package cli

import (
	"context"
	"fmt"
	"net/http"
	"path"
	"time"

	"github.com/ledgerwatch/turbo-geth/cmd/utils"
	"github.com/ledgerwatch/turbo-geth/core"
	"github.com/ledgerwatch/turbo-geth/ethdb"
	"github.com/ledgerwatch/turbo-geth/internal/debug"
	"github.com/ledgerwatch/turbo-geth/log"
	"github.com/ledgerwatch/turbo-geth/node"
	"github.com/ledgerwatch/turbo-geth/rpc"
	"github.com/ledgerwatch/turbo-geth/turbo/snapshotsync"
	"github.com/spf13/cobra"
)

type Flags struct {
	PrivateApiAddr       string
	SingleNodeMode       bool // TG's database can be read by separated processes on same machine - in read-only mode - with full support of transactions. It will share same "OS PageCache" with TG process.
	Datadir              string
	Chaindata            string
	SnapshotDir          string
	SnapshotMode         string
	HttpListenAddress    string
	TLSCertfile          string
	TLSCACert            string
	TLSKeyFile           string
	HttpPort             int
	HttpCORSDomain       []string
	HttpVirtualHost      []string
	API                  []string
	Gascap               uint64
	MaxTraces            uint64
	TraceType            string
	WebsocketEnabled     bool
	RpcAllowListFilePath string
}

var rootCmd = &cobra.Command{
	Use:   "rpcdaemon",
	Short: "rpcdaemon is JSON RPC server that connects to turbo-geth node for remote DB access",
}

func RootCommand() (*cobra.Command, *Flags) {
	utils.CobraFlags(rootCmd, append(debug.Flags, utils.MetricFlags...))

	cfg := &Flags{}
	rootCmd.PersistentFlags().StringVar(&cfg.PrivateApiAddr, "private.api.addr", "127.0.0.1:9090", "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.PersistentFlags().StringVar(&cfg.Datadir, "datadir", "", "path to turbo-geth working directory")
	rootCmd.PersistentFlags().StringVar(&cfg.Chaindata, "chaindata", "", "path to the database")
	rootCmd.PersistentFlags().StringVar(&cfg.SnapshotDir, "snapshot.dir", "", "path to snapshot dir(only for chaindata mode)")
	rootCmd.PersistentFlags().StringVar(&cfg.SnapshotMode, "snapshot.mode", "", `Configures the storage mode of the app(only for chaindata mode):
* h - use headers snapshot
* b - use bodies snapshot
* s - use state snapshot
* r - use receipts snapshot
`)
	rootCmd.PersistentFlags().StringVar(&cfg.HttpListenAddress, "http.addr", node.DefaultHTTPHost, "HTTP-RPC server listening interface")
	rootCmd.PersistentFlags().StringVar(&cfg.TLSCertfile, "tls.cert", "", "certificate for client side TLS handshake")
	rootCmd.PersistentFlags().StringVar(&cfg.TLSKeyFile, "tls.key", "", "key file for client side TLS handshake")
	rootCmd.PersistentFlags().StringVar(&cfg.TLSCACert, "tls.cacert", "", "CA certificate for client side TLS handshake")
	rootCmd.PersistentFlags().IntVar(&cfg.HttpPort, "http.port", node.DefaultHTTPPort, "HTTP-RPC server listening port")
	rootCmd.PersistentFlags().StringSliceVar(&cfg.HttpCORSDomain, "http.corsdomain", []string{}, "Comma separated list of domains from which to accept cross origin requests (browser enforced)")
	rootCmd.PersistentFlags().StringSliceVar(&cfg.HttpVirtualHost, "http.vhosts", node.DefaultConfig.HTTPVirtualHosts, "Comma separated list of virtual hostnames from which to accept requests (server enforced). Accepts '*' wildcard.")
	rootCmd.PersistentFlags().StringSliceVar(&cfg.API, "http.api", []string{"eth", "tg"}, "API's offered over the HTTP-RPC interface")
	rootCmd.PersistentFlags().Uint64Var(&cfg.Gascap, "rpc.gascap", 25000000, "Sets a cap on gas that can be used in eth_call/estimateGas")
	rootCmd.PersistentFlags().Uint64Var(&cfg.MaxTraces, "trace.maxtraces", 200, "Sets a limit on traces that can be returned in trace_filter")
	rootCmd.PersistentFlags().StringVar(&cfg.TraceType, "trace.type", "parity", "Specify the type of tracing [geth|parity*] (experimental)")
	rootCmd.PersistentFlags().BoolVar(&cfg.WebsocketEnabled, "ws", false, "Enable Websockets")
	rootCmd.PersistentFlags().StringVar(&cfg.RpcAllowListFilePath, "rpc.accessList", "", "Specify granular (method-by-method) API allowlist")

