/* SPDX-License-Identifier: GPL-2.0 */

/** \file audioc.c The client program used to connect to para_audiod(1).
 *
 * The code if this file is conceptually similar to \ref client.c because
 * para_audioc(1) also operates in one of three possible modes: completion,
 * interactive or non-interactive mode. Like the client code it calls \ref
 * i9e_open() of \ref interactive.c to create an interactive session.
 * See \ref audioc_common.c for the code to connect to para_audiod(1), which
 * is shared with para_gui.
 */

/* \cond doxygen_ignore */

#include "para.h"

#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <arpa/inet.h>
#include <sys/un.h>
#include <netdb.h>
#include <signal.h>
#include <lopsub.h>

#include "audiod_cmd.lsg.h"
#include "audioc.lsg.h"
#include "audioc.h"
#include "error.h"
#include "lsu.h"
#include "net.h"
#include "string.h"
#include "fd.h"
#include "sideband.h"

DEFINE_PARA_ERRLIST;

static const char *socket_name;
static struct lls_parse_result *lpr;

#define CMD_PTR (lls_cmd(0, audioc_suite))
#define OPT_RESULT(_name) \
	(lls_opt_result(LSG_AUDIOC_PARA_AUDIOC_OPT_ ## _name, lpr))
#define OPT_GIVEN(_name) (lls_opt_given(OPT_RESULT(_name)))
#define OPT_STRING_VAL(_name) (lls_string_val(0, OPT_RESULT(_name)))
#define OPT_UINT32_VAL(_name) (lls_uint32_val(0, OPT_RESULT(_name)))

static int loglevel;
INIT_STDERR_LOGGING(loglevel);

#ifdef HAVE_READLINE
#include "list.h"
#include "sched.h"
#include "buffer_tree.h"
#include "interactive.h"

static struct sched *sched;

struct audioc_task {
	int fd;
	struct btr_node *btrn;
	struct task *task;
	struct sb_context *ctx;
};

static const struct i9e_completer audiod_completers[];

I9E_DUMMY_COMPLETER(cycle);
I9E_DUMMY_COMPLETER(off);
I9E_DUMMY_COMPLETER(on);
I9E_DUMMY_COMPLETER(sb);
I9E_DUMMY_COMPLETER(tasks);
I9E_DUMMY_COMPLETER(term);

static void help_completer(struct i9e_completion_info *ci,
		struct i9e_completion_result *cr)
{
	char * const opts[] = {LSG_AUDIOD_CMD_HELP_OPTS, NULL};

	if (ci->word[0] == '-') {
		i9e_complete_option(opts, ci, cr);
		return;
	}
	if (i9e_get_nonopt_argnum(opts, ci) == 1)
		cr->matches = i9e_complete_commands(ci->word, audiod_completers);
}

static void ll_completer(struct i9e_completion_info *ci,
		struct i9e_completion_result *cr)
{
	i9e_ll_completer(ci, cr);
}

static void version_completer(struct i9e_completion_info *ci,
		struct i9e_completion_result *cr)
{
	char * const opts[] = {LSG_AUDIOD_CMD_VERSION_OPTS, NULL};

	if (ci->word[0] == '-')
		i9e_complete_option(opts, ci, cr);
}

static void stat_completer(struct i9e_completion_info *ci,
		struct i9e_completion_result *cr)
{
	char *sia[] = {STATUS_ITEMS NULL};
	char * const opts[] = {LSG_AUDIOD_CMD_STAT_OPTS, NULL};

	if (ci->word[0] == '-')
		return i9e_complete_option(opts, ci, cr);
	i9e_extract_completions(ci->word, sia, &cr->matches);
}

static void grab_completer(struct i9e_completion_info *ci,
		struct i9e_completion_result *cr)
{
	char * const opts[] = {LSG_AUDIOD_CMD_GRAB_OPTS, NULL};
	int num = i9e_cword_is_option_arg(opts, ci);

	if (num >= 0) {
		const char *opt = opts[num];
		if (!strcmp(opt, "-m=") || !strcmp(opt, "--mode=")) {
			cr->matches = arr_alloc(4, sizeof(char *));
			cr->matches[0] = make_message("%ss", opt);
			cr->matches[1] = make_message("%sp", opt);
			cr->matches[2] = make_message("%sa", opt);
			cr->matches[3] = NULL;
			return;
		}
	}
	i9e_complete_option(opts, ci, cr);
}

static const struct i9e_completer audiod_completers[] = {
#define LSG_AUDIOD_CMD_CMD(_name) {.name = #_name, \
	.completer = _name ## _completer}
	LSG_AUDIOD_CMD_SUBCOMMANDS
#undef LSG_AUDIOD_CMD_CMD
	{.name = NULL}
};

