/*
** Copyright 2011 Double Precision, Inc.
** See COPYING for distribution information.
**
*/

#include	"unicode_config.h"
#include	"unicode.h"

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

#include "linebreaktab_internal.h"

#include "linebreaktab.h"

#define UNICODE_LB_SOT	0xFF

struct unicode_lb_info {
	int (*cb_func)(int, void *);
	void *cb_arg;

	int opts;

	uint8_t savedclass;
	size_t savedcmcnt;

	uint8_t prevclass;
	uint8_t prevclass_nsp;

	int (*next_handler)(struct unicode_lb_info *, uint8_t);
	int (*end_handler)(struct unicode_lb_info *);
};


/* http://www.unicode.org/reports/tr14/#Algorithm */

static int next_def(unicode_lb_info_t, uint8_t);
static int end_def(unicode_lb_info_t);

static int next_lb25_seenophy(unicode_lb_info_t, uint8_t);
static int end_lb25_seenophy(unicode_lb_info_t);

static int next_lb25_seennu(unicode_lb_info_t, uint8_t);

static int next_lb25_seennuclcp(unicode_lb_info_t, uint8_t);

static void unicode_lb_reset(unicode_lb_info_t i)
{
	i->prevclass=i->prevclass_nsp=UNICODE_LB_SOT;
	i->next_handler=next_def;
	i->end_handler=end_def;
}

unicode_lb_info_t unicode_lb_init(int (*cb_func)(int, void *),
				  void *cb_arg)
{
	unicode_lb_info_t i=calloc(1, sizeof(struct unicode_lb_info));

	i->cb_func=cb_func;
	i->cb_arg=cb_arg;

	unicode_lb_reset(i);
	return i;
}

int unicode_lb_end(unicode_lb_info_t i)
{
	int rc=(*i->end_handler)(i);

	free(i);
	return rc;
}

void unicode_lb_set_opts(unicode_lb_info_t i, int opts)
{
	i->opts=opts;
}

/* Default end handler has nothing to do */

static int end_def(unicode_lb_info_t i)
{
	/* LB3 N/A */
	return 0;
}
#define RESULT(x) (*i->cb_func)((x), i->cb_arg)

int unicode_lb_next_cnt(unicode_lb_info_t i,
			const unicode_char *chars,
			size_t cnt)
{
	while (cnt)
	{
		int rc=unicode_lb_next(i, *chars);

		if (rc)
			return rc;

		++chars;
		--cnt;
	}
	return 0;
}

int unicode_lb_lookup(unicode_char ch)
{
	return unicode_tab_lookup(ch,
				  unicode_indextab,
				  sizeof(unicode_indextab)
				  / sizeof(unicode_indextab[0]),
				  unicode_rangetab,
				  unicode_classtab,
				  UNICODE_LB_AL /* XX, LB1 */);
}

int unicode_lb_next(unicode_lb_info_t i,
		    unicode_char ch)
{
	return (*i->next_handler)(i, unicode_lb_lookup(ch));
}

static int next_def_nolb25(unicode_lb_info_t i,
			   uint8_t uclass,
			   int nolb25);

/*
** Default logic for next unicode char.
*/
static int next_def(unicode_lb_info_t i,
		    uint8_t uclass)
{
	return next_def_nolb25(i, uclass, 0);
}

static int next_def_nolb25(unicode_lb_info_t i,
			   uint8_t uclass,

			   /* Flag -- recursively invoked after discarding LB25 */
			   int nolb25)
{

	/* Retrieve the previous unicode character's linebreak class. */

	uint8_t prevclass=i->prevclass;
	uint8_t prevclass_nsp=i->prevclass_nsp;

