/*
 * Helper to submit via JSON-RPC and get back response.
 */
#include <ccan/err/err.h>
#include <ccan/opt/opt.h>
#include <ccan/read_write_all/read_write_all.h>
#include <ccan/str/str.h>
#include <ccan/tal/str/str.h>
#include <common/configdir.h>
#include <common/json.h>
#include <common/memleak.h>
#include <common/utils.h>
#include <common/version.h>
#include <stdio.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/un.h>
#include <sys/wait.h>
#include <unistd.h>

#define NO_ERROR 0
#define ERROR_FROM_LIGHTNINGD 1
#define ERROR_TALKING_TO_LIGHTNINGD 2
#define ERROR_USAGE 3

/* Tal wrappers for opt. */
static void *opt_allocfn(size_t size)
{
	return tal_arr_label(NULL, char, size, TAL_LABEL("opt_allocfn", ""));
}

static void *tal_reallocfn(void *ptr, size_t size)
{
	if (!ptr)
		return opt_allocfn(size);
	tal_resize_(&ptr, 1, size, false);
	return ptr;
}

static void tal_freefn(void *ptr)
{
	tal_free(ptr);
}

struct netaddr;

/* Returns number of tokens digested */
static size_t human_readable(const char *buffer, const jsmntok_t *t, char term)
{
	size_t i, n;

	switch (t->type) {
	case JSMN_PRIMITIVE:
	case JSMN_STRING:
		for (i = t->start; i < t->end; i++) {
			/* We only translate \n and \t. */
			if (buffer[i] == '\\' && i + 1 < t->end) {
				if (buffer[i+1] == 'n') {
					fputc('\n', stdout);
					i++;
					continue;
				} else if (buffer[i+1] == 't') {
					fputc('\t', stdout);
					i++;
					continue;
				}
			}
			fputc(buffer[i], stdout);
		}
		fputc(term, stdout);
		return 1;
	case JSMN_ARRAY:
		n = 1;
		for (i = 0; i < t->size; i++)
			n += human_readable(buffer, t + n, '\n');
		return n;
	case JSMN_OBJECT:
		/* Elide single-field objects */
		if (t->size == 1)
			return human_readable(buffer, t + 2, '\n') + 3;
		n = 1;
		for (i = 0; i < t->size; i++) {
			n += human_readable(buffer, t + n, '=');
			n += human_readable(buffer, t + n, '\n');
		}
		return n;
	case JSMN_UNDEFINED:
		break;
	}
	abort();
}

static void human_help(const char *buffer, const jsmntok_t *result, bool has_command) {
	int i;
	const jsmntok_t * help_array = result + 2;
	/* the first command object */
	const jsmntok_t * curr = help_array + 1;
	/* iterate through all commands, printing the name and description */
	for (i = 0; i < help_array->size; i++) {
		curr += 2;
		printf("%.*s\n", curr->end - curr->start, buffer + curr->start);
		curr += 2;
		printf("    %.*s\n\n", curr->end - curr->start, buffer + curr->start);
		curr += 2;
		/* advance to next command */
		curr++;
	}

	if (!has_command)
		printf("---\nrun `lightning-cli help <command>` for more information on a specific command\n");
}

enum format {
	JSON,
	HUMAN,
	DEFAULT_FORMAT
};

static char *opt_set_human(enum format *format)
{
	*format = HUMAN;
	return NULL;
}

static char *opt_set_json(enum format *format)
{
	*format = JSON;
	return NULL;
}

enum input {
	KEYWORDS,
	ORDERED,
	DEFAULT_INPUT
};

static char *opt_set_keywords(enum input *input)
{
	*input = KEYWORDS;
	return NULL;
}

static char *opt_set_ordered(enum input *input)
{
	*input = ORDERED;
	return NULL;
}

static bool is_literal(const char *arg)
{
	size_t arglen = strlen(arg);
	if (arglen == 0) {
		return false;
	}
	return strspn(arg, "0123456789") == arglen
		|| streq(arg, "true")
		|| streq(arg, "false")
		|| streq(arg, "null")
		|| (arg[0] == '{' && arg[arglen - 1] == '}')
		|| (arg[0] == '[' && arg[arglen - 1] == ']')
		|| (arg[0] == '"' && arg[arglen - 1] == '"');
}

