// Package structs contains RPC wrappers for Notifications contract.
package structs

import (
	"crypto/elliptic"
	"errors"
	"fmt"
	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
	"github.com/nspcc-dev/neo-go/pkg/neorpc/result"
	"github.com/nspcc-dev/neo-go/pkg/util"
	"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
	"math/big"
	"unicode/utf8"
)

// Hash contains contract hash.
var Hash = util.Uint160{0x33, 0x22, 0x11, 0x0, 0xff, 0xee, 0xdd, 0xcc, 0xbb, 0xaa, 0x99, 0x88, 0x77, 0x66, 0x55, 0x44, 0x33, 0x22, 0x11, 0x0}

// LedgerBlock is a contract-specific ledger.Block type used by its methods.
type LedgerBlock struct {
	Hash util.Uint256
	Version *big.Int
	PrevHash util.Uint256
	MerkleRoot util.Uint256
	Timestamp *big.Int
	Nonce *big.Int
	Index *big.Int
	NextConsensus util.Uint160
	TransactionsLength *big.Int
}

// LedgerBlockSR is a contract-specific ledger.BlockSR type used by its methods.
type LedgerBlockSR struct {
	Hash util.Uint256
	Version *big.Int
	PrevHash util.Uint256
	MerkleRoot util.Uint256
	Timestamp *big.Int
	Nonce *big.Int
	Index *big.Int
	NextConsensus util.Uint160
	TransactionsLength *big.Int
	PrevStateRoot util.Uint256
}

// LedgerTransaction is a contract-specific ledger.Transaction type used by its methods.
type LedgerTransaction struct {
	Hash util.Uint256
	Version *big.Int
	Nonce *big.Int
	Sender util.Uint160
	SysFee *big.Int
	NetFee *big.Int
	ValidUntilBlock *big.Int
	Script []byte
}

// LedgerTransactionSigner is a contract-specific ledger.TransactionSigner type used by its methods.
type LedgerTransactionSigner struct {
	Account util.Uint160
	Scopes *big.Int
	AllowedContracts []util.Uint160
	AllowedGroups keys.PublicKeys
	Rules []*LedgerWitnessRule
}

// LedgerWitnessCondition is a contract-specific ledger.WitnessCondition type used by its methods.
type LedgerWitnessCondition struct {
	Type *big.Int
	Value any
}

// LedgerWitnessRule is a contract-specific ledger.WitnessRule type used by its methods.
type LedgerWitnessRule struct {
	Action *big.Int
	Condition *LedgerWitnessCondition
}

// Unnamed is a contract-specific unnamed type used by its methods.
type Unnamed struct {
	I *big.Int
	B bool
}

// ComplicatedNameEvent represents "! complicated name %$#" event emitted by the contract.
type ComplicatedNameEvent struct {
	ComplicatedParam string
}

// SomeMapEvent represents "SomeMap" event emitted by the contract.
type SomeMapEvent struct {
	M map[*big.Int][]map[string][]util.Uint160
}

// SomeStructEvent represents "SomeStruct" event emitted by the contract.
type SomeStructEvent struct {
	S []any
}

// SomeArrayEvent represents "SomeArray" event emitted by the contract.
type SomeArrayEvent struct {
	A [][]*big.Int
}

// Actor is used by Contract to call state-changing methods.
type Actor interface {
	MakeCall(contract util.Uint160, method string, params ...any) (*transaction.Transaction, error)
	MakeRun(script []byte) (*transaction.Transaction, error)
	MakeUnsignedCall(contract util.Uint160, method string, attrs []transaction.Attribute, params ...any) (*transaction.Transaction, error)
	MakeUnsignedRun(script []byte, attrs []transaction.Attribute) (*transaction.Transaction, error)
	SendCall(contract util.Uint160, method string, params ...any) (util.Uint256, uint32, error)
	SendRun(script []byte) (util.Uint256, uint32, error)
}

// Contract implements all contract methods.
type Contract struct {
	actor Actor
}

// New creates an instance of Contract using Hash and the given Actor.
func New(actor Actor) *Contract {
	return &Contract{actor}
}

// Array creates a transaction invoking `array` method of the contract.
// This transaction is signed and immediately sent to the network.
// The values returned are its hash, ValidUntilBlock value and error if any.
func (c *Contract) Array() (util.Uint256, uint32, error) {
	return c.actor.SendCall(Hash, "array")
}

