package bitcoinElectrum

import (
	"fmt"
	"os"

	"github.com/btcsuite/btcd/btcutil/hdkeychain"
)

type Provider struct {
	masterKey       *hdkeychain.ExtendedKey
	ynabAccountID   string // YNAB account ID this provider updates - all bitcoin addresses are summed up and mapped to this YNAB account
	spvServer       string
	gapLimit        int
	coinGeckoApiKey string
}

func (p *Provider) Name() string {
	return "Bitcoin - Electrum SPV"
}

func (p *Provider) Configure() error {
	var err error
	zpub := os.Getenv("bitcoin_zpub")
	p.ynabAccountID = os.Getenv("bitcoin_ynab_account")
	p.spvServer = os.Getenv("bitcoin_spv_server")
	p.coinGeckoApiKey = os.Getenv("bitcoin_coingecko_api_key")
	p.gapLimit = 10
	if zpub == "" || p.ynabAccountID == "" || p.spvServer == "" || p.coinGeckoApiKey == "" {
		return fmt.Errorf("this account provider is not configured")
	}

	p.masterKey, err = hdkeychain.NewKeyFromString(zpub)
	if err != nil {
		return fmt.Errorf("failed to obtain master key from zpub: %v", err)
	}

	return nil
}

// Returns slices of account balances and mapped YNAB account IDs, along with an error
func (p *Provider) GetBalances() ([]int, []string, error) {
	var totalSats int64

	// branch 0 = regular
	// branch 1 = change addresses
	for _, branch := range []uint32{0, 1} {
		branchSats, err := scanBranch(p.masterKey, branch, p.gapLimit, p.spvServer)
		if err != nil {
			return nil, nil, fmt.Errorf("failed to scan branch '%v': %v", branch, err)
		}
		totalSats += branchSats
	}

	cad, err := convertBTCToCAD(totalSats, p.coinGeckoApiKey)
	if err != nil {
		return nil, nil, fmt.Errorf("failed to convert sats to CAD: %v", err)
	}

	balances := make([]int, 0)
	accounts := make([]string, 0)
	balances = append(balances, int(cad))
	accounts = append(accounts, p.ynabAccountID)

	return balances, accounts, nil
}