/*
   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 leases

import (
	"context"

	"github.com/containerd/containerd/gc"
	"github.com/containerd/containerd/leases"
	"github.com/containerd/containerd/metadata"
	"github.com/containerd/containerd/plugin"
	"github.com/containerd/containerd/services"
	bolt "go.etcd.io/bbolt"
)

func init() {
	plugin.Register(&plugin.Registration{
		Type: plugin.ServicePlugin,
		ID:   services.LeasesService,
		Requires: []plugin.Type{
			plugin.MetadataPlugin,
		},
		InitFn: func(ic *plugin.InitContext) (interface{}, error) {
			m, err := ic.Get(plugin.MetadataPlugin)
			if err != nil {
				return nil, err
			}
			g, err := ic.Get(plugin.GCPlugin)
			if err != nil {
				return nil, err
			}
			return &local{
				db: m.(*metadata.DB),
				gc: g.(gcScheduler),
			}, nil
		},
	})
}

type gcScheduler interface {
	ScheduleAndWait(context.Context) (gc.Stats, error)
}

type local struct {
	db *metadata.DB
	gc gcScheduler
}

func (l *local) Create(ctx context.Context, opts ...leases.Opt) (leases.Lease, error) {
	var lease leases.Lease
	if err := l.db.Update(func(tx *bolt.Tx) error {
		var err error
		lease, err = metadata.NewLeaseManager(tx).Create(ctx, opts...)
		return err
	}); err != nil {
		return leases.Lease{}, err
	}
	return lease, nil
}

func (l *local) Delete(ctx context.Context, lease leases.Lease, opts ...leases.DeleteOpt) error {
	var do leases.DeleteOptions
	for _, opt := range opts {
		if err := opt(ctx, &do); err != nil {
			return err
		}
	}

	if err := l.db.Update(func(tx *bolt.Tx) error {
		return metadata.NewLeaseManager(tx).Delete(ctx, lease)
	}); err != nil {
		return err
	}

	if do.Synchronous {
		if _, err := l.gc.ScheduleAndWait(ctx); err != nil {
			return err
		}
	}

	return nil

}

func (l *local) List(ctx context.Context, filters ...string) ([]leases.Lease, error) {
	var ll []leases.Lease
	if err := l.db.View(func(tx *bolt.Tx) error {
		var err error
		ll, err = metadata.NewLeaseManager(tx).List(ctx, filters...)
		return err
	}); err != nil {
		return nil, err
	}
	return ll, nil
}

func (l *local) AddResource(ctx context.Context, lease leases.Lease, r leases.Resource) error {
	return l.db.Update(func(tx *bolt.Tx) error {
		return metadata.NewLeaseManager(tx).AddResource(ctx, lease, r)
	})
}

func (l *local) DeleteResource(ctx context.Context, lease leases.Lease, r leases.Resource) error {
	return l.db.Update(func(tx *bolt.Tx) error {
		return metadata.NewLeaseManager(tx).DeleteResource(ctx, lease, r)
	})
}

func (l *local) ListResources(ctx context.Context, lease leases.Lease) ([]leases.Resource, error) {
	var rs []leases.Resource
	if err := l.db.View(func(tx *bolt.Tx) error {
		var err error
		rs, err = metadata.NewLeaseManager(tx).ListResources(ctx, lease)
		return err
	}); err != nil {
		return nil, err
	}
	return rs, nil
}