package coreapi

import (
	"context"
	"fmt"

	"github.com/ipfs/go-ipfs/core"
	"github.com/ipfs/go-ipfs/filestore"

	"github.com/ipfs/go-ipfs/core/coreunix"

	dag "gx/ipfs/QmP9i4G9nRcfKBnpk1A7CwU7ppLkSn2j6vJeWn2AJ8rfcN/go-merkledag"
	merkledag "gx/ipfs/QmP9i4G9nRcfKBnpk1A7CwU7ppLkSn2j6vJeWn2AJ8rfcN/go-merkledag"
	dagtest "gx/ipfs/QmP9i4G9nRcfKBnpk1A7CwU7ppLkSn2j6vJeWn2AJ8rfcN/go-merkledag/test"
	files "gx/ipfs/QmQmhotPUzVrMEWNK3x1R5jQ5ZHWyL7tVUrmRPjrBrvyCb/go-ipfs-files"
	ft "gx/ipfs/QmSbCXEwpsog4vBf53YntmGk9uHsgZNuU5oBKv3o2kkTSe/go-unixfs"
	unixfile "gx/ipfs/QmSbCXEwpsog4vBf53YntmGk9uHsgZNuU5oBKv3o2kkTSe/go-unixfs/file"
	uio "gx/ipfs/QmSbCXEwpsog4vBf53YntmGk9uHsgZNuU5oBKv3o2kkTSe/go-unixfs/io"
	cid "gx/ipfs/QmTbxNB1NwDesLmKTscr4udL2tVP7MaxvXnD1D9yX7g3PN/go-cid"
	coreiface "gx/ipfs/QmVzvYWRABgGEv4iu3M9wivWbZKTW29qsU4VTZ2iZEoExX/interface-go-ipfs-core"
	"gx/ipfs/QmVzvYWRABgGEv4iu3M9wivWbZKTW29qsU4VTZ2iZEoExX/interface-go-ipfs-core/options"
	bstore "gx/ipfs/QmXjKkjMDTtXAiLBwstVexofB8LeruZmE2eBd85GwGFFLA/go-ipfs-blockstore"
	ipld "gx/ipfs/QmZ6nzCLwGLVfRzYLpD7pW6UNuBDKEcA2imJtVpbEx2rxy/go-ipld-format"
	mfs "gx/ipfs/QmZuXacgXW4YkAveAQWvFUyLW9vzPtWKADjeoqtk22GcEK/go-mfs"
	blockservice "gx/ipfs/Qmdvbc3xsufJasP1idu6dZKiLLfEzuaLpuriCyUK7Aukje/go-blockservice"
	cidutil "gx/ipfs/Qmf3gRH2L1QZy92gJHJEwKmBJKJGVf8RpN2kPPD2NQWg8G/go-cidutil"
)

type UnixfsAPI CoreAPI

// Add builds a merkledag node from a reader, adds it to the blockstore,
// and returns the key representing that node.
func (api *UnixfsAPI) Add(ctx context.Context, files files.Node, opts ...options.UnixfsAddOption) (coreiface.ResolvedPath, error) {
	settings, prefix, err := options.UnixfsAddOptions(opts...)
	if err != nil {
		return nil, err
	}

	cfg, err := api.repo.Config()
	if err != nil {
		return nil, err
	}

	// check if repo will exceed storage limit if added
	// TODO: this doesn't handle the case if the hashed file is already in blocks (deduplicated)
	// TODO: conditional GC is disabled due to it is somehow not possible to pass the size to the daemon
	//if err := corerepo.ConditionalGC(req.Context(), n, uint64(size)); err != nil {
	//	res.SetError(err, cmdkit.ErrNormal)
	//	return
	//}

	if settings.NoCopy && !cfg.Experimental.FilestoreEnabled {
		return nil, filestore.ErrFilestoreNotEnabled
	}

	addblockstore := api.blockstore
	if !(settings.FsCache || settings.NoCopy) {
		addblockstore = bstore.NewGCBlockstore(api.baseBlocks, api.blockstore)
	}
	exch := api.exchange
	pinning := api.pinning

	if settings.OnlyHash {
		nilnode, err := core.NewNode(ctx, &core.BuildCfg{
			//TODO: need this to be true or all files
			// hashed will be stored in memory!
			NilRepo: true,
		})
		if err != nil {
			return nil, err
		}
		addblockstore = nilnode.Blockstore
		exch = nilnode.Exchange
		pinning = nilnode.Pinning
	}

	bserv := blockservice.New(addblockstore, exch) // hash security 001
	dserv := dag.NewDAGService(bserv)

	fileAdder, err := coreunix.NewAdder(ctx, pinning, addblockstore, dserv)
	if err != nil {
		return nil, err
	}

