package commands

import (
	"context"
	"fmt"
	"io"
	"os"
	"os/signal"
	"runtime"
	"runtime/pprof"
	"strings"
	"syscall"

	"github.com/spf13/cobra"

	"github.com/ledgerwatch/turbo-geth/log"
	"github.com/ledgerwatch/turbo-geth/node"
)

type Config struct {
	privateApiAddr    string
	chaindata         string
	httpListenAddress string
	httpPort          int
	httpCORSDomain    string
	httpVirtualHost   string
	API               string
	gascap            uint64
}

var (
	cpuprofile     string
	cpuProfileFile io.WriteCloser

	memprofile string
	cfg        Config
)

func init() {
	rootCmd.PersistentFlags().StringVar(&cpuprofile, "pprof.cpuprofile", "", "write cpu profile `file`")
	rootCmd.PersistentFlags().StringVar(&memprofile, "memprofile", "", "write memory profile `file`")
	rootCmd.Flags().StringVar(&cfg.privateApiAddr, "private.api.addr", "", "private api network address, for example: 127.0.0.1:9090, empty string means not to start the listener. do not expose to public network. serves remote database interface")
	rootCmd.Flags().StringVar(&cfg.chaindata, "chaindata", "", "path to the database")
	rootCmd.Flags().StringVar(&cfg.httpListenAddress, "http.addr", node.DefaultHTTPHost, "HTTP-RPC server listening interface")
	rootCmd.Flags().IntVar(&cfg.httpPort, "http.port", node.DefaultHTTPPort, "HTTP-RPC server listening port")
	rootCmd.Flags().StringVar(&cfg.httpCORSDomain, "http.corsdomain", "", "Comma separated list of domains from which to accept cross origin requests (browser enforced)")
	rootCmd.Flags().StringVar(&cfg.httpVirtualHost, "http.vhosts", strings.Join(node.DefaultConfig.HTTPVirtualHosts, ","), "Comma separated list of virtual hostnames from which to accept requests (server enforced). Accepts '*' wildcard.")
	rootCmd.Flags().StringVar(&cfg.API, "http.api", "", "API's offered over the HTTP-RPC interface")

	rootCmd.Flags().Uint64Var(&cfg.gascap, "rpc.gascap", 0, "Sets a cap on gas that can be used in eth_call/estimateGas")
}

var rootCmd = &cobra.Command{
	Use:   "rpcdaemon",
	Short: "rpcdaemon is JSON RPC server that connects to turbo-geth node for remote DB access",
	PersistentPreRun: func(cmd *cobra.Command, args []string) {
		startProfilingIfNeeded()

	},
	PersistentPostRun: func(cmd *cobra.Command, args []string) {
		stopProfilingIfNeeded()
	},
	RunE: func(cmd *cobra.Command, args []string) error {
		daemon(cmd, cfg)
		return nil
	},
}

func Execute() {
	if err := rootCmd.ExecuteContext(rootContext()); err != nil {
		fmt.Println(err)
		os.Exit(1)
	}
}

func rootContext() context.Context {
	ctx, cancel := context.WithCancel(context.Background())
	go func() {
		ch := make(chan os.Signal, 1)
		signal.Notify(ch, os.Interrupt, syscall.SIGTERM)
		defer signal.Stop(ch)

		select {
		case <-ch:
			log.Info("Got interrupt, shutting down...")
		case <-ctx.Done():
		}

		cancel()
	}()
	return ctx
}

func startProfilingIfNeeded() {
	if cpuprofile != "" {
		fmt.Println("starting CPU profiling")
		cpuProfileFile, err := os.Create(cpuprofile)
		if err != nil {
			log.Error("could not create CPU profile", "error", err)
			return
		}
		if err := pprof.StartCPUProfile(cpuProfileFile); err != nil {
			log.Error("could not start CPU profile", "error", err)
			return
		}
	}
}

func stopProfilingIfNeeded() {
	if cpuprofile != "" {
		fmt.Println("stopping CPU profiling")
		pprof.StopCPUProfile()
	}

	if cpuProfileFile != nil {
		cpuProfileFile.Close()
	}
	if memprofile != "" {
		f, err := os.Create(memprofile)
		if err != nil {
			log.Error("could not create mem profile", "error", err)
			return
		}
		runtime.GC() // get up-to-date statistics
		if err := pprof.WriteHeapProfile(f); err != nil {
			log.Error("could not write memory profile", "error", err)
			return
		}
	}
}