/*
   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 client

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"maps"

	"github.com/containerd/containerd/v2/core/containers"
	"github.com/containerd/containerd/v2/core/content"
	"github.com/containerd/containerd/v2/core/images"
	"github.com/containerd/containerd/v2/core/snapshots"
	"github.com/containerd/containerd/v2/pkg/labels"
	"github.com/containerd/containerd/v2/pkg/namespaces"
	"github.com/containerd/containerd/v2/pkg/oci"
	"github.com/containerd/errdefs"
	"github.com/containerd/log"
	"github.com/containerd/typeurl/v2"
	"github.com/opencontainers/image-spec/identity"
	v1 "github.com/opencontainers/image-spec/specs-go/v1"
)

// DeleteOpts allows the caller to set options for the deletion of a container
type DeleteOpts func(ctx context.Context, client *Client, c containers.Container) error

// NewContainerOpts allows the caller to set additional options when creating a container
type NewContainerOpts func(ctx context.Context, client *Client, c *containers.Container) error

// UpdateContainerOpts allows the caller to set additional options when updating a container
type UpdateContainerOpts func(ctx context.Context, client *Client, c *containers.Container) error

// InfoOpts controls how container metadata is fetched and returned
type InfoOpts func(*InfoConfig)

// InfoConfig specifies how container metadata is fetched
type InfoConfig struct {
	// Refresh will to a fetch of the latest container metadata
	Refresh bool
}

// WithRuntime allows a user to specify the runtime name and additional options that should
// be used to create tasks for the container
func WithRuntime(name string, options interface{}) NewContainerOpts {
	return func(ctx context.Context, client *Client, c *containers.Container) error {
		var (
			opts typeurl.Any
			err  error
		)
		if options != nil {
			opts, err = typeurl.MarshalAny(options)
			if err != nil {
				return err
			}
		}
		c.Runtime = containers.RuntimeInfo{
			Name:    name,
			Options: opts,
		}
		return nil
	}
}

// WithSandbox joins the container to a container group (aka sandbox) from the given ID
// Note: shim runtime must support sandboxes environments.
func WithSandbox(sandboxID string) NewContainerOpts {
	return func(ctx context.Context, client *Client, c *containers.Container) error {
		c.SandboxID = sandboxID
		return nil
	}
}

// WithImage sets the provided image as the base for the container
func WithImage(i Image) NewContainerOpts {
	return func(ctx context.Context, client *Client, c *containers.Container) error {
		c.Image = i.Name()
		return nil
	}
}

// WithImageName allows setting the image name as the base for the container
func WithImageName(n string) NewContainerOpts {
	return func(ctx context.Context, _ *Client, c *containers.Container) error {
		c.Image = n
		return nil
	}
}

// WithContainerLabels sets the provided labels to the container.
// The existing labels are cleared.
// Use WithAdditionalContainerLabels to preserve the existing labels.
func WithContainerLabels(labels map[string]string) NewContainerOpts {
	return func(_ context.Context, _ *Client, c *containers.Container) error {
		c.Labels = labels
		return nil
	}
}

// WithImageConfigLabels sets the image config labels on the container.
// The existing labels are cleared as this is expected to be the first
// operation in setting up a container's labels. Use WithAdditionalContainerLabels
// to add/overwrite the existing image config labels.
//
// Image config labels in the namespaces reserved for containerd
// (containerd.io/) and the CRI plugin (io.cri-containerd) are not copied
// to the container.
func WithImageConfigLabels(image Image) NewContainerOpts {
	return func(ctx context.Context, _ *Client, c *containers.Container) error {
		ic, err := image.Config(ctx)
		if err != nil {
			return err
		}
		if !images.IsConfigType(ic.MediaType) {
			return fmt.Errorf("unknown image config media type %s", ic.MediaType)
		}

		var (
			ociimage v1.Image
			config   v1.ImageConfig
		)
		p, err := content.ReadBlob(ctx, image.ContentStore(), ic)
		if err != nil {
			return err
		}

		if err = json.Unmarshal(p, &ociimage); err != nil {
			return err
		}
		config = ociimage.Config

		c.Labels = config.Labels
		// Labels in the containerd.io/* namespace are interpreted by containerd
		// itself, and labels in the io.cri-containerd.* namespace are interpreted
		// by the CRI plugin, so they are not copied from untrusted image configs.
		maps.DeleteFunc(c.Labels, func(k, _ string) bool {
			if labels.IsReserved(k) {
				log.G(ctx).Warnf("skipping image label %q: the label namespace is reserved for containerd; possible malicious image attempting to alter containerd behavior", k)
				return true
			}
			return false
		})
		return nil
	}
}

// WithAdditionalContainerLabels adds the provided labels to the container
// The existing labels are preserved as long as they do not conflict with the added labels.
func WithAdditionalContainerLabels(labels map[string]string) NewContainerOpts {
	return func(_ context.Context, _ *Client, c *containers.Container) error {
		if c.Labels == nil {
			c.Labels = labels
			return nil
		}
		for k, v := range labels {
			c.Labels[k] = v
		}
		return nil
	}
}

// WithImageStopSignal sets a well-known containerd label (StopSignalLabel)
// on the container for storing the stop signal specified in the OCI image
// config
func WithImageStopSignal(image Image, defaultSignal string) NewContainerOpts {
	return func(ctx context.Context, _ *Client, c *containers.Container) error {
		if c.Labels == nil {
			c.Labels = make(map[string]string)
		}
		stopSignal, err := GetOCIStopSignal(ctx, image, defaultSignal)
		if err != nil {
			return err
		}
		c.Labels[StopSignalLabel] = stopSignal
		return nil
	}
}

