// Copyright 2014 ISRG.  All rights reserved
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.

// This package provides utilities that underlie the specific commands.
// The idea is to make the specific command files very small, e.g.:
//
//    func main() {
//      app := cmd.NewAppShell("command-name")
//      app.Action = func(c cmd.Config) {
//        // command logic
//      }
//      app.Run()
//    }
//
// All commands share the same invocation pattern.  They take a single
// parameter "-config", which is the name of a JSON file containing
// the configuration for the app.  This JSON file is unmarshalled into
// a Config object, which is provided to the app.

package cmd

import (
	"encoding/json"
	"encoding/pem"
	"errors"
	"fmt"
	"io/ioutil"
	"log"
	"net"
	"net/http"
	_ "net/http/pprof"
	"os"
	"runtime"
	"time"

	"github.com/letsencrypt/boulder/Godeps/_workspace/src/github.com/cactus/go-statsd-client/statsd"
	cfsslConfig "github.com/letsencrypt/boulder/Godeps/_workspace/src/github.com/cloudflare/cfssl/config"
	"github.com/letsencrypt/boulder/Godeps/_workspace/src/github.com/codegangsta/cli"

	"github.com/letsencrypt/boulder/core"
	blog "github.com/letsencrypt/boulder/log"
	"github.com/letsencrypt/boulder/publisher"
)

// Config stores configuration parameters that applications
// will need.  For simplicity, we just lump them all into
// one struct, and use encoding/json to read it from a file.
//
// Note: NO DEFAULTS are provided.
type Config struct {
	ActivityMonitor struct {
		// DebugAddr is the address to run the /debug handlers on.
		DebugAddr string
	}

	// General
	AMQP struct {
		Server    string
		Insecure  bool
		RA        Queue
		VA        Queue
		SA        Queue
		CA        Queue
		OCSP      Queue
		Publisher Queue
		TLS       *TLSConfig
	}

	WFE struct {
		BaseURL       string
		ListenAddress string

		CertCacheDuration           string
		CertNoCacheExpirationWindow string
		IndexCacheDuration          string
		IssuerCacheDuration         string

		ShutdownStopTimeout string
		ShutdownKillTimeout string

		// DebugAddr is the address to run the /debug handlers on.
		DebugAddr string
	}

	CA CAConfig

	Monolith struct {
		// DebugAddr is the address to run the /debug handlers on.
		DebugAddr string
	}

	RA struct {
		// DebugAddr is the address to run the /debug handlers on.
		DebugAddr string
	}

	SA struct {
		DBConnect string

		// DebugAddr is the address to run the /debug handlers on.
		DebugAddr string
	}

	VA struct {
		UserAgent string

		PortConfig struct {
			SimpleHTTPPort  int
			SimpleHTTPSPort int
			DVSNIPort       int
		}
		// DebugAddr is the address to run the /debug handlers on.
		DebugAddr string
	}

	SQL struct {
		SQLDebug bool
	}

	Statsd struct {
		Server string
		Prefix string
	}

	Syslog struct {
		Network string
		Server  string
		Tag     string
	}

	Revoker struct {
		DBConnect string
	}

	Mailer struct {
		Server   string
		Port     string
		Username string
		Password string

		DBConnect string

		CertLimit int
		NagTimes  []string
		// Path to a text/template email template
		EmailTemplate string

		// DebugAddr is the address to run the /debug handlers on.
		DebugAddr string
	}

	OCSPResponder struct {
		// Source indicates the source of pre-signed OCSP responses to be used. It
		// can be a DBConnect string or a file URL. The file URL style is used
		// when responding from a static file for intermediates and roots.
		Source string

		Path          string
		ListenAddress string
		// MaxAge is the max-age to set in the Cache-Controler response
		// header. It is a time.Duration formatted string.
		MaxAge JSONDuration

		ShutdownStopTimeout string
		ShutdownKillTimeout string

		// DebugAddr is the address to run the /debug handlers on.
		DebugAddr string
	}

	OCSPUpdater struct {
		DBConnect       string
		MinTimeToExpiry string
		ResponseLimit   int

