/*
Copyright IBM Corp. 2016 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 golang

import (
	"archive/tar"
	"errors"
	"fmt"

	"bytes"
	"encoding/hex"
	"io/ioutil"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"time"

	"github.com/golang/protobuf/proto"
	"github.com/hyperledger/fabric/common/flogging"
	"github.com/hyperledger/fabric/common/util"
	ccutil "github.com/hyperledger/fabric/core/chaincode/platforms/util"
	cutil "github.com/hyperledger/fabric/core/container/util"
	pb "github.com/hyperledger/fabric/protos/peer"
	"github.com/spf13/viper"
)

var includeFileTypes = map[string]bool{
	".c":    true,
	".h":    true,
	".go":   true,
	".yaml": true,
	".json": true,
}

var logger = flogging.MustGetLogger("golang-platform")

func getCodeFromHTTP(path string) (codegopath string, err error) {
	codegopath = ""
	err = nil
	logger.Debugf("getCodeFromHTTP %s", path)

	// The following could be done with os.Getenv("GOPATH") but we need to change it later so this prepares for that next step
	env := os.Environ()
	var origgopath string
	var gopathenvIndex int
	for i, v := range env {
		if strings.Index(v, "GOPATH=") == 0 {
			p := strings.SplitAfter(v, "GOPATH=")
			origgopath = p[1]
			gopathenvIndex = i
			break
		}
	}
	if origgopath == "" {
		err = errors.New("GOPATH not defined")
		return
	}
	// Only take the first element of GOPATH
	gopath := filepath.SplitList(origgopath)[0]

	// Define a new gopath in which to download the code
	newgopath := filepath.Join(gopath, "_usercode_")

	//ignore errors.. _usercode_ might exist. TempDir will catch any other errors
	os.Mkdir(newgopath, 0755)

	if codegopath, err = ioutil.TempDir(newgopath, ""); err != nil {
		err = fmt.Errorf("could not create tmp dir under %s(%s)", newgopath, err)
		return
	}

	//go paths can have multiple dirs. We create a GOPATH with two source tree's as follows
	//
	//    <temporary empty folder to download chaincode source> : <local go path with OBC source>
	//
	//This approach has several goodness:
	// . Go will pick the first path to download user code (which we will delete after processing)
	// . GO will not download OBC as it is in the second path. GO will use the local OBC for generating chaincode image
	//     . network savings
	//     . more secure
	//     . as we are not downloading OBC, private, password-protected OBC repo's become non-issue

	env[gopathenvIndex] = "GOPATH=" + codegopath + string(os.PathListSeparator) + origgopath

	// Use a 'go get' command to pull the chaincode from the given repo
	logger.Debugf("go get %s", path)
	cmd := exec.Command("go", "get", path)
	cmd.Env = env
	var out bytes.Buffer
	cmd.Stdout = &out
	var errBuf bytes.Buffer
	cmd.Stderr = &errBuf //capture Stderr and print it on error
	err = cmd.Start()

	// Create a go routine that will wait for the command to finish
	done := make(chan error, 1)
	go func() {
		done <- cmd.Wait()
	}()

	ccDeployTimeout := viper.GetDuration("chaincode.deploytimeout")
	if ccDeployTimeout < time.Duration(30)*time.Second {
		logger.Warningf("Invalid chaincode deploy timeout value %s (should be at least 30s); defaulting to 30s", ccDeployTimeout)
		ccDeployTimeout = time.Duration(30) * time.Second
	} else {
		logger.Debugf("Setting chaincode deploy timeout to %s", ccDeployTimeout)
	}
	select {
	case <-time.After(time.Duration(viper.GetInt("chaincode.deploytimeout")) * time.Millisecond):
		// If pulling repos takes too long, we should give up
		// (This can happen if a repo is private and the git clone asks for credentials)
		if err = cmd.Process.Kill(); err != nil {
			err = fmt.Errorf("failed to kill: %s", err)
		} else {
			err = errors.New("Getting chaincode took too long")
		}
	case err = <-done:
		// If we're here, the 'go get' command must have finished
		if err != nil {
			err = fmt.Errorf("'go get' failed with error: \"%s\"\n%s", err, string(errBuf.Bytes()))
		}
	}
	return
}

