package v1beta1

import (
	"context"
	"encoding/json"
	"fmt"
	"sort"
	"strings"

	"github.com/oliveagle/jsonpath"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/fields"
	"k8s.io/apimachinery/pkg/runtime"
	"k8s.io/apimachinery/pkg/runtime/schema"
	"k8s.io/apimachinery/pkg/selection"
	"k8s.io/klog/v2"
	"sigs.k8s.io/controller-runtime/pkg/client"

	"kubesphere.io/kubesphere/pkg/apiserver/query"
)

type ResourceManager interface {
	IsServed(schema.GroupVersionResource) (bool, error)
	CreateObjectFromRawData(gvr schema.GroupVersionResource, rawData []byte) (client.Object, error)

	CreateResource(ctx context.Context, object client.Object) error
	UpdateResource(ctx context.Context, object client.Object) error
	PatchResource(ctx context.Context, object client.Object) error
	DeleteResource(ctx context.Context, gvr schema.GroupVersionResource, namespace string, name string) error
	GetResource(ctx context.Context, gvr schema.GroupVersionResource, namespace string, name string) (client.Object, error)
	ListResources(ctx context.Context, gvr schema.GroupVersionResource, namespace string, query *query.Query) (client.ObjectList, error)

	Get(ctx context.Context, namespace, name string, object client.Object) error
	List(ctx context.Context, namespace string, query *query.Query, object client.ObjectList) error
	Create(ctx context.Context, object client.Object) error
	Delete(ctx context.Context, object client.Object) error
	Update(ctx context.Context, old, new client.Object) error
	Patch(ctx context.Context, old, new client.Object) error
}

// CompareFunc return true is left greater than right
type CompareFunc func(runtime.Object, runtime.Object, query.Field) bool

type FilterFunc func(runtime.Object, query.Filter) bool

type TransformFunc func(runtime.Object) runtime.Object

func DefaultList(objects []runtime.Object, q *query.Query, compareFunc CompareFunc, filterFunc FilterFunc, transformFuncs ...TransformFunc) ([]runtime.Object, *int64) {
	// selected matched ones
	var filtered []runtime.Object
	if len(q.Filters) != 0 {
		for _, object := range objects {
			selected := true
			for field, value := range q.Filters {
				if !filterFunc(object, query.Filter{Field: field, Value: value}) {
					selected = false
					break
				}
			}

			if selected {
				for _, transform := range transformFuncs {
					object = transform(object)
				}
				filtered = append(filtered, object)
			}
		}
	} else {
		filtered = objects
	}

	// sort by sortBy field
	sort.Slice(filtered, func(i, j int) bool {
		if !q.Ascending {
			return compareFunc(filtered[i], filtered[j], q.SortBy)
		}
		return !compareFunc(filtered[i], filtered[j], q.SortBy)
	})

	total := len(filtered)

	if q.Pagination == nil {
		q.Pagination = query.NoPagination
	}

	start, end := q.Pagination.GetValidPagination(total)
	remainingItemCount := int64(total - end)

	return filtered[start:end], &remainingItemCount
}

// DefaultObjectMetaCompare return true is left greater than right
func DefaultObjectMetaCompare(left, right metav1.Object, sortBy query.Field) bool {
	switch sortBy {
	// ?sortBy=name
	case query.FieldName:
		return strings.Compare(left.GetName(), right.GetName()) > 0
	//	?sortBy=creationTimestamp
	default:
		fallthrough
	case query.FieldCreateTime:
		fallthrough
	case query.FieldCreationTimeStamp:
		// compare by name if creation timestamp is equal
		ltime := left.GetCreationTimestamp()
		rtime := right.GetCreationTimestamp()
		if ltime.Equal(&rtime) {
			return strings.Compare(left.GetName(), right.GetName()) > 0
		}
		return left.GetCreationTimestamp().After(right.GetCreationTimestamp().Time)
	}
}

