/*
 * 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 AFB_BINDING_PRAGMA_NO_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 "afb-hook.h"
#include "afb-api.h"
#include "afb-apiset.h"
#include "afb-auth.h"
#include "jobs.h"
#include "verbose.h"

/******************************************************************************/

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

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, 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, obj, info);
		else
			xreq->queryitf->reply(xreq, 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, status, info);
		else
			xreq->queryitf->reply(xreq, 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_json_cb(xreq));
	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;
	__atomic_add_fetch(&xreq->refcount, 1, __ATOMIC_RELAXED);
}

static void xreq_unref_cb(void *closure)
{
	struct afb_xreq *xreq = closure;
	if (!__atomic_sub_fetch(&xreq->refcount, 1, __ATOMIC_RELAXED)) {
		xreq->queryitf->unref(xreq);
	}
}

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;
	return afb_xreq_subscribe(xreq, event);
}

int afb_xreq_subscribe(struct afb_xreq *xreq, struct afb_event event)
{
	if (xreq->listener)
		return afb_evt_add_watch(xreq->listener, event);
	if (xreq->queryitf->subscribe)
		return xreq->queryitf->subscribe(xreq, 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;
	return afb_xreq_unsubscribe(xreq, event);
}

int afb_xreq_unsubscribe(struct afb_xreq *xreq, struct afb_event event)
{
	if (xreq->listener)
		return afb_evt_remove_watch(xreq->listener, event);
	if (xreq->queryitf->unsubscribe)
		return xreq->queryitf->unsubscribe(xreq, 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;

	if (xreq->queryitf->subcall) {
		xreq->queryitf->subcall(xreq, api, verb, args, callback, cb_closure);
		json_object_put(args);
	} else {
		afb_subcall(xreq, api, verb, args, callback, cb_closure);
	}
}

struct xreq_sync
{
	struct afb_xreq *caller;
	const char *api;
	const char *verb;
	struct json_object *args;
	struct jobloop *jobloop;
	struct json_object *result;
	int iserror;
};

static void xreq_sync_leave(struct xreq_sync *sync)
{
	struct jobloop *jobloop = sync->jobloop;
	if (jobloop) {
		sync->jobloop = NULL;
		jobs_leave(jobloop);
	}
}

static void xreq_sync_reply(void *closure, int iserror, struct json_object *obj)
{
	struct xreq_sync *sync = closure;

	sync->iserror = iserror;
	sync->result = json_object_get(obj);
	xreq_sync_leave(sync);
}

static void xreq_sync_enter(int signum, void *closure, struct jobloop *jobloop)
{
	struct xreq_sync *sync = closure;

	if (!signum) {
		sync->jobloop = jobloop;
		xreq_subcall_cb(sync->caller, sync->api, sync->verb, json_object_get(sync->args), xreq_sync_reply, sync);
	} else {
		sync->iserror = 1;
		xreq_sync_leave(sync);
	}
}

static int xreq_subcallsync_cb(void *closure, const char *api, const char *verb, struct json_object *args, struct json_object **result)
{
	int rc;
	struct xreq_sync sync;
	struct afb_xreq *xreq = closure;

	sync.caller = xreq;
	sync.api = api;
	sync.verb = verb;
	sync.args = args;
	sync.jobloop = NULL;
	sync.result = NULL;
	sync.iserror = 1;

	rc = jobs_enter(NULL, 0, xreq_sync_enter, &sync);
	json_object_put(args);
	if (rc < 0 || sync.iserror) {
		*result = sync.result ? : afb_msg_json_internal_error();
		return 0;
	}
	*result = sync.result;
	return 1;
}

/******************************************************************************/

static struct json_object *xreq_hooked_json_cb(void *closure)
{
	struct json_object *r = xreq_json_cb(closure);
	struct afb_xreq *xreq = closure;
	return afb_hook_xreq_json(xreq, r);
}

static struct afb_arg xreq_hooked_get_cb(void *closure, const char *name)
{
	struct afb_arg r = xreq_get_cb(closure, name);
	struct afb_xreq *xreq = closure;
	return afb_hook_xreq_get(xreq, name, r);
}

static void xreq_hooked_success_cb(void *closure, struct json_object *obj, const char *info)
{
	struct afb_xreq *xreq = closure;
	afb_hook_xreq_success(xreq, obj, info);
	xreq_success_cb(closure, obj, info);
}

