package wallet

import (
	"context"
	"errors"
	"math/big"
	"time"

	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/common/hexutil"
	"github.com/ethereum/go-ethereum/log"
)

var (
	// ErrServiceNotInitialized returned when wallet is not initialized/started,.
	ErrServiceNotInitialized = errors.New("wallet service is not initialized")
)

func NewAPI(s *Service) *API {
	return &API{s}
}

// API is class with methods available over RPC.
type API struct {
	s *Service
}

// SetInitialBlocksRange sets initial blocks range
func (api *API) SetInitialBlocksRange(ctx context.Context) error {
	return api.s.SetInitialBlocksRange(api.s.db.network)
}

// GetTransfersByAddress returns transfers for a single address
func (api *API) GetTransfersByAddress(ctx context.Context, address common.Address, toBlock, limit *hexutil.Big, fetchMore bool) ([]TransferView, error) {
	log.Debug("[WalletAPI:: GetTransfersByAddress] get transfers for an address", "address", address, "block", toBlock, "limit", limit)
	if api.s.db == nil {
		log.Error("[WalletAPI:: GetTransfersByAddress] db is not initialized")
		return nil, ErrServiceNotInitialized
	}

	var toBlockBN *big.Int
	if toBlock != nil {
		toBlockBN = toBlock.ToInt()
	}

	rst, err := api.s.db.GetTransfersByAddress(address, toBlockBN, limit.ToInt().Int64())
	if err != nil {
		log.Error("[WalletAPI:: GetTransfersByAddress] can't fetch transfers", "err", err)
		return nil, err
	}

	transfersCount := big.NewInt(int64(len(rst)))
	if fetchMore && limit.ToInt().Cmp(transfersCount) == 1 {
		block, err := api.s.db.GetFirstKnownBlock(address)
		if err != nil {
			return nil, err
		}

		// if zero block was already checked there is nothing to find more
		if block == nil || big.NewInt(0).Cmp(block) == 0 {
			return castToTransferViews(rst), nil
		}

		from, err := findFirstRange(ctx, address, block, api.s.client)
		if err != nil {
			if nonArchivalNodeError(err) {
				api.s.feed.Send(Event{
					Type: EventNonArchivalNodeDetected,
				})
				from = big.NewInt(0).Sub(block, big.NewInt(100))
			} else {
				log.Error("first range error", "error", err)
				return nil, err
			}
		}
		fromByAddress := map[common.Address]*LastKnownBlock{address: &LastKnownBlock{
			Number: from,
		}}
		toByAddress := map[common.Address]*big.Int{address: block}

		balanceCache := newBalanceCache()
		blocksCommand := &findAndCheckBlockRangeCommand{
			accounts:      []common.Address{address},
			db:            api.s.db,
			chain:         api.s.reactor.chain,
			client:        api.s.client,
			balanceCache:  balanceCache,
			feed:          api.s.feed,
			fromByAddress: fromByAddress,
			toByAddress:   toByAddress,
		}

		if err = blocksCommand.Command()(ctx); err != nil {
			return nil, err
		}

		blocks, err := api.s.db.GetBlocksByAddress(address, numberOfBlocksCheckedPerIteration)
		if err != nil {
			return nil, err
		}

		log.Info("checking blocks again", "blocks", len(blocks))
		if len(blocks) > 0 {
			txCommand := &loadTransfersCommand{
				accounts: []common.Address{address},
				db:       api.s.db,
				chain:    api.s.reactor.chain,
				client:   api.s.client,
			}

			err = txCommand.Command()(ctx)
			if err != nil {
				return nil, err
			}
			rst, err = api.s.db.GetTransfersByAddress(address, toBlockBN, limit.ToInt().Int64())
			if err != nil {
				return nil, err
			}
		}
	}

	return castToTransferViews(rst), nil
}

// GetTokensBalances return mapping of token balances for every account.
func (api *API) GetTokensBalances(ctx context.Context, accounts, tokens []common.Address) (map[common.Address]map[common.Address]*hexutil.Big, error) {
	if api.s.client == nil {
		return nil, ErrServiceNotInitialized
	}
	return GetTokensBalances(ctx, api.s.client, accounts, tokens)
}

func (api *API) GetCustomTokens(ctx context.Context) ([]*Token, error) {
	log.Debug("call to get custom tokens")
	rst, err := api.s.db.GetCustomTokens()
	log.Debug("result from database for custom tokens", "len", len(rst))
	return rst, err
}

