/*
Copyright IBM Corp. 2017 All Rights Reserved.

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 main

import (
	"io/ioutil"
	"os"
	"path/filepath"

	"github.com/hyperledger/fabric/common/ledger/blkstorage/fsblkstorage"
	"github.com/hyperledger/fabric/orderer/ledger"
	fileledger "github.com/hyperledger/fabric/orderer/ledger/file"
	jsonledger "github.com/hyperledger/fabric/orderer/ledger/json"
	ramledger "github.com/hyperledger/fabric/orderer/ledger/ram"
	config "github.com/hyperledger/fabric/orderer/localconfig"
)

func createLedgerFactory(conf *config.TopLevel) (ledger.Factory, string) {
	var lf ledger.Factory
	var ld string
	switch conf.General.LedgerType {
	case "file":
		ld = conf.FileLedger.Location
		if ld == "" {
			ld = createTempDir(conf.FileLedger.Prefix)
		}
		logger.Debug("Ledger dir:", ld)
		lf = fileledger.New(ld)
		// The file-based ledger stores the blocks for each channel
		// in a fsblkstorage.ChainsDir sub-directory that we have
		// to create separately. Otherwise the call to the ledger
		// Factory's ChainIDs below will fail (dir won't exist).
		createSubDir(ld, fsblkstorage.ChainsDir)
	case "json":
		ld = conf.FileLedger.Location
		if ld == "" {
			ld = createTempDir(conf.FileLedger.Prefix)
		}
		logger.Debug("Ledger dir:", ld)
		lf = jsonledger.New(ld)
	case "ram":
		fallthrough
	default:
		lf = ramledger.New(int(conf.RAMLedger.HistorySize))
	}
	return lf, ld
}

func createTempDir(dirPrefix string) string {
	dirPath, err := ioutil.TempDir("", dirPrefix)
	if err != nil {
		logger.Panic("Error creating temp dir:", err)
	}
	return dirPath
}

func createSubDir(parentDirPath string, subDir string) (string, bool) {
	var created bool
	subDirPath := filepath.Join(parentDirPath, subDir)
	if _, err := os.Stat(subDirPath); err != nil {
		if os.IsNotExist(err) {
			if err = os.Mkdir(subDirPath, 0755); err != nil {
				logger.Panic("Error creating sub dir:", err)
			}
			created = true
		}
	} else {
		logger.Debugf("Found %s sub-dir and using it", fsblkstorage.ChainsDir)
	}
	return subDirPath, created
}