package main

import (
	"bytes"
	"encoding/base64"
	"fmt"
	"os"
	"path"
	"path/filepath"

	context "github.com/jbenet/go-ipfs/Godeps/_workspace/src/code.google.com/p/go.net/context"
	cmds "github.com/jbenet/go-ipfs/commands"
	config "github.com/jbenet/go-ipfs/config"
	core "github.com/jbenet/go-ipfs/core"
	corecmds "github.com/jbenet/go-ipfs/core/commands"
	imp "github.com/jbenet/go-ipfs/importer"
	chunk "github.com/jbenet/go-ipfs/importer/chunk"
	ci "github.com/jbenet/go-ipfs/p2p/crypto"
	peer "github.com/jbenet/go-ipfs/p2p/peer"
	repo "github.com/jbenet/go-ipfs/repo"
	u "github.com/jbenet/go-ipfs/util"
	debugerror "github.com/jbenet/go-ipfs/util/debugerror"
)

const nBitsForKeypairDefault = 4096

var initCmd = &cmds.Command{
	Helptext: cmds.HelpText{
		Tagline:          "Initializes IPFS config file",
		ShortDescription: "Initializes IPFS configuration files and generates a new keypair.",
	},

	Options: []cmds.Option{
		cmds.IntOption("bits", "b", "Number of bits to use in the generated RSA private key (defaults to 4096)"),
		cmds.StringOption("passphrase", "p", "Passphrase for encrypting the private key"),
		cmds.BoolOption("force", "f", "Overwrite existing config (if it exists)"),
		cmds.StringOption("datastore", "d", "Location for the IPFS data store"),

		// TODO need to decide whether to expose the override as a file or a
		// directory. That is: should we allow the user to also specify the
		// name of the file?
		// TODO cmds.StringOption("event-logs", "l", "Location for machine-readable event logs"),
	},
	Run: func(req cmds.Request) (interface{}, error) {

		dspathOverride, _, err := req.Option("d").String() // if !found it's okay. Let == ""
		if err != nil {
			return nil, err
		}

		force, _, err := req.Option("f").Bool() // if !found, it's okay force == false
		if err != nil {
			return nil, err
		}

		nBitsForKeypair, bitsOptFound, err := req.Option("b").Int()
		if err != nil {
			return nil, err
		}
		if !bitsOptFound {
			nBitsForKeypair = nBitsForKeypairDefault
		}

		return doInit(req.Context().ConfigRoot, dspathOverride, force, nBitsForKeypair)
	},
}

var errCannotInitConfigExists = debugerror.New(`ipfs configuration file already exists!
Reinitializing would overwrite your keys.
(use -f to force overwrite)
`)

var welcomeMsg = `Hello and Welcome to IPFS!

██╗██████╗ ███████╗███████╗
██║██╔══██╗██╔════╝██╔════╝
██║██████╔╝█████╗  ███████╗
██║██╔═══╝ ██╔══╝  ╚════██║
██║██║     ██║     ███████║
╚═╝╚═╝     ╚═╝     ╚══════╝

If you're seeing this, you have successfully installed
IPFS and are now interfacing with the ipfs merkledag!

For a short demo of what you can do, enter 'ipfs tour'
`

func initWithDefaults(configRoot string) error {
	_, err := doInit(configRoot, "", false, nBitsForKeypairDefault)
	return debugerror.Wrap(err)
}

func doInit(configRoot string, dspathOverride string, force bool, nBitsForKeypair int) (interface{}, error) {

	u.POut("initializing ipfs node at %s\n", configRoot)

	configFilename, err := config.Filename(configRoot)
	if err != nil {
		return nil, debugerror.New("Couldn't get home directory path")
	}

	if u.FileExists(configFilename) && !force {
		return nil, errCannotInitConfigExists
	}

	conf, err := initConfig(configFilename, dspathOverride, nBitsForKeypair)
	if err != nil {
		return nil, err
	}

	err = addTheWelcomeFile(conf)
	if err != nil {
		return nil, err
	}

	return nil, nil
}

// addTheWelcomeFile adds a file containing the welcome message to the newly
// minted node. On success, it calls onSuccess
func addTheWelcomeFile(conf *config.Config) error {
	// TODO extract this file creation operation into a function
	ctx, cancel := context.WithCancel(context.Background())
	nd, err := core.NewIPFSNode(ctx, core.Offline(conf))
	if err != nil {
		return err
	}
	defer nd.Close()
	defer cancel()

