package commands

import (
	"context"

	"github.com/ledgerwatch/erigon/common"
	"github.com/ledgerwatch/erigon/common/hexutil"
	"github.com/ledgerwatch/erigon/core/rawdb"
	"github.com/ledgerwatch/erigon/rpc"
	"github.com/ledgerwatch/erigon/turbo/adapter/ethapi"
)

// GetBlockByNumber implements eth_getBlockByNumber. Returns information about a block given the block's number.
func (api *APIImpl) GetBlockByNumber(ctx context.Context, number rpc.BlockNumber, fullTx bool) (map[string]interface{}, error) {
	tx, err := api.db.BeginRo(ctx)
	if err != nil {
		return nil, err
	}
	defer tx.Rollback()
	b, err := api.getBlockByNumber(number, tx)
	if err != nil {
		return nil, err
	}
	if b == nil {
		return nil, nil
	}
	additionalFields := make(map[string]interface{})

	td, err := rawdb.ReadTd(tx, b.Hash(), b.NumberU64())
	if err != nil {
		return nil, err
	}
	additionalFields["totalDifficulty"] = (*hexutil.Big)(td)
	response, err := ethapi.RPCMarshalBlock(b, true, fullTx, additionalFields)

	if err == nil && number == rpc.PendingBlockNumber {
		// Pending blocks need to nil out a few fields
		for _, field := range []string{"hash", "nonce", "miner"} {
			response[field] = nil
		}
	}
	return response, err
}

// GetBlockByHash implements eth_getBlockByHash. Returns information about a block given the block's hash.
func (api *APIImpl) GetBlockByHash(ctx context.Context, numberOrHash rpc.BlockNumberOrHash, fullTx bool) (map[string]interface{}, error) {
	if numberOrHash.BlockHash == nil {
		// some web3.js based apps (like ethstats client) for some reason call
		// eth_getBlockByHash with a block number as a parameter
		// so no matter how weird that is, we would love to support that.
		if numberOrHash.BlockNumber == nil {
			return nil, nil // not error, see https://github.com/ledgerwatch/turbo-geth/issues/1645
		}
		return api.GetBlockByNumber(ctx, *numberOrHash.BlockNumber, fullTx)
	}

	hash := *numberOrHash.BlockHash
	tx, err := api.db.BeginRo(ctx)
	if err != nil {
		return nil, err
	}
	defer tx.Rollback()

	additionalFields := make(map[string]interface{})

	block, err := rawdb.ReadBlockByHash(tx, hash)
	if err != nil {
		return nil, err
	}
	if block == nil {
		return nil, nil // not error, see https://github.com/ledgerwatch/turbo-geth/issues/1645
	}
	number := block.NumberU64()

	td, err := rawdb.ReadTd(tx, hash, number)
	if err != nil {
		return nil, err
	}
	additionalFields["totalDifficulty"] = (*hexutil.Big)(td)
	response, err := ethapi.RPCMarshalBlock(block, true, fullTx, additionalFields)

	if err == nil && int64(number) == rpc.PendingBlockNumber.Int64() {
		// Pending blocks need to nil out a few fields
		for _, field := range []string{"hash", "nonce", "miner"} {
			response[field] = nil
		}
	}
	return response, err
}

// GetBlockTransactionCountByNumber implements eth_getBlockTransactionCountByNumber. Returns the number of transactions in a block given the block's block number.
func (api *APIImpl) GetBlockTransactionCountByNumber(ctx context.Context, blockNr rpc.BlockNumber) (*hexutil.Uint, error) {
	tx, err := api.db.BeginRo(ctx)
	if err != nil {
		return nil, err
	}
	defer tx.Rollback()
	if blockNr == rpc.PendingBlockNumber {
		b, err := api.getBlockByNumber(blockNr, tx)
		if err != nil {
			return nil, err
		}
		if b == nil {
			return nil, nil
		}
		n := hexutil.Uint(len(b.Transactions()))
		return &n, nil
	}
	blockNum, err := getBlockNumber(blockNr, tx)
	if err != nil {
		return nil, err
	}
	body, _, txAmount, err := rawdb.ReadBodyByNumber(tx, blockNum)
	if err != nil {
		return nil, err
	}
	if body == nil {
		return nil, nil
	}
	n := hexutil.Uint(txAmount)
	return &n, nil
}

// GetBlockTransactionCountByHash implements eth_getBlockTransactionCountByHash. Returns the number of transactions in a block given the block's block hash.
func (api *APIImpl) GetBlockTransactionCountByHash(ctx context.Context, blockHash common.Hash) (*hexutil.Uint, error) {
	tx, err := api.db.BeginRo(ctx)
	if err != nil {
		return nil, err
	}
	defer tx.Rollback()

	num := rawdb.ReadHeaderNumber(tx, blockHash)
	if num == nil {
		return nil, nil
	}
	body, _, txAmount := rawdb.ReadBodyWithoutTransactions(tx, blockHash, *num)
	if body == nil {
		return nil, nil
	}
	n := hexutil.Uint(txAmount)
	return &n, nil
}