	/* Save this unicode char's linebreak class, for the next goaround */
	i->prevclass=uclass;

	if (uclass != UNICODE_LB_SP)
		i->prevclass_nsp=uclass;

	if (uclass == UNICODE_LB_NU)
		i->next_handler=next_lb25_seennu; /* LB25 */

	if (prevclass == UNICODE_LB_SOT)
	{
		if (uclass == UNICODE_LB_CM) /* LB9 */
			i->prevclass=i->prevclass_nsp=uclass=UNICODE_LB_AL;

		return RESULT(UNICODE_LB_NONE); /* LB2 */
	}

	if (prevclass == UNICODE_LB_CR && uclass == UNICODE_LB_LF)
		return RESULT(UNICODE_LB_NONE); /* LB5 */

	switch (prevclass) {
	case UNICODE_LB_BK:
	case UNICODE_LB_CR:
	case UNICODE_LB_LF:
	case UNICODE_LB_NL:

		if (uclass == UNICODE_LB_CM)
		{
			i->prevclass=i->prevclass_nsp=uclass=UNICODE_LB_AL;
			/* LB9 */
		}

		return RESULT(UNICODE_LB_MANDATORY); /* LB4, LB5 */

	case UNICODE_LB_SP:
	case UNICODE_LB_ZW:
		if (uclass == UNICODE_LB_CM)
			i->prevclass=i->prevclass_nsp=uclass=UNICODE_LB_AL;
		/* LB10 */
		break;
	default:
		break;
	}

	switch (uclass) {

		/* LB6: */
	case UNICODE_LB_BK:
	case UNICODE_LB_CR:
	case UNICODE_LB_LF:
	case UNICODE_LB_NL:

		/* LB7: */
	case UNICODE_LB_SP:
	case UNICODE_LB_ZW:

		return RESULT(UNICODE_LB_NONE);
	default:
		break;
	}

	if (prevclass_nsp == UNICODE_LB_ZW)
		return RESULT(UNICODE_LB_ALLOWED); /* LB8 */

	if (uclass == UNICODE_LB_CM)
	{
		i->prevclass=prevclass;
		i->prevclass_nsp=prevclass_nsp;
		return RESULT(UNICODE_LB_NONE); /* LB9 */
	}

	if (prevclass == UNICODE_LB_WJ || uclass == UNICODE_LB_WJ)
		return RESULT(UNICODE_LB_NONE); /* LB11 */

	if (prevclass == UNICODE_LB_GL)
		return RESULT(UNICODE_LB_NONE); /* LB12 */

	if (uclass == UNICODE_LB_GL &&
	    prevclass != UNICODE_LB_SP &&
	    prevclass != UNICODE_LB_BA &&
	    prevclass != UNICODE_LB_HY)
		return RESULT(UNICODE_LB_NONE); /* LB12a */


	switch (uclass) {
	case UNICODE_LB_SY:
		if (i->opts & UNICODE_LB_OPT_SYBREAK)
		{
			if (prevclass == UNICODE_LB_SP)
				return RESULT(UNICODE_LB_ALLOWED);
		}

	case UNICODE_LB_CL:
	case UNICODE_LB_CP:
	case UNICODE_LB_EX:
	case UNICODE_LB_IS:
		return RESULT(UNICODE_LB_NONE); /* LB13 */
	default:
		break;
	}

	if ((i->opts & UNICODE_LB_OPT_SYBREAK) && prevclass == UNICODE_LB_SY)
		switch (uclass) {
		case UNICODE_LB_EX:
		case UNICODE_LB_AL:
		case UNICODE_LB_ID:
			return RESULT(UNICODE_LB_NONE);
		}

	if (prevclass_nsp == UNICODE_LB_OP)
		return RESULT(UNICODE_LB_NONE); /* LB14 */

	if (prevclass_nsp == UNICODE_LB_QU && uclass == UNICODE_LB_OP)
		return RESULT(UNICODE_LB_NONE); /* LB15 */

	if ((prevclass_nsp == UNICODE_LB_CL || prevclass_nsp == UNICODE_LB_CP)
	    && uclass == UNICODE_LB_NS)
		return RESULT(UNICODE_LB_NONE); /* LB16 */

	if (prevclass_nsp == UNICODE_LB_B2 && uclass == UNICODE_LB_B2)
		return RESULT(UNICODE_LB_NONE); /* LB17 */

	if (prevclass == UNICODE_LB_SP)
		return RESULT(UNICODE_LB_ALLOWED); /* LB18 */

	if (uclass == UNICODE_LB_QU || prevclass == UNICODE_LB_QU)
		return RESULT(UNICODE_LB_NONE); /* LB19 */

	if (uclass == UNICODE_LB_CB || prevclass == UNICODE_LB_CB)
		return RESULT(UNICODE_LB_ALLOWED); /* LB20 */

