/*
 * Copyright (C) 2017 "IoT.bzh"
 * Author José Bollo <jose.bollo@iot.bzh>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#define _GNU_SOURCE
#define NO_BINDING_VERBOSE_MACRO

#include <stdlib.h>
#include <string.h>
#include <errno.h>

#include <json-c/json.h>
#include <afb/afb-binding.h>

#include "afb-context.h"
#include "afb-xreq.h"
#include "afb-evt.h"
#include "afb-msg-json.h"
#include "afb-subcall.h"
#include "jobs.h"
#include "verbose.h"


static struct json_object *xreq_json_cb(void *closure);
static struct afb_arg xreq_get_cb(void *closure, const char *name);

static void xreq_success_cb(void *closure, struct json_object *obj, const char *info);
static void xreq_fail_cb(void *closure, const char *status, const char *info);

static const char *xreq_raw_cb(void *closure, size_t *size);
static void xreq_send_cb(void *closure, const char *buffer, size_t size);

static void *xreq_context_get_cb(void *closure);
static void xreq_context_set_cb(void *closure, void *value, void (*free_value)(void*));

static void xreq_addref_cb(void *closure);
static void xreq_unref_cb(void *closure);

static void xreq_session_close_cb(void *closure);
static int xreq_session_set_LOA_cb(void *closure, unsigned level);

static int xreq_subscribe_cb(void *closure, struct afb_event event);
static int xreq_unsubscribe_cb(void *closure, struct afb_event event);

static void xreq_subcall_cb(
		void *closure,
		const char *api,
		const char *verb,
		struct json_object *args,
		void (*callback)(void*, int, struct json_object*),
		void *cb_closure);

const struct afb_req_itf xreq_itf = {
	.json = xreq_json_cb,
	.get = xreq_get_cb,
	.success = xreq_success_cb,
	.fail = xreq_fail_cb,
	.raw = xreq_raw_cb,
	.send = xreq_send_cb,
	.context_get = xreq_context_get_cb,
	.context_set = xreq_context_set_cb,
	.addref = xreq_addref_cb,
	.unref = xreq_unref_cb,
	.session_close = xreq_session_close_cb,
	.session_set_LOA = xreq_session_set_LOA_cb,
	.subscribe = xreq_subscribe_cb,
	.unsubscribe = xreq_unsubscribe_cb,
	.subcall = xreq_subcall_cb
};


static struct json_object *xreq_json_cb(void *closure)
{
	struct afb_xreq *xreq = closure;
	return xreq->queryitf->json(xreq->query);
}

static struct afb_arg xreq_get_cb(void *closure, const char *name)
{
	struct afb_xreq *xreq = closure;
	if (xreq->queryitf->get)
		return xreq->queryitf->get(xreq->query, name);
	else
		return afb_msg_json_get_arg(xreq_json_cb(closure), name);
}

static void xreq_success_cb(void *closure, struct json_object *obj, const char *info)
{
	struct afb_xreq *xreq = closure;
	if (xreq->replied) {
		ERROR("reply called more than one time!!");
		json_object_put(obj);
	} else {
		xreq->replied = 1;
		if (xreq->queryitf->success)
			xreq->queryitf->success(xreq->query, obj, info);
		else
			xreq->queryitf->reply(xreq->query, 0, afb_msg_json_reply_ok(info, obj, &xreq->context, NULL));
	}
}

static void xreq_fail_cb(void *closure, const char *status, const char *info)
{
	struct afb_xreq *xreq = closure;
	if (xreq->replied) {
		ERROR("reply called more than one time!!");
	} else {
		xreq->replied = 1;
		if (xreq->queryitf->fail)
			xreq->queryitf->fail(xreq->query, status, info);
		else
			xreq->queryitf->reply(xreq->query, 1, afb_msg_json_reply_error(status, info, &xreq->context, NULL));
	}
}

static const char *xreq_raw_cb(void *closure, size_t *size)
{
	struct afb_xreq *xreq = closure;
	const char *result = json_object_to_json_string(xreq->queryitf->json(xreq->query));
	if (size != NULL)
		*size = strlen(result);
	return result;
}

static void xreq_send_cb(void *closure, const char *buffer, size_t size)
{
	struct json_object *obj = json_tokener_parse(buffer);
	if (!obj == !buffer)
		xreq_success_cb(closure, obj, "fake send");
	else
		xreq_fail_cb(closure, "fake-send-failed", "fake send");
}

static void *xreq_context_get_cb(void *closure)
{
	struct afb_xreq *xreq = closure;
	return afb_context_get(&xreq->context);
}

static void xreq_context_set_cb(void *closure, void *value, void (*free_value)(void*))
{
	struct afb_xreq *xreq = closure;
	afb_context_set(&xreq->context, value, free_value);
}

static void xreq_addref_cb(void *closure)
{
	struct afb_xreq *xreq = closure;
	afb_xreq_addref(xreq);
}

void afb_xreq_addref(struct afb_xreq *xreq)
{
	xreq->refcount++;
}

static void xreq_unref_cb(void *closure)
{
	struct afb_xreq *xreq = closure;
	afb_xreq_unref(xreq);
}