// ArrayTransaction creates a transaction invoking `array` method of the contract.
// This transaction is signed, but not sent to the network, instead it's
// returned to the caller.
func (c *Contract) ArrayTransaction() (*transaction.Transaction, error) {
	return c.actor.MakeCall(Hash, "array")
}

// ArrayUnsigned creates a transaction invoking `array` method of the contract.
// This transaction is not signed, it's simply returned to the caller.
// Any fields of it that do not affect fees can be changed (ValidUntilBlock,
// Nonce), fee values (NetworkFee, SystemFee) can be increased as well.
func (c *Contract) ArrayUnsigned() (*transaction.Transaction, error) {
	return c.actor.MakeUnsignedCall(Hash, "array", nil)
}

// CrazyMap creates a transaction invoking `crazyMap` method of the contract.
// This transaction is signed and immediately sent to the network.
// The values returned are its hash, ValidUntilBlock value and error if any.
func (c *Contract) CrazyMap() (util.Uint256, uint32, error) {
	return c.actor.SendCall(Hash, "crazyMap")
}

// CrazyMapTransaction creates a transaction invoking `crazyMap` method of the contract.
// This transaction is signed, but not sent to the network, instead it's
// returned to the caller.
func (c *Contract) CrazyMapTransaction() (*transaction.Transaction, error) {
	return c.actor.MakeCall(Hash, "crazyMap")
}

// CrazyMapUnsigned creates a transaction invoking `crazyMap` method of the contract.
// This transaction is not signed, it's simply returned to the caller.
// Any fields of it that do not affect fees can be changed (ValidUntilBlock,
// Nonce), fee values (NetworkFee, SystemFee) can be increased as well.
func (c *Contract) CrazyMapUnsigned() (*transaction.Transaction, error) {
	return c.actor.MakeUnsignedCall(Hash, "crazyMap", nil)
}

// Main creates a transaction invoking `main` method of the contract.
// This transaction is signed and immediately sent to the network.
// The values returned are its hash, ValidUntilBlock value and error if any.
func (c *Contract) Main() (util.Uint256, uint32, error) {
	return c.actor.SendCall(Hash, "main")
}

// MainTransaction creates a transaction invoking `main` method of the contract.
// This transaction is signed, but not sent to the network, instead it's
// returned to the caller.
func (c *Contract) MainTransaction() (*transaction.Transaction, error) {
	return c.actor.MakeCall(Hash, "main")
}

// MainUnsigned creates a transaction invoking `main` method of the contract.
// This transaction is not signed, it's simply returned to the caller.
// Any fields of it that do not affect fees can be changed (ValidUntilBlock,
// Nonce), fee values (NetworkFee, SystemFee) can be increased as well.
func (c *Contract) MainUnsigned() (*transaction.Transaction, error) {
	return c.actor.MakeUnsignedCall(Hash, "main", nil)
}

// Struct creates a transaction invoking `struct` method of the contract.
// This transaction is signed and immediately sent to the network.
// The values returned are its hash, ValidUntilBlock value and error if any.
func (c *Contract) Struct() (util.Uint256, uint32, error) {
	return c.actor.SendCall(Hash, "struct")
}

// StructTransaction creates a transaction invoking `struct` method of the contract.
// This transaction is signed, but not sent to the network, instead it's
// returned to the caller.
func (c *Contract) StructTransaction() (*transaction.Transaction, error) {
	return c.actor.MakeCall(Hash, "struct")
}

// StructUnsigned creates a transaction invoking `struct` method of the contract.
// This transaction is not signed, it's simply returned to the caller.
// Any fields of it that do not affect fees can be changed (ValidUntilBlock,
// Nonce), fee values (NetworkFee, SystemFee) can be increased as well.
func (c *Contract) StructUnsigned() (*transaction.Transaction, error) {
	return c.actor.MakeUnsignedCall(Hash, "struct", nil)
}

// itemToLedgerBlock converts stack item into *LedgerBlock.
func itemToLedgerBlock(item stackitem.Item, err error) (*LedgerBlock, error) {
	if err != nil {
		return nil, err
	}
	var res = new(LedgerBlock)
	err = res.FromStackItem(item)
	return res, err
}

