/*
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 (
	"fmt"
	"io"
	"os"
	"path/filepath"
	"text/template"

	"gopkg.in/yaml.v2"

	"gopkg.in/alecthomas/kingpin.v2"

	"bytes"
	"io/ioutil"

	"github.com/hyperledger/fabric/common/tools/cryptogen/ca"
	"github.com/hyperledger/fabric/common/tools/cryptogen/metadata"
	"github.com/hyperledger/fabric/common/tools/cryptogen/msp"
)

const (
	userBaseName            = "User"
	adminBaseName           = "Admin"
	defaultHostnameTemplate = "{{.Prefix}}{{.Index}}"
	defaultCNTemplate       = "{{.Hostname}}.{{.Domain}}"
)

type HostnameData struct {
	Prefix string
	Index  int
	Domain string
}

type SpecData struct {
	Hostname   string
	Domain     string
	CommonName string
}

type NodeTemplate struct {
	Count    int      `yaml:"Count"`
	Start    int      `yaml:"Start"`
	Hostname string   `yaml:"Hostname"`
	SANS     []string `yaml:"SANS"`
}

type NodeSpec struct {
	Hostname   string   `yaml:"Hostname"`
	CommonName string   `yaml:"CommonName"`
	SANS       []string `yaml:"SANS"`
}

type UsersSpec struct {
	Count int `yaml:"Count"`
}

type OrgSpec struct {
	Name     string       `yaml:"Name"`
	Domain   string       `yaml:"Domain"`
	CA       NodeSpec     `yaml:"CA"`
	Template NodeTemplate `yaml:"Template"`
	Specs    []NodeSpec   `yaml:"Specs"`
	Users    UsersSpec    `yaml:"Users"`
}

type Config struct {
	OrdererOrgs []OrgSpec `yaml:"OrdererOrgs"`
	PeerOrgs    []OrgSpec `yaml:"PeerOrgs"`
}

var defaultConfig = `
# ---------------------------------------------------------------------------
# "OrdererOrgs" - Definition of organizations managing orderer nodes
# ---------------------------------------------------------------------------
OrdererOrgs:
  # ---------------------------------------------------------------------------
  # Orderer
  # ---------------------------------------------------------------------------
  - Name: Orderer
    Domain: example.com

    # ---------------------------------------------------------------------------
    # "Specs" - See PeerOrgs below for complete description
    # ---------------------------------------------------------------------------
    Specs:
      - Hostname: orderer

# ---------------------------------------------------------------------------
# "PeerOrgs" - Definition of organizations managing peer nodes
# ---------------------------------------------------------------------------
PeerOrgs:
  # ---------------------------------------------------------------------------
  # Org1
  # ---------------------------------------------------------------------------
  - Name: Org1
    Domain: org1.example.com

    # ---------------------------------------------------------------------------
    # "CA"
    # ---------------------------------------------------------------------------
    # Uncomment this section to enable the explicit definition of the CA for this
    # organization.  This entry is a Spec.  See "Specs" section below for details.
    # ---------------------------------------------------------------------------
    # CA:
    #    Hostname: ca # implicitly ca.org1.example.com

    # ---------------------------------------------------------------------------
    # "Specs"
    # ---------------------------------------------------------------------------
    # Uncomment this section to enable the explicit definition of hosts in your
    # configuration.  Most users will want to use Template, below
    #
    # Specs is an array of Spec entries.  Each Spec entry consists of two fields:
    #   - Hostname:   (Required) The desired hostname, sans the domain.
    #   - CommonName: (Optional) Specifies the template or explicit override for
    #                 the CN.  By default, this is the template:
    #
    #                              "{{.Hostname}}.{{.Domain}}"
    #
    #                 which obtains its values from the Spec.Hostname and
    #                 Org.Domain, respectively.
    #   - SANS:       (Optional) Specifies one or more Subject Alternative Names
    #                 the be set in the resulting x509.  Accepts template
    #                 variables {{.Hostname}}, {{.Domain}}, {{.CommonName}}
    #                 NOTE: Two implicit entries are created for you:
    #                     - {{ .CommonName }}
    #                     - {{ .Hostname }}
    # ---------------------------------------------------------------------------
    # Specs:
    #   - Hostname: foo # implicitly "foo.org1.example.com"
    #     CommonName: foo27.org5.example.com # overrides Hostname-based FQDN set above
    #     SANS:
    #       - "bar.{{.Domain}}"
    #       - "altfoo.{{.Domain}}"
    #       - "{{.Hostname}}.org6.net"
    #   - Hostname: bar
    #   - Hostname: baz