static void add_input(char **cmd, const char *input,
		      int i, int argc)
{
	/* Numbers, bools, objects and arrays are left unquoted,
	 * and quoted things left alone. */
	if (is_literal(input))
		tal_append_fmt(cmd, "%s", input);
	else
		tal_append_fmt(cmd, "\"%s\"", input);
	if (i != argc - 1)
		tal_append_fmt(cmd, ", ");
}

static void
try_exec_man (const char *page) {
	int status;

	switch (fork()) {
	case -1:
		err(1, "Forking man command");
	case 0:
		/* child, run man command. */
		execlp("man", "man", page, (char *)NULL);
		err(1, "Running man command");
	default:
		break;
	}

	wait(&status);
	if (WIFEXITED(status) && WEXITSTATUS(status) == 0)
		exit(0);
}

int main(int argc, char *argv[])
{
	setup_locale();

	int fd, i, off;
	const char *method;
	char *cmd, *resp, *idstr, *rpc_filename;
	struct sockaddr_un addr;
	jsmntok_t *toks;
	const jsmntok_t *result, *error, *id;
	char *lightning_dir;
	const tal_t *ctx = tal(NULL, char);
	jsmn_parser parser;
	int parserr;
	enum format format = DEFAULT_FORMAT;
	enum input input = DEFAULT_INPUT;
	char *command = NULL;

	err_set_progname(argv[0]);
	jsmn_init(&parser);

	opt_set_alloc(opt_allocfn, tal_reallocfn, tal_freefn);
	configdir_register_opts(ctx, &lightning_dir, &rpc_filename);

	opt_register_noarg("--help|-h", opt_usage_and_exit,
			   "<command> [<params>...]", "Show this message. Use the command help (without hyphens -- \"lightning-cli help\") to get a list of all RPC commands");
	opt_register_noarg("-H|--human-readable", opt_set_human, &format,
			   "Human-readable output (default for 'help')");
	opt_register_noarg("-J|--json", opt_set_json, &format,
			   "JSON output (default unless 'help')");
	opt_register_noarg("-k|--keywords", opt_set_keywords, &input,
			   "Use format key=value for <params>");
	opt_register_noarg("-o|--order", opt_set_ordered, &input,
			   "Use params in order for <params>");

	opt_register_version();

	opt_early_parse(argc, argv, opt_log_stderr_exit);
	opt_parse(&argc, argv, opt_log_stderr_exit);

	method = argv[1];
	if (!method) {
		char *usage = opt_usage(argv[0], NULL);
		printf("%s\n", usage);
		tal_free(usage);
		printf("Querying lightningd for available RPC commands (\"lightning-cli help\"):\n\n");
		method = "help";
	}

	if (format == DEFAULT_FORMAT) {
		if (streq(method, "help"))
			format = HUMAN;
		else
			format = JSON;
	}

	/* Launch a manpage if we have a help command with an argument. We do
	 * not need to have lightningd running in this case. */
	if (streq(method, "help") && format == HUMAN && argc >= 3) {
		command = argv[2];
		char page[strlen(command) + sizeof("lightning-")];
		snprintf(page, sizeof(page), "lightning-%s", command);
		try_exec_man(page);
	}

	if (chdir(lightning_dir) != 0)
		err(ERROR_TALKING_TO_LIGHTNINGD, "Moving into '%s'",
		    lightning_dir);

	fd = socket(AF_UNIX, SOCK_STREAM, 0);
	if (strlen(rpc_filename) + 1 > sizeof(addr.sun_path))
		errx(ERROR_USAGE, "rpc filename '%s' too long", rpc_filename);
	strcpy(addr.sun_path, rpc_filename);
	addr.sun_family = AF_UNIX;

	if (connect(fd, (struct sockaddr *)&addr, sizeof(addr)) != 0)
		err(ERROR_TALKING_TO_LIGHTNINGD,
		    "Connecting to '%s'", rpc_filename);

	idstr = tal_fmt(ctx, "lightning-cli-%i", getpid());
	cmd = tal_fmt(ctx,
		      "{ \"jsonrpc\" : \"2.0\", \"method\" : \"%s\", \"id\" : \"%s\", \"params\" :",
		      method, idstr);