static void audioc_pre_monitor(struct sched *s, void *context)
{
	struct audioc_task *at = context;
	int ret = btr_node_status(at->btrn, 0, BTR_NT_ROOT);

	if (ret < 0)
		sched_min_delay(s);
	sched_monitor_readfd(at->fd, s);
}

static void dispatch_sbb(struct sb_buffer *sbb, struct btr_node *btrn)
{
	if (sideband_log("audiod", sbb)) {
		free(sbb->iov.iov_base);
		sbb->iov.iov_base = NULL;
		return;
	}
	btr_add_output(sbb->iov.iov_base, sbb->iov.iov_len, btrn);
}

static int audioc_post_monitor(struct sched *s, void *context)
{
	size_t bufsize = PARA_MAX(1024U, OPT_UINT32_VAL(BUFSIZE));
	struct audioc_task *at = context;
	struct iovec iov;
	struct sb_buffer sbb;
	int ret = btr_node_status(at->btrn, 0, BTR_NT_ROOT);

	if (ret < 0)
		goto close_fd;
	if (!sched_read_ok(at->fd, s))
		return 0;
	if (!at->ctx)
		at->ctx = sb_new_recv(bufsize, NULL, NULL);
	sb_get_recv_buffer(at->ctx, &iov);
	ret = recv_bin_buffer(at->fd, iov.iov_base, iov.iov_len);
	if (ret < 0)
		goto free_ctx;
	if (ret == 0) {
		ret = -E_EOF;
		goto free_ctx;
	}
	ret = sb_received(at->ctx, ret, &sbb);
	if (ret < 0)
		goto free_ctx;
	if (ret == 0)
		return 0;
	at->ctx = NULL;
	dispatch_sbb(&sbb, at->btrn);
	return 1;
free_ctx:
	assert(ret < 0);
	sb_free(at->ctx);
	at->ctx = NULL;
close_fd:
	close(at->fd);
	btr_remove_node(&at->btrn);
	return ret;
}

static struct audioc_task audioc_task, *at = &audioc_task;

static int audioc_i9e_line_handler(char *line)
{
	int ret, argc;
	char **argv;

	PARA_DEBUG_LOG("line: %s\n", line);
	ret = create_argv(line, " ", &argv);
	if (ret <= 0)
		return ret;
	argc = ret;
	ret = connect_audiod(socket_name, argc, argv);
	free_argv(argv);
	if (ret < 0)
		return ret;
	at->fd = ret;
	ret = mark_fd_nonblocking(at->fd);
	if (ret < 0)
		goto close;
	at->btrn = btr_new_node(&(struct btr_node_description)
		EMBRACE(.name = "audioc line handler"));
	at->task = task_register(&(struct task_info) {
		.name = "audioc",
		.pre_monitor = audioc_pre_monitor,
		.post_monitor = audioc_post_monitor,
		.context = at,
	}, sched);
	i9e_attach_to_stdout(at->btrn);
	return 1;
close:
	close(at->fd);
	return ret;
}

__noreturn static void interactive_session(void)
{
	int ret;
	char *history_file;
	struct sigaction act;
	struct i9e_client_info ici = {
		.fds = {0, 1, 2},
		.prompt = "para_audioc> ",
		.line_handler = audioc_i9e_line_handler,
		.loglevel = loglevel,
		.completers = audiod_completers,
	};

	PARA_NOTICE_LOG("\n%s\n", version_text("audioc"));
	if (OPT_GIVEN(HISTORY_FILE))
		history_file = para_strdup(OPT_STRING_VAL(HISTORY_FILE));
	else {
		char *dot_para = create_dot_paraslash();
		history_file = make_message("%s/.audioc.history", dot_para);
		free(dot_para);
	}
	ici.history_file = history_file;

	act.sa_handler = i9e_signal_dispatch;
	sigemptyset(&act.sa_mask);
	act.sa_flags = 0;
	sigaction(SIGINT, &act, NULL);
	sched = sched_new(i9e_poll);
	ret = i9e_open(&ici, sched);
	if (ret < 0)
		goto out;
	para_log = i9e_log;
	ret = schedule(sched);
	sched_shutdown(sched);
	i9e_close();
	para_log = stderr_log;
out:
	free(history_file);
	if (ret < 0)
		PARA_ERROR_LOG("%s\n", para_strerror(-ret));
	exit(ret < 0? EXIT_FAILURE : EXIT_SUCCESS);
}

__noreturn static void print_completions(void)
{
	int ret = i9e_print_completions(audiod_completers);
	exit(ret <= 0? EXIT_FAILURE : EXIT_SUCCESS);
}

#else /* HAVE_READLINE */

__noreturn static void interactive_session(void)
{
	PARA_EMERG_LOG("interactive sessions not available\n");
	exit(EXIT_FAILURE);
}