// FromStackItem retrieves fields of LedgerBlock from the given stack item
// and returns an error if so.
func (res *LedgerBlock) FromStackItem(item stackitem.Item) error {
	arr, ok := item.Value().([]stackitem.Item)
	if !ok {
		return errors.New("not an array")
	}
	if len(arr) != 9 {
		return errors.New("wrong number of structure elements")
	}

	var (
		index = -1
		err error
	)
	index++
	res.Hash, err = func (item stackitem.Item) (util.Uint256, error) {
		b, err := item.TryBytes()
		if err != nil {
			return util.Uint256{}, err
		}
		u, err := util.Uint256DecodeBytesBE(b)
		if err != nil {
			return util.Uint256{}, err
		}
		return u, nil
	} (arr[index])
	if err != nil {
		return fmt.Errorf("field Hash: %w", err)
	}

	index++
	res.Version, err = arr[index].TryInteger()
	if err != nil {
		return fmt.Errorf("field Version: %w", err)
	}

	index++
	res.PrevHash, err = func (item stackitem.Item) (util.Uint256, error) {
		b, err := item.TryBytes()
		if err != nil {
			return util.Uint256{}, err
		}
		u, err := util.Uint256DecodeBytesBE(b)
		if err != nil {
			return util.Uint256{}, err
		}
		return u, nil
	} (arr[index])
	if err != nil {
		return fmt.Errorf("field PrevHash: %w", err)
	}

	index++
	res.MerkleRoot, err = func (item stackitem.Item) (util.Uint256, error) {
		b, err := item.TryBytes()
		if err != nil {
			return util.Uint256{}, err
		}
		u, err := util.Uint256DecodeBytesBE(b)
		if err != nil {
			return util.Uint256{}, err
		}
		return u, nil
	} (arr[index])
	if err != nil {
		return fmt.Errorf("field MerkleRoot: %w", err)
	}

	index++
	res.Timestamp, err = arr[index].TryInteger()
	if err != nil {
		return fmt.Errorf("field Timestamp: %w", err)
	}

	index++
	res.Nonce, err = arr[index].TryInteger()
	if err != nil {
		return fmt.Errorf("field Nonce: %w", err)
	}

	index++
	res.Index, err = arr[index].TryInteger()
	if err != nil {
		return fmt.Errorf("field Index: %w", err)
	}

	index++
	res.NextConsensus, err = func (item stackitem.Item) (util.Uint160, error) {
		b, err := item.TryBytes()
		if err != nil {
			return util.Uint160{}, err
		}
		u, err := util.Uint160DecodeBytesBE(b)
		if err != nil {
			return util.Uint160{}, err
		}
		return u, nil
	} (arr[index])
	if err != nil {
		return fmt.Errorf("field NextConsensus: %w", err)
	}

	index++
	res.TransactionsLength, err = arr[index].TryInteger()
	if err != nil {
		return fmt.Errorf("field TransactionsLength: %w", err)
	}

	return nil
}

// itemToLedgerBlockSR converts stack item into *LedgerBlockSR.
func itemToLedgerBlockSR(item stackitem.Item, err error) (*LedgerBlockSR, error) {
	if err != nil {
		return nil, err
	}
	var res = new(LedgerBlockSR)
	err = res.FromStackItem(item)
	return res, err
}

// FromStackItem retrieves fields of LedgerBlockSR from the given stack item
// and returns an error if so.
func (res *LedgerBlockSR) FromStackItem(item stackitem.Item) error {
	arr, ok := item.Value().([]stackitem.Item)
	if !ok {
		return errors.New("not an array")
	}
	if len(arr) != 10 {
		return errors.New("wrong number of structure elements")
	}

	var (
		index = -1
		err error
	)
	index++
	res.Hash, err = func (item stackitem.Item) (util.Uint256, error) {
		b, err := item.TryBytes()
		if err != nil {
			return util.Uint256{}, err
		}
		u, err := util.Uint256DecodeBytesBE(b)
		if err != nil {
			return util.Uint256{}, err
		}
		return u, nil
	} (arr[index])
	if err != nil {
		return fmt.Errorf("field Hash: %w", err)
	}

	index++
	res.Version, err = arr[index].TryInteger()
	if err != nil {
		return fmt.Errorf("field Version: %w", err)
	}

