package main

import (
	_ "expvar"
	"fmt"
	_ "github.com/ipfs/go-ipfs/Godeps/_workspace/src/github.com/codahale/metrics/runtime"
	"net/http"
	_ "net/http/pprof"
	"os"
	"strings"

	ma "github.com/ipfs/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-multiaddr"
	cmds "github.com/ipfs/go-ipfs/commands"
	"github.com/ipfs/go-ipfs/core"
	commands "github.com/ipfs/go-ipfs/core/commands"
	corehttp "github.com/ipfs/go-ipfs/core/corehttp"
	"github.com/ipfs/go-ipfs/core/corerouting"
	peer "github.com/ipfs/go-ipfs/p2p/peer"
	fsrepo "github.com/ipfs/go-ipfs/repo/fsrepo"
	util "github.com/ipfs/go-ipfs/util"
)

const (
	initOptionKwd             = "init"
	routingOptionKwd          = "routing"
	routingOptionSupernodeKwd = "supernode"
	mountKwd                  = "mount"
	writableKwd               = "writable"
	ipfsMountKwd              = "mount-ipfs"
	ipnsMountKwd              = "mount-ipns"
	// apiAddrKwd    = "address-api"
	// swarmAddrKwd  = "address-swarm"
)

var daemonCmd = &cmds.Command{
	Helptext: cmds.HelpText{
		Tagline: "Run a network-connected IPFS node",
		ShortDescription: `
'ipfs daemon' runs a persistent IPFS daemon that can serve commands
over the network. Most applications that use IPFS will do so by
communicating with a daemon over the HTTP API. While the daemon is
running, calls to 'ipfs' commands will be sent over the network to
the daemon.

The daemon will start listening on ports on the network, which are
documented in (and can be modified through) 'ipfs config Addresses'.
For example, to change the 'Gateway' port:

    ipfs config Addresses.Gateway /ip4/127.0.0.1/tcp/8082

The API address can be changed the same way:

   ipfs config Addresses.API /ip4/127.0.0.1/tcp/5002

Make sure to restart the daemon after changing addresses.

By default, the gateway is only accessible locally. To expose it to other computers
in the network, use 0.0.0.0 as the ip address:

   ipfs config Addresses.Gateway /ip4/0.0.0.0/tcp/8080

Be careful if you expose the API. It is a security risk, as anyone could use control
your node remotely. If you need to control the node remotely, make sure to protect
the port as you would other services or database (firewall, authenticated proxy, etc).`,
	},

	Options: []cmds.Option{
		cmds.BoolOption(initOptionKwd, "Initialize IPFS with default settings if not already initialized"),
		cmds.StringOption(routingOptionKwd, "Overrides the routing option (dht, supernode)"),
		cmds.BoolOption(mountKwd, "Mounts IPFS to the filesystem"),
		cmds.BoolOption(writableKwd, "Enable writing objects (with POST, PUT and DELETE)"),
		cmds.StringOption(ipfsMountKwd, "Path to the mountpoint for IPFS (if using --mount)"),
		cmds.StringOption(ipnsMountKwd, "Path to the mountpoint for IPNS (if using --mount)"),

		// TODO: add way to override addresses. tricky part: updating the config if also --init.
		// cmds.StringOption(apiAddrKwd, "Address for the daemon rpc API (overrides config)"),
		// cmds.StringOption(swarmAddrKwd, "Address for the swarm socket (overrides config)"),
	},
	Subcommands: map[string]*cmds.Command{},
	Run:         daemonFunc,
}

// defaultMux tells mux to serve path using the default muxer. This is
// mostly useful to hook up things that register in the default muxer,
// and don't provide a convenient http.Handler entry point, such as
// expvar and http/pprof.
func defaultMux(path string) func(node *core.IpfsNode, mux *http.ServeMux) (*http.ServeMux, error) {
	return func(node *core.IpfsNode, mux *http.ServeMux) (*http.ServeMux, error) {
		mux.Handle(path, http.DefaultServeMux)
		return mux, nil
	}
}

func daemonFunc(req cmds.Request, res cmds.Response) {
	// let the user know we're going.
	fmt.Printf("Initializing daemon...\n")

	ctx := req.Context()

	go func() {
		select {
		case <-ctx.Context.Done():
			fmt.Println("Received interrupt signal, shutting down...")
		}
	}()

	// first, whether user has provided the initialization flag. we may be
	// running in an uninitialized state.
	initialize, _, err := req.Option(initOptionKwd).Bool()
	if err != nil {
		res.SetError(err, cmds.ErrNormal)
		return
	}

	if initialize {

		// now, FileExists is our best method of detecting whether IPFS is
		// configured. Consider moving this into a config helper method
		// `IsInitialized` where the quality of the signal can be improved over
		// time, and many call-sites can benefit.
		if !util.FileExists(req.Context().ConfigRoot) {
			err := initWithDefaults(os.Stdout, req.Context().ConfigRoot)
			if err != nil {
				res.SetError(err, cmds.ErrNormal)
				return
			}
		}
	}

	// acquire the repo lock _before_ constructing a node. we need to make
	// sure we are permitted to access the resources (datastore, etc.)
	repo, err := fsrepo.Open(req.Context().ConfigRoot)
	if err != nil {
		res.SetError(err, cmds.ErrNormal)
		return
	}

	cfg, err := ctx.GetConfig()
	if err != nil {
		res.SetError(err, cmds.ErrNormal)
		return
	}