void afb_xreq_unref(struct afb_xreq *xreq)
{
	if (!--xreq->refcount) {
		xreq->queryitf->unref(xreq->query);
	}
}

static void xreq_session_close_cb(void *closure)
{
	struct afb_xreq *xreq = closure;
	afb_context_close(&xreq->context);
}

static int xreq_session_set_LOA_cb(void *closure, unsigned level)
{
	struct afb_xreq *xreq = closure;
	return afb_context_change_loa(&xreq->context, level);
}

static int xreq_subscribe_cb(void *closure, struct afb_event event)
{
	struct afb_xreq *xreq = closure;
	if (xreq->listener)
		return afb_evt_add_watch(xreq->listener, event);
	ERROR("no event listener, subscription impossible");
	errno = EINVAL;
	return -1;
}

static int xreq_unsubscribe_cb(void *closure, struct afb_event event)
{
	struct afb_xreq *xreq = closure;
	if (xreq->listener)
		return afb_evt_remove_watch(xreq->listener, event);
	ERROR("no event listener, unsubscription impossible");
	errno = EINVAL;
	return -1;
}

static void xreq_subcall_cb(void *closure, const char *api, const char *verb, struct json_object *args, void (*callback)(void*, int, struct json_object*), void *cb_closure)
{
	struct afb_xreq *xreq = closure;
	afb_subcall(&xreq->context, api, verb, args, callback, cb_closure, (struct afb_req){ .itf = &xreq_itf, .closure = xreq });
}

void afb_xreq_success_f(struct afb_xreq *xreq, struct json_object *obj, const char *info, ...)
{
	char *message;
	va_list args;
	va_start(args, info);
	if (info == NULL || vasprintf(&message, info, args) < 0)
		message = NULL;
	va_end(args);
	xreq_success_cb(xreq, obj, message);
	free(message);
}

void afb_xreq_fail_f(struct afb_xreq *xreq, const char *status, const char *info, ...)
{
	char *message;
	va_list args;
	va_start(args, info);
	if (info == NULL || vasprintf(&message, info, args) < 0)
		message = NULL;
	va_end(args);
	xreq_fail_cb(xreq, status, message);
	free(message);
}

static int xcheck(struct afb_xreq *xreq)
{
	int stag = xreq->sessionflags;

	if ((stag & (AFB_SESSION_CREATE|AFB_SESSION_CLOSE|AFB_SESSION_RENEW|AFB_SESSION_CHECK|AFB_SESSION_LOA_EQ)) != 0) {
		if (!afb_context_check(&xreq->context)) {
			afb_context_close(&xreq->context);
			afb_xreq_fail_f(xreq, "failed", "invalid token's identity");
			return 0;
		}
	}

	if ((stag & AFB_SESSION_CREATE) != 0) {
		if (afb_context_check_loa(&xreq->context, 1)) {
			afb_xreq_fail_f(xreq, "failed", "invalid creation state");
			return 0;
		}
		afb_context_change_loa(&xreq->context, 1);
		afb_context_refresh(&xreq->context);
	}

	if ((stag & (AFB_SESSION_CREATE | AFB_SESSION_RENEW)) != 0)
		afb_context_refresh(&xreq->context);

	if ((stag & AFB_SESSION_CLOSE) != 0) {
		afb_context_change_loa(&xreq->context, 0);
		afb_context_close(&xreq->context);
	}

	if ((stag & AFB_SESSION_LOA_GE) != 0) {
		int loa = (stag >> AFB_SESSION_LOA_SHIFT) & AFB_SESSION_LOA_MASK;
		if (!afb_context_check_loa(&xreq->context, loa)) {
			afb_xreq_fail_f(xreq, "failed", "invalid LOA");
			return 0;
		}
	}

	if ((stag & AFB_SESSION_LOA_LE) != 0) {
		int loa = (stag >> AFB_SESSION_LOA_SHIFT) & AFB_SESSION_LOA_MASK;
		if (afb_context_check_loa(&xreq->context, loa + 1)) {
			afb_xreq_fail_f(xreq, "failed", "invalid LOA");
			return 0;
		}
	}
	return 1;
}

static void xreq_run_cb(int signum, void *arg)
{
	struct afb_xreq *xreq = arg;

	if (signum == 0)
		xreq->callback((struct afb_req){ .itf = &xreq_itf, .closure = xreq });
	else {
		afb_xreq_fail_f(xreq, "aborted", "signal %s(%d) caught", strsignal(signum), signum);
		
	}
	afb_xreq_unref(xreq);
}

void afb_xreq_call(struct afb_xreq *xreq)
{
	int rc;
	if (xcheck(xreq)) {
		afb_xreq_addref(xreq);
		rc = jobs_queue(xreq->group, xreq->timeout, xreq_run_cb, xreq);
		if (rc < 0) {
			/* TODO: allows or not to proccess it directly as when no threading? (see above) */
			ERROR("can't process job with threads: %m");
			afb_xreq_fail_f(xreq, "cancelled", "not able to pipe a job for the task");
			xreq_unref_cb(xreq);
		}
	}
}