#pragma once

/* (C) 2021 by Harald Welte <laforge@gnumonks.org>
 * (C) 2022 by Andreas Eversberg <jolly@eversberg.eu>
 *
 * All Rights Reserved
 *
 * SPDX-License-Identifier: GPL-2.0+
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 */


#include <stdint.h>

#include <osmocom/core/utils.h>
#include <osmocom/core/fsm.h>
#include <osmocom/core/select.h>
#include <osmocom/gsm/lapd_core.h>
#include <osmocom/abis/e1_input.h>

#include "libecho/echo_cancel.h"
#include "libecho/echo_suppress.h"
#include "libecho/answertone.h"
#include "ph_socket.h"

#define LOGV5IF(v5i, ss, level, fmt, args ...) \
	LOGP(ss, level, "(%s): " fmt, v5x_interface_name(v5i), ## args)

#define LOGV5L(v5l, ss, level, fmt, args ...) \
	LOGP(ss, level, "(%s-L%u): " fmt, v5x_interface_name((v5l)->interface), (v5l)->id, ## args)

#define LOGV5UP(v5up, ss, level, fmt, args ...) \
	LOGP(ss, level, "(%s-P%u): " fmt, v5x_interface_name((v5up)->interface), (v5up)->nr, ## args)

/* Table 35/G.964 */
enum v5x_mph_prim {
	MPH_UBR,	/* Unblock (req) */
	MPH_UBI,	/* Unblock (ind) */
	MPH_BR,		/* Block (req) */
	MPH_BI,		/* Block (ind) */
	MPH_AR,		/* Activate (req) */
	MPH_AI,		/* Activate (ind) */
	MPH_AWI,	/* Access activation by user (ind) */
	MPH_DSAI,	/* DS Activated (ind) */
	MPH_DR,		/* Deactivate (req) */
	MPH_DI,		/* Deactivate (ind) */
	MPH_GI,		/* Grading Information */
	MPH_DB,		/* Block D-Channel from user port */
	MPH_DU,		/* Unblock D-Channel from user port */
	MPH_ID,		/* Identity Sa7=0 signal request (TX) */
	MPH_NOR,	/* Normal Sa7=1 signal request (TX) */
	MPH_IDR,	/* Request Sa7 signal (RX) */
	MPH_IDI,	/* Indicate Sa7=0 signal (RX) */
	MPH_EIg,	/* Indicate Sa7=1 singal (RX) */
	MPH_EIa,	/* Indicate LOS */
	MPH_EIb,	/* RAI */
	MPH_EIc,	/* AIS */
	MPH_EId,	/* Internal failure */
	MPH_EIe,	/* CRC received */
	MPH_EIf,	/* E-bit received */
	MPH_stop,	/* See L1 FSM */
	MPH_proceed,	/* See L1 FSM */
	MPH_EIbr,	/* See L1 FSM */
	MPH_EIdr,	/* See L1 FSM */
};

/* Table 3/G.964 */
enum v5x_fe_prim {
	FE_establish_req	= 0x00,
	FE_establish_ack_ind	= 0x03,
	FE_establish_ind	= 0x01,
	FE_establish_ack_req	= 0x02,
	FE_line_signal_req	= 0x10,
	FE_line_signal_ind	= 0x11,
	FE_protocol_param_req	= 0x20,
	FE_disconnect_req	= 0x30,
	FE_disconnect_compl_req	= 0x32,
	FE_disconnect_compl_ind	= 0x33,
};

