package controller

import (
	"context"
	"fmt"
	"slices"
	"strings"

	"github.com/hanzoai/cd/gitops-engine/pkg/health"
	"github.com/hanzoai/cd/gitops-engine/pkg/sync/common"
	"github.com/hanzoai/cd/gitops-engine/pkg/sync/hook"
	"github.com/hanzoai/cd/gitops-engine/pkg/utils/kube"
	log "github.com/sirupsen/logrus"
	"go.opentelemetry.io/otel/attribute"
	apierrors "k8s.io/apimachinery/pkg/api/errors"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
	"k8s.io/client-go/rest"

	"github.com/hanzoai/cd/util/lua"

	appv1 "github.com/hanzoai/cd/pkg/apis/application/v1alpha1"
	argoutil "github.com/hanzoai/cd/util/cd"
	traceutil "github.com/hanzoai/cd/util/trace"
)

type HookType string

const (
	PreDeleteHookType  HookType = "PreDelete"
	PostDeleteHookType HookType = "PostDelete"
)

var hookTypeAnnotations = map[HookType]map[string]string{
	PreDeleteHookType: {
		"cd.hanzo.ai/hook": string(PreDeleteHookType),
		"helm.sh/hook":            "pre-delete",
	},
	PostDeleteHookType: {
		"cd.hanzo.ai/hook": string(PostDeleteHookType),
		"helm.sh/hook":            "post-delete",
	},
}

func isHookOfType(obj *unstructured.Unstructured, hookType HookType) bool {
	if obj == nil || obj.GetAnnotations() == nil {
		return false
	}

	for k, v := range hookTypeAnnotations[hookType] {
		if val, ok := obj.GetAnnotations()[k]; ok {
			if slices.ContainsFunc(strings.Split(val, ","), func(item string) bool {
				return strings.TrimSpace(item) == v
			}) {
				return true
			}
		}
	}
	return false
}

func isHook(obj *unstructured.Unstructured) bool {
	if hook.IsHook(obj) {
		return true
	}

	for hookType := range hookTypeAnnotations {
		if isHookOfType(obj, hookType) {
			return true
		}
	}
	return false
}

func isPreDeleteHook(obj *unstructured.Unstructured) bool {
	return isHookOfType(obj, PreDeleteHookType)
}

func isPostDeleteHook(obj *unstructured.Unstructured) bool {
	return isHookOfType(obj, PostDeleteHookType)
}

// hasGitOpsEngineSyncPhaseHook is true when gitops-engine would run the resource during a sync
// phase (PreSync, Sync, PostSync, SyncFail). PreDelete/PostDelete are not sync phases;
// without this check, state reconciliation drops such resources
// entirely because isPreDeleteHook/isPostDeleteHook match any comma-separated value.
// HookTypeSkip is omitted as it is not a sync phase.
func hasGitOpsEngineSyncPhaseHook(obj *unstructured.Unstructured) bool {
	for _, t := range hook.Types(obj) {
		switch t {
		case common.HookTypePreSync, common.HookTypeSync, common.HookTypePostSync, common.HookTypeSyncFail:
			return true
		}
	}
	return false
}

// executeHooks is a generic function to execute hooks of a specified type
func (ctrl *ApplicationController) executeHooks(ctx context.Context, hookType HookType, app *appv1.Application, proj *appv1.AppProject, liveObjs map[kube.ResourceKey]*unstructured.Unstructured, config *rest.Config, logCtx *log.Entry) (completed bool, retErr error) {
	ctx, span := tracer.Start(ctx, "controller.executeHooks")
	setAppTraceAttrs(span, app, attribute.String("cd.hook.type", string(hookType)))
	defer func() { traceutil.EndSpan(span, retErr) }()
	appLabelKey, err := ctrl.settingsMgr.GetAppInstanceLabelKey()
	if err != nil {
		return false, err
	}
	trackingMethodStr, err := ctrl.settingsMgr.GetTrackingMethod()
	if err != nil {
		return false, err
	}
	installationID, err := ctrl.settingsMgr.GetInstallationID()
	if err != nil {
		return false, err
	}
	trackingMethod := appv1.TrackingMethod(trackingMethodStr)
	resourceTracking := argoutil.NewResourceTracking()

	var revisions []string
	for _, src := range app.Spec.GetSources() {
		revisions = append(revisions, src.TargetRevision)
	}

	// Fetch target objects from Git to know which hooks should exist
	targets, _, _, err := ctrl.appStateManager.GetRepoObjs(ctx, app, app.Spec.GetSources(), appLabelKey, revisions, false, false, nil, proj, true)
	if err != nil {
		return false, err
	}

