/* Code providing a ccid_slot_ops implementation based on iso7716_fsm,
 * (which in turn sits on top of card_uart) */

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

#include <osmocom/core/msgb.h>
#include <osmocom/core/timer.h>
#include <osmocom/core/logging.h>
#include <osmocom/core/fsm.h>

#include "ccid_device.h"
#include "cuart.h"
#include "iso7816_fsm.h"
#include "iso7816_3.h"

struct iso_fsm_slot {
	/* CCID slot above us */
	struct ccid_slot *cs;
	/* main ISO7816-3 FSM instance beneath us */
	struct osmo_fsm_inst *fi;
	/* UART beneath the ISO7816-3 FSM */
	struct card_uart *cuart;
	/* bSeq of the operation currently in progress */
	uint8_t seq;
};

struct iso_fsm_slot_instance {
	struct iso_fsm_slot slot[NR_SLOTS];
};

static struct iso_fsm_slot_instance g_si;

static struct iso_fsm_slot *ccid_slot2iso_fsm_slot(struct ccid_slot *cs)
{
	OSMO_ASSERT(cs->slot_nr < ARRAY_SIZE(g_si.slot));
	return &g_si.slot[cs->slot_nr];
}

struct card_uart *cuart4slot_nr(uint8_t slot_nr)
{
	OSMO_ASSERT(slot_nr < ARRAY_SIZE(g_si.slot));
	return g_si.slot[slot_nr].cuart;
}

static const uint8_t sysmousim_sjs1_atr[] = {
		0x3B, 0x9F, 0x96, 0x80, 0x1F, 0xC7, 0x80, 0x31,
		0xA0, 0x73, 0xBE, 0x21, 0x13, 0x67, 0x43, 0x20,
		0x07, 0x18, 0x00, 0x00, 0x01, 0xA5 };

static const struct ccid_pars_decoded iso_fsm_def_pars = {
	.fi = 372,
	.di = 1,
	.clock_stop = CCID_CLOCK_STOP_NOTALLOWED,
	.inverse_convention = false,
	.t0 = {
		.guard_time_etu = 0,
		.waiting_integer = 0,
	},
	/* FIXME: T=1 */
};

static void iso_fsm_slot_pre_proc_cb(struct ccid_slot *cs, struct msgb *msg)
{
	/* do nothing; real hardware would update the slot related state here */
}

static void iso_fsm_slot_icc_set_insertion_status(struct ccid_slot *cs, bool present) {
	struct iso_fsm_slot *ss = ccid_slot2iso_fsm_slot(cs);

	if(present == cs->icc_present)
		return;

	cs->icc_present = present;

	if (!present) {
		osmo_fsm_inst_dispatch(ss->fi, ISO7816_E_CARD_REMOVAL, NULL);
		card_uart_ctrl(ss->cuart, CUART_CTL_RST, true);
		card_uart_ctrl(ss->cuart, CUART_CTL_POWER, false);
		cs->icc_powered = false;
		cs->cmd_busy = false;
	}
}

static void iso_fsm_slot_icc_power_on_async(struct ccid_slot *cs, struct msgb *msg,
					const struct ccid_pc_to_rdr_icc_power_on *ipo)
{
	struct iso_fsm_slot *ss = ccid_slot2iso_fsm_slot(cs);

	ss->seq = ipo->hdr.bSeq;
	LOGPCS(cs, LOGL_DEBUG, "scheduling power-up\n");

	/* FIXME: do this via a FSM? */
	card_uart_ctrl(ss->cuart, CUART_CTL_RST, true);
	osmo_fsm_inst_dispatch(ss->fi, ISO7816_E_RESET_ACT_IND, NULL);
	card_uart_ctrl(ss->cuart, CUART_CTL_POWER, true);
	osmo_fsm_inst_dispatch(ss->fi, ISO7816_E_POWER_UP_IND, NULL);
	cs->icc_powered = true;
	card_uart_ctrl(ss->cuart, CUART_CTL_CLOCK, true);
	delay_us(10000);

	osmo_fsm_inst_dispatch(ss->fi, ISO7816_E_RESET_REL_IND, NULL);
	card_uart_ctrl(ss->cuart, CUART_CTL_RST, false);

