package tests

import (
	"errors"
	"path"
	"testing"

	"github.com/nspcc-dev/neo-go/pkg/config/netmode"
	"github.com/nspcc-dev/neo-go/pkg/core/native/nativenames"
	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
	"github.com/nspcc-dev/neo-go/pkg/crypto/hash"
	"github.com/nspcc-dev/neo-go/pkg/io"
	"github.com/nspcc-dev/neo-go/pkg/neotest"
	"github.com/nspcc-dev/neo-go/pkg/util"
	"github.com/nspcc-dev/neo-go/pkg/vm/emit"
	"github.com/nspcc-dev/neo-go/pkg/vm/opcode"
	"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
	"github.com/stretchr/testify/require"
)

const proxyPath = "../proxy"

func deployProxyContract(t *testing.T, e *neotest.Executor, addrNetmap util.Uint160) util.Uint160 {
	args := make([]any, 1)
	args[0] = addrNetmap

	c := neotest.CompileFile(t, e.CommitteeHash, proxyPath, path.Join(proxyPath, "config.yml"))
	e.DeployContract(t, c, args)
	return c.Hash
}

func newProxyInvoker(t *testing.T) *neotest.ContractInvoker {
	e := newExecutor(t)

	ctrNetmap := neotest.CompileFile(t, e.CommitteeHash, netmapPath, path.Join(netmapPath, "config.yml"))
	ctrBalance := neotest.CompileFile(t, e.CommitteeHash, balancePath, path.Join(balancePath, "config.yml"))
	ctrContainer := neotest.CompileFile(t, e.CommitteeHash, containerPath, path.Join(containerPath, "config.yml"))
	ctrProxy := neotest.CompileFile(t, e.CommitteeHash, proxyPath, path.Join(proxyPath, "config.yml"))

	deployNetmapContract(t, e, ctrBalance.Hash, ctrContainer.Hash)
	deployProxyContract(t, e, ctrNetmap.Hash)

	return e.CommitteeInvoker(ctrProxy.Hash)
}

func TestVerify(t *testing.T) {
	e := newProxyInvoker(t)
	acc := e.NewAccount(t)

	gas := e.NewInvoker(e.NativeHash(t, nativenames.Gas), e.Validator)
	gas.Invoke(t, true, "transfer", e.Validator.ScriptHash(), e.Hash, 100_0000_0000, nil)

	t.Run("proxy + committee", func(t *testing.T) {
		s := &proxySigner{contract: e.Hash, account: e.CommitteeHash}
		tx := e.PrepareInvocation(t, []byte{byte(opcode.RET)}, []neotest.Signer{s, e.Committee})
		require.NoError(t, e.Chain.VerifyTx(tx))
	})
	t.Run("proxy + custom account", func(t *testing.T) {
		s := &proxySigner{contract: e.Hash, account: acc.ScriptHash()}
		t.Run("bad, only proxy", func(t *testing.T) {
			tx := e.PrepareInvocation(t, []byte{byte(opcode.RET)}, []neotest.Signer{s, acc})
			require.Error(t, e.Chain.VerifyTx(tx))
		})

		e.Invoke(t, stackitem.Null{}, "addAccount", s.account)

		tx := e.PrepareInvocation(t, []byte{byte(opcode.RET)}, []neotest.Signer{s, acc})
		require.NoError(t, e.Chain.VerifyTx(tx))
	})
}

type proxySigner struct {
	contract util.Uint160
	account  util.Uint160
}

var _ neotest.ContractSigner = (*proxySigner)(nil)

func (s *proxySigner) Script() []byte {
	return nil
}
func (s *proxySigner) ScriptHash() util.Uint160 {
	return s.contract
}
func (s *proxySigner) SignHashable(uint32, hash.Hashable) []byte {
	panic("not implemented")
}
func (s *proxySigner) SignTx(_ netmode.Magic, tx *transaction.Transaction) error {
	pos := -1
	for i := range tx.Signers {
		if tx.Signers[i].Account.Equals(s.contract) {
			pos = i
			break
		}
	}
	if pos < 0 {
		return errors.New("transaction is not signed by this account")
	}
	if len(tx.Scripts) < pos {
		return errors.New("transaction is not yet signed by the previous signer")
	}

	invoc, err := s.InvocationScript(tx)
	if err != nil {
		return err
	}

	w := transaction.Witness{InvocationScript: invoc}
	if len(tx.Scripts) == pos {
		tx.Scripts = append(tx.Scripts, w)
	} else {
		tx.Scripts[pos].InvocationScript = invoc
	}
	return nil
}
func (s *proxySigner) InvocationScript(tx *transaction.Transaction) ([]byte, error) {
	w := io.NewBufBinWriter()
	emit.Any(w.BinWriter, s.account)
	return w.Bytes(), nil
}