// Package tron implements the subset of TRON blockchain interaction required by
// the kisstron CLI wallet: key/address handling, HTTP node access, transaction
// building/signing/broadcasting and minimal TRC20 calls.
package tron

import "errors"

// Sentinel errors mirror tronpy.exceptions so API failures can be mapped the
// same way the original Python implementation does.
var (
  ErrBadAddress          = errors.New("invalid address")
  ErrAddressNotFound     = errors.New("account not found on-chain")
  ErrBadKey              = errors.New("invalid private key")
  ErrBadSignature        = errors.New("bad signature")
  ErrBadHash             = errors.New("wrong transaction hash length")
  ErrTapos               = errors.New("tapos error")
  ErrTransaction         = errors.New("transaction error")
  ErrTvm                 = errors.New("tvm error")
  ErrValidation          = errors.New("validation error")
  ErrAPI                 = errors.New("api error")
  ErrNotFound            = errors.New("not found")
  ErrTransactionNotFound = errors.New("transaction not found")
  ErrContractNotFound    = errors.New("contract address not found")
)

// apiError carries a node message while unwrapping to a sentinel error, so its
// Error() string matches Python's `str(e)` (the bare message) and errors.Is
// still identifies the failure class.
type apiError struct {
  sentinel error
  msg      string
}

func (e *apiError) Error() string { return e.msg }
func (e *apiError) Unwrap() error { return e.sentinel }

// wrapErr attaches a message to a sentinel error.
func wrapErr(sentinel error, msg string) error {
  if msg == "" {
    return sentinel
  }
  return &apiError{sentinel: sentinel, msg: msg}
}