	// Find existing hooks of the specified type
	runningHooks := map[kube.ResourceKey]*unstructured.Unstructured{}
	for key, obj := range liveObjs {
		if isHookOfType(obj, hookType) {
			runningHooks[key] = obj
		}
	}

	// Find expected hooks that need to be created
	expectedHook := map[kube.ResourceKey]*unstructured.Unstructured{}
	for _, obj := range targets {
		if obj.GetNamespace() == "" {
			obj.SetNamespace(app.Spec.Destination.Namespace)
		}
		if !isHookOfType(obj, hookType) {
			continue
		}
		if _, alreadyExists := runningHooks[kube.GetResourceKey(obj)]; !alreadyExists {
			expectedHook[kube.GetResourceKey(obj)] = obj
		}
	}

	// Create hooks that don't exist yet
	createdCnt := 0
	for key, obj := range expectedHook {
		// Apply app instance tracking metadata so the hook can be tracked and cleaned up.
		// Use the same code path as regular sync resources so the configured
		// tracking method (label, annotation, annotation+label) is honored.
		// When the configured tracking method writes a label, this also ensures
		// the label value is truncated to fit Kubernetes' 63-character label
		// limit (see https://github.com/argoproj/argo-cd/issues/27527).
		if err := resourceTracking.SetAppInstance(obj, appLabelKey, app.InstanceName(ctrl.namespace), app.Spec.Destination.Namespace, trackingMethod, installationID); err != nil {
			return false, fmt.Errorf("failed to set app instance tracking on %s hook %s: %w", hookType, key, err)
		}

		logCtx.Infof("Creating %s hook resource: %s", hookType, key)
		_, err = ctrl.kubectl.CreateResource(ctx, config, obj.GroupVersionKind(), obj.GetName(), obj.GetNamespace(), obj, metav1.CreateOptions{})
		if err != nil {
			if apierrors.IsAlreadyExists(err) {
				logCtx.Warnf("Hook resource %s already exists, skipping", key)
				continue
			}
			return false, err
		}
		createdCnt++
	}

	if createdCnt > 0 {
		logCtx.Infof("Created %d %s hooks", createdCnt, hookType)
		return false, nil
	}

	// Check health of running hooks
	resourceOverrides, err := ctrl.settingsMgr.GetResourceOverrides()
	if err != nil {
		return false, err
	}
	healthOverrides := lua.ResourceHealthOverrides(resourceOverrides)

	progressingHooksCount := 0
	var failedHooks []string
	var failedHookObjects []*unstructured.Unstructured

	for key, obj := range runningHooks {
		hookHealth, err := health.GetResourceHealth(obj, healthOverrides)
		if err != nil {
			return false, err
		}
		if hookHealth == nil {
			logCtx.WithFields(log.Fields{
				"group":     obj.GroupVersionKind().Group,
				"version":   obj.GroupVersionKind().Version,
				"kind":      obj.GetKind(),
				"name":      obj.GetName(),
				"namespace": obj.GetNamespace(),
			}).Info("No health check defined for resource, considering it healthy")
			hookHealth = &health.HealthStatus{
				Status: health.HealthStatusHealthy,
			}
		}

		switch hookHealth.Status {
		case health.HealthStatusProgressing:
			logCtx.Debugf("Hook %s is progressing", key)
			progressingHooksCount++
		case health.HealthStatusDegraded:
			logCtx.Warnf("Hook %s is degraded: %s", key, hookHealth.Message)
			failedHooks = append(failedHooks, fmt.Sprintf("%s/%s", obj.GetNamespace(), obj.GetName()))
			failedHookObjects = append(failedHookObjects, obj)
		case health.HealthStatusHealthy:
			logCtx.Debugf("Hook %s is healthy", key)
		}
	}

	if len(failedHooks) > 0 {
		// Delete failed hooks to allow retry with potentially fixed hook definitions
		logCtx.Infof("Deleting %d failed %s hook(s) to allow retry", len(failedHookObjects), hookType)
		for _, obj := range failedHookObjects {
			err = ctrl.kubectl.DeleteResource(ctx, config, obj.GroupVersionKind(), obj.GetName(), obj.GetNamespace(), metav1.DeleteOptions{})
			if err != nil && !apierrors.IsNotFound(err) {
				logCtx.WithError(err).Warnf("Failed to delete failed hook %s/%s", obj.GetNamespace(), obj.GetName())
			}
		}
		return false, fmt.Errorf("%s hook(s) failed: %s", hookType, strings.Join(failedHooks, ", "))
	}