	msgb_free(msg);
	/* continues in iso_fsm_clot_user_cb once ATR is received */
}
static void iso_fsm_clot_user_cb(struct osmo_fsm_inst *fi, int event, int cause, void *data)
{
	struct iso_fsm_slot *ss = iso7816_fsm_get_user_priv(fi);
	struct ccid_slot *cs = ss->cs;

	switch (event) {
	case ISO7816_E_ATR_DONE_IND:
	case ISO7816_E_ATR_ERR_IND:
	case ISO7816_E_TPDU_DONE_IND:
	case ISO7816_E_TPDU_FAILED_IND:
	case ISO7816_E_PPS_DONE_IND:
	case ISO7816_E_PPS_FAILED_IND:
		cs->event_data = data;
		asm volatile("dmb st": : :"memory");
		cs->event = event;
		break;
	default:
		LOGPCS(cs, LOGL_NOTICE, "%s(event=%d, cause=%d, data=%p) unhandled\n",
			__func__, event, cause, data);
		break;
	}
}

static int iso_handle_fsm_events(struct ccid_slot *cs, bool enable){
	struct iso_fsm_slot *ss = ccid_slot2iso_fsm_slot(cs);
	struct msgb *tpdu, *resp;
	volatile uint32_t event = cs->event;
	volatile void * volatile data = cs->event_data;

	if(!event)
		return 0;
	if(event && !data)
		return 0;

	switch (event) {
	case ISO7816_E_ATR_DONE_IND:
		tpdu = data;
		LOGPCS(cs, LOGL_DEBUG, "%s(event=%d, data=%s)\n", __func__, event,
			msgb_hexdump(tpdu));
		resp = ccid_gen_data_block(cs, ss->seq, CCID_CMD_STATUS_OK, 0,
					   msgb_data(tpdu), msgb_length(tpdu));
		ccid_slot_send_unbusy(cs, resp);
		/* Don't free "TPDU" here, as the ATR should survive */
		cs->event = 0;
		break;
	case ISO7816_E_ATR_ERR_IND:
		tpdu = data;
		LOGPCS(cs, LOGL_DEBUG, "%s(event=%d, data=%s)\n", __func__, event,
			msgb_hexdump(tpdu));
		resp = ccid_gen_data_block(cs, ss->seq, CCID_CMD_STATUS_FAILED, CCID_ERR_ICC_MUTE,
					   msgb_data(tpdu), msgb_length(tpdu));
		ccid_slot_send_unbusy(cs, resp);
		/* Don't free "TPDU" here, as the ATR should survive */
		cs->event = 0;
		break;
		break;
	case ISO7816_E_TPDU_DONE_IND:
		tpdu = data;
		LOGPCS(cs, LOGL_DEBUG, "%s(event=%d, data=%s)\n", __func__, event,
			msgb_hexdump(tpdu));
		resp = ccid_gen_data_block(cs, ss->seq, CCID_CMD_STATUS_OK, 0, msgb_l2(tpdu), msgb_l2len(tpdu));
		ccid_slot_send_unbusy(cs, resp);
		msgb_free(tpdu);
		cs->event = 0;
		break;
	case ISO7816_E_TPDU_FAILED_IND:
		tpdu = data;
		LOGPCS(cs, LOGL_DEBUG, "%s(event=%d, data=%s)\n", __func__, event,
			msgb_hexdump(tpdu));
		/* FIXME: other error causes than card removal?*/
		resp = ccid_gen_data_block(cs, ss->seq, CCID_CMD_STATUS_FAILED, CCID_ERR_ICC_MUTE, msgb_l2(tpdu), 0);
		ccid_slot_send_unbusy(cs, resp);
		msgb_free(tpdu);
		cs->event = 0;
		break;
	case ISO7816_E_PPS_DONE_IND:
		tpdu = data;
		/* pps was successful, so we know these values are fine */
		uint16_t F = iso7816_3_fi_table[cs->proposed_pars.fi];
		uint8_t D = iso7816_3_di_table[cs->proposed_pars.di];
		uint32_t fmax = iso7816_3_fmax_table[cs->proposed_pars.fi];

