/* Code for talking to bitcoind.  We use bitcoin-cli. */
#include "bitcoin/base58.h"
#include "bitcoin/shadouble.h"
#include "bitcoin/tx.h"
#include "bitcoind.h"
#include "json.h"
#include "lightningd.h"
#include "log.h"
#include <ccan/cast/cast.h>
#include <ccan/io/io.h>
#include <ccan/pipecmd/pipecmd.h>
#include <ccan/str/hex/hex.h>
#include <ccan/tal/str/str.h>
#include <ccan/tal/tal.h>
#include <errno.h>

#define BITCOIN_CLI "bitcoin-cli"

static char **gather_args(const tal_t *ctx, const char *cmd, va_list ap)
{
	size_t n = 2;
	char **args = tal_arr(ctx, char *, n+1);

	args[0] = BITCOIN_CLI;
	args[1] = cast_const(char *, cmd);

	while ((args[n] = va_arg(ap, char *)) != NULL) {
		args[n] = tal_strdup(args, args[n]);
		n++;
		tal_resize(&args, n + 1);
	}
	return args;
}

struct bitcoin_cli {
	struct lightningd_state *state;
	int fd;
	pid_t pid;
	char **args;
	char *output;
	size_t output_bytes;
	size_t new_output;
	void (*process)(struct bitcoin_cli *);
	void *cb;
	void *cb_arg;
};

static struct io_plan *read_more(struct io_conn *conn, struct bitcoin_cli *bcli)
{
	bcli->output_bytes += bcli->new_output;
	if (bcli->output_bytes == tal_count(bcli->output))
		tal_resize(&bcli->output, bcli->output_bytes * 2);
	return io_read_partial(conn, bcli->output + bcli->output_bytes,
			       tal_count(bcli->output) - bcli->output_bytes,
			       &bcli->new_output, read_more, bcli);
}

static struct io_plan *output_init(struct io_conn *conn, struct bitcoin_cli *bcli)
{
	bcli->output_bytes = bcli->new_output = 0;
	bcli->output = tal_arr(bcli, char, 100);
	return read_more(conn, bcli);
}

static void bcli_finished(struct io_conn *conn, struct bitcoin_cli *bcli)
{
	int ret, status;

	/* FIXME: If we waited for SIGCHILD, this could never hang! */
	ret = waitpid(bcli->pid, &status, 0);
	if (ret != bcli->pid)
		fatal("bitcoind: '%s' '%s' %s",
		      bcli->args[0], bcli->args[1],
		      ret == 0 ? "not exited?" : strerror(errno));

	if (!WIFEXITED(status))
		fatal("bitcoind: '%s' '%s' died with signal %i",
		      bcli->args[0], bcli->args[1],
		      WTERMSIG(status));

	if (WEXITSTATUS(status) != 0)
		fatal("bitcoind: '%s' '%s' failed (%i '%.*s')",
		      bcli->args[0], bcli->args[1], WEXITSTATUS(status),
		      (int)bcli->output_bytes, bcli->output);

	assert(bcli->state->bitcoind_in_progress);
	bcli->state->bitcoind_in_progress--;
	bcli->process(bcli);
}

static void
start_bitcoin_cli(struct lightningd_state *state,
		  void (*process)(struct bitcoin_cli *),
		  void *cb, void *cb_arg,
		  char *cmd, ...)
{
	va_list ap;
	struct bitcoin_cli *bcli = tal(state, struct bitcoin_cli);
	struct io_conn *conn;

	bcli->state = state;
	bcli->process = process;
	bcli->cb = cb;
	bcli->cb_arg = cb_arg;
	va_start(ap, cmd);
	bcli->args = gather_args(bcli, cmd, ap);
	va_end(ap);

	bcli->pid = pipecmdarr(&bcli->fd, NULL, &bcli->fd, bcli->args);
	if (bcli->pid < 0)
		fatal("%s exec failed: %s", bcli->args[0], strerror(errno));

	conn = io_new_conn(state, bcli->fd, output_init, bcli);
	tal_steal(conn, bcli);
	state->bitcoind_in_progress++;
	io_set_finish(conn, bcli_finished, bcli);
}