		// DebugAddr is the address to run the /debug handlers on.
		DebugAddr string
	}

	Publisher struct {
		CT publisher.CTConfig

		// DebugAddr is the address to run the /debug handlers on.
		DebugAddr string
	}

	ExternalCertImporter struct {
		CertsToImportCSVFilename   string
		DomainsToImportCSVFilename string
		CertsToRemoveCSVFilename   string
		StatsdRate                 float32
	}

	PA PAConfig

	Common struct {
		BaseURL string
		// Path to a PEM-encoded copy of the issuer certificate.
		IssuerCert string

		DNSResolver               string
		DNSTimeout                string
		DNSAllowLoopbackAddresses bool
	}

	CertChecker struct {
		Workers             int
		ReportDirectoryPath string
		DBConnect           string
	}

	SubscriberAgreementURL string
}

type CAConfig struct {
	Profile      string
	TestMode     bool
	DBConnect    string
	SerialPrefix int
	Key          KeyConfig
	// LifespanOCSP is how long OCSP responses are valid for; It should be longer
	// than the minTimeToExpiry field for the OCSP Updater.
	LifespanOCSP string
	// How long issued certificates are valid for, should match expiry field
	// in cfssl config.
	Expiry string
	// The maximum number of subjectAltNames in a single certificate
	MaxNames int
	CFSSL    cfsslConfig.Config

	// DebugAddr is the address to run the /debug handlers on.
	DebugAddr string
}

type PAConfig struct {
	DBConnect              string
	EnforcePolicyWhitelist bool
}

// KeyConfig should contain either a File path to a PEM-format private key,
// or a PKCS11Config defining how to load a module for an HSM.
type KeyConfig struct {
	File   string
	PKCS11 PKCS11Config
}

// PKCS11Config defines how to load a module for an HSM.
type PKCS11Config struct {
	Module          string
	TokenLabel      string
	PIN             string
	PrivateKeyLabel string
}

// TLSConfig reprents certificates and a key for authenticated TLS.
type TLSConfig struct {
	CertFile   *string
	KeyFile    *string
	CACertFile *string
}

// Queue describes a queue name
type Queue struct {
	Server string
}

// AppShell contains CLI Metadata
type AppShell struct {
	Action func(Config)
	Config func(*cli.Context, Config) Config
	App    *cli.App
}

func Version() string {
	return fmt.Sprintf("0.1.0 [%s]", core.GetBuildID())
}

// NewAppShell creates a basic AppShell object containing CLI metadata
func NewAppShell(name, usage string) (shell *AppShell) {
	app := cli.NewApp()

	app.Name = name
	app.Usage = usage
	app.Version = Version()
	app.Author = "Boulder contributors"
	app.Email = "ca-dev@letsencrypt.org"

	app.Flags = []cli.Flag{
		cli.StringFlag{
			Name:   "config",
			Value:  "config.json",
			EnvVar: "BOULDER_CONFIG",
			Usage:  "Path to Config JSON",
		},
	}

	return &AppShell{App: app}
}

// Run begins the application context, reading config and passing
// control to the default commandline action.
func (as *AppShell) Run() {
	as.App.Action = func(c *cli.Context) {
		configFileName := c.GlobalString("config")
		configJSON, err := ioutil.ReadFile(configFileName)
		FailOnError(err, "Unable to read config file")

		var config Config
		err = json.Unmarshal(configJSON, &config)
		FailOnError(err, "Failed to read configuration")

		if as.Config != nil {
			config = as.Config(c, config)
		}

		as.Action(config)
	}

	err := as.App.Run(os.Args)
	FailOnError(err, "Failed to run application")
}

// VersionString produces a friendly Application version string
func (as *AppShell) VersionString() string {
	return fmt.Sprintf("Versions: %s=(%s %s) Golang=(%s) BuildHost=(%s)", as.App.Name, core.GetBuildID(), core.GetBuildTime(), runtime.Version(), core.GetBuildHost())
}