func getCodeFromFS(path string) (codegopath string, err error) {
	logger.Debugf("getCodeFromFS %s", path)
	gopath := os.Getenv("GOPATH")
	if gopath == "" {
		err = errors.New("GOPATH not defined")
		return
	}
	// Only take the first element of GOPATH
	codegopath = filepath.SplitList(gopath)[0]

	return
}

//collectChaincodeFiles collects chaincode files and generates hashcode for the
//package. If path is a HTTP(s) url it downloads the code first.
//NOTE: for dev mode, user builds and runs chaincode manually. The name provided
//by the user is equivalent to the path. This method will treat the name
//as codebytes and compute the hash from it. ie, user cannot run the chaincode
//with the same (name, input, args)
func collectChaincodeFiles(spec *pb.ChaincodeSpec, tw *tar.Writer) (string, error) {
	if spec == nil {
		return "", errors.New("Cannot collect files from nil spec")
	}

	chaincodeID := spec.ChaincodeId
	if chaincodeID == nil || chaincodeID.Path == "" {
		return "", errors.New("Cannot collect files from empty chaincode path")
	}

	//install will not have inputs and we don't have to collect hash for it
	var inputbytes []byte

	var err error
	if spec.Input == nil || len(spec.Input.Args) == 0 {
		logger.Debugf("not using input for hash computation for %v ", chaincodeID)
	} else {
		inputbytes, err = proto.Marshal(spec.Input)
		if err != nil {
			return "", fmt.Errorf("Error marshalling constructor: %s", err)
		}
	}

	//code root will point to the directory where the code exists
	//in the case of http it will be a temporary dir that
	//will have to be deleted
	var codegopath string

	var ishttp bool
	defer func() {
		if ishttp && codegopath != "" {
			os.RemoveAll(codegopath)
		}
	}()

	path := chaincodeID.Path

	var actualcodepath string
	if strings.HasPrefix(path, "http://") {
		ishttp = true
		actualcodepath = path[7:]
		codegopath, err = getCodeFromHTTP(actualcodepath)
	} else if strings.HasPrefix(path, "https://") {
		ishttp = true
		actualcodepath = path[8:]
		codegopath, err = getCodeFromHTTP(actualcodepath)
	} else {
		actualcodepath = path
		codegopath, err = getCodeFromFS(path)
	}

	if err != nil {
		return "", fmt.Errorf("Error getting code %s", err)
	}

	tmppath := filepath.Join(codegopath, "src", actualcodepath)
	if err = ccutil.IsCodeExist(tmppath); err != nil {
		return "", fmt.Errorf("code does not exist %s", err)
	}

	hash := []byte{}
	if inputbytes != nil {
		hash = util.GenerateHashFromSignature(actualcodepath, inputbytes)
	}

	hash, err = ccutil.HashFilesInDir(filepath.Join(codegopath, "src"), actualcodepath, hash, tw)
	if err != nil {
		return "", fmt.Errorf("Could not get hashcode for %s - %s\n", path, err)
	}

	return hex.EncodeToString(hash[:]), nil
}

//WriteGopathSrc tars up files under gopath src
func writeGopathSrc(tw *tar.Writer, excludeDir string) error {
	gopath := os.Getenv("GOPATH")
	// Only take the first element of GOPATH
	gopath = filepath.SplitList(gopath)[0]

	rootDirectory := filepath.Join(gopath, "src")
	logger.Infof("rootDirectory = %s", rootDirectory)

	if err := cutil.WriteFolderToTarPackage(tw, rootDirectory, excludeDir, includeFileTypes, nil); err != nil {
		logger.Errorf("Error writing folder to tar package %s", err)
		return err
	}

	// Write the tar file out
	if err := tw.Close(); err != nil {
		return err
	}
	//ioutil.WriteFile("/tmp/chaincode_deployment.tar", inputbuf.Bytes(), 0644)
	return nil
}

//tw is expected to have the chaincode in it from GenerateHashcode. This method
//will just package rest of the bytes
func writeChaincodePackage(spec *pb.ChaincodeSpec, tw *tar.Writer) error {

	urlLocation, err := decodeUrl(spec)
	if err != nil {
		return fmt.Errorf("could not decode url: %s", err)
	}

	err = writeGopathSrc(tw, urlLocation)
	if err != nil {
		return fmt.Errorf("Error writing Chaincode package contents: %s", err)
	}
	return nil
}