package command

import (
	"os"
	"os/signal"
	"strings"
	"syscall"
	"time"

	"contrib.go.opencensus.io/exporter/jaeger"
	"contrib.go.opencensus.io/exporter/ocagent"
	"contrib.go.opencensus.io/exporter/zipkin"
	"github.com/micro/cli"
	"github.com/micro/go-micro/config/cmd"
	gorun "github.com/micro/go-micro/runtime"
	openzipkin "github.com/openzipkin/zipkin-go"
	zipkinhttp "github.com/openzipkin/zipkin-go/reporter/http"
	"github.com/owncloud/ocis-pkg/log"
	"github.com/owncloud/ocis/pkg/config"
	"github.com/owncloud/ocis/pkg/flagset"
	"go.opencensus.io/stats/view"
	"go.opencensus.io/trace"
)

// Services to start as part of the fullstack option
var services = []string{
	"network",  // :8085
	"runtime",  // :8088
	"registry", // :8000
	"broker",   // :8001
	"store",    // :8002
	"tunnel",   // :8083
	"router",   // :8084
	"monitor",  // :????
	"debug",    // :????
	"proxy",    // :8081
	"api",      // :8080
	"web",      // :8082
	"bot",      // :????

	// extensions
	"hello",
	"phoenix",
	"graph",
	"ocs",
	"webdav",
}

// Server is the entrypoint for the server command.
func Server(cfg *config.Config) cli.Command {
	app := cli.Command{
		Name:     "server",
		Usage:    "Start fullstack server",
		Category: "Fullstack",
		Flags:    flagset.ServerWithConfig(cfg),
		Before: func(c *cli.Context) error {
			if cfg.HTTP.Root != "/" {
				cfg.HTTP.Root = strings.TrimSuffix(cfg.HTTP.Root, "/")
			}

			return nil
		},
		Action: func(c *cli.Context) error {
			logger := NewLogger(cfg)

			if cfg.Tracing.Enabled {
				switch t := cfg.Tracing.Type; t {
				case "agent":
					exporter, err := ocagent.NewExporter(
						ocagent.WithReconnectionPeriod(5*time.Second),
						ocagent.WithAddress(cfg.Tracing.Endpoint),
						ocagent.WithServiceName(cfg.Tracing.Service),
					)

					if err != nil {
						logger.Error().
							Err(err).
							Str("endpoint", cfg.Tracing.Endpoint).
							Str("collector", cfg.Tracing.Collector).
							Msg("Failed to create agent tracing")

						return err
					}

					trace.RegisterExporter(exporter)
					view.RegisterExporter(exporter)

				case "jaeger":
					exporter, err := jaeger.NewExporter(
						jaeger.Options{
							AgentEndpoint:     cfg.Tracing.Endpoint,
							CollectorEndpoint: cfg.Tracing.Collector,
							ServiceName:       cfg.Tracing.Service,
						},
					)

					if err != nil {
						logger.Error().
							Err(err).
							Str("endpoint", cfg.Tracing.Endpoint).
							Str("collector", cfg.Tracing.Collector).
							Msg("Failed to create jaeger tracing")

						return err
					}

					trace.RegisterExporter(exporter)

				case "zipkin":
					endpoint, err := openzipkin.NewEndpoint(
						cfg.Tracing.Service,
						cfg.Tracing.Endpoint,
					)

					if err != nil {
						logger.Error().
							Err(err).
							Str("endpoint", cfg.Tracing.Endpoint).
							Str("collector", cfg.Tracing.Collector).
							Msg("Failed to create zipkin tracing")

						return err
					}

					exporter := zipkin.NewExporter(
						zipkinhttp.NewReporter(
							cfg.Tracing.Collector,
						),
						endpoint,
					)

					trace.RegisterExporter(exporter)

				default:
					logger.Warn().
						Str("type", t).
						Msg("Unknown tracing backend")
				}

				trace.ApplyConfig(
					trace.Config{
						DefaultSampler: trace.AlwaysSample(),
					},
				)
			} else {
				logger.Debug().
					Msg("Tracing is not enabled")
			}

			mruntime := cmd.DefaultCmd.Options().Runtime

			// fork uses the micro runtime to fork go-micro services
			forkServices(logger, mruntime)

			// trap blocks until a kill signal is sent
			trap(logger, mruntime)
			return nil
		},
	}
	return app
}

func trap(logger log.Logger, runtime *gorun.Runtime) {
	shutdown := make(chan os.Signal, 1)
	signal.Notify(shutdown, syscall.SIGTERM, syscall.SIGINT, syscall.SIGQUIT)

	logger.Info().Msg("Starting service runtime")
	if err := (*runtime).Start(); err != nil {
		os.Exit(1)
	}

	logger.Info().Msgf("Service runtime started")

	// block until there is a value
	for range shutdown {
		logger.Info().Msg("shutdown signal received")
		logger.Info().Msg("stopping service runtime")
		close(shutdown)
	}

	if err := (*runtime).Stop(); err != nil {
		logger.Err(err)
	}

	logger.Info().Msgf("Service runtime shutdown")
	os.Exit(0)
}

func forkServices(logger log.Logger, runtime *gorun.Runtime) {
	env := os.Environ()

	for _, service := range services {
		args := []gorun.CreateOption{
			// the binary calls itself with the micro service as a subcommand as first argument
			gorun.WithCommand(os.Args[0], service),
			gorun.WithEnv(env),
			// and logs to STDOUT. Perhaps this can be overridden to use a log.Logger
			gorun.WithOutput(os.Stdout),
		}

		muService := &gorun.Service{Name: service}
		if err := (*runtime).Create(muService, args...); err != nil {
			logger.Error().Msgf("Failed to create runtime enviroment: %v", err)
		}
	}
}