	if (input == DEFAULT_INPUT) {
		/* Hacky autodetect; only matters if more than single arg */
		if (argc > 2 && strchr(argv[2], '='))
			input = KEYWORDS;
		else
			input = ORDERED;
	}

	if (input == KEYWORDS) {
		tal_append_fmt(&cmd, "{ ");
		for (i = 2; i < argc; i++) {
			const char *eq = strchr(argv[i], '=');

			if (!eq)
				err(ERROR_USAGE, "Expected key=value in '%s'",
				    argv[i]);

			tal_append_fmt(&cmd, "\"%.*s\" : ",
				       (int)(eq - argv[i]), argv[i]);

			add_input(&cmd, eq + 1, i, argc);
		}
		tal_append_fmt(&cmd, "} }");
	} else {
		tal_append_fmt(&cmd, "[ ");
		for (i = 2; i < argc; i++)
			add_input(&cmd, argv[i], i, argc);
		tal_append_fmt(&cmd, "] }");
	}

	if (!write_all(fd, cmd, strlen(cmd)))
		err(ERROR_TALKING_TO_LIGHTNINGD, "Writing command");

	/* Start with 1000 characters, 100 tokens. */
	resp = tal_arr(ctx, char, 1000);
	toks = tal_arr(ctx, jsmntok_t, 100);
	off = 0;
	parserr = 0;
	while (parserr <= 0) {
		/* Read more if parser says, or we have 0 tokens. */
		if (parserr == 0 || parserr == JSMN_ERROR_PART) {
			i = read(fd, resp + off, tal_count(resp) - 1 - off);
			if (i <= 0)
				err(ERROR_TALKING_TO_LIGHTNINGD,
				    "reading response");
			off += i;
			/* NUL terminate */
			resp[off] = '\0';
		}

		/* (Continue) parsing */
		parserr = jsmn_parse(&parser, resp, off, toks, tal_count(toks));

		switch (parserr) {
		case JSMN_ERROR_INVAL:
			errx(ERROR_TALKING_TO_LIGHTNINGD,
			     "Malformed response '%s'", resp);
		case JSMN_ERROR_NOMEM:
			/* Need more tokens, double it */
			tal_resize(&toks, tal_count(toks) * 2);
			break;
		case JSMN_ERROR_PART:
			/* Need more data: make room if necessary */
			if (off == tal_count(resp) - 1)
				tal_resize(&resp, tal_count(resp) * 2);
			break;
		}
	}

	if (toks->type != JSMN_OBJECT)
		errx(ERROR_TALKING_TO_LIGHTNINGD,
		     "Non-object response '%s'", resp);

	result = json_get_member(resp, toks, "result");
	error = json_get_member(resp, toks, "error");
	if (!error && !result)
		errx(ERROR_TALKING_TO_LIGHTNINGD,
		     "Either 'result' or 'error' must be returned in response '%s'", resp);
	id = json_get_member(resp, toks, "id");
	if (!id)
		errx(ERROR_TALKING_TO_LIGHTNINGD,
		     "Missing 'id' in response '%s'", resp);
	if (!json_tok_streq(resp, id, idstr))
		errx(ERROR_TALKING_TO_LIGHTNINGD,
		     "Incorrect 'id' in response: %.*s",
		     json_tok_full_len(id), json_tok_full(resp, id));

	if (!error || json_tok_is_null(resp, error)) {
		// if we have specific help command
		if (format == HUMAN)
			if (streq(method, "help") && command == NULL)
				human_help(resp, result, false);
			else
				human_readable(resp, result, '\n');
		else
			printf("%.*s\n",
			       json_tok_full_len(result),
			       json_tok_full(resp, result));
		tal_free(lightning_dir);
		tal_free(rpc_filename);
		tal_free(ctx);
		opt_free_table();
		return 0;
	}

	printf("%.*s\n",
	       json_tok_full_len(error), json_tok_full(resp, error));
	tal_free(lightning_dir);
	tal_free(rpc_filename);
	tal_free(ctx);
	opt_free_table();
	return 1;
}