    # ---------------------------------------------------------------------------
    # "Template"
    # ---------------------------------------------------------------------------
    # Allows for the definition of 1 or more hosts that are created sequentially
    # from a template. By default, this looks like "peer%d" from 0 to Count-1.
    # You may override the number of nodes (Count), the starting index (Start)
    # or the template used to construct the name (Hostname).
    #
    # Note: Template and Specs are not mutually exclusive.  You may define both
    # sections and the aggregate nodes will be created for you.  Take care with
    # name collisions
    # ---------------------------------------------------------------------------
    Template:
      Count: 1
      # Start: 5
      # Hostname: {{.Prefix}}{{.Index}} # default
      # SANS:
      #   - "{{.Hostname}}.alt.{{.Domain}}"

    # ---------------------------------------------------------------------------
    # "Users"
    # ---------------------------------------------------------------------------
    # Count: The number of user accounts _in addition_ to Admin
    # ---------------------------------------------------------------------------
    Users:
      Count: 1

  # ---------------------------------------------------------------------------
  # Org2: See "Org1" for full specification
  # ---------------------------------------------------------------------------
  - Name: Org2
    Domain: org2.example.com
    Template:
      Count: 1
    Users:
      Count: 1
`

//command line flags
var (
	app = kingpin.New("cryptogen", "Utility for generating Hyperledger Fabric key material")

	gen        = app.Command("generate", "Generate key material")
	outputDir  = gen.Flag("output", "The output directory in which to place artifacts").Default("crypto-config").String()
	configFile = gen.Flag("config", "The configuration template to use").File()

	showtemplate = app.Command("showtemplate", "Show the default configuration template")

	version = app.Command("version", "Show version information")
)

func main() {
	kingpin.Version("0.0.1")
	switch kingpin.MustParse(app.Parse(os.Args[1:])) {

	// "generate" command
	case gen.FullCommand():
		generate()

	// "showtemplate" command
	case showtemplate.FullCommand():
		fmt.Print(defaultConfig)
		os.Exit(0)

	// "version" command
	case version.FullCommand():
		printVersion()
	}

}

func getConfig() (*Config, error) {
	var configData string

	if *configFile != nil {
		data, err := ioutil.ReadAll(*configFile)
		if err != nil {
			return nil, fmt.Errorf("Error reading configuration: %s", err)
		}

		configData = string(data)
	} else {
		configData = defaultConfig
	}

	config := &Config{}
	err := yaml.Unmarshal([]byte(configData), &config)
	if err != nil {
		return nil, fmt.Errorf("Error Unmarshaling YAML: %s", err)
	}

	return config, nil
}

func generate() {

	config, err := getConfig()
	if err != nil {
		fmt.Printf("Error reading config: %s", err)
		os.Exit(-1)
	}

	for _, orgSpec := range config.PeerOrgs {
		err = renderOrgSpec(&orgSpec, "peer")
		if err != nil {
			fmt.Printf("Error processing peer configuration: %s", err)
			os.Exit(-1)
		}
		generatePeerOrg(*outputDir, orgSpec)
	}

	for _, orgSpec := range config.OrdererOrgs {
		renderOrgSpec(&orgSpec, "orderer")
		if err != nil {
			fmt.Printf("Error processing orderer configuration: %s", err)
			os.Exit(-1)
		}
		generateOrdererOrg(*outputDir, orgSpec)
	}
}

func parseTemplate(input string, data interface{}) (string, error) {

	t, err := template.New("parse").Parse(input)
	if err != nil {
		return "", fmt.Errorf("Error parsing template: %s", err)
	}

	output := new(bytes.Buffer)
	err = t.Execute(output, data)
	if err != nil {
		return "", fmt.Errorf("Error executing template: %s", err)
	}

	return output.String(), nil
}

func parseTemplateWithDefault(input, defaultInput string, data interface{}) (string, error) {

	// Use the default if the input is an empty string
	if len(input) == 0 {
		input = defaultInput
	}

	return parseTemplate(input, data)
}

func renderNodeSpec(domain string, spec *NodeSpec) error {
	data := SpecData{
		Hostname: spec.Hostname,
		Domain:   domain,
	}

