package proxy

import (
	"context"
	"net/http"

	amino "github.com/tendermint/go-amino"

	"github.com/tendermint/tendermint/libs/bytes"
	"github.com/tendermint/tendermint/libs/log"
	"github.com/tendermint/tendermint/rpc/client"
	rpcclient "github.com/tendermint/tendermint/rpc/client"
	"github.com/tendermint/tendermint/rpc/core"
	ctypes "github.com/tendermint/tendermint/rpc/core/types"
	rpcserver "github.com/tendermint/tendermint/rpc/lib/server"
	rpctypes "github.com/tendermint/tendermint/rpc/lib/types"
	"github.com/tendermint/tendermint/types"
)

const (
	wsEndpoint = "/websocket"
)

// StartProxy will start the websocket manager on the client,
// set up the rpc routes to proxy via the given client,
// and start up an http/rpc server on the location given by bind (eg. :1234)
// NOTE: This function blocks - you may want to call it in a go-routine.
func StartProxy(c rpcclient.Client, listenAddr string, logger log.Logger, maxOpenConnections int) error {
	err := c.Start()
	if err != nil {
		return err
	}

	cdc := amino.NewCodec()
	ctypes.RegisterAmino(cdc)
	r := RPCRoutes(c)

	// build the handler...
	mux := http.NewServeMux()
	rpcserver.RegisterRPCFuncs(mux, r, cdc, logger)

	unsubscribeFromAllEvents := func(remoteAddr string) {
		if err := c.UnsubscribeAll(context.Background(), remoteAddr); err != nil {
			logger.Error("Failed to unsubscribe from events", "err", err)
		}
	}
	wm := rpcserver.NewWebsocketManager(r, cdc, rpcserver.OnDisconnect(unsubscribeFromAllEvents))
	wm.SetLogger(logger)
	core.SetLogger(logger)
	mux.HandleFunc(wsEndpoint, wm.WebsocketHandler)

	config := rpcserver.DefaultConfig()
	config.MaxOpenConnections = maxOpenConnections
	l, err := rpcserver.Listen(listenAddr, config)
	if err != nil {
		return err
	}
	return rpcserver.StartHTTPServer(l, mux, logger, config)
}

// RPCRoutes just routes everything to the given client, as if it were
// a tendermint fullnode.
//
// if we want security, the client must implement it as a secure client
func RPCRoutes(c rpcclient.Client) map[string]*rpcserver.RPCFunc {
	return map[string]*rpcserver.RPCFunc{
		// Subscribe/unsubscribe are reserved for websocket events.
		"subscribe":       rpcserver.NewWSRPCFunc(c.(Wrapper).SubscribeWS, "query"),
		"unsubscribe":     rpcserver.NewWSRPCFunc(c.(Wrapper).UnsubscribeWS, "query"),
		"unsubscribe_all": rpcserver.NewWSRPCFunc(c.(Wrapper).UnsubscribeAllWS, ""),

		// info API
		"status":     rpcserver.NewRPCFunc(makeStatusFunc(c), ""),
		"blockchain": rpcserver.NewRPCFunc(makeBlockchainInfoFunc(c), "minHeight,maxHeight"),
		"genesis":    rpcserver.NewRPCFunc(makeGenesisFunc(c), ""),
		"block":      rpcserver.NewRPCFunc(makeBlockFunc(c), "height"),
		"commit":     rpcserver.NewRPCFunc(makeCommitFunc(c), "height"),
		"tx":         rpcserver.NewRPCFunc(makeTxFunc(c), "hash,prove"),
		"validators": rpcserver.NewRPCFunc(makeValidatorsFunc(c), "height"),

		// broadcast API
		"broadcast_tx_commit": rpcserver.NewRPCFunc(makeBroadcastTxCommitFunc(c), "tx"),
		"broadcast_tx_sync":   rpcserver.NewRPCFunc(makeBroadcastTxSyncFunc(c), "tx"),
		"broadcast_tx_async":  rpcserver.NewRPCFunc(makeBroadcastTxAsyncFunc(c), "tx"),