	/* LB21: */

	switch (uclass) {
	case UNICODE_LB_BA:
	case UNICODE_LB_HY:
	case UNICODE_LB_NS:
		return RESULT(UNICODE_LB_NONE);
	default:
		break;
	}

	if (prevclass == UNICODE_LB_BB)
		return RESULT(UNICODE_LB_NONE);

	if (uclass == UNICODE_LB_IN)
		switch (prevclass) {
		case UNICODE_LB_AL:
		case UNICODE_LB_ID:
		case UNICODE_LB_IN:
		case UNICODE_LB_NU:
			return RESULT(UNICODE_LB_NONE); /* LB22 */
		default:
			break;
		}


	if (prevclass == UNICODE_LB_ID && uclass == UNICODE_LB_PO)
		return RESULT(UNICODE_LB_NONE); /* LB23 */
	if (prevclass == UNICODE_LB_AL && uclass == UNICODE_LB_NU)
		return RESULT(UNICODE_LB_NONE); /* LB23 */

	if (prevclass == UNICODE_LB_NU && uclass == UNICODE_LB_AL)
		return RESULT(UNICODE_LB_NONE); /* LB23 */


	if (prevclass == UNICODE_LB_PR && uclass == UNICODE_LB_ID)
		return RESULT(UNICODE_LB_NONE); /* LB24 */
	if (prevclass == UNICODE_LB_PR && uclass == UNICODE_LB_AL)
		return RESULT(UNICODE_LB_NONE); /* LB24 */
	if (prevclass == UNICODE_LB_PO && uclass == UNICODE_LB_AL)
		return RESULT(UNICODE_LB_NONE); /* LB24 */

	if ((i->opts & UNICODE_LB_OPT_PRBREAK) && uclass == UNICODE_LB_PR)
		switch (prevclass) {
		case UNICODE_LB_PR:
		case UNICODE_LB_AL:
		case UNICODE_LB_ID:
			return RESULT(UNICODE_LB_NONE);
		}
		
	if (!nolb25 &&
	    (prevclass == UNICODE_LB_PR || prevclass == UNICODE_LB_PO))
	{
		if (uclass == UNICODE_LB_NU)
			return RESULT(UNICODE_LB_NONE); /* LB25 */

		if (uclass == UNICODE_LB_OP || uclass == UNICODE_LB_HY)
		{
			i->prevclass=prevclass;
			i->prevclass_nsp=prevclass_nsp;

			i->savedclass=uclass;
			i->savedcmcnt=0;
			i->next_handler=next_lb25_seenophy;
			i->end_handler=end_lb25_seenophy;
			return 0;
		}
	}

	if ((prevclass == UNICODE_LB_OP || prevclass == UNICODE_LB_HY) &&
	    uclass == UNICODE_LB_NU)
		return RESULT(UNICODE_LB_NONE); /* LB25 */

	/*****/

	if (prevclass == UNICODE_LB_JL)
		switch (uclass) {
		case UNICODE_LB_JL:
		case UNICODE_LB_JV:
		case UNICODE_LB_H2:
		case UNICODE_LB_H3:
			return RESULT(UNICODE_LB_NONE); /* LB26 */
		default:
			break;
		}

	if ((prevclass == UNICODE_LB_JV ||
	     prevclass == UNICODE_LB_H2) &&
	    (uclass == UNICODE_LB_JV ||
	     uclass == UNICODE_LB_JT))
		return RESULT(UNICODE_LB_NONE); /* LB26 */

	if ((prevclass == UNICODE_LB_JT ||
	     prevclass == UNICODE_LB_H3) &&
	    uclass == UNICODE_LB_JT)
		return RESULT(UNICODE_LB_NONE); /* LB26 */


	switch (prevclass) {
	case UNICODE_LB_JL:
	case UNICODE_LB_JV:
	case UNICODE_LB_JT:
	case UNICODE_LB_H2:
	case UNICODE_LB_H3:
		if (uclass == UNICODE_LB_IN || uclass == UNICODE_LB_PO)
			return RESULT(UNICODE_LB_NONE); /* LB27 */
	default:
		break;
	}

