
	Metadata struct {
		Name        string            `json:"name"`
		Annotations map[string]string `json:"annotations"`
		Labels      map[string]string `json:"labels"`
	} `json:"metadata"`
	Spec struct {
		Unschedulable bool `json:"unschedulable"`
		Taints        []struct {
			Key       string    `json:"key"`
			TimeAdded time.Time `json:"timeAdded"`
		} `json:"taints"`
	} `json:"spec"`
	Status struct {
		Conditions []struct {
			Type   string `json:"type"`
			Status string `json:"status"`
		} `json:"conditions"`
	} `json:"status"`
}

type readyNodeCandidate struct {
	Name          string
	Unschedulable bool
}

type podDeleteList struct {
	Items []struct {
		Metadata struct {
			Namespace         string     `json:"namespace"`
			Name              string     `json:"name"`
			DeletionTimestamp *time.Time `json:"deletionTimestamp"`
		} `json:"metadata"`
		Spec struct {
			NodeName string `json:"nodeName"`
		} `json:"spec"`
	} `json:"items"`
}

// RunPostStartAutoHeal runs one orchestration or CLI step.
// Signature: (o *Orchestrator) RunPostStartAutoHeal(ctx context.Context) error.
// Why: gives the long-running daemon a narrow, testable repair entrypoint for
// post-start drift without rerunning the full startup flow.
func (o *Orchestrator) RunPostStartAutoHeal(ctx context.Context) error {
	return o.postStartAutoHeal(ctx)
}

// postStartAutoHeal runs one orchestration or CLI step.
// Signature: (o *Orchestrator) postStartAutoHeal(ctx context.Context) error.
// Why: centralizes bounded post-start repair actions so recurring outage
// patterns only trigger the specific remediation they need.
func (o *Orchestrator) postStartAutoHeal(ctx context.Context) error {
	if o.runner.DryRun {
		return nil
	}

	errs := []string{}
	requestReconcile := false

	if err := o.ensureRequiredNodeLabels(ctx); err != nil {
		errs = append(errs, fmt.Sprintf("required node labels: %v", err))
	}

	longhornRepairs, err := o.reconcileLonghornKubernetesReadiness(ctx)
	if err != nil {
		errs = append(errs, fmt.Sprintf("longhorn/kubernetes readiness drift: %v", err))
	} else if longhornRepairs > 0 {
		requestReconcile = true
		o.log.Printf("post-start auto-heal repaired %d Longhorn/Kubernetes readiness drift item(s)", longhornRepairs)
	}

	releasedCordons, err := o.enforceRecoveryCordonLeases(ctx)
	if err != nil {
		errs = append(errs, fmt.Sprintf("recovery cordon lease check: %v", err))
	} else if releasedCordons > 0 {
		requestReconcile = true
	}

	vaultRecovered, err := o.autoRecoverSealedVault(ctx)
	if err != nil {
		errs = append(errs, fmt.Sprintf("vault auto-recovery: %v", err))
	} else if vaultRecovered {
		requestReconcile = true
		if err := o.rerunVaultK8sAuthConfigJob(ctx); err != nil {
			errs = append(errs, fmt.Sprintf("vault k8s auth config rerun: %v", err))
		}
	}

	cleaned, err := o.cleanupTerminatingPodsOnUnavailableNodes(ctx)
	if err != nil {
		errs = append(errs, fmt.Sprintf("dead-node terminating pod cleanup: %v", err))
	} else if cleaned > 0 {
		requestReconcile = true
	}

	serviceRepairs, err := o.healUnreadyConfiguredServiceBackends(ctx)
	if err != nil {
		errs = append(errs, fmt.Sprintf("configured service backend repair: %v", err))
	} else if len(serviceRepairs) > 0 {
		requestReconcile = true
		sort.Strings(serviceRepairs)
		o.log.Printf("post-start auto-heal repaired configured service backend(s): %s", joinLimited(serviceRepairs, 8))
	}

	imagePullCredentialRepairs, err := o.healImagePullCredentialSync(ctx)
	if err != nil {
		errs = append(errs, fmt.Sprintf("image-pull credential sync repair: %v", err))
	} else if len(imagePullCredentialRepairs) > 0 {
		requestReconcile = true
		sort.Strings(imagePullCredentialRepairs)
		o.log.Printf("post-start auto-heal refreshed image-pull credential sync deployment(s): %s", joinLimited(imagePullCredentialRepairs, 8))
		o.noteStartupAutoHeal(fmt.Sprintf("refreshed image-pull credential sync deployment(s): %s", joinLimited(imagePullCredentialRepairs, 8)))
	}

	repairedProxies, err := o.repairBrokenKubeletProxies(ctx)
	if err != nil {
		errs = append(errs, fmt.Sprintf("kubelet proxy auto-repair: %v", err))
	} else if repairedProxies > 0 {
		o.log.Printf("post-start auto-heal repaired %d broken kubelet proxy node(s)", repairedProxies)
	}

	if requestReconcile {
		o.bestEffort("request flux reconcile after post-start auto-heal", func() error {
			return o.requestFluxReconcile(ctx)
		})
	}

	if len(errs) > 0 {
		return errors.New(strings.Join(errs, "; "))
	}
	return nil
}