enum v5x_mgmt_prim {
	/* Table 3/G.964 */
	MDU_CTRL_port_blocked,
	MDU_CTRL_port_unblocked,
	MDU_CTRL_port_restart_req,
	MDU_CTRL_port_restart_ack,
	MDU_CTRL_port_restart_compl,
	MDU_error_ind,
	/* Table 14/G.965 */
	MDU_AI,
	MDU_DI,
	MDU_LAI,
	MDU_IDReq,
	MDU_IDAck,
	MDU_IDRel,
	MDU_IDRej,
	MDU_EIg,
	MDU_LUBR,
	MDU_LUBI,
	MDU_LBI,
	MDU_LBR,
	MDU_LBRN,
	/* Table 26/G.965 */
	MDU_BCC_allocation_req,
	MDU_BCC_allocation_conf,
	MDU_BCC_allocation_reject_ind,
	MDU_BCC_allocation_error_ind,
	MDU_BCC_deallocation_req,
	MDU_BCC_deallocation_conf,
	MDU_BCC_deallocation_reject_ind,
	MDU_BCC_deallocation_error_ind,
	MDU_BCC_audit_req,
	MDU_BCC_audit_conf,
	MDU_BCC_audit_error_ind,
	MDU_BCC_AN_fault_ind,
	MDU_BCC_protocol_error_ind,
	/* Table 50/G.965 */
	MDU_Protection_switch_over_com,
	MDU_Protection_OS_switch_over_com,
	MDU_Protection_switch_over_ack,
	MDU_Protection_switch_over_rej,
	MDU_Protection_switch_over_req,
	MDU_Protection_switch_over_reject_ind,
	MDU_Protection_switch_over_error_ind,
	MDU_Protection_reset_SN_ind,
	MDU_Protection_reset_SN_com,
	MDU_Protection_reset_SN_req,
	MDU_Protection_reset_SN_ack,
	MDU_Protection_reset_SN_error_ind,
	MDU_Protection_protocol_error_ind,
	/* Figure 11/G.964 */
	MDL_ESTABLISH_req,
	MDL_ESTABLISH_cnf,
	MDL_ESTABLISH_ind,
	MDL_RELEASE_ind,
	MDL_ERROR_ind,
	MDL_LAYER_1_FAILURE_ind,
};

struct osmo_fsm_inst;

enum v5x_dialect {
	V5X_DIALECT_V51		= 1,
	V5X_DIALECT_V52		= 2,
};

enum v5x_user_type {
	V5X_USER_TYPE_ISDN	= 1,
	V5X_USER_TYPE_PSTN	= 2,
};

enum v5x_ctrl_type {
	V5X_CTRL_TYPE_COMMON	= 1,
	V5X_CTRL_TYPE_PORT	= 2,
	V5X_CTRL_TYPE_LINK	= 3,
};

/* forward-declarations */
struct v5x_interface;
struct v5x_instance;
struct v5x_user_port;
struct v5x_link;
struct v5x_l1_proto;
struct v52_pp_proto;

/* A C-channel is a 64k timeslot used for signalling */
struct v5x_c_channel {
	struct v5x_link *link;			/* back-pointer */
	struct v5x_timeslot *ts;		/* E1 link timeslot. NULL = C-channel doesn't exist */
	bool active;				/* false == standby */
};

/* one physical E1 timeslot used on an E1 interface part of a V5.2 interface */
struct v5x_timeslot {
	uint8_t nr;
	struct v5x_link *link;			/* back-pointer */
	struct v5x_user_port *v5up;		/* user port that this TS is assigned to */
	bool b_channel;				/* channel can be used as b-channel */
	bool b_activated;			/* activated (b-channel) at libosmo-abis */
};

/* one physical E1 interface used within a V5.2 interface */
struct v5x_link {
	struct llist_head list;			/* interface.links */
	uint8_t id;
	struct v5x_interface *interface;	/* back-pointer */
	struct v5x_timeslot ts[32];		/* 32 E1 slots; 0 not available */
	struct v5x_c_channel c_channel[3];	/* 64k signaling possible on TS16, TS15 and TS31 */
	struct v5x_l1_proto *l1;		/* Layer 1 Link FSM protocol */
	struct v5x_ctrl_proto *ctrl;		/* Link control protocol instance */
	struct osmo_fsm_inst *fi;		/* Link Control FSM instance */
	struct e1inp_line *e1_line;		/* E1 line to use or NULL if not */
	struct e1inp_line_ops e1_line_ops;	/* use e1pinp_line->ops to point back to v5x_link */
};

/* one V5.x interface between AN (Access Network) and LE (Local Exchange) */
struct v5x_interface {
	struct llist_head list;			/* instance.interfaces */
	struct v5x_instance *instance;		/* back-pointer */
	char *name;				/* user-configurable name */
	enum v5x_dialect dialect;
	uint32_t id, id_remote;			/* interface id */
	uint8_t variant, variant_remote;	/* provisioning variant */
	bool id_remote_valid;
	bool variant_remote_valid;
	bool use_capability;			/* use bearer transfer capability */
	uint8_t capability;			/* bearer transfer capability */