		// abci API
		"abci_query": rpcserver.NewRPCFunc(makeABCIQueryFunc(c), "path,data"),
		"abci_info":  rpcserver.NewRPCFunc(makeABCIInfoFunc(c), ""),
	}
}

func makeStatusFunc(c client.StatusClient) func(ctx *rpctypes.Context) (*ctypes.ResultStatus, error) {
	return func(ctx *rpctypes.Context) (*ctypes.ResultStatus, error) {
		return c.Status()
	}
}

func makeBlockchainInfoFunc(c rpcclient.Client) func(
	ctx *rpctypes.Context,
	minHeight,
	maxHeight int64,
) (*ctypes.ResultBlockchainInfo, error) {
	return func(ctx *rpctypes.Context, minHeight, maxHeight int64) (*ctypes.ResultBlockchainInfo, error) {
		return c.BlockchainInfo(minHeight, maxHeight)
	}
}

func makeGenesisFunc(c rpcclient.Client) func(ctx *rpctypes.Context) (*ctypes.ResultGenesis, error) {
	return func(ctx *rpctypes.Context) (*ctypes.ResultGenesis, error) {
		return c.Genesis()
	}
}

func makeBlockFunc(c rpcclient.Client) func(ctx *rpctypes.Context, height *int64) (*ctypes.ResultBlock, error) {
	return func(ctx *rpctypes.Context, height *int64) (*ctypes.ResultBlock, error) {
		return c.Block(height)
	}
}

func makeCommitFunc(c rpcclient.Client) func(ctx *rpctypes.Context, height *int64) (*ctypes.ResultCommit, error) {
	return func(ctx *rpctypes.Context, height *int64) (*ctypes.ResultCommit, error) {
		return c.Commit(height)
	}
}

func makeTxFunc(c rpcclient.Client) func(ctx *rpctypes.Context, hash []byte, prove bool) (*ctypes.ResultTx, error) {
	return func(ctx *rpctypes.Context, hash []byte, prove bool) (*ctypes.ResultTx, error) {
		return c.Tx(hash, prove)
	}
}

func makeValidatorsFunc(c rpcclient.Client) func(
	ctx *rpctypes.Context,
	height *int64,
) (*ctypes.ResultValidators, error) {
	return func(ctx *rpctypes.Context, height *int64) (*ctypes.ResultValidators, error) {
		return c.Validators(height, 0, 0)
	}
}

func makeBroadcastTxCommitFunc(c rpcclient.Client) func(
	ctx *rpctypes.Context,
	tx types.Tx,
) (*ctypes.ResultBroadcastTxCommit, error) {
	return func(ctx *rpctypes.Context, tx types.Tx) (*ctypes.ResultBroadcastTxCommit, error) {
		return c.BroadcastTxCommit(tx)
	}
}

func makeBroadcastTxSyncFunc(c rpcclient.Client) func(
	ctx *rpctypes.Context,
	tx types.Tx,
) (*ctypes.ResultBroadcastTx, error) {
	return func(ctx *rpctypes.Context, tx types.Tx) (*ctypes.ResultBroadcastTx, error) {
		return c.BroadcastTxSync(tx)
	}
}

func makeBroadcastTxAsyncFunc(c rpcclient.Client) func(
	ctx *rpctypes.Context,
	tx types.Tx,
) (*ctypes.ResultBroadcastTx, error) {
	return func(ctx *rpctypes.Context, tx types.Tx) (*ctypes.ResultBroadcastTx, error) {
		return c.BroadcastTxAsync(tx)
	}
}

func makeABCIQueryFunc(c rpcclient.Client) func(
	ctx *rpctypes.Context,
	path string,
	data bytes.HexBytes,
) (*ctypes.ResultABCIQuery, error) {
	return func(ctx *rpctypes.Context, path string, data bytes.HexBytes) (*ctypes.ResultABCIQuery, error) {
		return c.ABCIQuery(path, data)
	}
}

func makeABCIInfoFunc(c rpcclient.Client) func(ctx *rpctypes.Context) (*ctypes.ResultABCIInfo, error) {
	return func(ctx *rpctypes.Context) (*ctypes.ResultABCIInfo, error) {
		return c.ABCIInfo()
	}
}