	index++
	res.PrevHash, err = func (item stackitem.Item) (util.Uint256, error) {
		b, err := item.TryBytes()
		if err != nil {
			return util.Uint256{}, err
		}
		u, err := util.Uint256DecodeBytesBE(b)
		if err != nil {
			return util.Uint256{}, err
		}
		return u, nil
	} (arr[index])
	if err != nil {
		return fmt.Errorf("field PrevHash: %w", err)
	}

	index++
	res.MerkleRoot, err = func (item stackitem.Item) (util.Uint256, error) {
		b, err := item.TryBytes()
		if err != nil {
			return util.Uint256{}, err
		}
		u, err := util.Uint256DecodeBytesBE(b)
		if err != nil {
			return util.Uint256{}, err
		}
		return u, nil
	} (arr[index])
	if err != nil {
		return fmt.Errorf("field MerkleRoot: %w", err)
	}

	index++
	res.Timestamp, err = arr[index].TryInteger()
	if err != nil {
		return fmt.Errorf("field Timestamp: %w", err)
	}

	index++
	res.Nonce, err = arr[index].TryInteger()
	if err != nil {
		return fmt.Errorf("field Nonce: %w", err)
	}

	index++
	res.Index, err = arr[index].TryInteger()
	if err != nil {
		return fmt.Errorf("field Index: %w", err)
	}

	index++
	res.NextConsensus, err = func (item stackitem.Item) (util.Uint160, error) {
		b, err := item.TryBytes()
		if err != nil {
			return util.Uint160{}, err
		}
		u, err := util.Uint160DecodeBytesBE(b)
		if err != nil {
			return util.Uint160{}, err
		}
		return u, nil
	} (arr[index])
	if err != nil {
		return fmt.Errorf("field NextConsensus: %w", err)
	}

	index++
	res.TransactionsLength, err = arr[index].TryInteger()
	if err != nil {
		return fmt.Errorf("field TransactionsLength: %w", err)
	}

	index++
	res.PrevStateRoot, err = func (item stackitem.Item) (util.Uint256, error) {
		b, err := item.TryBytes()
		if err != nil {
			return util.Uint256{}, err
		}
		u, err := util.Uint256DecodeBytesBE(b)
		if err != nil {
			return util.Uint256{}, err
		}
		return u, nil
	} (arr[index])
	if err != nil {
		return fmt.Errorf("field PrevStateRoot: %w", err)
	}

	return nil
}

// itemToLedgerTransaction converts stack item into *LedgerTransaction.
func itemToLedgerTransaction(item stackitem.Item, err error) (*LedgerTransaction, error) {
	if err != nil {
		return nil, err
	}
	var res = new(LedgerTransaction)
	err = res.FromStackItem(item)
	return res, err
}

// FromStackItem retrieves fields of LedgerTransaction from the given stack item
// and returns an error if so.
func (res *LedgerTransaction) FromStackItem(item stackitem.Item) error {
	arr, ok := item.Value().([]stackitem.Item)
	if !ok {
		return errors.New("not an array")
	}
	if len(arr) != 8 {
		return errors.New("wrong number of structure elements")
	}

	var (
		index = -1
		err error
	)
	index++
	res.Hash, err = func (item stackitem.Item) (util.Uint256, error) {
		b, err := item.TryBytes()
		if err != nil {
			return util.Uint256{}, err
		}
		u, err := util.Uint256DecodeBytesBE(b)
		if err != nil {
			return util.Uint256{}, err
		}
		return u, nil
	} (arr[index])
	if err != nil {
		return fmt.Errorf("field Hash: %w", err)
	}

	index++
	res.Version, err = arr[index].TryInteger()
	if err != nil {
		return fmt.Errorf("field Version: %w", err)
	}

	index++
	res.Nonce, err = arr[index].TryInteger()
	if err != nil {
		return fmt.Errorf("field Nonce: %w", err)
	}

	index++
	res.Sender, err = func (item stackitem.Item) (util.Uint160, error) {
		b, err := item.TryBytes()
		if err != nil {
			return util.Uint160{}, err
		}
		u, err := util.Uint160DecodeBytesBE(b)
		if err != nil {
			return util.Uint160{}, err
		}
		return u, nil
	} (arr[index])
	if err != nil {
		return fmt.Errorf("field Sender: %w", err)
	}

	index++
	res.SysFee, err = arr[index].TryInteger()
	if err != nil {
		return fmt.Errorf("field SysFee: %w", err)
	}