// Default metadata filter
func DefaultObjectMetaFilter(item metav1.Object, filter query.Filter) bool {
	switch filter.Field {
	case query.FieldNames:
		for _, name := range strings.Split(string(filter.Value), ",") {
			if item.GetName() == name {
				return true
			}
		}
		return false
	// /namespaces?page=1&limit=10&name=default
	case query.FieldName:
		return strings.Contains(item.GetName(), string(filter.Value))
		// /namespaces?page=1&limit=10&uid=a8a8d6cf-f6a5-4fea-9c1b-e57610115706
	case query.FieldUID:
		return strings.Compare(string(item.GetUID()), string(filter.Value)) == 0
		// /deployments?page=1&limit=10&namespace=kubesphere-system
	case query.FieldNamespace:
		return strings.Compare(item.GetNamespace(), string(filter.Value)) == 0
		// /namespaces?page=1&limit=10&ownerReference=a8a8d6cf-f6a5-4fea-9c1b-e57610115706
	case query.FieldOwnerReference:
		for _, ownerReference := range item.GetOwnerReferences() {
			if strings.Compare(string(ownerReference.UID), string(filter.Value)) == 0 {
				return true
			}
		}
		return false
		// /namespaces?page=1&limit=10&ownerKind=Workspace
	case query.FieldOwnerKind:
		for _, ownerReference := range item.GetOwnerReferences() {
			if strings.Compare(ownerReference.Kind, string(filter.Value)) == 0 {
				return true
			}
		}
		return false
		// /namespaces?page=1&limit=10&annotation=openpitrix_runtime
	case query.FieldAnnotation:
		return labelMatch(item.GetAnnotations(), string(filter.Value))
		// /namespaces?page=1&limit=10&label=kubesphere.io/workspace:system-workspace
	case query.FieldLabel:
		return labelMatch(item.GetLabels(), string(filter.Value))
	case query.ParameterFieldSelector:
		return contains(item.(runtime.Object), filter.Value)
	default:
		return false
	}
}

func labelMatch(labels map[string]string, filter string) bool {
	fields := strings.SplitN(filter, "=", 2)
	var key, value string
	var opposite bool
	if len(fields) == 2 {
		key = fields[0]
		if strings.HasSuffix(key, "!") {
			key = strings.TrimSuffix(key, "!")
			opposite = true
		}
		value = fields[1]
	} else {
		key = fields[0]
		value = "*"
	}
	for k, v := range labels {
		if opposite {
			if (k == key) && v != value {
				return true
			}
		} else {
			if (k == key) && (value == "*" || v == value) {
				return true
			}
		}
	}
	return false
}

// implement a generic query filter to support multiple field selectors with "jsonpath.JsonPathLookup"
// https://github.com/oliveagle/jsonpath/blob/master/readme.md
func contains(object runtime.Object, queryValue query.Value) bool {
	// call the ParseSelector function of "k8s.io/apimachinery/pkg/fields/selector.go" to validate and parse the selector
	fieldSelector, err := fields.ParseSelector(string(queryValue))
	if err != nil {
		klog.V(4).Infof("failed parse selector error: %s", err)
		return false
	}
	for _, requirement := range fieldSelector.Requirements() {
		var negative bool
		// supports '=', '==' and '!='.(e.g. ?fieldSelector=key1=value1,key2=value2)
		// fields.ParseSelector(FieldSelector) has handled the case where the operator is '==' and converted it to '=',
		// so case selection.DoubleEquals can be ignored here.
		switch requirement.Operator {
		case selection.NotEquals:
			negative = true
		case selection.Equals:
			negative = false
		}
		key := requirement.Field
		value := requirement.Value

		var input map[string]interface{}
		data, err := json.Marshal(object)
		if err != nil {
			klog.V(4).Infof("failed marshal to JSON string: %s", err)
			return false
		}
		if err = json.Unmarshal(data, &input); err != nil {
			klog.V(4).Infof("failed unmarshal to map object: %s", err)
			return false
		}
		rawValue, err := jsonpath.JsonPathLookup(input, "$."+key)
		if err != nil {
			klog.V(4).Infof("failed to lookup jsonpath: %s", err)
			return false
		}
		if (negative && fmt.Sprintf("%v", rawValue) != value) || (!negative && fmt.Sprintf("%v", rawValue) == value) {
			continue
		} else {
			return false
		}
	}
	return true
}