	// Process our CommonName
	cn, err := parseTemplateWithDefault(spec.CommonName, defaultCNTemplate, data)
	if err != nil {
		return err
	}

	spec.CommonName = cn
	data.CommonName = cn

	// Save off our original, unprocessed SANS entries
	origSANS := spec.SANS

	// Set our implicit SANS entries for CN/Hostname
	spec.SANS = []string{cn, spec.Hostname}

	// Finally, process any remaining SANS entries
	for _, _san := range origSANS {
		san, err := parseTemplate(_san, data)
		if err != nil {
			return err
		}

		spec.SANS = append(spec.SANS, san)
	}

	return nil
}

func renderOrgSpec(orgSpec *OrgSpec, prefix string) error {
	// First process all of our templated nodes
	for i := 0; i < orgSpec.Template.Count; i++ {
		data := HostnameData{
			Prefix: prefix,
			Index:  i + orgSpec.Template.Start,
			Domain: orgSpec.Domain,
		}

		hostname, err := parseTemplateWithDefault(orgSpec.Template.Hostname, defaultHostnameTemplate, data)
		if err != nil {
			return err
		}

		spec := NodeSpec{
			Hostname: hostname,
			SANS:     orgSpec.Template.SANS,
		}
		orgSpec.Specs = append(orgSpec.Specs, spec)
	}

	// Touch up all general node-specs to add the domain
	for idx, spec := range orgSpec.Specs {
		err := renderNodeSpec(orgSpec.Domain, &spec)
		if err != nil {
			return err
		}

		orgSpec.Specs[idx] = spec
	}

	// Process the CA node-spec in the same manner
	if len(orgSpec.CA.Hostname) == 0 {
		orgSpec.CA.Hostname = "ca"
	}
	err := renderNodeSpec(orgSpec.Domain, &orgSpec.CA)
	if err != nil {
		return err
	}

	return nil
}

func generatePeerOrg(baseDir string, orgSpec OrgSpec) {

	orgName := orgSpec.Domain

	fmt.Println(orgName)
	// generate CAs
	orgDir := filepath.Join(baseDir, "peerOrganizations", orgName)
	caDir := filepath.Join(orgDir, "ca")
	tlsCADir := filepath.Join(orgDir, "tlsca")
	mspDir := filepath.Join(orgDir, "msp")
	peersDir := filepath.Join(orgDir, "peers")
	usersDir := filepath.Join(orgDir, "users")
	adminCertsDir := filepath.Join(mspDir, "admincerts")
	// generate signing CA
	signCA, err := ca.NewCA(caDir, orgName, orgSpec.CA.CommonName)
	if err != nil {
		fmt.Printf("Error generating signCA for org %s:\n%v\n", orgName, err)
		os.Exit(1)
	}
	// generate TLS CA
	tlsCA, err := ca.NewCA(tlsCADir, orgName, "tls"+orgSpec.CA.CommonName)
	if err != nil {
		fmt.Printf("Error generating tlsCA for org %s:\n%v\n", orgName, err)
		os.Exit(1)
	}

	err = msp.GenerateVerifyingMSP(mspDir, signCA, tlsCA)
	if err != nil {
		fmt.Printf("Error generating MSP for org %s:\n%v\n", orgName, err)
		os.Exit(1)
	}

	generateNodes(peersDir, orgSpec.Specs, signCA, tlsCA)

	// TODO: add ability to specify usernames
	users := []NodeSpec{}
	for j := 1; j <= orgSpec.Users.Count; j++ {
		user := NodeSpec{
			CommonName: fmt.Sprintf("%s%d@%s", userBaseName, j, orgName),
		}

		users = append(users, user)
	}
	// add an admin user
	adminUser := NodeSpec{
		CommonName: fmt.Sprintf("%s@%s", adminBaseName, orgName),
	}

	users = append(users, adminUser)
	generateNodes(usersDir, users, signCA, tlsCA)

	// copy the admin cert to the org's MSP admincerts
	err = copyAdminCert(usersDir, adminCertsDir, adminUser.CommonName)
	if err != nil {
		fmt.Printf("Error copying admin cert for org %s:\n%v\n",
			orgName, err)
		os.Exit(1)
	}