	index++
	res.NetFee, err = arr[index].TryInteger()
	if err != nil {
		return fmt.Errorf("field NetFee: %w", err)
	}

	index++
	res.ValidUntilBlock, err = arr[index].TryInteger()
	if err != nil {
		return fmt.Errorf("field ValidUntilBlock: %w", err)
	}

	index++
	res.Script, err = arr[index].TryBytes()
	if err != nil {
		return fmt.Errorf("field Script: %w", err)
	}

	return nil
}

// itemToLedgerTransactionSigner converts stack item into *LedgerTransactionSigner.
func itemToLedgerTransactionSigner(item stackitem.Item, err error) (*LedgerTransactionSigner, error) {
	if err != nil {
		return nil, err
	}
	var res = new(LedgerTransactionSigner)
	err = res.FromStackItem(item)
	return res, err
}

// FromStackItem retrieves fields of LedgerTransactionSigner from the given stack item
// and returns an error if so.
func (res *LedgerTransactionSigner) FromStackItem(item stackitem.Item) error {
	arr, ok := item.Value().([]stackitem.Item)
	if !ok {
		return errors.New("not an array")
	}
	if len(arr) != 5 {
		return errors.New("wrong number of structure elements")
	}

	var (
		index = -1
		err error
	)
	index++
	res.Account, err = func (item stackitem.Item) (util.Uint160, error) {
		b, err := item.TryBytes()
		if err != nil {
			return util.Uint160{}, err
		}
		u, err := util.Uint160DecodeBytesBE(b)
		if err != nil {
			return util.Uint160{}, err
		}
		return u, nil
	} (arr[index])
	if err != nil {
		return fmt.Errorf("field Account: %w", err)
	}

	index++
	res.Scopes, err = arr[index].TryInteger()
	if err != nil {
		return fmt.Errorf("field Scopes: %w", err)
	}

	index++
	res.AllowedContracts, err = func (item stackitem.Item) ([]util.Uint160, error) {
		arr, ok := item.Value().([]stackitem.Item)
		if !ok {
			return nil, errors.New("not an array")
		}
		res := make([]util.Uint160, len(arr))
		for i := range res {
			res[i], err = func (item stackitem.Item) (util.Uint160, error) {
				b, err := item.TryBytes()
				if err != nil {
					return util.Uint160{}, err
				}
				u, err := util.Uint160DecodeBytesBE(b)
				if err != nil {
					return util.Uint160{}, err
				}
				return u, nil
			} (arr[i])
			if err != nil {
				return nil, fmt.Errorf("item %d: %w", i, err)
			}
		}
		return res, nil
	} (arr[index])
	if err != nil {
		return fmt.Errorf("field AllowedContracts: %w", err)
	}

	index++
	res.AllowedGroups, err = func (item stackitem.Item) (keys.PublicKeys, error) {
		arr, ok := item.Value().([]stackitem.Item)
		if !ok {
			return nil, errors.New("not an array")
		}
		res := make(keys.PublicKeys, len(arr))
		for i := range res {
			res[i], err = func (item stackitem.Item) (*keys.PublicKey, error) {
				b, err := item.TryBytes()
				if err != nil {
					return nil, err
				}
				k, err := keys.NewPublicKeyFromBytes(b, elliptic.P256())
				if err != nil {
					return nil, err
				}
				return k, nil
			} (arr[i])
			if err != nil {
				return nil, fmt.Errorf("item %d: %w", i, err)
			}
		}
		return res, nil
	} (arr[index])
	if err != nil {
		return fmt.Errorf("field AllowedGroups: %w", err)
	}

	index++
	res.Rules, err = func (item stackitem.Item) ([]*LedgerWitnessRule, error) {
		arr, ok := item.Value().([]stackitem.Item)
		if !ok {
			return nil, errors.New("not an array")
		}
		res := make([]*LedgerWitnessRule, len(arr))
		for i := range res {
			res[i], err = itemToLedgerWitnessRule(arr[i], nil)
			if err != nil {
				return nil, fmt.Errorf("item %d: %w", i, err)
			}
		}
		return res, nil
	} (arr[index])
	if err != nil {
		return fmt.Errorf("field Rules: %w", err)
	}

	return nil
}

// itemToLedgerWitnessCondition converts stack item into *LedgerWitnessCondition.
func itemToLedgerWitnessCondition(item stackitem.Item, err error) (*LedgerWitnessCondition, error) {
	if err != nil {
		return nil, err
	}
	var res = new(LedgerWitnessCondition)
	err = res.FromStackItem(item)
	return res, err
}