	if err := rootCmd.MarkPersistentFlagFilename("rpc.accessList", "json"); err != nil {
		panic(err)
	}
	if err := rootCmd.MarkPersistentFlagDirname("datadir"); err != nil {
		panic(err)
	}
	if err := rootCmd.MarkPersistentFlagDirname("chaindata"); err != nil {
		panic(err)
	}
	if err := rootCmd.MarkPersistentFlagDirname("snapshot.dir"); err != nil {
		panic(err)
	}

	rootCmd.PersistentPreRunE = func(cmd *cobra.Command, args []string) error {
		cfg.SingleNodeMode = cfg.Datadir != "" || cfg.Chaindata != ""
		if cfg.SingleNodeMode {
			if cfg.Datadir == "" {
				cfg.Datadir = node.DefaultDataDir()
			}
			if cfg.Chaindata == "" {
				cfg.Chaindata = path.Join(cfg.Datadir, "tg", "chaindata")
			}
			//if cfg.SnapshotDir == "" {
			//	cfg.SnapshotDir = path.Join(cfg.Datadir, "tg", "snapshot")
			//}
		}
		return nil
	}
	rootCmd.PersistentPostRunE = func(cmd *cobra.Command, args []string) error {
		utils.StopDebug()
		return nil
	}

	return rootCmd, cfg
}

func OpenDB(cfg Flags) (ethdb.RoKV, core.ApiBackend, error) {
	var db ethdb.RwKV
	var ethBackend core.ApiBackend
	var err error
	// Do not change the order of these checks. Chaindata needs to be checked first, because PrivateApiAddr has default value which is not ""
	// If PrivateApiAddr is checked first, the Chaindata option will never work
	if cfg.SingleNodeMode {
		if database, errOpen := ethdb.Open(cfg.Chaindata, true); errOpen == nil {
			db = database.RwKV()
		} else {
			err = errOpen
			_ = err
		}
		mode, innerErr := snapshotsync.SnapshotModeFromString(cfg.SnapshotMode)
		if innerErr != nil {
			return nil, nil, fmt.Errorf("can't process snapshot-mode err:%w", innerErr)
		}
		kv, innerErr := snapshotsync.WrapBySnapshotsFromDir(db, cfg.SnapshotDir, mode)
		if innerErr != nil {
			return nil, nil, fmt.Errorf("can't wrap by snapshots err:%w", innerErr)
		}
		db = kv
	}
	if cfg.PrivateApiAddr != "" {
		var remoteKv ethdb.RwKV
		remoteKv, err = ethdb.NewRemote().Path(cfg.PrivateApiAddr).Open(cfg.TLSCertfile, cfg.TLSKeyFile, cfg.TLSCACert)
		if err != nil {
			return nil, nil, fmt.Errorf("could not connect to remoteKv: %w", err)
		}
		ethBackend = core.NewRemoteBackend(remoteKv)
		if db == nil {
			db = remoteKv
		}
	} else {
		return nil, nil, fmt.Errorf("either remote db or lmdb must be specified")
	}

	return db, ethBackend, err
}

func StartRpcServer(ctx context.Context, cfg Flags, rpcAPI []rpc.API) error {
	// register apis and create handler stack
	httpEndpoint := fmt.Sprintf("%s:%d", cfg.HttpListenAddress, cfg.HttpPort)

	srv := rpc.NewServer()

	allowListForRPC, err := parseAllowListForRPC(cfg.RpcAllowListFilePath)
	if err != nil {
		return err
	}
	srv.SetAllowList(allowListForRPC)

	if err := node.RegisterApisFromWhitelist(rpcAPI, cfg.API, srv, false); err != nil {
		return fmt.Errorf("could not start register RPC apis: %w", err)
	}

	httpHandler := node.NewHTTPHandlerStack(srv, cfg.HttpCORSDomain, cfg.HttpVirtualHost)
	var wsHandler http.Handler
	if cfg.WebsocketEnabled {
		wsHandler = srv.WebsocketHandler([]string{"*"})
	}

	var handler http.Handler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if cfg.WebsocketEnabled && r.Method == "GET" {
			wsHandler.ServeHTTP(w, r)
		}
		httpHandler.ServeHTTP(w, r)
	})

	listener, _, err := node.StartHTTPEndpoint(httpEndpoint, rpc.DefaultHTTPTimeouts, handler)
	if err != nil {
		return fmt.Errorf("could not start RPC api: %w", err)
	}

	// TODO(tjayrush): remove TraceType
	if cfg.TraceType != "parity" {
		log.Info("Tracing output type: ", cfg.TraceType)
	}
	log.Info("HTTP endpoint opened", "url", httpEndpoint, "ws", cfg.WebsocketEnabled)

	defer func() {
		srv.Stop()
		shutdownCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
		defer cancel()
		_ = listener.Shutdown(shutdownCtx)
		log.Info("HTTP endpoint closed", "url", httpEndpoint)
	}()
	<-ctx.Done()
	log.Info("Exiting...")
	return nil
}