// Copyright 2017 clair authors
//
// 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 (
	"flag"
	"math/rand"
	"os"
	"os/exec"
	"os/signal"
	"runtime/pprof"
	"strings"
	"syscall"
	"time"

	"github.com/coreos/pkg/capnslog"

	"github.com/coreos/clair/api"
	"github.com/coreos/clair/api/context"
	"github.com/coreos/clair/config"
	"github.com/coreos/clair/database"
	"github.com/coreos/clair/notifier"
	"github.com/coreos/clair/pkg/stopper"
	"github.com/coreos/clair/updater"

	// Register database driver.
	_ "github.com/coreos/clair/database/pgsql"

	// Register extensions.
	_ "github.com/coreos/clair/ext/featurefmt/apk"
	_ "github.com/coreos/clair/ext/featurefmt/dpkg"
	_ "github.com/coreos/clair/ext/featurefmt/rpm"
	_ "github.com/coreos/clair/ext/featurens/alpinerelease"
	_ "github.com/coreos/clair/ext/featurens/aptsources"
	_ "github.com/coreos/clair/ext/featurens/lsbrelease"
	_ "github.com/coreos/clair/ext/featurens/osrelease"
	_ "github.com/coreos/clair/ext/featurens/redhatrelease"
	_ "github.com/coreos/clair/ext/imagefmt/aci"
	_ "github.com/coreos/clair/ext/imagefmt/docker"
	_ "github.com/coreos/clair/ext/notification/webhook"
	_ "github.com/coreos/clair/ext/vulnmdsrc/nvd"
	_ "github.com/coreos/clair/ext/vulnsrc/alpine"
	_ "github.com/coreos/clair/ext/vulnsrc/debian"
	_ "github.com/coreos/clair/ext/vulnsrc/oracle"
	_ "github.com/coreos/clair/ext/vulnsrc/rhel"
	_ "github.com/coreos/clair/ext/vulnsrc/ubuntu"
)

var log = capnslog.NewPackageLogger("github.com/coreos/clair/cmd/clair", "main")

func waitForSignals(signals ...os.Signal) {
	interrupts := make(chan os.Signal, 1)
	signal.Notify(interrupts, signals...)
	<-interrupts
}

func startCPUProfiling(path string) *os.File {
	f, err := os.Create(path)
	if err != nil {
		log.Fatalf("failed to create profile file: %s", err)
	}

	err = pprof.StartCPUProfile(f)
	if err != nil {
		log.Fatalf("failed to start CPU profiling: %s", err)
	}

	log.Info("started CPU profiling")

	return f
}

func stopCPUProfiling(f *os.File) {
	pprof.StopCPUProfile()
	f.Close()
	log.Info("stopped CPU profiling")
}

// Boot starts Clair instance with the provided config.
func Boot(config *config.Config) {
	rand.Seed(time.Now().UnixNano())
	st := stopper.NewStopper()

	// Open database
	db, err := database.Open(config.Database)
	if err != nil {
		log.Fatal(err)
	}
	defer db.Close()

	// Start notifier
	st.Begin()
	go notifier.Run(config.Notifier, db, st)

	// Start API
	st.Begin()
	go api.Run(config.API, &context.RouteContext{db, config.API}, st)
	st.Begin()
	go api.RunHealth(config.API, &context.RouteContext{db, config.API}, st)

	// Start updater
	st.Begin()
	go updater.Run(config.Updater, db, st)

	// Wait for interruption and shutdown gracefully.
	waitForSignals(syscall.SIGINT, syscall.SIGTERM)
	log.Info("Received interruption, gracefully stopping ...")
	st.Stop()
}

func main() {
	// Parse command-line arguments
	flag.CommandLine = flag.NewFlagSet(os.Args[0], flag.ExitOnError)
	flagConfigPath := flag.String("config", "/etc/clair/config.yaml", "Load configuration from the specified file.")
	flagCPUProfilePath := flag.String("cpu-profile", "", "Write a CPU profile to the specified file before exiting.")
	flagLogLevel := flag.String("log-level", "info", "Define the logging level.")
	flag.Parse()

	// Check for dependencies.
	for _, bin := range []string{"git", "bzr", "rpm", "xz"} {
		_, err := exec.LookPath(bin)
		if err != nil {
			log.Fatalf("failed to find dependency: %s", bin)
		}
	}

	// Load configuration
	config, err := config.Load(*flagConfigPath)
	if err != nil {
		log.Fatalf("failed to load configuration: %s", err)
	}

	// Initialize logging system
	logLevel, err := capnslog.ParseLevel(strings.ToUpper(*flagLogLevel))
	capnslog.SetGlobalLogLevel(logLevel)
	capnslog.SetFormatter(capnslog.NewPrettyFormatter(os.Stdout, false))

	// Enable CPU Profiling if specified
	if *flagCPUProfilePath != "" {
		defer stopCPUProfiling(startCPUProfiling(*flagCPUProfilePath))
	}

	Boot(config)
}