// FromStackItem retrieves fields of LedgerWitnessCondition from the given stack item
// and returns an error if so.
func (res *LedgerWitnessCondition) FromStackItem(item stackitem.Item) error {
	arr, ok := item.Value().([]stackitem.Item)
	if !ok {
		return errors.New("not an array")
	}
	if len(arr) != 2 {
		return errors.New("wrong number of structure elements")
	}

	var (
		index = -1
		err error
	)
	index++
	res.Type, err = arr[index].TryInteger()
	if err != nil {
		return fmt.Errorf("field Type: %w", err)
	}

	index++
	res.Value, err = arr[index].Value(), error(nil)
	if err != nil {
		return fmt.Errorf("field Value: %w", err)
	}

	return nil
}

// itemToLedgerWitnessRule converts stack item into *LedgerWitnessRule.
func itemToLedgerWitnessRule(item stackitem.Item, err error) (*LedgerWitnessRule, error) {
	if err != nil {
		return nil, err
	}
	var res = new(LedgerWitnessRule)
	err = res.FromStackItem(item)
	return res, err
}

// FromStackItem retrieves fields of LedgerWitnessRule from the given stack item
// and returns an error if so.
func (res *LedgerWitnessRule) FromStackItem(item stackitem.Item) error {
	arr, ok := item.Value().([]stackitem.Item)
	if !ok {
		return errors.New("not an array")
	}
	if len(arr) != 2 {
		return errors.New("wrong number of structure elements")
	}

	var (
		index = -1
		err error
	)
	index++
	res.Action, err = arr[index].TryInteger()
	if err != nil {
		return fmt.Errorf("field Action: %w", err)
	}

	index++
	res.Condition, err = itemToLedgerWitnessCondition(arr[index], nil)
	if err != nil {
		return fmt.Errorf("field Condition: %w", err)
	}

	return nil
}

// itemToUnnamed converts stack item into *Unnamed.
func itemToUnnamed(item stackitem.Item, err error) (*Unnamed, error) {
	if err != nil {
		return nil, err
	}
	var res = new(Unnamed)
	err = res.FromStackItem(item)
	return res, err
}

// FromStackItem retrieves fields of Unnamed from the given stack item
// and returns an error if so.
func (res *Unnamed) FromStackItem(item stackitem.Item) error {
	arr, ok := item.Value().([]stackitem.Item)
	if !ok {
		return errors.New("not an array")
	}
	if len(arr) != 2 {
		return errors.New("wrong number of structure elements")
	}

	var (
		index = -1
		err error
	)
	index++
	res.I, err = arr[index].TryInteger()
	if err != nil {
		return fmt.Errorf("field I: %w", err)
	}

	index++
	res.B, err = arr[index].TryBool()
	if err != nil {
		return fmt.Errorf("field B: %w", err)
	}

	return nil
}

// ComplicatedNameEventsFromApplicationLog retrieves a set of all emitted events
// with "! complicated name %$#" name from the provided ApplicationLog.
func ComplicatedNameEventsFromApplicationLog(log *result.ApplicationLog) ([]*ComplicatedNameEvent, error) {
	if log == nil {
		return nil, errors.New("nil application log")
	}

	var res []*ComplicatedNameEvent
	for i, ex := range log.Executions {
		for j, e := range ex.Events {
			if e.Name != "! complicated name %$#" {
				continue
			}
			event := new(ComplicatedNameEvent)
			err := event.FromStackItem(e.Item)
			if err != nil {
				return nil, fmt.Errorf("failed to deserialize ComplicatedNameEvent from stackitem (execution %d, event %d): %w", i, j, err)
			}
			res = append(res, event)
		}
	}

	return res, nil
}

// FromStackItem converts provided stackitem.Array to ComplicatedNameEvent and
// returns an error if so.
func (e *ComplicatedNameEvent) FromStackItem(item *stackitem.Array) error {
	if item == nil {
		return errors.New("nil item")
	}
	arr, ok := item.Value().([]stackitem.Item)
	if !ok {
		return errors.New("not an array")
	}
	if len(arr) != 1 {
		return errors.New("wrong number of structure elements")
	}