func (api *API) AddCustomToken(ctx context.Context, token Token) error {
	log.Debug("call to create or edit custom token")
	err := api.s.db.AddCustomToken(token)
	log.Debug("result from database for create or edit custom token", "err", err)
	return err
}

func (api *API) DeleteCustomToken(ctx context.Context, address common.Address) error {
	log.Debug("call to remove custom token")
	err := api.s.db.DeleteCustomToken(address)
	log.Debug("result from database for remove custom token", "err", err)
	return err
}

func (api *API) GetPendingTransactions(ctx context.Context) ([]*PendingTransaction, error) {
	log.Debug("call to get pending transactions")
	rst, err := api.s.db.getAllPendingTransactions()
	log.Debug("result from database for pending transactions", "len", len(rst))
	return rst, err
}

func (api *API) GetPendingOutboundTransactionsByAddress(ctx context.Context, address common.Address) ([]*PendingTransaction, error) {
	log.Debug("call to get pending transactions by address")
	rst, err := api.s.db.getPendingOutboundTransactionsByAddress(address)
	log.Debug("result from database for pending transactions by address", "len", len(rst))
	return rst, err
}

func (api *API) StorePendingTransaction(ctx context.Context, trx PendingTransaction) error {
	log.Debug("call to create or edit pending transaction")
	err := api.s.db.addPendingTransaction(trx)
	log.Debug("result from database for creating or editing a pending transaction", "err", err)
	return err
}

func (api *API) DeletePendingTransaction(ctx context.Context, transactionHash common.Hash) error {
	log.Debug("call to remove pending transaction")
	err := api.s.db.deletePendingTransaction(transactionHash)
	log.Debug("result from database for remove pending transaction", "err", err)
	return err
}

func (api *API) GetFavourites(ctx context.Context) ([]*Favourite, error) {
	log.Debug("call to get favourites")
	rst, err := api.s.db.GetFavourites()
	log.Debug("result from database for favourites", "len", len(rst))
	return rst, err
}

func (api *API) AddFavourite(ctx context.Context, favourite Favourite) error {
	log.Debug("call to create or update favourites")
	err := api.s.db.AddFavourite(favourite)
	log.Debug("result from database for create or update favourites", "err", err)
	return err
}

func (api *API) GetCryptoOnRamps(ctx context.Context) ([]CryptoOnRamp, error) {
	if api.s.cryptoOnRampManager == nil {
		// TODO Add settings and then build options based on settings
		opts := &CryptoOnRampOptions{
			dataSourceType: DataSourceStatic,
		}
		api.s.cryptoOnRampManager = NewCryptoOnRampManager(opts)
	}

	rs, err := api.s.cryptoOnRampManager.Get()
	if err != nil {
		return nil, err
	}

	return rs, nil
}

func (api *API) WatchTransaction(ctx context.Context, transactionHash common.Hash) error {
	watchTxCommand := &watchTransactionCommand{
		hash:   transactionHash,
		client: api.s.client,
		feed:   api.s.feed,
	}

	commandContext, cancel := context.WithTimeout(ctx, 10*time.Minute)
	defer cancel()

	return watchTxCommand.Command()(commandContext)
}

func (api *API) CheckRecentHistory(ctx context.Context, addresses []common.Address) error {
	if len(addresses) == 0 {
		log.Info("no addresses provided")
		return nil
	}
	err := api.s.MergeBlocksRanges(addresses, api.s.db.network)
	if err != nil {
		return err
	}

	return api.s.StartReactor(
		api.s.client.client,
		addresses,
		new(big.Int).SetUint64(api.s.db.network))
}

type LastKnownBlockView struct {
	Address common.Address `json:"address"`
	Number  *big.Int       `json:"blockNumber"`
	Balance BigInt         `json:"balance"`
	Nonce   *int64         `json:"nonce"`
}

func blocksToViews(blocks map[common.Address]*LastKnownBlock) []LastKnownBlockView {
	blocksViews := []LastKnownBlockView{}
	for address, block := range blocks {
		view := LastKnownBlockView{
			Address: address,
			Number:  block.Number,
			Balance: BigInt{block.Balance},
			Nonce:   block.Nonce,
		}
		blocksViews = append(blocksViews, view)
	}

	return blocksViews
}

func (api *API) GetCachedBalances(ctx context.Context, addresses []common.Address) ([]LastKnownBlockView, error) {
	result, error := api.s.db.getLastKnownBalances(addresses)
	if error != nil {
		return nil, error
	}

	return blocksToViews(result), nil
}