#include <ccan/crypto/shachain/shachain.h>
#include <ccan/short_types/short_types.h>
#include <ccan/tal/tal.h>
#include <ccan/opt/opt.h>
#include <ccan/str/hex/hex.h>
#include <ccan/err/err.h>
#include <ccan/read_write_all/read_write_all.h>
#include <ccan/structeq/structeq.h>
#include "lightning.pb-c.h"
#include "anchor.h"
#include "bitcoin/base58.h"
#include "pkt.h"
#include "bitcoin/script.h"
#include "permute_tx.h"
#include "bitcoin/signature.h"
#include "commit_tx.h"
#include "bitcoin/pubkey.h"
#include "find_p2sh_out.h"
#include "protobuf_convert.h"
#include <unistd.h>

int main(int argc, char *argv[])
{
	const tal_t *ctx = tal_arr(NULL, char, 0);
	struct sha256 seed, revocation_hash, our_rhash, their_rhash, preimage;
	OpenChannel *o1, *o2;
	OpenAnchor *oa1, *oa2;
	UpdateSignature *us;
	Update *update;
	struct pkt *pkt;
	struct bitcoin_tx *commit;
	struct pubkey pubkey1, pubkey2, final1, final2;
	size_t i, num_updates, inmap[2];
	struct sha256_double anchor_txid1, anchor_txid2;
	struct sha256 escape_hash1, escape_hash2;
	int64_t delta;

	err_set_progname(argv[0]);

	opt_register_noarg("--help|-h", opt_usage_and_exit,
			   "<seed> <open-channel-file1> <open-channel-file2> <open-anchor-file1> <open-anchor-file2> <update-protobuf> <update-signature-protobuf> [previous-updates]\n"
			   "Create a new update-complete message",
			   "Print this message.");

 	opt_parse(&argc, argv, opt_log_stderr_exit);

	if (argc < 8)
		opt_usage_exit_fail("Expected 7+ arguments");

	if (!hex_decode(argv[1], strlen(argv[1]), &seed, sizeof(seed)))
		errx(1, "Invalid seed '%s' - need 256 hex bits", argv[1]);

	o1 = pkt_from_file(argv[2], PKT__PKT_OPEN)->open;
	proto_to_sha256(o1->escape_hash, &escape_hash1);
	o2 = pkt_from_file(argv[3], PKT__PKT_OPEN)->open;
	proto_to_sha256(o2->escape_hash, &escape_hash2);
	oa1 = pkt_from_file(argv[4], PKT__PKT_OPEN_ANCHOR)->open_anchor;
	oa2 = pkt_from_file(argv[5], PKT__PKT_OPEN_ANCHOR)->open_anchor;
	proto_to_sha256(oa1->anchor_txid, &anchor_txid1.sha);
	proto_to_sha256(oa2->anchor_txid, &anchor_txid2.sha);
	update = pkt_from_file(argv[6], PKT__PKT_UPDATE)->update;
	us = pkt_from_file(argv[7], PKT__PKT_UPDATE_SIGNATURE)->update_signature;
	
	/* We need last revocation hash (either in update or update-accept),
	 * and the delta */
	proto_to_sha256(o2->revocation_hash, &revocation_hash);
	num_updates = 0;
	delta = update->delta;
	for (i = 8; i < argc; i++) {
		Pkt *p = any_pkt_from_file(argv[i]);
		switch (p->pkt_case) {
		case PKT__PKT_UPDATE:
			proto_to_sha256(p->update->revocation_hash,
					&revocation_hash);
			delta += p->update->delta;
			num_updates++;
			break;
		case PKT__PKT_UPDATE_ACCEPT:
			if (i != argc - 1)
				errx(1, "Only need last update_accept");
			proto_to_sha256(p->update_accept->revocation_hash,
					&revocation_hash);
			break;
		default:
			errx(1, "Expected update/update-accept in %s", argv[i]);
		}
	}

	/* They gave us right preimage to match rhash of previous commit tx? */
	proto_to_sha256(us->revocation_preimage, &preimage);
	sha256(&their_rhash, preimage.u.u8, sizeof(preimage.u.u8));
	if (!structeq(&their_rhash, &revocation_hash))
		errx(1, "Their preimage was incorrect");

	/* Get pubkeys */
	if (!proto_to_pubkey(o1->commitkey, &pubkey1))
		errx(1, "Invalid o1 commit pubkey");
	if (!proto_to_pubkey(o1->final, &final1))
		errx(1, "Invalid o2 final pubkey");
	if (!proto_to_pubkey(o2->commitkey, &pubkey2))
		errx(1, "Invalid o2 commit pubkey");
	if (!proto_to_pubkey(o2->final, &final2))
		errx(1, "Invalid o2 final pubkey");

	/* Check their signature signs our new commit tx correctly. */
	shachain_from_seed(&seed, num_updates + 1, &preimage);
	sha256(&our_rhash, &preimage, sizeof(preimage));
	commit = create_commit_tx(ctx, o1, o2, &our_rhash, delta,
				  &anchor_txid1, oa1->index, o1->total_input,
				  &anchor_txid2, oa2->index, o2->total_input,
				  inmap);
	if (!commit)
		errx(1, "Delta too large");

	if (!check_anchor_spend(commit, inmap,
				&pubkey1, &final1, &escape_hash1,
				&pubkey2, &final2, &escape_hash2,
				&pubkey2, us->sigs))
		errx(1, "Bad signatures");
	
	/* Hand over our preimage for previous tx. */
	shachain_from_seed(&seed, num_updates, &preimage);
	pkt = update_complete_pkt(ctx, &preimage);
	if (!write_all(STDOUT_FILENO, pkt, pkt_totlen(pkt)))
		err(1, "Writing out packet");

	tal_free(ctx);
	return 0;
}