// autoRecoverSealedVault runs one orchestration or CLI step.
// Signature: (o *Orchestrator) autoRecoverSealedVault(ctx context.Context) (bool, error).
// Why: lets the daemon repair a later Vault reseal without waiting for a new
// bootstrap run.
func (o *Orchestrator) autoRecoverSealedVault(ctx context.Context) (bool, error) {
	if o.runner.DryRun {
		return false, nil
	}

	phase, err := o.kubectl(ctx, 15*time.Second, "-n", "vault", "get", "pod", "vault-0", "-o", "jsonpath={.status.phase}")
	if err != nil {
		if isNotFoundErr(err) {
			return false, nil
		}
		return false, fmt.Errorf("vault pod phase check failed: %w", err)
	}
	if strings.TrimSpace(phase) != "Running" {
		return false, nil
	}

	sealed, err := o.vaultSealed(ctx)
	if err != nil {
		return false, err
	}
	if !sealed {
		return false, nil
	}

	o.log.Printf("warning: detected sealed Vault after startup; attempting post-start auto-recovery")
	if err := o.ensureVaultUnsealed(ctx); err != nil {
		return false, err
	}
	return true, nil
}

// rerunVaultK8sAuthConfigJob runs one orchestration or CLI step.
// Signature: (o *Orchestrator) rerunVaultK8sAuthConfigJob(ctx context.Context) error.
// Why: post-unseal Vault recovery needs the auth-config job retriggered so
// downstream secret consumers stop carrying stale failures from the sealed window.
func (o *Orchestrator) rerunVaultK8sAuthConfigJob(ctx context.Context) error {
	if o.runner.DryRun {
		return nil
	}
	jobName := fmt.Sprintf("vault-k8s-auth-config-autoheal-%d", time.Now().Unix())
	if _, err := o.kubectl(
		ctx,
		25*time.Second,
		"-n", "vault",
		"create", "job",
		"--from=cronjob/vault-k8s-auth-config",
		jobName,
	); err != nil {
		return fmt.Errorf("create job %s: %w", jobName, err)
	}
	o.log.Printf("triggered vault k8s auth config job %s after vault recovery", jobName)
	return nil
}

// repairBrokenKubeletProxies runs one orchestration or CLI step.
// Signature: (o *Orchestrator) repairBrokenKubeletProxies(ctx context.Context) (int, error).
// Why: a Ready node can still have a dead kubelet tunnel, which breaks Jenkins
// exec/websocket agents until the k3s agent is restarted on that exact node.
func (o *Orchestrator) repairBrokenKubeletProxies(ctx context.Context) (int, error) {
	if o.runner.DryRun {
		return 0, nil
	}

	nodes, err := o.readyNodeCandidates(ctx)
	if err != nil {
		return 0, err
	}

	repaired := 0
	errs := []string{}
	for _, node := range nodes {
		healthy, checkErr := o.kubeletProxyHealthy(ctx, node.Name)
		if healthy {
			continue
		}
		if checkErr != nil && !isRepairableKubeletProxyErr(checkErr) {
			errs = append(errs, fmt.Sprintf("%s proxy health check: %v", node.Name, checkErr))
			continue
		}
		if !o.sshManaged(node.Name) {
			errs = append(errs, fmt.Sprintf("%s proxy broken but node is not SSH-managed", node.Name))
			continue
		}

		if err := o.recoverManagedNodeRuntime(ctx, node.Name, node.Unschedulable, "broken kubelet proxy before k3s-agent restart"); err != nil {
			errs = append(errs, fmt.Sprintf("%s %v", node.Name, err))
			continue
		}
		repaired++
	}

	if len(errs) > 0 {
		return repaired, errors.New(strings.Join(errs, "; "))
	}
	return repaired, nil
}

// readyNodeCandidates runs one orchestration or CLI step.
// Signature: (o *Orchestrator) readyNodeCandidates(ctx context.Context) ([]readyNodeCandidate, error).
// Why: kubelet proxy repair should only touch nodes Kubernetes says are Ready,
// preserving existing cordons when a node was intentionally kept out of service.
func (o *Orchestrator) readyNodeCandidates(ctx context.Context) ([]readyNodeCandidate, error) {
	out, err := o.kubectl(ctx, 20*time.Second, "get", "nodes", "-o", "json")
	if err != nil {
		return nil, fmt.Errorf("query nodes: %w", err)
	}
	var nodes nodeReadyList
	if err := json.Unmarshal([]byte(out), &nodes); err != nil {
		return nil, fmt.Errorf("decode nodes: %w", err)
	}

	readyNodes := []readyNodeCandidate{}
	for _, item := range nodes.Items {
		ready := ""
		for _, cond := range item.Status.Conditions {
			if strings.EqualFold(strings.TrimSpace(cond.Type), "Ready") {
				ready = strings.TrimSpace(cond.Status)
				break
			}
		}
		if ready == "True" && item.Metadata.Name != "" {
			readyNodes = append(readyNodes, readyNodeCandidate{
				Name:          item.Metadata.Name,
				Unschedulable: item.Spec.Unschedulable,
			})
		}
	}
	return readyNodes, nil
}