		/* 7816-3 5.2.3
		 * No  information  shall  be  exchanged  when  switching  the
		 * frequency  value.  Two  different  times  are  recommended
		 * for switching the frequency value, either
		 * - after ATR while card is idle
		 * - after PPS while card is idle
		 */
		card_uart_ctrl(ss->cuart, CUART_CTL_SET_CLOCK_FREQ, fmax);
		card_uart_ctrl(ss->cuart, CUART_CTL_SET_FD, F/D);
		card_uart_ctrl(ss->cuart, CUART_CTL_WTIME, cs->proposed_pars.t0.waiting_integer);

		cs->pars = cs->proposed_pars;
		resp = ccid_gen_parameters_t0(cs, ss->seq, CCID_CMD_STATUS_OK, 0);

		ccid_slot_send_unbusy(cs, resp);

		/* this frees the pps req from the host, pps resp buffer stays with the pps fsm */
		msgb_free(tpdu);
		cs->event = 0;
		break;
	case ISO7816_E_PPS_FAILED_IND:
		tpdu = data;
		/* failed fi/di */
		resp = ccid_gen_parameters_t0(cs, ss->seq, CCID_CMD_STATUS_FAILED, 10);
		ccid_slot_send_unbusy(cs, resp);
		/* this frees the pps req from the host, pps resp buffer stays with the pps fsm */
		msgb_free(tpdu);
		cs->event = 0;
		break;
	case 0:
		break;
	default:
		LOGPCS(cs, LOGL_NOTICE, "%s(event=%d, data=%p) unhandled\n",
			__func__, event, data);
		break;
	}
}

static int iso_fsm_slot_xfr_block_async(struct ccid_slot *cs, struct msgb *msg,
				const struct ccid_pc_to_rdr_xfr_block *xfb)
{
	struct iso_fsm_slot *ss = ccid_slot2iso_fsm_slot(cs);


	ss->seq = xfb->hdr.bSeq;

	/* must be '0' for TPDU level exchanges or for short APDU */
	OSMO_ASSERT(xfb->wLevelParameter == 0x0000);
	OSMO_ASSERT(msgb_length(msg) > xfb->hdr.dwLength);

	msgb_pull(msg, 10);

	LOGPCS(cs, LOGL_DEBUG, "scheduling TPDU transfer: %s\n", msgb_hexdump(msg));
	osmo_fsm_inst_dispatch(ss->fi, ISO7816_E_XCEIVE_TPDU_CMD, msg);
	/* continues in iso_fsm_clot_user_cb once response/error/timeout is received */
	return 0;
}


static void iso_fsm_slot_set_power(struct ccid_slot *cs, bool enable)
{
	struct iso_fsm_slot *ss = ccid_slot2iso_fsm_slot(cs);

	if (enable) {
		card_uart_ctrl(ss->cuart, CUART_CTL_POWER, true);
		cs->icc_powered = true;
	} else {
		card_uart_ctrl(ss->cuart, CUART_CTL_POWER, false);
		cs->icc_powered = false;
	}
}

static void iso_fsm_slot_set_clock(struct ccid_slot *cs, enum ccid_clock_command cmd)
{
	struct iso_fsm_slot *ss = ccid_slot2iso_fsm_slot(cs);

	switch (cmd) {
	case CCID_CLOCK_CMD_STOP:
		card_uart_ctrl(ss->cuart, CUART_CTL_CLOCK, false);
		break;
	case CCID_CLOCK_CMD_RESTART:
		card_uart_ctrl(ss->cuart, CUART_CTL_CLOCK, true);
		break;
	default:
		OSMO_ASSERT(0);
	}
}

static int iso_fsm_slot_set_params(struct ccid_slot *cs, uint8_t seq, enum ccid_protocol_num proto,
				const struct ccid_pars_decoded *pars_dec)
{
	struct iso_fsm_slot *ss = ccid_slot2iso_fsm_slot(cs);
	struct msgb *tpdu;

	/* see 6.1.7 for error offsets */
	if(proto != CCID_PROTOCOL_NUM_T0)
		return -7;

	if(pars_dec->t0.guard_time_etu != 0)
		return -12;

	if(pars_dec->clock_stop != CCID_CLOCK_STOP_NOTALLOWED)
		return -14;

	ss->seq = seq;

