package commands

import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"io"
	"io/ioutil"
	"os"

	util "github.com/ipfs/go-ipfs/blocks/blockstoreutil"
	e "github.com/ipfs/go-ipfs/core/commands/e"

	"gx/ipfs/QmSKYWC84fqkKB54Te5JMcov2MBVzucXaRGxFqByzzCbHe/go-ipfs-cmds"
	mh "gx/ipfs/QmZyZDi491cCNTLfAhwcaDii2Kg4pwKRkhqQzURGDvY6ua/go-multihash"
	cid "gx/ipfs/QmcZfnkapfECQGcLZaf9B79NRg7cRa9EnZh4LSbkCzwNvY/go-cid"
	"gx/ipfs/QmceUdzxkimdYsgtX733uNgzf1DLHyBKN6ehGSp85ayppM/go-ipfs-cmdkit"
	blocks "gx/ipfs/Qmej7nf81hi2x2tvjRBF3mcp74sQyuDH4VMYDGd1YtXjb2/go-block-format"
)

type BlockStat struct {
	Key  string
	Size int
}

func (bs BlockStat) String() string {
	return fmt.Sprintf("Key: %s\nSize: %d\n", bs.Key, bs.Size)
}

var BlockCmd = &cmds.Command{
	Helptext: cmdkit.HelpText{
		Tagline: "Interact with raw IPFS blocks.",
		ShortDescription: `
'ipfs block' is a plumbing command used to manipulate raw IPFS blocks.
Reads from stdin or writes to stdout, and <key> is a base58 encoded
multihash.
`,
	},

	Subcommands: map[string]*cmds.Command{
		"stat": blockStatCmd,
		"get":  blockGetCmd,
		"put":  blockPutCmd,
		"rm":   blockRmCmd,
	},
}

var blockStatCmd = &cmds.Command{
	Helptext: cmdkit.HelpText{
		Tagline: "Print information of a raw IPFS block.",
		ShortDescription: `
'ipfs block stat' is a plumbing command for retrieving information
on raw IPFS blocks. It outputs the following to stdout:

	Key  - the base58 encoded multihash
	Size - the size of the block in bytes

`,
	},

	Arguments: []cmdkit.Argument{
		cmdkit.StringArg("key", true, false, "The base58 multihash of an existing block to stat.").EnableStdin(),
	},
	Run: func(req *cmds.Request, res cmds.ResponseEmitter, env cmds.Environment) {
		b, err := getBlockForKey(req.Context, env, req.Arguments[0])
		if err != nil {
			res.SetError(err, cmdkit.ErrNormal)
			return
		}

		err = cmds.EmitOnce(res, &BlockStat{
			Key:  b.Cid().String(),
			Size: len(b.RawData()),
		})
		if err != nil {
			log.Error(err)
		}
	},
	Type: BlockStat{},
	Encoders: cmds.EncoderMap{
		cmds.Text: cmds.MakeEncoder(func(req *cmds.Request, w io.Writer, v interface{}) error {
			bs, ok := v.(*BlockStat)
			if !ok {
				return e.TypeErr(bs, v)
			}
			_, err := fmt.Fprintf(w, "%s", bs)
			return err
		}),
	},
}

var blockGetCmd = &cmds.Command{
	Helptext: cmdkit.HelpText{
		Tagline: "Get a raw IPFS block.",
		ShortDescription: `
'ipfs block get' is a plumbing command for retrieving raw IPFS blocks.
It outputs to stdout, and <key> is a base58 encoded multihash.
`,
	},

	Arguments: []cmdkit.Argument{
		cmdkit.StringArg("key", true, false, "The base58 multihash of an existing block to get.").EnableStdin(),
	},
	Run: func(req *cmds.Request, res cmds.ResponseEmitter, env cmds.Environment) {
		b, err := getBlockForKey(req.Context, env, req.Arguments[0])
		if err != nil {
			res.SetError(err, cmdkit.ErrNormal)
			return
		}

		err = res.Emit(bytes.NewReader(b.RawData()))
		if err != nil {
			log.Error(err)
		}
	},
}

var blockPutCmd = &cmds.Command{
	Helptext: cmdkit.HelpText{
		Tagline: "Store input as an IPFS block.",
		ShortDescription: `
'ipfs block put' is a plumbing command for storing raw IPFS blocks.
It reads from stdin, and <key> is a base58 encoded multihash.

By default CIDv0 is going to be generated. Setting 'mhtype' to anything other
than 'sha2-256' or format to anything other than 'v0' will result in CIDv1.
`,
	},