// WithSnapshotter sets the provided snapshotter for use by the container
//
// This option must appear before other snapshotter options to have an effect.
func WithSnapshotter(name string) NewContainerOpts {
	return func(ctx context.Context, client *Client, c *containers.Container) error {
		c.Snapshotter = name
		return nil
	}
}

// WithSnapshot uses an existing root filesystem for the container
func WithSnapshot(id string) NewContainerOpts {
	return func(ctx context.Context, client *Client, c *containers.Container) error {
		// check that the snapshot exists, if not, fail on creation
		var err error
		c.Snapshotter, err = client.resolveSnapshotterName(ctx, c.Snapshotter)
		if err != nil {
			return err
		}
		s, err := client.getSnapshotter(ctx, c.Snapshotter)
		if err != nil {
			return err
		}
		if _, err := s.Mounts(ctx, id); err != nil {
			return err
		}
		c.SnapshotKey = id
		return nil
	}
}

// WithSnapshotCleanup deletes the rootfs snapshot allocated for the container
func WithSnapshotCleanup(ctx context.Context, client *Client, c containers.Container) error {
	if c.SnapshotKey != "" {
		if c.Snapshotter == "" {
			return fmt.Errorf("container.Snapshotter must be set to cleanup rootfs snapshot: %w", errdefs.ErrInvalidArgument)
		}
		s, err := client.getSnapshotter(ctx, c.Snapshotter)
		if err != nil {
			return err
		}
		if err := s.Remove(ctx, c.SnapshotKey); err != nil && !errdefs.IsNotFound(err) {
			return err
		}
	}
	return nil
}

// WithNewSnapshot allocates a new snapshot to be used by the container as the
// root filesystem in read-write mode
func WithNewSnapshot(id string, i Image, opts ...snapshots.Opt) NewContainerOpts {
	return withNewSnapshot(id, i, false, opts...)
}

// WithNewSnapshotView allocates a new snapshot to be used by the container as the
// root filesystem in read-only mode
func WithNewSnapshotView(id string, i Image, opts ...snapshots.Opt) NewContainerOpts {
	return withNewSnapshot(id, i, true, opts...)
}

func withNewSnapshot(id string, i Image, readonly bool, opts ...snapshots.Opt) NewContainerOpts {
	return func(ctx context.Context, client *Client, c *containers.Container) error {
		diffIDs, err := i.RootFS(ctx)
		if err != nil {
			return err
		}

		parent := identity.ChainID(diffIDs).String()
		c.Snapshotter, err = client.resolveSnapshotterName(ctx, c.Snapshotter)
		if err != nil {
			return err
		}
		s, err := client.getSnapshotter(ctx, c.Snapshotter)
		if err != nil {
			return err
		}
		parent, err = resolveSnapshotOptions(ctx, client, c.Snapshotter, s, parent, opts...)
		if err != nil {
			return err
		}

		if readonly {
			_, err = s.View(ctx, id, parent, opts...)
		} else {
			_, err = s.Prepare(ctx, id, parent, opts...)
		}
		if err != nil {
			return err
		}
		c.SnapshotKey = id
		c.Image = i.Name()
		return nil
	}
}

// WithContainerExtension appends extension data to the container object.
// Use this to decorate the container object with additional data for the client
// integration.
//
// Make sure to register the type of `extension` in the typeurl package via
// `typeurl.Register` or container creation may fail.
func WithContainerExtension(name string, extension interface{}) NewContainerOpts {
	return func(ctx context.Context, client *Client, c *containers.Container) error {
		if name == "" {
			return fmt.Errorf("extension key must not be zero-length: %w", errdefs.ErrInvalidArgument)
		}

		ext, err := typeurl.MarshalAny(extension)
		if err != nil {
			if errors.Is(err, typeurl.ErrNotFound) {
				return fmt.Errorf("extension %q is not registered with the typeurl package, see `typeurl.Register`: %w", name, err)
			}
			return fmt.Errorf("error marshalling extension: %w", err)
		}

		if c.Extensions == nil {
			c.Extensions = make(map[string]typeurl.Any)
		}
		c.Extensions[name] = ext
		return nil
	}
}

// WithNewSpec generates a new spec for a new container
func WithNewSpec(opts ...oci.SpecOpts) NewContainerOpts {
	return func(ctx context.Context, client *Client, c *containers.Container) error {
		if _, ok := namespaces.Namespace(ctx); !ok {
			ctx = namespaces.WithNamespace(ctx, client.DefaultNamespace())
		}
		s, err := oci.GenerateSpec(ctx, client, c, opts...)
		if err != nil {
			return err
		}
		c.Spec, err = typeurl.MarshalAny(s)
		return err
	}
}

// WithSpec sets the provided spec on the container
func WithSpec(s *oci.Spec, opts ...oci.SpecOpts) NewContainerOpts {
	return func(ctx context.Context, client *Client, c *containers.Container) error {
		if err := oci.ApplyOpts(ctx, client, c, s, opts...); err != nil {
			return err
		}

		var err error
		c.Spec, err = typeurl.MarshalAnyToProto(s)
		return err
	}
}

// WithoutRefreshedMetadata will use the current metadata attached to the container object
func WithoutRefreshedMetadata(i *InfoConfig) {
	i.Refresh = false
}
