/*
   Copyright The containerd 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 docker

import (
	"fmt"
	"sync"

	"github.com/containerd/containerd/content"
	"github.com/containerd/containerd/errdefs"
	"github.com/moby/locker"
)

// Status of a content operation
type Status struct {
	content.Status

	Committed bool

	// ErrClosed contains error encountered on close.
	ErrClosed error

	// UploadUUID is used by the Docker registry to reference blob uploads
	UploadUUID string

	// PushStatus contains status related to push.
	PushStatus
}

type PushStatus struct {
	// MountedFrom is the source content was cross-repo mounted from (empty if no cross-repo mount was performed).
	MountedFrom string

	// Exists indicates whether content already exists in the repository and wasn't uploaded.
	Exists bool
}

// StatusTracker to track status of operations
type StatusTracker interface {
	GetStatus(string) (Status, error)
	SetStatus(string, Status)
}

// StatusTrackLocker to track status of operations with lock
type StatusTrackLocker interface {
	StatusTracker
	Lock(string)
	Unlock(string)
}

type memoryStatusTracker struct {
	statuses map[string]Status
	m        sync.Mutex
	locker   *locker.Locker
}

// NewInMemoryTracker returns a StatusTracker that tracks content status in-memory
func NewInMemoryTracker() StatusTrackLocker {
	return &memoryStatusTracker{
		statuses: map[string]Status{},
		locker:   locker.New(),
	}
}

func (t *memoryStatusTracker) GetStatus(ref string) (Status, error) {
	t.m.Lock()
	defer t.m.Unlock()
	status, ok := t.statuses[ref]
	if !ok {
		return Status{}, fmt.Errorf("status for ref %v: %w", ref, errdefs.ErrNotFound)
	}
	return status, nil
}

func (t *memoryStatusTracker) SetStatus(ref string, status Status) {
	t.m.Lock()
	t.statuses[ref] = status
	t.m.Unlock()
}

func (t *memoryStatusTracker) Lock(ref string) {
	t.locker.Lock(ref)
}

func (t *memoryStatusTracker) Unlock(ref string) {
	t.locker.Unlock(ref)
}