// kubeletProxyHealthy runs one orchestration or CLI step.
// Signature: (o *Orchestrator) kubeletProxyHealthy(ctx context.Context, node string) (bool, error).
// Why: the apiserver node proxy is the path Jenkins uses for pod exec; checking
// it catches Ready-but-unusable nodes before agents start failing websockets.
func (o *Orchestrator) kubeletProxyHealthy(ctx context.Context, node string) (bool, error) {
	var lastErr error
	for attempt := 0; attempt < 2; attempt++ {
		healthy, err := o.kubeletProxyHealthyOnce(ctx, node)
		if err == nil || !isTransientKubeletProxyCheckErr(err) {
			return healthy, err
		}
		lastErr = err
		o.log.Printf("warning: transient kubelet proxy health check failure for %s: %v; retrying", node, err)
	}
	return false, lastErr
}

// kubeletProxyHealthyOnce runs one orchestration or CLI step.
// Signature: (o *Orchestrator) kubeletProxyHealthyOnce(ctx context.Context, node string) (bool, error).
// Why: transient apiserver/kubectl cancellations should be retried by the caller
// without losing the exact kubelet proxy error when the node is really broken.
func (o *Orchestrator) kubeletProxyHealthyOnce(ctx context.Context, node string) (bool, error) {
	out, err := o.kubectl(ctx, 25*time.Second, "get", "--raw", fmt.Sprintf("/api/v1/nodes/%s/proxy/healthz", node), "--request-timeout=20s")
	if err != nil {
		if strings.TrimSpace(out) != "" {
			return false, fmt.Errorf("%w: %s", err, strings.TrimSpace(out))
		}
		return false, err
	}
	return true, nil
}

// isTransientKubeletProxyCheckErr runs one orchestration or CLI step.
// Signature: isTransientKubeletProxyCheckErr(err error) bool.
// Why: a killed or timed-out kubectl health probe is not proof the node proxy is
// broken; retry before reporting or repairing a Ready node.
func isTransientKubeletProxyCheckErr(err error) bool {
	if err == nil {
		return false
	}
	msg := strings.ToLower(err.Error())
	transient := []string{
		"signal: killed",
		"context deadline exceeded",
		"deadline exceeded",
		"i/o timeout",
		"request canceled",
		"client.timeout",
		"timeout awaiting",
	}
	for _, needle := range transient {
		if strings.Contains(msg, needle) {
			return true
		}
	}
	return false
}

// isRepairableKubeletProxyErr runs one orchestration or CLI step.
// Signature: isRepairableKubeletProxyErr(err error) bool.
// Why: keep this repair narrow so Ananke restarts k3s-agent for the known
// kubelet-tunnel failure, not for every transient kubectl problem.
func isRepairableKubeletProxyErr(err error) bool {
	if err == nil {
		return false
	}
	msg := strings.ToLower(err.Error())
	repairable := []string{
		"502",
		"bad gateway",
		"failed to find session",
		"error trying to reach service",
		"10250",
	}
	for _, needle := range repairable {
		if strings.Contains(msg, needle) {
			return true
		}
	}
	return false
}

// requestFluxReconcile runs one orchestration or CLI step.
// Signature: (o *Orchestrator) requestFluxReconcile(ctx context.Context) error.
// Why: post-start repairs need a lightweight way to refresh GitOps health
// without reusing the broader startup flux-resume flow.
func (o *Orchestrator) requestFluxReconcile(ctx context.Context) error {
	if o.runner.DryRun {
		return nil
	}

	now := time.Now().UTC().Format(time.RFC3339)
	if _, err := o.kubectl(
		ctx,
		25*time.Second,
		"-n", "flux-system",
		"annotate", "gitrepository", "flux-system",
		"reconcile.fluxcd.io/requestedAt="+now,
		"--overwrite",
	); err != nil {
		return fmt.Errorf("annotate flux source reconcile: %w", err)
	}
	if _, err := o.kubectl(
		ctx,
		25*time.Second,
		"-n", "flux-system",
		"annotate",
		"kustomizations.kustomize.toolkit.fluxcd.io",
		"--all",
		"reconcile.fluxcd.io/requestedAt="+now,
		"--overwrite",
	); err != nil {
		return fmt.Errorf("annotate flux kustomizations reconcile: %w", err)
	}
	if _, err := o.kubectl(
		ctx,
		25*time.Second,
		"annotate",
		"--all-namespaces",
		"helmreleases.helm.toolkit.fluxcd.io",
		"--all",
		"reconcile.fluxcd.io/requestedAt="+now,
		"--overwrite",
	); err != nil {
		o.log.Printf("warning: annotate helmreleases for post-start reconcile failed: %v", err)
	}
	if o.runOverride == nil && o.runner.CommandExists("flux") {
		if _, err := o.run(ctx, 75*time.Second, "flux", "reconcile", "source", "git", "flux-system", "-n", "flux-system", "--timeout=60s"); err != nil {
			o.log.Printf("warning: flux source reconcile command failed during post-start auto-heal: %v", err)
		}
	}
	return nil
}