	/* FIXME:
	When  using  D=64,  the  interface  device  shall  ensure  a  delay
	  of  at  least  16  etu  between  the  leading  edge  of  the last
	   received character and the leading edge of the character transmitted
	    for initiating a command.
	    -> we can't really do 4 stop bits?!
	*/

	/* Hardware does not support SPU, so no PPS2, and PPS3 is reserved anyway */
	tpdu = msgb_alloc(6, "PPSRQ");
	OSMO_ASSERT(tpdu);
	msgb_put_u8(tpdu, 0xff);
	msgb_put_u8(tpdu, (1 << 4)); /* only PPS1, T=0 */
	msgb_put_u8(tpdu, (pars_dec->fi << 4 | pars_dec->di));
	msgb_put_u8(tpdu, 0xff ^ (1 << 4) ^ (pars_dec->fi << 4 | pars_dec->di));


	LOGPCS(cs, LOGL_DEBUG, "scheduling PPS transfer: %s\n", msgb_hexdump(tpdu));
	osmo_fsm_inst_dispatch(ss->fi, ISO7816_E_XCEIVE_PPS_CMD, tpdu);
	/* continues in iso_fsm_clot_user_cb once response/error/timeout is received */
	return 0;
}

static int iso_fsm_slot_set_rate_and_clock(struct ccid_slot *cs, uint32_t freq_hz, uint32_t rate_bps)
{
	/* we always acknowledge all rates/clocks */
	return 0;
}

extern void *g_tall_ctx;
static int iso_fsm_slot_init(struct ccid_slot *cs)
{
	void *ctx = g_tall_ctx; /* FIXME */
	struct iso_fsm_slot *ss = ccid_slot2iso_fsm_slot(cs);
	struct card_uart *cuart = talloc_zero(ctx, struct card_uart);
	char id_buf[16] = "SIM0";
	char devname[] = "foobar";
	int rc;

	LOGPCS(cs, LOGL_DEBUG, "%s\n", __func__);

	/* HACK: make this in some way configurable so it works both in the firmware
	 * and on the host (functionfs) */
//	if (cs->slot_nr == 0) {
//		cs->icc_present = true;
//		devname = "/dev/ttyUSB5";
//	}
	devname[0] = cs->slot_nr +0x30;
	devname[1] = 0;
	//sprintf(devname, "%d", cs->slot_nr);

	if (!cuart)
		return -ENOMEM;

	//snprintf(id_buf, sizeof(id_buf), "SIM%d", cs->slot_nr);
	id_buf[3] = cs->slot_nr +0x30;
	if (devname) {
		rc = card_uart_open(cuart, "asf4", devname);
		if (rc < 0) {
			LOGPCS(cs, LOGL_ERROR, "Cannot open UART %s: %d\n", devname, rc);
			talloc_free(cuart);
			return rc;
		}
	}
	ss->fi = iso7816_fsm_alloc(ctx, LOGL_DEBUG, id_buf, cuart, iso_fsm_clot_user_cb, ss);
	if (!ss->fi) {
		LOGPCS(cs, LOGL_ERROR, "Cannot allocate ISO FSM\n");
		talloc_free(cuart);
		return -1;
	}

	cs->default_pars = &iso_fsm_def_pars;
	ss->cuart = cuart;
	ss->cs = cs;


	return 0;
}

const struct ccid_slot_ops iso_fsm_slot_ops = {
	.init = iso_fsm_slot_init,
	.pre_proc_cb = iso_fsm_slot_pre_proc_cb,
	.icc_power_on_async = iso_fsm_slot_icc_power_on_async,
	.icc_set_insertion_status = iso_fsm_slot_icc_set_insertion_status,
	.xfr_block_async = iso_fsm_slot_xfr_block_async,
	.set_power = iso_fsm_slot_set_power,
	.set_clock = iso_fsm_slot_set_clock,
	.set_params = iso_fsm_slot_set_params,
	.set_rate_and_clock = iso_fsm_slot_set_rate_and_clock,
	.handle_fsm_events = iso_handle_fsm_events,
};