	Arguments: []cmdkit.Argument{
		cmdkit.FileArg("data", true, false, "The data to be stored as an IPFS block.").EnableStdin(),
	},
	Options: []cmdkit.Option{
		cmdkit.StringOption("format", "f", "cid format for blocks to be created with."),
		cmdkit.StringOption("mhtype", "multihash hash function").WithDefault("sha2-256"),
		cmdkit.IntOption("mhlen", "multihash hash length").WithDefault(-1),
	},
	Run: func(req *cmds.Request, res cmds.ResponseEmitter, env cmds.Environment) {
		n, err := GetNode(env)
		if err != nil {
			res.SetError(err, cmdkit.ErrNormal)
			return
		}

		file, err := req.Files.NextFile()
		if err != nil {
			res.SetError(err, cmdkit.ErrNormal)
			return
		}

		data, err := ioutil.ReadAll(file)
		if err != nil {
			res.SetError(err, cmdkit.ErrNormal)
			return
		}

		err = file.Close()
		if err != nil {
			res.SetError(err, cmdkit.ErrNormal)
			return
		}

		mhtype, _ := req.Options["mhtype"].(string)
		mhtval, ok := mh.Names[mhtype]
		if !ok {
			err := fmt.Errorf("unrecognized multihash function: %s", mhtype)
			res.SetError(err, cmdkit.ErrNormal)
			return
		}

		var pref cid.Prefix
		pref.Version = 1

		format, formatSet := req.Options["format"].(string)
		if !formatSet {
			if mhtval == mh.SHA2_256 {
				format = "v0"
			} else {
				format = "protobuf"
			}
		}

		if format == "v0" {
			pref.Version = 0
		}
		formatval, ok := cid.Codecs[format]
		if !ok {
			res.SetError(fmt.Errorf("unrecognized format: '%s'", format), cmdkit.ErrNormal)
			return
		}
		if mhtval != mh.SHA2_256 && pref.Version == 0 {
			res.SetError(errors.New("cannot generate CIDv0 with non-sha256 hash function"), cmdkit.ErrNormal)
			return
		}

		pref.Codec = formatval
		pref.MhType = mhtval

		mhlen, ok := req.Options["mhlen"].(int)
		if !ok {
			res.SetError("missing option \"mhlen\"", cmdkit.ErrNormal)
			return
		}
		pref.MhLength = mhlen

		bcid, err := pref.Sum(data)
		if err != nil {
			res.SetError(err, cmdkit.ErrNormal)
			return
		}

		b, err := blocks.NewBlockWithCid(data, bcid)
		if err != nil {
			res.SetError(err, cmdkit.ErrNormal)
			return
		}

		err = n.Blocks.AddBlock(b)
		if err != nil {
			res.SetError(err, cmdkit.ErrNormal)
			return
		}

		err = cmds.EmitOnce(res, &BlockStat{
			Key:  b.Cid().String(),
			Size: len(data),
		})
		if err != nil {
			log.Error(err)
		}
	},
	Encoders: cmds.EncoderMap{
		cmds.Text: cmds.MakeEncoder(func(req *cmds.Request, w io.Writer, v interface{}) error {
			bs, ok := v.(*BlockStat)
			if !ok {
				return e.TypeErr(bs, v)
			}
			_, err := fmt.Fprintf(w, "%s\n", bs.Key)
			return err
		}),
	},
	Type: BlockStat{},
}

func getBlockForKey(ctx context.Context, env cmds.Environment, skey string) (blocks.Block, error) {
	if len(skey) == 0 {
		return nil, fmt.Errorf("zero length cid invalid")
	}

	n, err := GetNode(env)
	if err != nil {
		return nil, err
	}

	c, err := cid.Decode(skey)
	if err != nil {
		return nil, err
	}

	b, err := n.Blocks.GetBlock(ctx, c)
	if err != nil {
		return nil, err
	}

	return b, nil
}

var blockRmCmd = &cmds.Command{
	Helptext: cmdkit.HelpText{
		Tagline: "Remove IPFS block(s).",
		ShortDescription: `
'ipfs block rm' is a plumbing command for removing raw ipfs blocks.
It takes a list of base58 encoded multihashes to remove.
`,
	},
	Arguments: []cmdkit.Argument{
		cmdkit.StringArg("hash", true, true, "Bash58 encoded multihash of block(s) to remove."),
	},
	Options: []cmdkit.Option{
		cmdkit.BoolOption("force", "f", "Ignore nonexistent blocks."),
		cmdkit.BoolOption("quiet", "q", "Write minimal output."),
	},
	Run: func(req *cmds.Request, res cmds.ResponseEmitter, env cmds.Environment) {
		n, err := GetNode(env)
		if err != nil {
			res.SetError(err, cmdkit.ErrNormal)
			return
		}
		hashes := req.Arguments
		force, _ := req.Options["force"].(bool)
		quiet, _ := req.Options["quiet"].(bool)
		cids := make([]*cid.Cid, 0, len(hashes))
		for _, hash := range hashes {
			c, err := cid.Decode(hash)
			if err != nil {
				err = fmt.Errorf("invalid content id: %s (%s)", hash, err)
				res.SetError(err, cmdkit.ErrNormal)
				return
			}

			cids = append(cids, c)
		}
		ch, err := util.RmBlocks(n.Blockstore, n.Pinning, cids, util.RmBlocksOpts{
			Quiet: quiet,
			Force: force,
		})

		if err != nil {
			res.SetError(err, cmdkit.ErrNormal)
			return
		}

		err = res.Emit(ch)
		if err != nil {
			log.Error(err)
		}
	},
	PostRun: cmds.PostRunMap{
		cmds.CLI: func(req *cmds.Request, re cmds.ResponseEmitter) cmds.ResponseEmitter {
			reNext, res := cmds.NewChanResponsePair(req)

			go func() {
				defer re.Close()

				err := util.ProcRmOutput(res.Next, os.Stdout, os.Stderr)
				cmds.HandleError(err, res, re)
			}()

			return reNext
		},
	},
	Type: util.RemovedBlock{},
}