	// copy the admin cert to each of the org's peer's MSP admincerts
	for _, spec := range orgSpec.Specs {
		err = copyAdminCert(usersDir,
			filepath.Join(peersDir, spec.CommonName, "msp", "admincerts"), adminUser.CommonName)
		if err != nil {
			fmt.Printf("Error copying admin cert for org %s peer %s:\n%v\n",
				orgName, spec.CommonName, err)
			os.Exit(1)
		}
	}
}

func copyAdminCert(usersDir, adminCertsDir, adminUserName string) error {
	// delete the contents of admincerts
	err := os.RemoveAll(adminCertsDir)
	if err != nil {
		return err
	}
	// recreate the admincerts directory
	err = os.MkdirAll(adminCertsDir, 0755)
	if err != nil {
		return err
	}
	err = copyFile(filepath.Join(usersDir, adminUserName, "msp", "signcerts",
		adminUserName+"-cert.pem"), filepath.Join(adminCertsDir,
		adminUserName+"-cert.pem"))
	if err != nil {
		return err
	}
	return nil

}

func generateNodes(baseDir string, nodes []NodeSpec, signCA *ca.CA, tlsCA *ca.CA) {

	for _, node := range nodes {
		nodeDir := filepath.Join(baseDir, node.CommonName)
		err := msp.GenerateLocalMSP(nodeDir, node.CommonName, node.SANS, signCA, tlsCA)
		if err != nil {
			fmt.Printf("Error generating local MSP for %s:\n%v\n", node, err)
			os.Exit(1)
		}
	}
}

func generateOrdererOrg(baseDir string, orgSpec OrgSpec) {

	orgName := orgSpec.Domain

	// generate CAs
	orgDir := filepath.Join(baseDir, "ordererOrganizations", orgName)
	caDir := filepath.Join(orgDir, "ca")
	tlsCADir := filepath.Join(orgDir, "tlsca")
	mspDir := filepath.Join(orgDir, "msp")
	orderersDir := filepath.Join(orgDir, "orderers")
	usersDir := filepath.Join(orgDir, "users")
	adminCertsDir := filepath.Join(mspDir, "admincerts")
	// generate signing CA
	signCA, err := ca.NewCA(caDir, orgName, orgSpec.CA.CommonName)
	if err != nil {
		fmt.Printf("Error generating signCA for org %s:\n%v\n", orgName, err)
		os.Exit(1)
	}
	// generate TLS CA
	tlsCA, err := ca.NewCA(tlsCADir, orgName, "tls"+orgSpec.CA.CommonName)
	if err != nil {
		fmt.Printf("Error generating tlsCA for org %s:\n%v\n", orgName, err)
		os.Exit(1)
	}

	err = msp.GenerateVerifyingMSP(mspDir, signCA, tlsCA)
	if err != nil {
		fmt.Printf("Error generating MSP for org %s:\n%v\n", orgName, err)
		os.Exit(1)
	}

	generateNodes(orderersDir, orgSpec.Specs, signCA, tlsCA)

	adminUser := NodeSpec{
		CommonName: fmt.Sprintf("%s@%s", adminBaseName, orgName),
	}

	// generate an admin for the orderer org
	users := []NodeSpec{}
	// add an admin user
	users = append(users, adminUser)
	generateNodes(usersDir, users, signCA, tlsCA)

	// copy the admin cert to the org's MSP admincerts
	err = copyAdminCert(usersDir, adminCertsDir, adminUser.CommonName)
	if err != nil {
		fmt.Printf("Error copying admin cert for org %s:\n%v\n",
			orgName, err)
		os.Exit(1)
	}

	// copy the admin cert to each of the org's orderers's MSP admincerts
	for _, spec := range orgSpec.Specs {
		err = copyAdminCert(usersDir,
			filepath.Join(orderersDir, spec.CommonName, "msp", "admincerts"), adminUser.CommonName)
		if err != nil {
			fmt.Printf("Error copying admin cert for org %s orderer %s:\n%v\n",
				orgName, spec.CommonName, err)
			os.Exit(1)
		}
	}

}

func copyFile(src, dst string) error {
	in, err := os.Open(src)
	if err != nil {
		return err
	}
	defer in.Close()
	out, err := os.Create(dst)
	if err != nil {
		return err
	}
	defer out.Close()
	_, err = io.Copy(out, in)
	cerr := out.Close()
	if err != nil {
		return err
	}
	return cerr
}

func printVersion() {
	fmt.Println(metadata.GetVersionInfo())
}