// Copyright 2016 CNI 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 version

import (
	"encoding/json"
	"fmt"

	"github.com/containernetworking/cni/pkg/types"
	"github.com/containernetworking/cni/pkg/types/020"
	"github.com/containernetworking/cni/pkg/types/current"
)

// Current reports the version of the CNI spec implemented by this library
func Current() string {
	return "0.4.0"
}

// Legacy PluginInfo describes a plugin that is backwards compatible with the
// CNI spec version 0.1.0.  In particular, a runtime compiled against the 0.1.0
// library ought to work correctly with a plugin that reports support for
// Legacy versions.
//
// Any future CNI spec versions which meet this definition should be added to
// this list.
var Legacy = PluginSupports("0.1.0", "0.2.0")
var All = PluginSupports("0.1.0", "0.2.0", "0.3.0", "0.3.1", "0.4.0")

var resultFactories = []struct {
	supportedVersions []string
	newResult         types.ResultFactoryFunc
}{
	{current.SupportedVersions, current.NewResult},
	{types020.SupportedVersions, types020.NewResult},
}

// Finds a Result object matching the requested version (if any) and asks
// that object to parse the plugin result, returning an error if parsing failed.
func NewResult(version string, resultBytes []byte) (types.Result, error) {
	reconciler := &Reconciler{}
	for _, resultFactory := range resultFactories {
		err := reconciler.CheckRaw(version, resultFactory.supportedVersions)
		if err == nil {
			// Result supports this version
			return resultFactory.newResult(resultBytes)
		}
	}

	return nil, fmt.Errorf("unsupported CNI result version %q", version)
}

// ParsePrevResult parses a prevResult in a NetConf structure and sets
// the NetConf's PrevResult member to the parsed Result object.
func ParsePrevResult(conf *types.NetConf) error {
	if conf.RawPrevResult == nil {
		return nil
	}

	resultBytes, err := json.Marshal(conf.RawPrevResult)
	if err != nil {
		return fmt.Errorf("could not serialize prevResult: %v", err)
	}

	conf.RawPrevResult = nil
	conf.PrevResult, err = NewResult(conf.CNIVersion, resultBytes)
	if err != nil {
		return fmt.Errorf("could not parse prevResult: %v", err)
	}

	return nil
}