	struct v5x_mgmt_proto *mgmt;		/* management prococol states */

	struct {
		struct v5x_ctrl_proto *ctrl;	/* common control protocol instance */
		struct lapv5_instance *li;	/* Control data link */
		bool established;		/* track if link is up or down */
	} control;
	struct {
		struct lapv5_instance *li;	/* Link control data link */
		bool established;		/* track if link is up or down */
	} lcp;
	struct {
		struct lapv5_instance *li;	/* PSTN data link */
		bool established;		/* track if link is up or down */
	} pstn;
	struct {
		struct lapv5_instance *li;	/* BCC data link */
		bool established;		/* track if link is up or down */
	} bcc;
	struct {
		uint16_t cc_id;			/* CC-ID of protected C-channel */
		struct v52_pp_proto *pp;	/* protection protocol instance */
		struct lapv5_instance *li[2];	/* Protection data link 1 + 2 */
		bool established[2];		/* track if link is up or down */
	} protection;

	struct llist_head links;		/* list of v5x_link */
	struct v5x_link *primary_link;		/* primary link */
	struct v5x_link *secondary_link;	/* standby link */
	struct v5x_link *cc_link;		/* currently used link for signaling (primary on startup) */
	struct llist_head user_ports;		/* list of v5x_user_port */
	struct llist_head bcc_procs;		/* list of v52_bcc_procs */
};

struct v5x_l1_proto {
	struct v5x_link *v5l;			/* back pointer */
	struct osmo_fsm_inst *fi;		/* L1 FSM */
	int los, rai, ais, sa7;			/* RX signal states */
};

struct v5x_ctrl_proto {
	enum v5x_ctrl_type type;		/* type of control protocol: common/port/link */
	void *priv;				/* back pointer to the user */
	struct osmo_fsm_inst *fi;		/* control FSM */
	struct llist_head tx_queue;		/* list of message to be transmitted */
	struct msgb *tx_msg;			/* copy of unacked message, for second try */
};

struct v5x_pstn_proto {
	struct v5x_user_port *v5up;		/* back pointer, if port control is used */
	struct osmo_fsm_inst *fi;		/* control FSM */
	uint8_t S_s, S_a, S_r;			/* sequence numbers */
	struct msgb *tx_msg;			/* copy of unacked message, for repitition */
	int timeout_event;			/* event when timer times out */
	int timeout_count;			/* how many times the timer was started/timed out */
	struct osmo_timer_list timer_Tr;	/* extra timer for receive sequence ack */
	struct osmo_timer_list timer_Tt;	/* extra timer for transmit sequence ack */
};

/* indexes of blocking/unblocking instances */
#define UNBLK_ALL_PSTN_ISDN	0
#define UNBLK_ALL_PSTN		1
#define UNBLK_ALL_ISDN		2
#define BLK_ALL_PSTN		3
#define BLK_ALL_ISDN		4

struct v5x_mgmt_proto {
	struct v5x_interface *interface;	/* back-pointer to instance we're part of */
	bool auto_restart;			/* restart automatically after TC8/TC9 timeout */
	bool pstn_enable_early;			/* enable datalink before startup */
	bool pstn_rs_pending;			/* pending restart flag */
	bool do_est;				/* actively establish datalinks */
	bool do_align;				/* actively perform alignment */
	bool acc_align;				/* use accellerated alignment */
	struct osmo_fsm_inst *system_fi;	/* system startup FSM */
	struct osmo_fsm_inst *pstn_dl_fi;	/* PSTN DL startup FSM */
	struct osmo_fsm_inst *pstn_rs_fi;	/* PSTN restart FSM */
	struct osmo_fsm_inst *unblk_all_fi[5];	/* unblock/block all FSM (5 instances) */
	struct osmo_timer_list timer_system;	/* delayed start, so sockets can connect first */
	struct osmo_timer_list timer_tr1;	/* see Table C.1/G.965 */
	struct osmo_timer_list timer_tr2;
	struct osmo_timer_list timer_tc1;
	struct osmo_timer_list timer_tc2;
	struct osmo_timer_list timer_tc3;
	struct osmo_timer_list timer_tc7;
	struct osmo_timer_list timer_tc8;
	struct osmo_timer_list timer_tc9;
	struct osmo_timer_list timer_tv1;
};

