package event

import (
	"next.orly.dev/pkg/nostr/interfaces/signer"
	"next.orly.dev/pkg/nostr/interfaces/signer/p8k"
	"next.orly.dev/pkg/nostr/utils"
	"next.orly.dev/pkg/lol/chk"
	"next.orly.dev/pkg/lol/errorf"
	"next.orly.dev/pkg/lol/log"
)

// Sign the event using the signer.I. Uses github.com/bitcoin-core/secp256k1 if
// available for much faster signatures.
//
// Note that this only populates the Pubkey, ID and Sig. The caller must
// set the CreatedAt timestamp as intended.
func (ev *E) Sign(keys signer.I) (err error) {
	// Copy Pub() and Sign() results — signers may return internal buffers
	// that are reused on subsequent calls (e.g. P256K1Signer.sigBuf).
	pub := keys.Pub()
	ev.Pubkey = make([]byte, len(pub))
	copy(ev.Pubkey, pub)
	ev.ID = ev.GetIDBytes()
	var sig []byte
	if sig, err = keys.Sign(ev.ID); chk.E(err) {
		return
	}
	ev.Sig = make([]byte, len(sig))
	copy(ev.Sig, sig)
	return
}

// Verify an event is signed by the pubkey it contains. Uses
// github.com/bitcoin-core/secp256k1 if available for faster verification.
func (ev *E) Verify() (valid bool, err error) {
	var keys *p8k.Signer
	if keys, err = p8k.New(); chk.E(err) {
		return
	}
	if err = keys.InitPub(ev.Pubkey); chk.E(err) {
		return
	}
	if valid, err = keys.Verify(ev.ID, ev.Sig); chk.T(err) {
		// check that this isn't because of a bogus ID
		id := ev.GetIDBytes()
		if !utils.FastEqual(id, ev.ID) {
			log.E.Ln("event Subscription incorrect")
			ev.ID = id
			err = nil
			if valid, err = keys.Verify(ev.ID, ev.Sig); chk.E(err) {
				return
			}
			err = errorf.W("event Subscription incorrect but signature is valid on correct Subscription")
		}
		return
	}
	return
}