static void xreq_hooked_fail_cb(void *closure, const char *status, const char *info)
{
	struct afb_xreq *xreq = closure;
	afb_hook_xreq_fail(xreq, status, info);
	xreq_fail_cb(closure, status, info);
}

static const char *xreq_hooked_raw_cb(void *closure, size_t *size)
{
	size_t s;
	const char *r = xreq_raw_cb(closure, size ? : &s);
	struct afb_xreq *xreq = closure;
	return afb_hook_xreq_raw(xreq, r, *(size ? : &s));
}

static void xreq_hooked_send_cb(void *closure, const char *buffer, size_t size)
{
	struct afb_xreq *xreq = closure;
	afb_hook_xreq_send(xreq, buffer, size);
	xreq_send_cb(closure, buffer, size);
}

static void *xreq_hooked_context_get_cb(void *closure)
{
	void *r = xreq_context_get_cb(closure);
	struct afb_xreq *xreq = closure;
	return afb_hook_xreq_context_get(xreq, r);
}

static void xreq_hooked_context_set_cb(void *closure, void *value, void (*free_value)(void*))
{
	struct afb_xreq *xreq = closure;
	afb_hook_xreq_context_set(xreq, value, free_value);
	xreq_context_set_cb(closure, value, free_value);
}

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

static void xreq_hooked_unref_cb(void *closure)
{
	struct afb_xreq *xreq = closure;
	afb_hook_xreq_unref(xreq);
	if (!__atomic_sub_fetch(&xreq->refcount, 1, __ATOMIC_RELAXED)) {
		afb_hook_xreq_end(xreq);
		xreq->queryitf->unref(xreq);
	}
}

static void xreq_hooked_session_close_cb(void *closure)
{
	struct afb_xreq *xreq = closure;
	afb_hook_xreq_session_close(xreq);
	xreq_session_close_cb(closure);
}

static int xreq_hooked_session_set_LOA_cb(void *closure, unsigned level)
{
	int r = xreq_session_set_LOA_cb(closure, level);
	struct afb_xreq *xreq = closure;
	return afb_hook_xreq_session_set_LOA(xreq, level, r);
}

static int xreq_hooked_subscribe_cb(void *closure, struct afb_event event)
{
	int r = xreq_subscribe_cb(closure, event);
	struct afb_xreq *xreq = closure;
	return afb_hook_xreq_subscribe(xreq, event, r);
}

static int xreq_hooked_unsubscribe_cb(void *closure, struct afb_event event)
{
	int r = xreq_unsubscribe_cb(closure, event);
	struct afb_xreq *xreq = closure;
	return afb_hook_xreq_unsubscribe(xreq, event, r);
}

struct reply
{
	struct afb_xreq *xreq;
	void (*callback)(void*, int, struct json_object*);
	void *closure;
};

static void xreq_hooked_subcall_reply_cb(void *closure, int iserror, struct json_object *result)
{
	struct reply *reply = closure;
	
	afb_hook_xreq_subcall_result(reply->xreq, iserror, result);
	reply->callback(reply->closure, iserror, result);
	free(reply);
}

static void xreq_hooked_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 reply *reply = malloc(sizeof *reply);
	struct afb_xreq *xreq = closure;
	afb_hook_xreq_subcall(xreq, api, verb, args);
	if (reply) {
		reply->xreq = xreq;
		reply->callback = callback;
		reply->closure = cb_closure;
		xreq_subcall_cb(closure, api, verb, args, xreq_hooked_subcall_reply_cb, reply);
	} else {
		ERROR("out of memory");
		xreq_subcall_cb(closure, api, verb, args, callback, cb_closure);
	}
}

static int xreq_hooked_subcallsync_cb(void *closure, const char *api, const char *verb, struct json_object *args, struct json_object **result)
{
	int r;
	struct afb_xreq *xreq = closure;
	afb_hook_xreq_subcallsync(xreq, api, verb, args);
	r = xreq_subcallsync_cb(closure, api, verb, args, result);
	return afb_hook_xreq_subcallsync_result(xreq, r, *result);
}

