/*
Package contract provides functions to work with contracts.
*/
package contract

import "github.com/nspcc-dev/neo-go/pkg/interop"

// Contract represents a Neo contract and is used in interop functions. It's
// a data structure that you can manipulate with using functions from
// this package. It's similar in function to the Contract class in the Neo .net
// framework.
type Contract struct {
	Script   []byte
	Manifest []byte
}

// CallFlag specifies valid call flags.
type CallFlag byte

// Using `smartcontract` package from compiled contract requires moderate
// compiler refactoring, thus all flags are mirrored here.
const (
	AllowStates CallFlag = 1 << iota
	AllowModifyStates
	AllowCall
	AllowNotify
	ReadOnly          = AllowStates | AllowCall | AllowNotify
	All               = ReadOnly | AllowModifyStates
	NoneFlag CallFlag = 0
)

// Create creates a new contract using a set of input parameters:
//     script      contract's bytecode (limited in length by 1M)
//     manifest    contract's manifest (limited in length by 2 KiB)
// It returns this new created Contract when successful (and fails transaction
// if not). It uses `System.Contract.Create` syscall.
func Create(script []byte, manifest []byte) *Contract {
	return &Contract{}
}

// Update updates script and manifest of the calling contract (that is the one that calls Update)
// to the new ones. Its parameters have exactly the same semantics as for
// Create. The old contract will be deleted by this call, if it has any storage
// associated it will be migrated to the new contract. New contract is returned.
// This function uses `System.Contract.Update` syscall.
func Update(script []byte, manifest []byte) {
	return
}

// Destroy deletes calling contract (the one that calls Destroy) from the
// blockchain, so it's only possible to do that from the contract itself and
// not by any outside code. When contract is deleted all associated storage
// items are deleted too. This function uses `System.Contract.Destroy` syscall.
func Destroy() {}

// IsStandard checks if contract with provided hash is a standard signature/multisig contract.
// This function uses `System.Contract.IsStandard` syscall.
func IsStandard(h interop.Hash160) bool {
	return false
}

// CreateStandardAccount calculates script hash of a given public key.
// This function uses `System.Contract.CreateStandardAccount` syscall.
func CreateStandardAccount(pub interop.PublicKey) []byte {
	return nil
}

// GetCallFlags returns calling flags which execution context was created with.
// This function uses `System.Contract.GetCallFlags` syscall.
func GetCallFlags() int64 {
	return 0
}

// Call executes previously deployed blockchain contract with specified hash
// (20 bytes in BE form) using provided arguments.
// It returns whatever this contract returns. This function uses
// `System.Contract.Call` syscall.
func Call(scriptHash interop.Hash160, method string, args ...interface{}) interface{} {
	return nil
}

// CallEx executes previously deployed blockchain contract with specified hash
// (20 bytes in BE form) using provided arguments and call flags.
// It returns whatever this contract returns. This function uses
// `System.Contract.CallEx` syscall.
func CallEx(f CallFlag, scriptHash interop.Hash160, method string, args ...interface{}) interface{} {
	return nil
}