	var (
		index = -1
		err error
	)
	index++
	e.ComplicatedParam, err = func (item stackitem.Item) (string, error) {
		b, err := item.TryBytes()
		if err != nil {
			return "", err
		}
		if !utf8.Valid(b) {
			return "", errors.New("not a UTF-8 string")
		}
		return string(b), nil
	} (arr[index])
	if err != nil {
		return fmt.Errorf("field ComplicatedParam: %w", err)
	}

	return nil
}

// SomeMapEventsFromApplicationLog retrieves a set of all emitted events
// with "SomeMap" name from the provided ApplicationLog.
func SomeMapEventsFromApplicationLog(log *result.ApplicationLog) ([]*SomeMapEvent, error) {
	if log == nil {
		return nil, errors.New("nil application log")
	}

	var res []*SomeMapEvent
	for i, ex := range log.Executions {
		for j, e := range ex.Events {
			if e.Name != "SomeMap" {
				continue
			}
			event := new(SomeMapEvent)
			err := event.FromStackItem(e.Item)
			if err != nil {
				return nil, fmt.Errorf("failed to deserialize SomeMapEvent from stackitem (execution %d, event %d): %w", i, j, err)
			}
			res = append(res, event)
		}
	}

	return res, nil
}

// FromStackItem converts provided stackitem.Array to SomeMapEvent and
// returns an error if so.
func (e *SomeMapEvent) FromStackItem(item *stackitem.Array) error {
	if item == nil {
		return errors.New("nil item")
	}
	arr, ok := item.Value().([]stackitem.Item)
	if !ok {
		return errors.New("not an array")
	}
	if len(arr) != 1 {
		return errors.New("wrong number of structure elements")
	}

	var (
		index = -1
		err error
	)
	index++
	e.M, err = func (item stackitem.Item) (map[*big.Int][]map[string][]util.Uint160, error) {
		m, ok := item.Value().([]stackitem.MapElement)
		if !ok {
			return nil, fmt.Errorf("%s is not a map", item.Type().String())
		}
		res := make(map[*big.Int][]map[string][]util.Uint160)
		for i := range m {
			k, err := m[i].Key.TryInteger()
			if err != nil {
				return nil, fmt.Errorf("key %d: %w", i, err)
			}
			v, err := func (item stackitem.Item) ([]map[string][]util.Uint160, error) {
				arr, ok := item.Value().([]stackitem.Item)
				if !ok {
					return nil, errors.New("not an array")
				}
				res := make([]map[string][]util.Uint160, len(arr))
				for i := range res {
					res[i], err = func (item stackitem.Item) (map[string][]util.Uint160, error) {
						m, ok := item.Value().([]stackitem.MapElement)
						if !ok {
							return nil, fmt.Errorf("%s is not a map", item.Type().String())
						}
						res := make(map[string][]util.Uint160)
						for i := range m {
							k, err := func (item stackitem.Item) (string, error) {
								b, err := item.TryBytes()
								if err != nil {
									return "", err
								}
								if !utf8.Valid(b) {
									return "", errors.New("not a UTF-8 string")
								}
								return string(b), nil
							} (m[i].Key)
							if err != nil {
								return nil, fmt.Errorf("key %d: %w", i, err)
							}
							v, err := func (item stackitem.Item) ([]util.Uint160, error) {
								arr, ok := item.Value().([]stackitem.Item)
								if !ok {
									return nil, errors.New("not an array")
								}
								res := make([]util.Uint160, len(arr))
								for i := range res {
									res[i], err = func (item stackitem.Item) (util.Uint160, error) {
										b, err := item.TryBytes()
										if err != nil {
											return util.Uint160{}, err
										}
										u, err := util.Uint160DecodeBytesBE(b)
										if err != nil {
											return util.Uint160{}, err
										}
										return u, nil
									} (arr[i])
									if err != nil {
										return nil, fmt.Errorf("item %d: %w", i, err)
									}
								}
								return res, nil
							} (m[i].Value)
							if err != nil {
								return nil, fmt.Errorf("value %d: %w", i, err)
							}
							res[k] = v
						}
						return res, nil
					} (arr[i])
					if err != nil {
						return nil, fmt.Errorf("item %d: %w", i, err)
					}
				}
				return res, nil
			} (m[i].Value)
			if err != nil {
				return nil, fmt.Errorf("value %d: %w", i, err)
			}
			res[k] = v
		}
		return res, nil
	} (arr[index])
	if err != nil {
		return fmt.Errorf("field M: %w", err)
	}