static void process_importaddress(struct bitcoin_cli *bcli)
{
	if (bcli->output_bytes != 0)
		fatal("bitcoind: '%s' '%s' unexpeced output '%.*s'",
		      bcli->args[0], bcli->args[1],
		      (int)bcli->output_bytes, bcli->output);
}

void bitcoind_watch_addr(struct lightningd_state *state,
			 const struct ripemd160 *redeemhash)
{
	char *p2shaddr = p2sh_to_base58(state, state->config.testnet,
					redeemhash);

	start_bitcoin_cli(state, process_importaddress, NULL, NULL,
			  "importaddress", p2shaddr, "", "false", NULL);
	tal_free(p2shaddr);
}

static void process_transactions(struct bitcoin_cli *bcli)
{
	const jsmntok_t *tokens, *t, *end;
	bool valid;
	void (*cb)(struct lightningd_state *state,
		   const struct sha256_double *txid,
		   int confirmations) = bcli->cb;

	tokens = json_parse_input(bcli->output, bcli->output_bytes, &valid);
	if (!tokens)
		fatal("bitcoind: '%s' '%s' %s response",
		      bcli->args[0], bcli->args[1],
		      valid ? "partial" : "invalid");

	if (tokens[0].type != JSMN_ARRAY)
		fatal("listtransactions: '%s' '%s' gave non-array (%.*s)?",
		      bcli->args[0], bcli->args[1],
		      (int)bcli->output_bytes, bcli->output);

	end = json_next(tokens);
	for (t = tokens + 1; t < end; t = json_next(t)) {
		struct sha256_double txid;
		const jsmntok_t *txidtok, *conftok;
		long int conf;
		char *end;

		txidtok = json_get_member(bcli->output, t, "txid");
		conftok = json_get_member(bcli->output, t, "confirmations");
		if (!txidtok || !conftok)
			fatal("listtransactions: no %s field!",
			      txidtok ? "confirmations" : "txid");
		if (!bitcoin_txid_from_hex(bcli->output + txidtok->start,
					   txidtok->end - txidtok->start,
					   &txid)) {
			fatal("listtransactions: bad txid '%.*s'",
			      (int)(txidtok->end - txidtok->start),
			      bcli->output + txidtok->start);
		}
		conf = strtol(bcli->output + conftok->start, &end, 10);
		if (end != bcli->output + conftok->end)
			fatal("listtransactions: bad confirmations '%.*s'",
			      (int)(conftok->end - conftok->start),
			      bcli->output + conftok->start);

		/* FIXME: log txid */
		log_debug(bcli->state->base_log,
			  "txid %02x%02x%02x%02x..., conf %li",
			  txid.sha.u.u8[0], txid.sha.u.u8[1],
			  txid.sha.u.u8[2], txid.sha.u.u8[3],
			  conf);

		cb(bcli->state, &txid, conf);
	}
}

void bitcoind_poll_transactions(struct lightningd_state *state,
				void (*cb)(struct lightningd_state *state,
					   const struct sha256_double *txid,
					   int confirmations))
{
	/* FIXME: Iterate and detect duplicates. */
	start_bitcoin_cli(state, process_transactions, cb, NULL,
			  "listtransactions", "*", "100000", "0", "true",
			  NULL);
}

static void process_rawtx(struct bitcoin_cli *bcli)
{
	struct bitcoin_tx *tx;
	void (*cb)(struct lightningd_state *state,
		   const struct bitcoin_tx *tx, void *arg) = bcli->cb;

	tx = bitcoin_tx_from_hex(bcli, bcli->output, bcli->output_bytes);
	if (!tx)
		fatal("Unknown txid (output %.*s)",
		      (int)bcli->output_bytes, (char *)bcli->output);
	cb(bcli->state, tx, bcli->cb_arg);
}

/* FIXME: Cache! */
void bitcoind_txid_lookup_(struct lightningd_state *state,
			   const struct sha256_double *txid,
			   void (*cb)(struct lightningd_state *state,
				      const struct bitcoin_tx *tx,
				      void *arg),
			   void *arg)
{
	char txidhex[hex_str_size(sizeof(*txid))];

	if (!bitcoin_txid_to_hex(txid, txidhex, sizeof(txidhex)))
		fatal("Incorrect txid size");
	start_bitcoin_cli(state, process_rawtx, cb, arg,
			  "getrawtransaction", txidhex, NULL);
}