	fileAdder.Chunker = settings.Chunker
	if settings.Events != nil {
		fileAdder.Out = settings.Events
		fileAdder.Progress = settings.Progress
	}
	fileAdder.Hidden = settings.Hidden
	fileAdder.Wrap = settings.Wrap
	fileAdder.Pin = settings.Pin && !settings.OnlyHash
	fileAdder.Silent = settings.Silent
	fileAdder.RawLeaves = settings.RawLeaves
	fileAdder.NoCopy = settings.NoCopy
	fileAdder.Name = settings.StdinName
	fileAdder.CidBuilder = prefix

	switch settings.Layout {
	case options.BalancedLayout:
		// Default
	case options.TrickleLayout:
		fileAdder.Trickle = true
	default:
		return nil, fmt.Errorf("unknown layout: %d", settings.Layout)
	}

	if settings.Inline {
		fileAdder.CidBuilder = cidutil.InlineBuilder{
			Builder: fileAdder.CidBuilder,
			Limit:   settings.InlineLimit,
		}
	}

	if settings.OnlyHash {
		md := dagtest.Mock()
		emptyDirNode := ft.EmptyDirNode()
		// Use the same prefix for the "empty" MFS root as for the file adder.
		emptyDirNode.SetCidBuilder(fileAdder.CidBuilder)
		mr, err := mfs.NewRoot(ctx, md, emptyDirNode, nil)
		if err != nil {
			return nil, err
		}

		fileAdder.SetMfsRoot(mr)
	}

	nd, err := fileAdder.AddAllAndPin(files)
	if err != nil {
		return nil, err
	}
	return coreiface.IpfsPath(nd.Cid()), nil
}

func (api *UnixfsAPI) Get(ctx context.Context, p coreiface.Path) (files.Node, error) {
	ses := api.core().getSession(ctx)

	nd, err := ses.ResolveNode(ctx, p)
	if err != nil {
		return nil, err
	}

	return unixfile.NewUnixfsFile(ctx, ses.dag, nd)
}

// Ls returns the contents of an IPFS or IPNS object(s) at path p, with the format:
// `<link base58 hash> <link size in bytes> <link name>`
func (api *UnixfsAPI) Ls(ctx context.Context, p coreiface.Path, opts ...options.UnixfsLsOption) (<-chan coreiface.LsLink, error) {
	settings, err := options.UnixfsLsOptions(opts...)
	if err != nil {
		return nil, err
	}

	ses := api.core().getSession(ctx)
	uses := (*UnixfsAPI)(ses)

	dagnode, err := ses.ResolveNode(ctx, p)
	if err != nil {
		return nil, err
	}

	dir, err := uio.NewDirectoryFromNode(ses.dag, dagnode)
	if err == uio.ErrNotADir {
		return uses.lsFromLinks(ctx, dagnode.Links(), settings)
	}
	if err != nil {
		return nil, err
	}

	return uses.lsFromLinksAsync(ctx, dir, settings)
}

func (api *UnixfsAPI) processLink(ctx context.Context, linkres ft.LinkResult, settings *options.UnixfsLsSettings) coreiface.LsLink {
	lnk := coreiface.LsLink{
		Link: linkres.Link,
		Err:  linkres.Err,
	}
	if lnk.Err != nil {
		return lnk
	}

	switch lnk.Link.Cid.Type() {
	case cid.Raw:
		// No need to check with raw leaves
		lnk.Type = coreiface.TFile
		lnk.Size = lnk.Link.Size
	case cid.DagProtobuf:
		if !settings.ResolveChildren {
			break
		}

		linkNode, err := lnk.Link.GetNode(ctx, api.dag)
		if err != nil {
			lnk.Err = err
			break
		}

		if pn, ok := linkNode.(*merkledag.ProtoNode); ok {
			d, err := ft.FSNodeFromBytes(pn.Data())
			if err != nil {
				lnk.Err = err
				break
			}
			lnk.Type = coreiface.FileType(d.Type())
			lnk.Size = d.FileSize()
		}
	}

	return lnk
}

func (api *UnixfsAPI) lsFromLinksAsync(ctx context.Context, dir uio.Directory, settings *options.UnixfsLsSettings) (<-chan coreiface.LsLink, error) {
	out := make(chan coreiface.LsLink)

	go func() {
		defer close(out)
		for l := range dir.EnumLinksAsync(ctx) {
			select {
			case out <- api.processLink(ctx, l, settings): //TODO: perf: processing can be done in background and in parallel
			case <-ctx.Done():
				return
			}
		}
	}()

	return out, nil
}

func (api *UnixfsAPI) lsFromLinks(ctx context.Context, ndlinks []*ipld.Link, settings *options.UnixfsLsSettings) (<-chan coreiface.LsLink, error) {
	links := make(chan coreiface.LsLink, len(ndlinks))
	for _, l := range ndlinks {
		lr := ft.LinkResult{Link: &ipld.Link{Name: l.Name, Size: l.Size, Cid: l.Cid}}

		links <- api.processLink(ctx, lr, settings) //TODO: can be parallel if settings.Async
	}
	close(links)
	return links, nil
}

func (api *UnixfsAPI) core() *CoreAPI {
	return (*CoreAPI)(api)
}