/*
Copyright 2021 The Kubernetes Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package state

import (
	"sync"

	"k8s.io/api/core/v1"
	"k8s.io/klog/v2"
)

type stateMemory struct {
	sync.RWMutex
	podAllocation   PodResourceAllocation
	podResizeStatus PodResizeStatus
}

var _ State = &stateMemory{}

// NewStateMemory creates new State to track resources allocated to pods
func NewStateMemory() State {
	klog.V(2).InfoS("Initialized new in-memory state store for pod resource allocation tracking")
	return &stateMemory{
		podAllocation:   PodResourceAllocation{},
		podResizeStatus: PodResizeStatus{},
	}
}

func (s *stateMemory) GetContainerResourceAllocation(podUID string, containerName string) (v1.ResourceList, bool) {
	s.RLock()
	defer s.RUnlock()

	alloc, ok := s.podAllocation[podUID][containerName]
	return alloc.DeepCopy(), ok
}

func (s *stateMemory) GetPodResourceAllocation() PodResourceAllocation {
	s.RLock()
	defer s.RUnlock()
	return s.podAllocation.Clone()
}

func (s *stateMemory) GetPodResizeStatus(podUID string) (v1.PodResizeStatus, bool) {
	s.RLock()
	defer s.RUnlock()

	resizeStatus, ok := s.podResizeStatus[podUID]
	return resizeStatus, ok
}

func (s *stateMemory) GetResizeStatus() PodResizeStatus {
	s.RLock()
	defer s.RUnlock()
	prs := make(map[string]v1.PodResizeStatus)
	for k, v := range s.podResizeStatus {
		prs[k] = v
	}
	return prs
}

func (s *stateMemory) SetContainerResourceAllocation(podUID string, containerName string, alloc v1.ResourceList) error {
	s.Lock()
	defer s.Unlock()

	if _, ok := s.podAllocation[podUID]; !ok {
		s.podAllocation[podUID] = make(map[string]v1.ResourceList)
	}

	s.podAllocation[podUID][containerName] = alloc
	klog.V(3).InfoS("Updated container resource allocation", "podUID", podUID, "containerName", containerName, "alloc", alloc)
	return nil
}

func (s *stateMemory) SetPodResourceAllocation(a PodResourceAllocation) error {
	s.Lock()
	defer s.Unlock()

	s.podAllocation = a.Clone()
	klog.V(3).InfoS("Updated pod resource allocation", "allocation", a)
	return nil
}

func (s *stateMemory) SetPodResizeStatus(podUID string, resizeStatus v1.PodResizeStatus) error {
	s.Lock()
	defer s.Unlock()

	if resizeStatus != "" {
		s.podResizeStatus[podUID] = resizeStatus
	} else {
		delete(s.podResizeStatus, podUID)
	}
	klog.V(3).InfoS("Updated pod resize state", "podUID", podUID, "resizeStatus", resizeStatus)
	return nil
}

func (s *stateMemory) SetResizeStatus(rs PodResizeStatus) error {
	s.Lock()
	defer s.Unlock()
	prs := make(map[string]v1.PodResizeStatus)
	for k, v := range rs {
		prs[k] = v
	}
	s.podResizeStatus = prs
	klog.V(3).InfoS("Updated pod resize state", "resizes", rs)
	return nil
}

func (s *stateMemory) deleteContainer(podUID string, containerName string) {
	delete(s.podAllocation[podUID], containerName)
	if len(s.podAllocation[podUID]) == 0 {
		delete(s.podAllocation, podUID)
		delete(s.podResizeStatus, podUID)
	}
	klog.V(3).InfoS("Deleted pod resource allocation", "podUID", podUID, "containerName", containerName)
}

func (s *stateMemory) Delete(podUID string, containerName string) error {
	s.Lock()
	defer s.Unlock()
	if len(containerName) == 0 {
		delete(s.podAllocation, podUID)
		delete(s.podResizeStatus, podUID)
		klog.V(3).InfoS("Deleted pod resource allocation and resize state", "podUID", podUID)
		return nil
	}
	s.deleteContainer(podUID, containerName)
	return nil
}

func (s *stateMemory) ClearState() error {
	s.Lock()
	defer s.Unlock()

	s.podAllocation = make(PodResourceAllocation)
	s.podResizeStatus = make(PodResizeStatus)
	klog.V(3).InfoS("Cleared state")
	return nil
}