package wallet

import (
	"bytes"
	"crypto/sha256"
	"fmt"

	"github.com/btcsuite/btcd/btcutil/base58"
)

// DecodeTronAddress decodes a base58check TRON address ("T...") to its 21-byte
// payload (0x41 || 20-byte body), validating the checksum. The 20-byte body
// (payload[1:]) is what TRON ABI parameters use (left-padded to 32 bytes).
func DecodeTronAddress(addr string) ([]byte, error) {
	raw := base58.Decode(addr)
	if len(raw) != 25 { // 21 payload + 4 checksum
		return nil, fmt.Errorf("wallet: bad TRON address length %d", len(raw))
	}
	payload, sum := raw[:21], raw[21:]
	h1 := sha256.Sum256(payload)
	h2 := sha256.Sum256(h1[:])
	if !bytes.Equal(h2[:4], sum) {
		return nil, fmt.Errorf("wallet: bad TRON address checksum")
	}
	if payload[0] != tronAddrPrefix {
		return nil, fmt.Errorf("wallet: bad TRON address prefix 0x%02x", payload[0])
	}
	return payload, nil
}

// TronAddressBodyHex returns the 20-byte address body as hex (no 0x41 prefix) —
// used to build/verify ABI-encoded transfer recipients.
func TronAddressBodyHex(addr string) (string, error) {
	payload, err := DecodeTronAddress(addr)
	if err != nil {
		return "", err
	}
	return fmt.Sprintf("%x", payload[1:]), nil
}