package unixfs

import (
	"fmt"
	"io"
	"sort"
	"text/tabwriter"

	cmdenv "gitlab.dms3.io/dms3/go-dms3/core/commands/cmdenv"

	cmds "gitlab.dms3.io/dms3/go-dms3-cmds"
	merkledag "gitlab.dms3.io/dms3/go-merkledag"
	unixfs "gitlab.dms3.io/dms3/go-unixfs"
	path "gitlab.dms3.io/dms3/interface-go-dms3-core/path"
)

type LsLink struct {
	Name, Hash string
	Size       uint64
	Type       string
}

type LsObject struct {
	Hash  string
	Size  uint64
	Type  string
	Links []LsLink
}

type LsOutput struct {
	Arguments map[string]string
	Objects   map[string]*LsObject
}

var LsCmd = &cmds.Command{
	Helptext: cmds.HelpText{
		Tagline: "List directory contents for Unix filesystem objects. Deprecated: Use 'dms3 ls' instead.",
		ShortDescription: `
Displays the contents of an DMS3 or DMS3NS object(s) at the given path.

The JSON output contains size information. For files, the child size
is the total size of the file contents. For directories, the child
size is the DMS3 link size.

This functionality is deprecated, and will be removed in future versions as it duplicates the functionality of 'dms3 ls'.
If possible, please use 'dms3 ls' instead.
`,
		LongDescription: `
Displays the contents of an DMS3 or DMS3NS object(s) at the given path.

The JSON output contains size information. For files, the child size
is the total size of the file contents. For directories, the child
size is the DMS3 link size.

The path can be a prefixless ref; in this case, we assume it to be an
/dms3 ref and not /dms3ns.

Example:

    > dms3 file ls QmW2WQi7j6c7UgJTarActp7tDNikE4B2qXtFCfLPdsgaTQ
    cat.jpg
    > dms3 file ls /dms3/QmW2WQi7j6c7UgJTarActp7tDNikE4B2qXtFCfLPdsgaTQ
    cat.jpg

This functionality is deprecated, and will be removed in future versions as it duplicates the functionality of 'dms3 ls'.
If possible, please use 'dms3 ls' instead.
`,
	},

	Arguments: []cmds.Argument{
		cmds.StringArg("dms3-path", true, true, "The path to the DMS3 object(s) to list links from.").EnableStdin(),
	},
	Run: func(req *cmds.Request, res cmds.ResponseEmitter, env cmds.Environment) error {
		nd, err := cmdenv.GetNode(env)
		if err != nil {
			return err
		}

		api, err := cmdenv.GetApi(env, req)
		if err != nil {
			return err
		}

		if err := req.ParseBodyArgs(); err != nil {
			return err
		}

		paths := req.Arguments

		output := LsOutput{
			Arguments: map[string]string{},
			Objects:   map[string]*LsObject{},
		}

		for _, p := range paths {
			ctx := req.Context

			merkleNode, err := api.ResolveNode(ctx, path.New(p))
			if err != nil {
				return err
			}

			c := merkleNode.Cid()

			hash := c.String()
			output.Arguments[p] = hash

			if _, ok := output.Objects[hash]; ok {
				// duplicate argument for an already-listed node
				continue
			}

			ndpb, ok := merkleNode.(*merkledag.ProtoNode)
			if !ok {
				return merkledag.ErrNotProtobuf
			}

			unixFSNode, err := unixfs.FSNodeFromBytes(ndpb.Data())
			if err != nil {
				return err
			}

			t := unixFSNode.Type()

			output.Objects[hash] = &LsObject{
				Hash: c.String(),
				Type: t.String(),
				Size: unixFSNode.FileSize(),
			}

			switch t {
			case unixfs.TFile:
				break
			case unixfs.THAMTShard:
				// We need a streaming ls API for this.
				return fmt.Errorf("cannot list large directories yet")
			case unixfs.TDirectory:
				links := make([]LsLink, len(merkleNode.Links()))
				output.Objects[hash].Links = links
				for i, link := range merkleNode.Links() {
					linkNode, err := link.GetNode(ctx, nd.DAG)
					if err != nil {
						return err
					}
					lnpb, ok := linkNode.(*merkledag.ProtoNode)
					if !ok {
						return merkledag.ErrNotProtobuf
					}

					d, err := unixfs.FSNodeFromBytes(lnpb.Data())
					if err != nil {
						return err
					}
					t := d.Type()
					lsLink := LsLink{
						Name: link.Name,
						Hash: link.Cid.String(),
						Type: t.String(),
					}
					if t == unixfs.TFile {
						lsLink.Size = d.FileSize()
					} else {
						lsLink.Size = link.Size
					}
					links[i] = lsLink
				}
			case unixfs.TSymlink:
				return fmt.Errorf("cannot list symlinks yet")
			default:
				return fmt.Errorf("unrecognized type: %s", t)
			}
		}

		return cmds.EmitOnce(res, &output)
	},
	Encoders: cmds.EncoderMap{
		cmds.Text: cmds.MakeTypedEncoder(func(req *cmds.Request, w io.Writer, out *LsOutput) error {
			tw := tabwriter.NewWriter(w, 1, 2, 1, ' ', 0)

			nonDirectories := []string{}
			directories := []string{}
			for argument, hash := range out.Arguments {
				object, ok := out.Objects[hash]
				if !ok {
					return fmt.Errorf("unresolved hash: %s", hash)
				}

				if object.Type == "Directory" {
					directories = append(directories, argument)
				} else {
					nonDirectories = append(nonDirectories, argument)
				}
			}
			sort.Strings(nonDirectories)
			sort.Strings(directories)

			for _, argument := range nonDirectories {
				fmt.Fprintf(tw, "%s\n", argument)
			}

			seen := map[string]bool{}
			for i, argument := range directories {
				hash := out.Arguments[argument]
				if _, ok := seen[hash]; ok {
					continue
				}
				seen[hash] = true

				object := out.Objects[hash]
				if i > 0 || len(nonDirectories) > 0 {
					fmt.Fprintln(tw)
				}
				if len(out.Arguments) > 1 {
					for _, arg := range directories[i:] {
						if out.Arguments[arg] == hash {
							fmt.Fprintf(tw, "%s:\n", cmdenv.EscNonPrint(arg))
						}
					}
				}
				for _, link := range object.Links {
					fmt.Fprintf(tw, "%s\n", cmdenv.EscNonPrint(link.Name))
				}
			}
			tw.Flush()

			return nil
		}),
	},
	Type: LsOutput{},
}