/******************************************************************************/

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,
	.subcallsync = xreq_subcallsync_cb
};

const struct afb_req_itf xreq_hooked_itf = {
	.json = xreq_hooked_json_cb,
	.get = xreq_hooked_get_cb,
	.success = xreq_hooked_success_cb,
	.fail = xreq_hooked_fail_cb,
	.raw = xreq_hooked_raw_cb,
	.send = xreq_hooked_send_cb,
	.context_get = xreq_hooked_context_get_cb,
	.context_set = xreq_hooked_context_set_cb,
	.addref = xreq_hooked_addref_cb,
	.unref = xreq_hooked_unref_cb,
	.session_close = xreq_hooked_session_close_cb,
	.session_set_LOA = xreq_hooked_session_set_LOA_cb,
	.subscribe = xreq_hooked_subscribe_cb,
	.unsubscribe = xreq_hooked_unsubscribe_cb,
	.subcall = xreq_hooked_subcall_cb,
	.subcallsync = xreq_hooked_subcallsync_cb
};

static inline struct afb_req to_req(struct afb_xreq *xreq)
{
	return (struct afb_req){ .itf = xreq->hookflags ? &xreq_hooked_itf : &xreq_itf, .closure = xreq };
}

/******************************************************************************/

struct json_object *afb_xreq_json(struct afb_xreq *xreq)
{
	return afb_req_json(to_req(xreq));
}

void afb_xreq_success(struct afb_xreq *xreq, struct json_object *obj, const char *info)
{
	afb_req_success(to_req(xreq), obj, info);
}

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);
	afb_xreq_success(xreq, obj, message);
	free(message);
}

void afb_xreq_fail(struct afb_xreq *xreq, const char *status, const char *info)
{
	afb_req_fail(to_req(xreq), status, info);
}

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);
	afb_xreq_fail(xreq, status, message);
	free(message);
}

const char *afb_xreq_raw(struct afb_xreq *xreq, size_t *size)
{
	return afb_req_raw(to_req(xreq), size);
}

void afb_xreq_addref(struct afb_xreq *xreq)
{
	afb_req_addref(to_req(xreq));
}

void afb_xreq_unref(struct afb_xreq *xreq)
{
	afb_req_unref(to_req(xreq));
}

void afb_xreq_unhooked_subcall(struct afb_xreq *xreq, const char *api, const char *verb, struct json_object *args, void (*callback)(void*, int, struct json_object*), void *cb_closure)
{
	xreq_subcall_cb(xreq, api, verb, args, callback, cb_closure);
}

void afb_xreq_subcall(struct afb_xreq *xreq, const char *api, const char *verb, struct json_object *args, void (*callback)(void*, int, struct json_object*), void *cb_closure)
{
	afb_req_subcall(to_req(xreq), api, verb, args, callback, cb_closure);
}

int afb_xreq_unhooked_subcall_sync(struct afb_xreq *xreq, const char *api, const char *verb, struct json_object *args, struct json_object **result)
{
	return xreq_subcallsync_cb(xreq, api, verb, args, result);
}

int afb_xreq_subcall_sync(struct afb_xreq *xreq, const char *api, const char *verb, struct json_object *args, struct json_object **result)
{
	return afb_req_subcall_sync(to_req(xreq), api, verb, args, result);
}

static int xreq_session_check_apply_v1(struct afb_xreq *xreq, int sessionflags)
{
	int loa;

	if ((sessionflags & (AFB_SESSION_CLOSE_V1|AFB_SESSION_RENEW_V1|AFB_SESSION_CHECK_V1|AFB_SESSION_LOA_EQ_V1)) != 0) {
		if (!afb_context_check(&xreq->context)) {
			afb_context_close(&xreq->context);
			afb_xreq_fail_f(xreq, "denied", "invalid token's identity");
			errno = EINVAL;
			return -1;
		}
	}

	if ((sessionflags & AFB_SESSION_LOA_GE_V1) != 0) {
		loa = (sessionflags >> AFB_SESSION_LOA_SHIFT_V1) & AFB_SESSION_LOA_MASK_V1;
		if (!afb_context_check_loa(&xreq->context, loa)) {
			afb_xreq_fail_f(xreq, "denied", "invalid LOA");
			errno = EPERM;
			return -1;
		}
	}