// FailOnError exits and prints an error message if we encountered a problem
func FailOnError(err error, msg string) {
	if err != nil {
		// AUDIT[ Error Conditions ] 9cc4d537-8534-4970-8665-4b382abe82f3
		logger := blog.GetAuditLogger()
		logger.Err(fmt.Sprintf("%s: %s", msg, err))
		fmt.Fprintf(os.Stderr, "%s: %s\n", msg, err)
		os.Exit(1)
	}
}

// ProfileCmd runs forever, sending Go runtime statistics to StatsD.
func ProfileCmd(profileName string, stats statsd.Statter) {
	c := time.Tick(1 * time.Second)
	for range c {
		var memoryStats runtime.MemStats
		runtime.ReadMemStats(&memoryStats)

		stats.Gauge(fmt.Sprintf("%s.Gostats.Goroutines", profileName), int64(runtime.NumGoroutine()), 1.0)

		stats.Gauge(fmt.Sprintf("%s.Gostats.Heap.Alloc", profileName), int64(memoryStats.HeapAlloc), 1.0)
		stats.Gauge(fmt.Sprintf("%s.Gostats.Heap.Objects", profileName), int64(memoryStats.HeapObjects), 1.0)
		stats.Gauge(fmt.Sprintf("%s.Gostats.Heap.Idle", profileName), int64(memoryStats.HeapIdle), 1.0)
		stats.Gauge(fmt.Sprintf("%s.Gostats.Heap.InUse", profileName), int64(memoryStats.HeapInuse), 1.0)
		stats.Gauge(fmt.Sprintf("%s.Gostats.Heap.Released", profileName), int64(memoryStats.HeapReleased), 1.0)

		// Calculate average and last and convert from nanoseconds to milliseconds
		gcPauseAvg := (int64(memoryStats.PauseTotalNs) / int64(len(memoryStats.PauseNs))) / 1000000
		lastGC := int64(memoryStats.PauseNs[(memoryStats.NumGC+255)%256]) / 1000000
		stats.Timing(fmt.Sprintf("%s.Gostats.Gc.PauseAvg", profileName), gcPauseAvg, 1.0)
		stats.Gauge(fmt.Sprintf("%s.Gostats.Gc.LastPauseLatency", profileName), lastGC, 1.0)
		stats.Gauge(fmt.Sprintf("%s.Gostats.Gc.NextAt", profileName), int64(memoryStats.NextGC), 1.0)
	}
}

// LoadCert loads a PEM-formatted certificate from the provided path, returning
// it as a byte array, or an error if it couldn't be decoded.
func LoadCert(path string) (cert []byte, err error) {
	if path == "" {
		err = errors.New("Issuer certificate was not provided in config.")
		return
	}
	pemBytes, err := ioutil.ReadFile(path)
	if err != nil {
		return
	}

	block, _ := pem.Decode(pemBytes)
	if block == nil || block.Type != "CERTIFICATE" {
		err = errors.New("Invalid certificate value returned")
		return
	}

	cert = block.Bytes
	return
}

func DebugServer(addr string) {
	if addr == "" {
		log.Fatalf("unable to boot debug server because no address was given for it. Set debugAddr.")
	}
	ln, err := net.Listen("tcp", addr)
	if err != nil {
		log.Fatalf("unable to boot debug server on %#v", addr)
	}
	log.Printf("booting debug server at %#v", addr)
	log.Println(http.Serve(ln, nil))
}

type JSONDuration struct {
	time.Duration
}

var ErrDurationMustBeString = errors.New("cannot JSON unmarshal something other than a string into a JSONDuration")

func (d *JSONDuration) UnmarshalJSON(b []byte) error {
	s := ""
	err := json.Unmarshal(b, &s)
	if err != nil {
		if _, ok := err.(*json.UnmarshalTypeError); ok {
			return ErrDurationMustBeString
		}
		return err
	}
	dd, err := time.ParseDuration(s)
	d.Duration = dd
	return err
}

func (d JSONDuration) MarshalJSON() ([]byte, error) {
	return []byte(d.Duration.String()), nil
}