package ethapi

import (
	"context"
	"github.com/ethereum/go-ethereum/core"
	"github.com/ethereum/go-ethereum/core/vm"
	"github.com/ethereum/go-ethereum/rpc"
	"time"
)

type PublicEthereum2API struct {
	b Backend
}

func NewEthereum2API(b Backend) *PublicEthereum2API {
	return &PublicEthereum2API{b}
}

func (s *PublicEthereum2API) Call(ctx context.Context, args CallArgs, blockNrOrHash rpc.BlockNumberOrHash, overrides *StateOverride) (CallResult, error) {
	result, err := DoCall(ctx, s.b, args, blockNrOrHash, overrides, vm.Config{}, 5*time.Second, s.b.RPCGasCap())
	if err != nil {
		return CallResult{Success: false, Msg: err.Error()}, err
	} else {
		if len(result.Revert()) > 0 {
			revertErr := newRevertError(result)
			return CallResult{Success: false, Data: result.Revert(), Msg: revertErr.Error()}, nil
		}

		return CallResult{Success: true, Data: result.Return()}, nil
	}
}

// BatchCall executes a series of transactions on the state of a given block as base.
// The base state can be overridden once before transactions are executed.
//
// Additionally, each call can override block context fields such as number.
//
// Note, this function doesn't make any changes in the state/blockchain and is
// useful to execute and retrieve values.
func (s *PublicEthereum2API) BatchCall(ctx context.Context, config BatchCallConfig) ([]CallResult, error) {
	state, header, err := s.b.StateAndHeaderByNumberOrHash(ctx, config.Block)
	if state == nil || err != nil {
		return nil, err
	}
	// State overrides are applied once before all calls
	if err := config.StateOverrides.Apply(state); err != nil {
		return nil, err
	}

	// Setup context so it may be cancelled before the calls completed
	// or, in case of unmetered gas, setup a context with a timeout.
	var (
		cancel context.CancelFunc
		//timeout = s.b.RPCEVMTimeout()
		timeout = time.Duration(5000000000)
	)
	if timeout > 0 {
		ctx, cancel = context.WithTimeout(ctx, timeout)
	} else {
		ctx, cancel = context.WithCancel(ctx)
	}
	// Make sure the context is cancelled when the call has completed
	// this makes sure resources are cleaned up.
	defer cancel()
	var (
		results []CallResult
		// Each tx and all the series of txes shouldn't consume more gas than cap
		globalGasCap = s.b.RPCGasCap()
		gp           = new(core.GasPool).AddGas(globalGasCap)
	)
	for _, call := range config.Calls {
		blockContext := core.NewEVMBlockContext(header, NewChainContext(ctx, s.b), nil)
		if call.BlockOverrides != nil {
			call.BlockOverrides.Apply(&blockContext)
		}
		result, doCallErr := doCall(ctx, s.b, call.CallArgs, state, header, timeout, gp, &blockContext)
		if doCallErr != nil {
			results = append(results, CallResult{Success: false, Msg: doCallErr.Error()})
		} else {
			if len(result.Revert()) > 0 {
				revertErr := newRevertError(result)
				results = append(results, CallResult{Success: false, Data: result.Revert(), Msg: revertErr.Error()})
			} else {
				results = append(results, CallResult{Success: true, Data: result.Return()})
			}
		}
	}
	return results, nil
}