// Copyright 2023 The AthanorLabs/atomic-swap Authors
// SPDX-License-Identifier: LGPL-3.0-only

//go:build !prod

package coins

import (
	"fmt"
	"math/big"

	"github.com/cockroachdb/apd/v3"
)

//
// FUNCTIONS ONLY FOR UNIT TESTS
//

// StrToDecimal converts strings to apd.Decimal for tests, panicking on error.
// This function is intended for use with string constants, so panic is arguably
// correct and allows variables to be declared outside a test function.
func StrToDecimal(amount string) *apd.Decimal {
	a, _, err := new(apd.Decimal).SetString(amount)
	if err != nil {
		panic(err)
	}
	return a
}

// StrToETHAsset converts a string into the EthAssetAmount. Pass nil for the
// token if the asset is ETH.
func StrToETHAsset(amount string, optionalToken *ERC20TokenInfo) EthAssetAmount {
	return NewEthAssetAmount(StrToDecimal(amount), optionalToken)
}

// StrToExchangeRate converts strings to ExchangeRate for tests, panicking on error.
func StrToExchangeRate(rate string) *ExchangeRate {
	r := new(ExchangeRate)
	if err := r.UnmarshalText([]byte(rate)); err != nil {
		panic(err) // test only function
	}
	return r
}

// IntToWei converts some amount of Wei into an WeiAmount for unit tests.
func IntToWei(amount int64) *WeiAmount {
	if amount < 0 {
		panic(fmt.Sprintf("Wei amount %d is negative", amount)) // test only function
	}
	return NewWeiAmount(big.NewInt(amount))
}

// Sub returns the value of a-b in a newly allocated WeiAmount variable.
// If a or b is NaN, this function will panic, but we exclude such values
// during input validation.
func (a *WeiAmount) Sub(b *WeiAmount) *WeiAmount {
	result := new(WeiAmount)
	_, err := decimalCtx.Sub(result.Decimal(), a.Decimal(), b.Decimal())
	if err != nil {
		panic(err)
	}
	return result
}
