/*
Package coreapi provides direct access to the core commands in IPFS. If you are
embedding IPFS directly in your Go program, this package is the public
interface you should use to read and write files or otherwise control IPFS.

If you are running IPFS as a separate process, you should use `go-ipfs-api` to
work with it via HTTP. As we finalize the interfaces here, `go-ipfs-api` will
transparently adopt them so you can use the same code with either package.

**NOTE: this package is experimental.** `go-ipfs` has mainly been developed
as a standalone application and library-style use of this package is still new.
Interfaces here aren't yet completely stable.
*/
package coreapi

import (
	"context"
	"errors"

	core "github.com/ipfs/go-ipfs/core"
	coreiface "github.com/ipfs/go-ipfs/core/coreapi/interface"
	options "github.com/ipfs/go-ipfs/core/coreapi/interface/options"
	namesys "github.com/ipfs/go-ipfs/namesys"
	pin "github.com/ipfs/go-ipfs/pin"
	repo "github.com/ipfs/go-ipfs/repo"

	ci "gx/ipfs/QmNiJiXwWE3kRhZrC5ej3kSjWHm337pYfhjLGSCDNKJP2s/go-libp2p-crypto"
	exchange "gx/ipfs/QmP2g3VxmC7g7fyRJDj1VJ72KHZbJ9UW24YjSWEj1XTb4H/go-ipfs-exchange-interface"
	bserv "gx/ipfs/QmPoh3SrQzFBWtdGK6qmHDV4EanKR6kYPj4DD3J2NLoEmZ/go-blockservice"
	routing "gx/ipfs/QmRASJXJUFygM5qU4YrH7k7jD6S4Hg8nJmgqJ4bYJvLatd/go-libp2p-routing"
	blockstore "gx/ipfs/QmS2aqUZLJp8kF1ihE5rvDGE5LvmKDPnx32w9Z1BW9xLV5/go-ipfs-blockstore"
	peer "gx/ipfs/QmY5Grm8pJdiSSVsYxx4uNRgweY72EmYwuSDbRnbFok3iY/go-libp2p-peer"
	pstore "gx/ipfs/QmZ9zH2FnLcxv1xyzFeUpDUeo55xEhZQHgveZijcxr7TLj/go-libp2p-peerstore"
	pubsub "gx/ipfs/QmaqGyUhWLsJbVo1QAujSu13mxNjFJ98Kt2VWGSnShGE1Q/go-libp2p-pubsub"
	ipld "gx/ipfs/QmcKKBwfz6FyQdHR2jsXrrF6XeSBXYL86anmWNewpFpoF5/go-ipld-format"
	logging "gx/ipfs/QmcuXC5cxs79ro2cUuHs4HQ2bkDLJUYokwL8aivcX6HW3C/go-log"
	dag "gx/ipfs/QmdV35UHnL1FM52baPkeUo6u7Fxm2CRUkPTLRPxeF8a4Ap/go-merkledag"
	record "gx/ipfs/QmfARXVCzpwFXQdepAJZuqyNDgV9doEsMnVCo1ssmuSe1U/go-libp2p-record"
	p2phost "gx/ipfs/QmfD51tKgJiTMnW9JEiDiPwsCY4mqUoxkhKhBfyW12spTC/go-libp2p-host"
)

var log = logging.Logger("core/coreapi")

type CoreAPI struct {
	nctx context.Context

	identity   peer.ID //TODO: check mutable structs
	privateKey ci.PrivKey

	repo       repo.Repo
	blockstore blockstore.GCBlockstore
	baseBlocks blockstore.Blockstore
	blocks     bserv.BlockService
	dag        ipld.DAGService
	pinning    pin.Pinner

	peerstore       pstore.Peerstore
	peerHost        p2phost.Host
	namesys         namesys.NameSystem
	recordValidator record.Validator
	exchange        exchange.Interface

	routing routing.IpfsRouting
	pubSub  *pubsub.PubSub

	checkRouting func(bool) error

	// TODO: this can be generalized to all functions when we implement some
	// api based security mechanism
	isPublishAllowed func() error
}

// NewCoreAPI creates new instance of IPFS CoreAPI backed by go-ipfs Node.
func NewCoreAPI(n *core.IpfsNode, opts ...options.ApiOption) coreiface.CoreAPI {
	api := &CoreAPI{
		nctx: n.Context(),

		identity:   n.Identity,
		privateKey: n.PrivateKey,

		repo:       n.Repo,
		blockstore: n.Blockstore,
		baseBlocks: n.BaseBlocks,
		blocks:     n.Blocks,
		dag:        n.DAG,
		pinning:    n.Pinning,

		peerstore:       n.Peerstore,
		peerHost:        n.PeerHost,
		namesys:         n.Namesys,
		recordValidator: n.RecordValidator,
		exchange:        n.Exchange,

		routing: n.Routing,
		pubSub:  n.PubSub,

		checkRouting: func(allowOffline bool) error {
			if !n.OnlineMode() {
				if !allowOffline {
					return coreiface.ErrOffline
				}
				return n.SetupOfflineRouting()
			}
			return nil
		},

		isPublishAllowed: func() error {
			if n.Mounts.Ipns != nil && n.Mounts.Ipns.IsActive() {
				return errors.New("cannot manually publish while IPNS is mounted")
			}
			return nil
		},
	}

	return api
}

// Unixfs returns the UnixfsAPI interface implementation backed by the go-ipfs node
func (api *CoreAPI) Unixfs() coreiface.UnixfsAPI {
	return (*UnixfsAPI)(api)
}

// Block returns the BlockAPI interface implementation backed by the go-ipfs node
func (api *CoreAPI) Block() coreiface.BlockAPI {
	return (*BlockAPI)(api)
}

// Dag returns the DagAPI interface implementation backed by the go-ipfs node
func (api *CoreAPI) Dag() coreiface.DagAPI {
	return (*DagAPI)(api)
}

// Name returns the NameAPI interface implementation backed by the go-ipfs node
func (api *CoreAPI) Name() coreiface.NameAPI {
	return (*NameAPI)(api)
}

// Key returns the KeyAPI interface implementation backed by the go-ipfs node
func (api *CoreAPI) Key() coreiface.KeyAPI {
	return (*KeyAPI)(api)
}

// Object returns the ObjectAPI interface implementation backed by the go-ipfs node
func (api *CoreAPI) Object() coreiface.ObjectAPI {
	return (*ObjectAPI)(api)
}

// Pin returns the PinAPI interface implementation backed by the go-ipfs node
func (api *CoreAPI) Pin() coreiface.PinAPI {
	return (*PinAPI)(api)
}

// Dht returns the DhtAPI interface implementation backed by the go-ipfs node
func (api *CoreAPI) Dht() coreiface.DhtAPI {
	return (*DhtAPI)(api)
}

// Swarm returns the SwarmAPI interface implementation backed by the go-ipfs node
func (api *CoreAPI) Swarm() coreiface.SwarmAPI {
	return (*SwarmAPI)(api)
}

// PubSub returns the PubSubAPI interface implementation backed by the go-ipfs node
func (api *CoreAPI) PubSub() coreiface.PubSubAPI {
	return (*PubSubAPI)(api)
}

// getSession returns new api backed by the same node with a read-only session DAG
func (api *CoreAPI) getSession(ctx context.Context) *CoreAPI {
	sesApi := *api

	//TODO: we may want to apply this to other things too
	sesApi.dag = dag.NewReadOnlyDagService(dag.NewSession(ctx, api.dag))

	return &sesApi
}