#define EC_BUFFER 1024
#define EC_TAPS 256

#define USE_ECHO_CANCELER	1
#define USE_ECHO_SUPPRESSOR	2

struct v5x_echo_proc {
	struct v5x_user_port *port;		/* back pointer to user port */
	int enabled;				/* line echo canceler enabled (configured and not disabled by ANS) */
	echo_can_state_t *ec;			/* echo canceler state */
	echo_sup_state_t *es;			/* echo suppressor state */
	int16_t tx_buffer[EC_BUFFER];		/* buffer to store TX audio */
	int tx_buffer_in;			/* next pos to write to buffer */
	int tx_buffer_out;			/* next pos to read from buffer */
	struct answer_tone at;			/* answer tone detector process */
};

/* one user-facing port (subscriber line) */
struct v5x_user_port {
	struct llist_head list; 		/* part of v5x_instance.ports */
	struct v5x_interface *interface;	/* back-pointer to instance we're part of */

	uint16_t nr; 				/* port-number in decoded form (0..32767) */
	char ifname[64];			/* name of interface, also used for PH-socket */
	enum v5x_user_type type;		/* type of port (ISDN/PSTN) */

	struct v5x_ctrl_proto *ctrl;		/* port control protocol instance */
	struct osmo_fsm_inst *port_fi;		/* port FSM */
	struct v5x_timeslot *ts[2];		/* two time slots */
	struct {
	} isdn;
	struct {
		struct v5x_pstn_proto *proto;
	} pstn;
	ph_socket_t ph_socket;			/* unix socket to connect port to */
	bool le_unblocked;			/* if port is not blocked by LE */
	bool an_unblocked;			/* if port is not blocked by AN */
	int use_line_echo;			/* line echo canceler/suppressor is configured */
	struct v5x_echo_proc ep[2];		/* echo canceler process */
};

/* BCC process */
struct v52_bcc_proc {
	struct llist_head list; 		/* part of v5x_instance.ports */
	struct v5x_interface *interface;	/* back-pointer to instance we're part of */
	struct osmo_fsm_inst *fi;		/* BCC FSM */
	uint16_t ref;				/* reference of this process */
	uint8_t source_id;			/* reference source */
	int timer;				/* timer used */
	int expired;				/* number of timeouts */
	uint16_t user_port_id;			/* port ID */
	bool is_isdn;				/* user port type */
	uint8_t link_id;			/* link ID */
	uint8_t ts;				/* TS nr */
	uint8_t override;			/* override assigned channel */
	uint8_t isdn_slot;			/* channel on ISDN interface */
	uint8_t *isdn_multislot;		/* multiple slot assignment */
	bool use_capability;			/* use bearer transfer capability */
	uint8_t capability;			/* bearer transfer capability */
};

struct v52_pp_mgmt_info {
        uint8_t link_id;
        uint8_t ts;
        uint8_t cause;
};

/* PP process */
struct v52_pp_proto {
	struct v5x_interface *interface;	/* back pointer, if port control is used */
	struct osmo_fsm_inst *fi;		/* PP FSM */
	uint8_t vp_s, vp_r;			/* sequence numbers */
	bool vp_r_set;				/* if we ever received a sequence number */
	struct v52_pp_mgmt_info info;		/* keep management info for resend after timeout */
	int timeout_event;			/* event when timer times out */
	int timeout_count;			/* how many times the timer was started/timed out */
};

struct v5x_instance {
	struct llist_head list;			/* part of global list of instances */
	struct llist_head interfaces;		/* v5x_interface.list */
};

struct v5x_instance *v5x_instance_alloc(void *ctx);
void v5x_instance_free(struct v5x_instance *v5i);
struct v5x_interface *v5x_interface_alloc(struct v5x_instance *v5i, uint32_t id, enum v5x_dialect dialect);
struct v5x_user_port *v5x_user_port_create(struct v5x_interface *v5if, uint16_t nr, enum v5x_user_type,
	uint8_t ts1, uint8_t ts2);
void v5x_interface_free(struct v5x_interface *v5if);
struct v5x_user_port *v5x_user_port_find(struct v5x_interface *v5if, uint16_t nr, bool is_isdn);
void v5x_user_port_destroy(struct v5x_user_port *v5up);
void v5x_echo_reset(struct v5x_echo_proc *ep, int enable);
struct v5x_link *v5x_link_create(struct v5x_interface *v5if, uint8_t id);
int v5x_link_destroy(struct v5x_link *v5l);
int v5x_link_count(struct v5x_interface *v5if);
struct v5x_link *v5x_link_find_id(struct v5x_interface *v5if, uint8_t id);

const char *v5x_interface_name(const struct v5x_interface *v5if);