	return nil
}

// SomeStructEventsFromApplicationLog retrieves a set of all emitted events
// with "SomeStruct" name from the provided ApplicationLog.
func SomeStructEventsFromApplicationLog(log *result.ApplicationLog) ([]*SomeStructEvent, error) {
	if log == nil {
		return nil, errors.New("nil application log")
	}

	var res []*SomeStructEvent
	for i, ex := range log.Executions {
		for j, e := range ex.Events {
			if e.Name != "SomeStruct" {
				continue
			}
			event := new(SomeStructEvent)
			err := event.FromStackItem(e.Item)
			if err != nil {
				return nil, fmt.Errorf("failed to deserialize SomeStructEvent from stackitem (execution %d, event %d): %w", i, j, err)
			}
			res = append(res, event)
		}
	}

	return res, nil
}

// FromStackItem converts provided stackitem.Array to SomeStructEvent and
// returns an error if so.
func (e *SomeStructEvent) FromStackItem(item *stackitem.Array) error {
	if item == nil {
		return errors.New("nil item")
	}
	arr, ok := item.Value().([]stackitem.Item)
	if !ok {
		return errors.New("not an array")
	}
	if len(arr) != 1 {
		return errors.New("wrong number of structure elements")
	}

	var (
		index = -1
		err error
	)
	index++
	e.S, err = func (item stackitem.Item) ([]any, error) {
		arr, ok := item.Value().([]stackitem.Item)
		if !ok {
			return nil, errors.New("not an array")
		}
		res := make([]any, len(arr))
		for i := range res {
			res[i], err = arr[i].Value(), error(nil)
			if err != nil {
				return nil, fmt.Errorf("item %d: %w", i, err)
			}
		}
		return res, nil
	} (arr[index])
	if err != nil {
		return fmt.Errorf("field S: %w", err)
	}

	return nil
}

// SomeArrayEventsFromApplicationLog retrieves a set of all emitted events
// with "SomeArray" name from the provided ApplicationLog.
func SomeArrayEventsFromApplicationLog(log *result.ApplicationLog) ([]*SomeArrayEvent, error) {
	if log == nil {
		return nil, errors.New("nil application log")
	}

	var res []*SomeArrayEvent
	for i, ex := range log.Executions {
		for j, e := range ex.Events {
			if e.Name != "SomeArray" {
				continue
			}
			event := new(SomeArrayEvent)
			err := event.FromStackItem(e.Item)
			if err != nil {
				return nil, fmt.Errorf("failed to deserialize SomeArrayEvent from stackitem (execution %d, event %d): %w", i, j, err)
			}
			res = append(res, event)
		}
	}

	return res, nil
}

// FromStackItem converts provided stackitem.Array to SomeArrayEvent and
// returns an error if so.
func (e *SomeArrayEvent) FromStackItem(item *stackitem.Array) error {
	if item == nil {
		return errors.New("nil item")
	}
	arr, ok := item.Value().([]stackitem.Item)
	if !ok {
		return errors.New("not an array")
	}
	if len(arr) != 1 {
		return errors.New("wrong number of structure elements")
	}

	var (
		index = -1
		err error
	)
	index++
	e.A, err = func (item stackitem.Item) ([][]*big.Int, error) {
		arr, ok := item.Value().([]stackitem.Item)
		if !ok {
			return nil, errors.New("not an array")
		}
		res := make([][]*big.Int, len(arr))
		for i := range res {
			res[i], err = func (item stackitem.Item) ([]*big.Int, error) {
				arr, ok := item.Value().([]stackitem.Item)
				if !ok {
					return nil, errors.New("not an array")
				}
				res := make([]*big.Int, len(arr))
				for i := range res {
					res[i], err = arr[i].TryInteger()
					if err != nil {
						return nil, fmt.Errorf("item %d: %w", i, err)
					}
				}
				return res, nil
			} (arr[i])
			if err != nil {
				return nil, fmt.Errorf("item %d: %w", i, err)
			}
		}
		return res, nil
	} (arr[index])
	if err != nil {
		return fmt.Errorf("field A: %w", err)
	}

	return nil
}