package client

// Various non-policy things from native contracts.

import (
	"crypto/elliptic"
	"fmt"

	"github.com/nspcc-dev/neo-go/pkg/core/native/nativenames"
	"github.com/nspcc-dev/neo-go/pkg/core/native/noderoles"
	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
	"github.com/nspcc-dev/neo-go/pkg/smartcontract"
	"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
)

// GetOraclePrice invokes `getPrice` method on a native Oracle contract.
func (c *Client) GetOraclePrice() (int64, error) {
	oracleHash, err := c.GetNativeContractHash(nativenames.Notary)
	if err != nil {
		return 0, fmt.Errorf("failed to get native Oracle hash: %w", err)
	}
	return c.invokeNativeGetMethod(oracleHash, "getPrice")
}

// GetNNSPrice invokes `getPrice` method on a native NameService contract.
func (c *Client) GetNNSPrice() (int64, error) {
	nnsHash, err := c.GetNativeContractHash(nativenames.NameService)
	if err != nil {
		return 0, fmt.Errorf("failed to get native NameService hash: %w", err)
	}
	return c.invokeNativeGetMethod(nnsHash, "getPrice")
}

// GetGasPerBlock invokes `getGasPerBlock` method on a native NEO contract.
func (c *Client) GetGasPerBlock() (int64, error) {
	neoHash, err := c.GetNativeContractHash(nativenames.Neo)
	if err != nil {
		return 0, fmt.Errorf("failed to get native NEO hash: %w", err)
	}
	return c.invokeNativeGetMethod(neoHash, "getGasPerBlock")
}

// GetDesignatedByRole invokes `getDesignatedByRole` method on a native RoleManagement contract.
func (c *Client) GetDesignatedByRole(role noderoles.Role, index uint32) (keys.PublicKeys, error) {
	rmHash, err := c.GetNativeContractHash(nativenames.Designation)
	if err != nil {
		return nil, fmt.Errorf("failed to get native RoleManagement hash: %w", err)
	}
	result, err := c.InvokeFunction(rmHash, "getDesignatedByRole", []smartcontract.Parameter{
		{
			Type:  smartcontract.IntegerType,
			Value: int64(role),
		},
		{
			Type:  smartcontract.IntegerType,
			Value: int64(index),
		},
	}, nil)
	if err != nil {
		return nil, err
	}
	err = getInvocationError(result)
	if err != nil {
		return nil, fmt.Errorf("`getDesignatedByRole`: %w", err)
	}
	return topPublicKeysFromStack(result.Stack)
}

// topPublicKeysFromStack returns the top array of public keys from stack.
func topPublicKeysFromStack(st []stackitem.Item) (keys.PublicKeys, error) {
	index := len(st) - 1 // top stack element is last in the array
	var (
		pks keys.PublicKeys
		err error
	)
	items, ok := st[index].Value().([]stackitem.Item)
	if !ok {
		return nil, fmt.Errorf("invalid stack item type: %s", st[index].Type())
	}
	pks = make(keys.PublicKeys, len(items))
	for i, item := range items {
		val, ok := item.Value().([]byte)
		if !ok {
			return nil, fmt.Errorf("invalid array element #%d: %s", i, item.Type())
		}
		pks[i], err = keys.NewPublicKeyFromBytes(val, elliptic.P256())
		if err != nil {
			return nil, err
		}
	}
	return pks, nil
}