	// Set up default file
	reader := bytes.NewBufferString(welcomeMsg)

	defnd, err := imp.BuildDagFromReader(reader, nd.DAG, nd.Pinning.GetManual(), chunk.DefaultSplitter)
	if err != nil {
		return err
	}

	k, err := defnd.Key()
	if err != nil {
		return fmt.Errorf("failed to write test file: %s", err)
	}
	fmt.Printf("\nto get started, enter: ipfs cat %s\n", k)
	return nil
}

func datastoreConfig(dspath string) (config.Datastore, error) {
	ds := config.Datastore{}
	if len(dspath) == 0 {
		var err error
		dspath, err = config.DataStorePath("")
		if err != nil {
			return ds, err
		}
	}
	ds.Path = dspath
	ds.Type = "leveldb"

	err := initCheckDir(dspath)
	if err != nil {
		return ds, debugerror.Errorf("datastore: %s", err)
	}

	return ds, nil
}

func initConfig(configFilename string, dspathOverride string, nBitsForKeypair int) (*config.Config, error) {
	ds, err := datastoreConfig(dspathOverride)
	if err != nil {
		return nil, err
	}

	identity, err := identityConfig(nBitsForKeypair)
	if err != nil {
		return nil, err
	}

	logConfig, err := initLogs("") // TODO allow user to override dir
	if err != nil {
		return nil, err
	}

	bootstrapPeers, err := corecmds.DefaultBootstrapPeers()
	if err != nil {
		return nil, err
	}

	conf := &config.Config{

		// setup the node's default addresses.
		// Note: two swarm listen addrs, one tcp, one utp.
		Addresses: config.Addresses{
			Swarm: []string{
				"/ip4/0.0.0.0/tcp/4001",
				// "/ip4/0.0.0.0/udp/4002/utp", // disabled for now.
			},
			API: "/ip4/127.0.0.1/tcp/5001",
		},

		Bootstrap: bootstrapPeers,
		Datastore: ds,
		Logs:      logConfig,
		Identity:  identity,

		// setup the node mount points.
		Mounts: config.Mounts{
			IPFS: "/ipfs",
			IPNS: "/ipns",
		},

		// tracking ipfs version used to generate the init folder and adding
		// update checker default setting.
		Version: config.VersionDefaultValue(),
	}

	if err := config.WriteConfigFile(configFilename, conf); err != nil {
		return nil, err
	}

	return conf, nil
}

// identityConfig initializes a new identity.
func identityConfig(nbits int) (config.Identity, error) {
	// TODO guard higher up
	ident := config.Identity{}
	if nbits < 1024 {
		return ident, debugerror.New("Bitsize less than 1024 is considered unsafe.")
	}

	fmt.Printf("generating key pair...")
	sk, pk, err := ci.GenerateKeyPair(ci.RSA, nbits)
	if err != nil {
		return ident, err
	}
	fmt.Printf("done\n")

	// currently storing key unencrypted. in the future we need to encrypt it.
	// TODO(security)
	skbytes, err := sk.Bytes()
	if err != nil {
		return ident, err
	}
	ident.PrivKey = base64.StdEncoding.EncodeToString(skbytes)

	id, err := peer.IDFromPublicKey(pk)
	if err != nil {
		return ident, err
	}
	ident.PeerID = id.Pretty()
	fmt.Printf("peer identity: %s\n", ident.PeerID)
	return ident, nil
}

// initLogs initializes the event logger at the specified path. It uses the
// default log path if no path is provided.
func initLogs(logpath string) (config.Logs, error) {
	if len(logpath) == 0 {
		var err error
		logpath, err = config.LogsPath("")
		if err != nil {
			return config.Logs{}, debugerror.Wrap(err)
		}
	}
	err := initCheckDir(logpath)
	if err != nil {
		return config.Logs{}, debugerror.Errorf("logs: %s", err)
	}
	conf := config.Logs{
		Filename: path.Join(logpath, "events.log"),
	}
	err = repo.ConfigureEventLogger(conf)
	if err != nil {
		return conf, err
	}
	return conf, nil
}

// initCheckDir ensures the directory exists and is writable
func initCheckDir(path string) error {
	// Construct the path if missing
	if err := os.MkdirAll(path, os.ModePerm); err != nil {
		return err
	}

	// Check the directory is writeable
	if f, err := os.Create(filepath.Join(path, "._check_writeable")); err == nil {
		os.Remove(f.Name())
	} else {
		return debugerror.New("'" + path + "' is not writeable")
	}
	return nil
}