	// Start assembling corebuilder
	nb := core.NewNodeBuilder().Online()
	nb.SetRepo(repo)

	routingOption, _, err := req.Option(routingOptionKwd).String()
	if err != nil {
		res.SetError(err, cmds.ErrNormal)
		return
	}
	if routingOption == routingOptionSupernodeKwd {
		servers, err := repo.Config().SupernodeRouting.ServerIPFSAddrs()
		if err != nil {
			res.SetError(err, cmds.ErrNormal)
			repo.Close() // because ownership hasn't been transferred to the node
			return
		}
		var infos []peer.PeerInfo
		for _, addr := range servers {
			infos = append(infos, peer.PeerInfo{
				ID:    addr.ID(),
				Addrs: []ma.Multiaddr{addr.Transport()},
			})
		}
		nb.SetRouting(corerouting.SupernodeClient(infos...))
	}

	node, err := nb.Build(ctx.Context)
	if err != nil {
		log.Error("error from node construction: ", err)
		res.SetError(err, cmds.ErrNormal)
		return
	}

	defer func() {
		// We wait for the node to close first, as the node has children
		// that it will wait for before closing, such as the API server.
		node.Close()

		select {
		case <-ctx.Context.Done():
			log.Info("Gracefully shut down daemon")
		default:
		}
	}()

	req.Context().ConstructNode = func() (*core.IpfsNode, error) {
		return node, nil
	}

	// verify api address is valid multiaddr
	apiMaddr, err := ma.NewMultiaddr(cfg.Addresses.API)
	if err != nil {
		res.SetError(err, cmds.ErrNormal)
		return
	}

	var gatewayMaddr ma.Multiaddr
	if len(cfg.Addresses.Gateway) > 0 {
		// ignore error for gateway address
		// if there is an error (invalid address), then don't run the gateway
		gatewayMaddr, _ = ma.NewMultiaddr(cfg.Addresses.Gateway)
		if gatewayMaddr == nil {
			log.Errorf("Invalid gateway address: %s", cfg.Addresses.Gateway)
		}
	}

	// mount if the user provided the --mount flag
	mount, _, err := req.Option(mountKwd).Bool()
	if err != nil {
		res.SetError(err, cmds.ErrNormal)
		return
	}
	if mount {
		fsdir, found, err := req.Option(ipfsMountKwd).String()
		if err != nil {
			res.SetError(err, cmds.ErrNormal)
			return
		}
		if !found {
			fsdir = cfg.Mounts.IPFS
		}

		nsdir, found, err := req.Option(ipnsMountKwd).String()
		if err != nil {
			res.SetError(err, cmds.ErrNormal)
			return
		}
		if !found {
			nsdir = cfg.Mounts.IPNS
		}

		err = commands.Mount(node, fsdir, nsdir)
		if err != nil {
			res.SetError(err, cmds.ErrNormal)
			return
		}
		fmt.Printf("IPFS mounted at: %s\n", fsdir)
		fmt.Printf("IPNS mounted at: %s\n", nsdir)
	}

	var rootRedirect corehttp.ServeOption
	if len(cfg.Gateway.RootRedirect) > 0 {
		rootRedirect = corehttp.RedirectOption("", cfg.Gateway.RootRedirect)
	}

	writable, writableOptionFound, err := req.Option(writableKwd).Bool()
	if err != nil {
		res.SetError(err, cmds.ErrNormal)
		return
	}
	if !writableOptionFound {
		writable = cfg.Gateway.Writable
	}

	if gatewayMaddr != nil {
		go func() {
			var opts = []corehttp.ServeOption{
				corehttp.VersionOption(),
				corehttp.IPNSHostnameOption(),
				corehttp.GatewayOption(writable),
			}
			if rootRedirect != nil {
				opts = append(opts, rootRedirect)
			}
			if writable {
				fmt.Printf("Gateway (writable) server listening on %s\n", gatewayMaddr)
			} else {
				fmt.Printf("Gateway (readonly) server listening on %s\n", gatewayMaddr)
			}
			err := corehttp.ListenAndServe(node, gatewayMaddr.String(), opts...)
			if err != nil {
				log.Error(err)
			}
		}()
	}

	gateway := corehttp.NewGateway(corehttp.GatewayConfig{
		Writable: true,
		BlockList: &corehttp.BlockList{
			Decider: func(s string) bool {
				// for now, only allow paths in the WebUI path
				for _, webuipath := range corehttp.WebUIPaths {
					if strings.HasPrefix(s, webuipath) {
						return true
					}
				}
				return false
			},
		},
	})
	var opts = []corehttp.ServeOption{
		corehttp.CommandsOption(*req.Context()),
		corehttp.WebUIOption,
		gateway.ServeOption(),
		corehttp.VersionOption(),
		defaultMux("/debug/vars"),
		defaultMux("/debug/pprof/"),
	}

	if rootRedirect != nil {
		opts = append(opts, rootRedirect)
	}
	fmt.Printf("API server listening on %s\n", apiMaddr)
	if err := corehttp.ListenAndServe(node, apiMaddr.String(), opts...); err != nil {
		res.SetError(err, cmds.ErrNormal)
		return
	}
}