__noreturn static void print_completions(void)
{
	PARA_EMERG_LOG("command completion not available\n");
	exit(EXIT_FAILURE);
}

#endif /* HAVE_READLINE */

static void handle_help_flag(void)
{
	char *help;

	if (OPT_GIVEN(DETAILED_HELP))
		help = lls_long_help(CMD_PTR);
	else if (OPT_GIVEN(HELP))
		help = lls_short_help(CMD_PTR);
	else
		return;
	printf("%s\n", help);
	free(help);
	exit(EXIT_SUCCESS);
}

static int create_argv_and_connect(void)
{
	unsigned n = lls_num_inputs(lpr);
	char **argv = arr_alloc(n + 1, sizeof(char *));
	int ret;

	for (unsigned k = 0; k < n; k++)
		argv[k] = para_strdup(lls_input(k, lpr));
	argv[n] = NULL;
	ret = connect_audiod(socket_name, n, argv);
	free_argv(argv);
	return ret;
}

/** \endcond */

/**
 * The client program to connect to para_audiod.
 *
 * \param argc Options are defined in the audioc lopsub suite.
 * \param argv The audioc suite defines no subcommands.
 *
 * It connects to the "well-known" local socket to communicate with
 * para_audiod. Authentication is performed by sending a ucred buffer
 * containing the user id to the local socket.
 *
 * Any data received from the socket is written to stdout, employing the
 * buffer tree subsystem.
 *
 * \return EXIT_SUCCESS or EXIT_FAILURE.
 *
 * \sa para_audioc(1), para_audiod(1).
 */
int main(int argc, char *argv[])
{
	int ret, fd;
	char *errctx = NULL;
	size_t bufsize;
	struct sb_context *ctx;
	struct iovec iov;
	struct sb_buffer sbb;

	ret = lls(lls_parse(argc, argv, CMD_PTR, &lpr, &errctx));
	if (ret < 0)
		goto free_errctx;
	version_handle_flag("audioc", OPT_GIVEN(VERSION));
	handle_help_flag();
	ret = lsu_merge_config_file_options(NULL, "audioc.conf",
		&lpr, CMD_PTR, audioc_suite, 0 /* default flags */);
	if (ret < 0)
		goto free_lpr;
	loglevel = OPT_UINT32_VAL(LOGLEVEL);
	if (OPT_GIVEN(COMPLETE))
		print_completions();
	if (OPT_GIVEN(SOCKET))
		socket_name = OPT_STRING_VAL(SOCKET);
	if (lls_num_inputs(lpr) == 0)
		interactive_session();
	ret = create_argv_and_connect();
	if (ret < 0)
		goto free_lpr;
	fd = ret;
	ret = mark_fd_blocking(STDOUT_FILENO);
	if (ret < 0)
		goto free_lpr;
	bufsize = PARA_MAX(1024U, OPT_UINT32_VAL(BUFSIZE));
	for (;;) {
		ctx = sb_new_recv(bufsize, NULL, NULL);
		do {
			sb_get_recv_buffer(ctx, &iov);
			ret = recv_bin_buffer(fd, iov.iov_base, iov.iov_len);
			if (ret < 0)
				goto free_ctx;
			if (ret == 0) {
				ret = -E_EOF;
				goto free_ctx;
			}
			ret = sb_received(ctx, ret, &sbb);
			if (ret < 0)
				goto free_ctx;
		} while (ret == 0);
		ctx = NULL;
		if (sideband_log("audiod", &sbb))
			free(sbb.iov.iov_base);
		else switch (sbb.band) {
		case SBD_OUTPUT:
			ret = write_all(STDOUT_FILENO, sbb.iov.iov_base, sbb.iov.iov_len);
			free(sbb.iov.iov_base);
			if (ret < 0)
				goto free_lpr;
			break;
		case SBD_EXIT__SUCCESS:
			ret = 1;
			goto free_lpr;
		case SBD_EXIT__FAILURE:
			ret = -E_AUDIOD_DISPATCH;
			goto free_lpr;
		default:
			ret = -E_BAD_BAND;
			PARA_ERROR_LOG("invalid sideband packet (band = %u)\n",
				sbb.band);
			goto free_lpr;
		}
	}
free_ctx:
	sb_free(ctx);
free_lpr:
	lls_free_parse_result(lpr, CMD_PTR);
free_errctx:
	if (errctx)
		PARA_ERROR_LOG("%s\n", errctx);
	free(errctx);
	if (ret < 0)
		PARA_ERROR_LOG("%s\n", para_strerror(-ret));
	return ret < 0? EXIT_FAILURE : EXIT_SUCCESS;
}