package main

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"os"
	"path/filepath"
	"strings"

	assets "github.com/ipfs/go-ipfs/assets"
	oldcmds "github.com/ipfs/go-ipfs/commands"
	core "github.com/ipfs/go-ipfs/core"
	"github.com/ipfs/go-ipfs/core/commands"
	namesys "github.com/ipfs/go-ipfs/namesys"
	fsrepo "github.com/ipfs/go-ipfs/repo/fsrepo"

	cmds "github.com/ipfs/go-ipfs-cmds"
	config "github.com/ipfs/go-ipfs-config"
	files "github.com/ipfs/go-ipfs-files"
	options "github.com/ipfs/interface-go-ipfs-core/options"
)

const (
	algorithmDefault    = options.Ed25519Key
	algorithmOptionName = "algorithm"
	bitsOptionName      = "bits"
	emptyRepoOptionName = "empty-repo"
	profileOptionName   = "profile"
)

var errRepoExists = errors.New(`ipfs configuration file already exists!
Reinitializing would overwrite your keys.
`)

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

If you are going to run IPFS in server environment, you may want to
initialize it using 'server' profile.

For the list of available profiles see 'ipfs config profile --help'

ipfs uses a repository in the local file system. By default, the repo is
located at ~/.ipfs. To change the repo location, set the $IPFS_PATH
environment variable:

    export IPFS_PATH=/path/to/ipfsrepo
`,
	},
	Arguments: []cmds.Argument{
		cmds.FileArg("default-config", false, false, "Initialize with the given configuration.").EnableStdin(),
	},
	Options: []cmds.Option{
		cmds.StringOption(algorithmOptionName, "a", "Cryptographic algorithm to use for key generation.").WithDefault(algorithmDefault),
		cmds.IntOption(bitsOptionName, "b", "Number of bits to use in the generated RSA private key."),
		cmds.BoolOption(emptyRepoOptionName, "e", "Don't add and pin help files to the local storage."),
		cmds.StringOption(profileOptionName, "p", "Apply profile settings to config. Multiple profiles can be separated by ','"),

		// 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."),
	},
	NoRemote: true,
	Extra:    commands.CreateCmdExtras(commands.SetDoesNotUseRepo(true), commands.SetDoesNotUseConfigAsInput(true)),
	PreRun:   commands.DaemonNotRunning,
	Run: func(req *cmds.Request, res cmds.ResponseEmitter, env cmds.Environment) error {
		cctx := env.(*oldcmds.Context)
		empty, _ := req.Options[emptyRepoOptionName].(bool)
		algorithm, _ := req.Options[algorithmOptionName].(string)
		nBitsForKeypair, nBitsGiven := req.Options[bitsOptionName].(int)

		var conf *config.Config

		f := req.Files
		if f != nil {
			it := req.Files.Entries()
			if !it.Next() {
				if it.Err() != nil {
					return it.Err()
				}
				return fmt.Errorf("file argument was nil")
			}
			file := files.FileFromEntry(it)
			if file == nil {
				return fmt.Errorf("expected a regular file")
			}

			conf = &config.Config{}
			if err := json.NewDecoder(file).Decode(conf); err != nil {
				return err
			}
		}

		if conf == nil {
			var err error
			var identity config.Identity
			if nBitsGiven {
				identity, err = config.CreateIdentity(os.Stdout, []options.KeyGenerateOption{
					options.Key.Size(nBitsForKeypair),
					options.Key.Type(algorithm),
				})
			} else {
				identity, err = config.CreateIdentity(os.Stdout, []options.KeyGenerateOption{
					options.Key.Type(algorithm),
				})
			}
			if err != nil {
				return err
			}
			conf, err = config.InitWithIdentity(identity)
			if err != nil {
				return err
			}
		}

		profiles, _ := req.Options[profileOptionName].(string)
		return doInit(os.Stdout, cctx.ConfigRoot, empty, profiles, conf)
	},
}

func applyProfiles(conf *config.Config, profiles string) error {
	if profiles == "" {
		return nil
	}

	for _, profile := range strings.Split(profiles, ",") {
		transformer, ok := config.Profiles[profile]
		if !ok {
			return fmt.Errorf("invalid configuration profile: %s", profile)
		}

		if err := transformer.Transform(conf); err != nil {
			return err
		}
	}
	return nil
}

func doInit(out io.Writer, repoRoot string, empty bool, confProfiles string, conf *config.Config) error {
	if _, err := fmt.Fprintf(out, "initializing IPFS node at %s\n", repoRoot); err != nil {
		return err
	}

	if err := checkWritable(repoRoot); err != nil {
		return err
	}

	if fsrepo.IsInitialized(repoRoot) {
		return errRepoExists
	}

	if err := applyProfiles(conf, confProfiles); err != nil {
		return err
	}

	if err := fsrepo.Init(repoRoot, conf); err != nil {
		return err
	}

	if !empty {
		if err := addDefaultAssets(out, repoRoot); err != nil {
			return err
		}
	}

	return initializeIpnsKeyspace(repoRoot)
}

func checkWritable(dir string) error {
	_, err := os.Stat(dir)
	if err == nil {
		// dir exists, make sure we can write to it
		testfile := filepath.Join(dir, "test")
		fi, err := os.Create(testfile)
		if err != nil {
			if os.IsPermission(err) {
				return fmt.Errorf("%s is not writeable by the current user", dir)
			}
			return fmt.Errorf("unexpected error while checking writeablility of repo root: %s", err)
		}
		fi.Close()
		return os.Remove(testfile)
	}

	if os.IsNotExist(err) {
		// dir doesn't exist, check that we can create it
		return os.Mkdir(dir, 0775)
	}

	if os.IsPermission(err) {
		return fmt.Errorf("cannot write to %s, incorrect permissions", err)
	}

	return err
}

func addDefaultAssets(out io.Writer, repoRoot string) error {
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	r, err := fsrepo.Open(repoRoot)
	if err != nil { // NB: repo is owned by the node
		return err
	}

	nd, err := core.NewNode(ctx, &core.BuildCfg{Repo: r})
	if err != nil {
		return err
	}
	defer nd.Close()

	dkey, err := assets.SeedInitDocs(nd)
	if err != nil {
		return fmt.Errorf("init: seeding init docs failed: %s", err)
	}
	log.Debugf("init: seeded init docs %s", dkey)

	if _, err = fmt.Fprintf(out, "to get started, enter:\n"); err != nil {
		return err
	}

	_, err = fmt.Fprintf(out, "\n\tipfs cat /ipfs/%s/readme\n\n", dkey)
	return err
}

func initializeIpnsKeyspace(repoRoot string) error {
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	r, err := fsrepo.Open(repoRoot)
	if err != nil { // NB: repo is owned by the node
		return err
	}

	nd, err := core.NewNode(ctx, &core.BuildCfg{Repo: r})
	if err != nil {
		return err
	}
	defer nd.Close()

	return namesys.InitializeKeyspace(ctx, nd.Namesys, nd.Pinning, nd.PrivateKey)
}