package latest

import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"path"

	configapi "github.com/openshift/origin/pkg/cmd/server/api"
	"k8s.io/kubernetes/pkg/runtime"
	kyaml "k8s.io/kubernetes/pkg/util/yaml"

	"github.com/ghodss/yaml"
)

func ReadSessionSecrets(filename string) (*configapi.SessionSecrets, error) {
	config := &configapi.SessionSecrets{}
	if err := ReadYAMLFile(filename, config); err != nil {
		return nil, err
	}
	return config, nil
}

func ReadMasterConfig(filename string) (*configapi.MasterConfig, error) {
	config := &configapi.MasterConfig{}
	if err := ReadYAMLFile(filename, config); err != nil {
		return nil, err
	}
	return config, nil
}

func ReadAndResolveMasterConfig(filename string) (*configapi.MasterConfig, error) {
	masterConfig, err := ReadMasterConfig(filename)
	if err != nil {
		return nil, err
	}

	if err := configapi.ResolveMasterConfigPaths(masterConfig, path.Dir(filename)); err != nil {
		return nil, err
	}

	return masterConfig, nil
}

func ReadNodeConfig(filename string) (*configapi.NodeConfig, error) {
	config := &configapi.NodeConfig{}
	if err := ReadYAMLFile(filename, config); err != nil {
		return nil, err
	}
	return config, nil
}

func ReadAndResolveNodeConfig(filename string) (*configapi.NodeConfig, error) {
	nodeConfig, err := ReadNodeConfig(filename)
	if err != nil {
		return nil, err
	}

	if err := configapi.ResolveNodeConfigPaths(nodeConfig, path.Dir(filename)); err != nil {
		return nil, err
	}

	return nodeConfig, nil
}

func WriteYAML(obj runtime.Object) ([]byte, error) {
	json, err := Codec.Encode(obj)
	if err != nil {
		return nil, err
	}

	content, err := yaml.JSONToYAML(json)
	if err != nil {
		return nil, err
	}
	return content, err
}

func ReadYAMLFile(filename string, obj runtime.Object) error {
	data, err := ioutil.ReadFile(filename)
	if err != nil {
		return err
	}
	data, err = kyaml.ToJSON(data)
	if err != nil {
		return err
	}
	err = Codec.DecodeInto(data, obj)
	return captureSurroundingJSONForError(fmt.Sprintf("could not load config file %q due to a error: ", filename), data, err)
}

// TODO: we ultimately want a better decoder for JSON that allows us exact line numbers and better
// surrounding text description. This should be removed / replaced when that happens.
func captureSurroundingJSONForError(prefix string, data []byte, err error) error {
	if syntaxErr, ok := err.(*json.SyntaxError); err != nil && ok {
		offset := syntaxErr.Offset
		begin := offset - 20
		if begin < 0 {
			begin = 0
		}
		end := offset + 20
		if end > int64(len(data)) {
			end = int64(len(data))
		}
		return fmt.Errorf("%s%v (found near '%s')", prefix, err, string(data[begin:end]))
	}
	if err != nil {
		return fmt.Errorf("%s%v", prefix, err)
	}
	return err
}