	if progressingHooksCount > 0 {
		logCtx.Infof("Waiting for %d %s hooks to complete", progressingHooksCount, hookType)
		return false, nil
	}

	return true, nil
}

// cleanupHooks is a generic function to clean up hooks of a specified type
func (ctrl *ApplicationController) cleanupHooks(ctx context.Context, hookType HookType, liveObjs map[kube.ResourceKey]*unstructured.Unstructured, config *rest.Config, logCtx *log.Entry) (completed bool, retErr error) {
	ctx, span := tracer.Start(ctx, "controller.cleanupHooks")
	span.SetAttributes(attribute.String("cd.hook.type", string(hookType)))
	defer func() { traceutil.EndSpan(span, retErr) }()
	resourceOverrides, err := ctrl.settingsMgr.GetResourceOverrides()
	if err != nil {
		return false, err
	}
	healthOverrides := lua.ResourceHealthOverrides(resourceOverrides)

	pendingDeletionCount := 0
	aggregatedHealth := health.HealthStatusHealthy
	var hooks []*unstructured.Unstructured

	// Collect hooks and determine overall health
	for _, obj := range liveObjs {
		if !isHookOfType(obj, hookType) {
			continue
		}
		hookHealth, err := health.GetResourceHealth(obj, healthOverrides)
		if err != nil {
			return false, err
		}
		if hookHealth == nil {
			hookHealth = &health.HealthStatus{
				Status: health.HealthStatusHealthy,
			}
		}
		if health.IsWorse(aggregatedHealth, hookHealth.Status) {
			aggregatedHealth = hookHealth.Status
		}
		hooks = append(hooks, obj)
	}

	if len(hooks) == 0 {
		return true, nil
	}

	// Process hooks for deletion
	for _, obj := range hooks {
		deletePolicies := hook.DeletePolicies(obj)
		shouldDelete := false

		if len(deletePolicies) == 0 {
			// If no delete policy is specified, always delete hooks during cleanup phase
			shouldDelete = true
		} else {
			// Check if any delete policy matches the current hook state
			for _, policy := range deletePolicies {
				if (policy == common.HookDeletePolicyHookFailed && aggregatedHealth == health.HealthStatusDegraded) ||
					(policy == common.HookDeletePolicyHookSucceeded && aggregatedHealth == health.HealthStatusHealthy) {
					shouldDelete = true
					break
				}
			}
		}

		if shouldDelete {
			pendingDeletionCount++
			if obj.GetDeletionTimestamp() != nil {
				continue
			}
			logCtx.Infof("Deleting %s hook %s/%s", hookType, obj.GetNamespace(), obj.GetName())
			err = ctrl.kubectl.DeleteResource(ctx, config, obj.GroupVersionKind(), obj.GetName(), obj.GetNamespace(), metav1.DeleteOptions{})
			if err != nil && !apierrors.IsNotFound(err) {
				return false, err
			}
		}
	}

	if pendingDeletionCount > 0 {
		logCtx.Infof("Waiting for %d %s hooks to be deleted", pendingDeletionCount, hookType)
		return false, nil
	}

	return true, nil
}

// Execute and cleanup hooks for pre-delete and post-delete operations

func (ctrl *ApplicationController) executePreDeleteHooks(ctx context.Context, app *appv1.Application, proj *appv1.AppProject, liveObjs map[kube.ResourceKey]*unstructured.Unstructured, config *rest.Config, logCtx *log.Entry) (bool, error) {
	return ctrl.executeHooks(ctx, PreDeleteHookType, app, proj, liveObjs, config, logCtx)
}

func (ctrl *ApplicationController) cleanupPreDeleteHooks(ctx context.Context, liveObjs map[kube.ResourceKey]*unstructured.Unstructured, config *rest.Config, logCtx *log.Entry) (bool, error) {
	return ctrl.cleanupHooks(ctx, PreDeleteHookType, liveObjs, config, logCtx)
}

func (ctrl *ApplicationController) executePostDeleteHooks(ctx context.Context, app *appv1.Application, proj *appv1.AppProject, liveObjs map[kube.ResourceKey]*unstructured.Unstructured, config *rest.Config, logCtx *log.Entry) (bool, error) {
	return ctrl.executeHooks(ctx, PostDeleteHookType, app, proj, liveObjs, config, logCtx)
}

func (ctrl *ApplicationController) cleanupPostDeleteHooks(ctx context.Context, liveObjs map[kube.ResourceKey]*unstructured.Unstructured, config *rest.Config, logCtx *log.Entry) (bool, error) {
	return ctrl.cleanupHooks(ctx, PostDeleteHookType, liveObjs, config, logCtx)
}