	if ((sessionflags & AFB_SESSION_LOA_LE_V1) != 0) {
		loa = (sessionflags >> AFB_SESSION_LOA_SHIFT_V1) & AFB_SESSION_LOA_MASK_V1;
		if (afb_context_check_loa(&xreq->context, loa + 1)) {
			afb_xreq_fail_f(xreq, "denied", "invalid LOA");
			errno = EPERM;
			return -1;
		}
	}

	if ((sessionflags & AFB_SESSION_RENEW_V1) != 0) {
		afb_context_refresh(&xreq->context);
	}
	if ((sessionflags & AFB_SESSION_CLOSE_V1) != 0) {
		afb_context_change_loa(&xreq->context, 0);
		afb_context_close(&xreq->context);
	}

	return 0;
}

static int xreq_session_check_apply_v2(struct afb_xreq *xreq, uint32_t sessionflags, const struct afb_auth *auth)
{
	int loa;

	if (sessionflags != 0) {
		if (!afb_context_check(&xreq->context)) {
			afb_context_close(&xreq->context);
			afb_xreq_fail_f(xreq, "denied", "invalid token's identity");
			errno = EINVAL;
			return -1;
		}
	}

	loa = (int)(sessionflags & AFB_SESSION_LOA_MASK_V2);
	if (loa && !afb_context_check_loa(&xreq->context, loa)) {
		afb_xreq_fail_f(xreq, "denied", "invalid LOA");
		errno = EPERM;
		return -1;
	}

	if (auth && !afb_auth_check(auth, xreq)) {
		afb_xreq_fail_f(xreq, "denied", "authorisation refused");
		errno = EPERM;
		return -1;
	}

	if ((sessionflags & AFB_SESSION_REFRESH_V2) != 0) {
		afb_context_refresh(&xreq->context);
	}
	if ((sessionflags & AFB_SESSION_CLOSE_V2) != 0) {
		afb_context_close(&xreq->context);
	}

	return 0;
}

void afb_xreq_call_verb_v1(struct afb_xreq *xreq, const struct afb_verb_desc_v1 *verb)
{
	if (!verb)
		afb_xreq_fail_unknown_verb(xreq);
	else
		if (!xreq_session_check_apply_v1(xreq, verb->session))
			verb->callback(to_req(xreq));
}

void afb_xreq_call_verb_v2(struct afb_xreq *xreq, const struct afb_verb_v2 *verb)
{
	if (!verb)
		afb_xreq_fail_unknown_verb(xreq);
	else
		if (!xreq_session_check_apply_v2(xreq, verb->session, verb->auth))
			verb->callback(to_req(xreq));
}

void afb_xreq_init(struct afb_xreq *xreq, const struct afb_xreq_query_itf *queryitf)
{
	memset(xreq, 0, sizeof *xreq);
	xreq->refcount = 1;
	xreq->queryitf = queryitf;
}

void afb_xreq_fail_unknown_api(struct afb_xreq *xreq)
{
	afb_xreq_fail_f(xreq, "unknown-api", "api %s not found (for verb %s)", xreq->api, xreq->verb);
}

void afb_xreq_fail_unknown_verb(struct afb_xreq *xreq)
{
	afb_xreq_fail_f(xreq, "unknown-verb", "verb %s unknown within api %s", xreq->verb, xreq->api);
}

static void process_sync(struct afb_xreq *xreq)
{
	struct afb_api api;

	/* init hooking */
	afb_hook_init_xreq(xreq);
	if (xreq->hookflags)
		afb_hook_xreq_begin(xreq);

	/* search the api */
	if (afb_apiset_get(xreq->apiset, xreq->api, &api) < 0) {
		afb_xreq_fail_f(xreq, "unknown-api", "api %s not found", xreq->api);
	} else {
		xreq->context.api_key = api.closure;
		api.itf->call(api.closure, xreq);
	}
}

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

	if (signum != 0) {
		afb_xreq_fail_f(xreq, "aborted", "signal %s(%d) caught", strsignal(signum), signum);
	} else {
		process_sync(xreq);
	}
	afb_xreq_unref(xreq);
}

void afb_xreq_process(struct afb_xreq *xreq, struct afb_apiset *apiset)
{
	xreq->apiset = apiset;

	afb_xreq_addref(xreq);
	if (jobs_queue(NULL, afb_apiset_timeout_get(apiset), process_async, xreq) < 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 create a job for the task");
		afb_xreq_unref(xreq);
	}
	afb_xreq_unref(xreq);
}