	switch (uclass) {
	case UNICODE_LB_JL:
	case UNICODE_LB_JV:
	case UNICODE_LB_JT:
	case UNICODE_LB_H2:
	case UNICODE_LB_H3:
		if (prevclass == UNICODE_LB_PR)
			return RESULT(UNICODE_LB_NONE); /* LB27 */
	default:
		break;
	}

	if (prevclass == UNICODE_LB_AL && uclass == UNICODE_LB_AL)
		return RESULT(UNICODE_LB_NONE); /* LB28 */

	if (prevclass == UNICODE_LB_IS && uclass == UNICODE_LB_AL)
		return RESULT(UNICODE_LB_NONE); /* LB29 */

	if ((prevclass == UNICODE_LB_AL || prevclass == UNICODE_LB_NU) &&
	    uclass == UNICODE_LB_OP)
		return RESULT(UNICODE_LB_NONE); /* LB30 */

	if ((uclass == UNICODE_LB_AL || uclass == UNICODE_LB_NU) &&
	    prevclass == UNICODE_LB_CP)
		return RESULT(UNICODE_LB_NONE); /* LB30 */

	return RESULT(UNICODE_LB_ALLOWED); /* LB31 */
}

/*
** Seen (PR|PO)(OP|HY), without returning the linebreak property for the second
** character, but NU did not follow. Backtrack.
*/

static int unwind_lb25_seenophy(unicode_lb_info_t i)
{
	int rc;

	uint8_t class=i->savedclass;
	int nolb25_flag=1;

	i->next_handler=next_def;
	i->end_handler=end_def;

	do
	{
		rc=next_def_nolb25(i, i->savedclass, nolb25_flag);

		if (rc)
			return rc;

		class=UNICODE_LB_CM;
		nolb25_flag=0;
	} while (i->savedcmcnt--);
	return 0;
}

/*
** Seen (PR|PO)(OP|HY), without returning the linebreak property for the second
** character. If there's now a NU, we found the modified LB25 regexp.
*/

static int next_lb25_seenophy(unicode_lb_info_t i,
			      uint8_t uclass)
{
	int rc;

	if (uclass == UNICODE_LB_CM)
	{
		++i->savedcmcnt; /* Keep track of CMs, and try again */
		return 0;
	}

	if (uclass != UNICODE_LB_NU)
	{
		rc=unwind_lb25_seenophy(i);

		if (rc)
			return rc;

		return next_def_nolb25(i, uclass, 0);
	}

	do
	{
		rc=RESULT(UNICODE_LB_NONE); /* (OP|HY) feedback */

		if (rc)
			return rc;
	} while (i->savedcmcnt--);

	i->next_handler=next_lb25_seennu;
	i->end_handler=end_def;
	i->prevclass=i->prevclass_nsp=uclass;
	return RESULT(UNICODE_LB_NONE);
}

/*
** Seen (PR|PO)(OP|HY), and now The End. Unwind, and give up.
*/

static int end_lb25_seenophy(unicode_lb_info_t i)
{
	int rc=unwind_lb25_seenophy(i);

	if (rc == 0)
		rc=end_def(i);
	return rc;
}

/*
** Seen an NU, modified LB25 regexp.
*/
static int next_lb25_seennu(unicode_lb_info_t i, uint8_t uclass)
{
	if (uclass == UNICODE_LB_NU || uclass == UNICODE_LB_SY ||
	    uclass == UNICODE_LB_IS)
	{
		i->prevclass=i->prevclass_nsp=uclass;
		return RESULT(UNICODE_LB_NONE);
	}

	if (uclass == UNICODE_LB_CM)
		return RESULT(UNICODE_LB_NONE); /* LB9 */

	if (uclass == UNICODE_LB_CL || uclass == UNICODE_LB_CP)
	{
		i->prevclass=i->prevclass_nsp=uclass;
		i->next_handler=next_lb25_seennuclcp;
		i->end_handler=end_def;
		return RESULT(UNICODE_LB_NONE);
	}

	i->next_handler=next_def;
	i->end_handler=end_def;

	if (uclass == UNICODE_LB_PR || uclass == UNICODE_LB_PO)
	{
		i->prevclass=i->prevclass_nsp=uclass;
		return RESULT(UNICODE_LB_NONE);
	}

	return next_def(i, uclass); /* Not a prefix, process normally */
}

/*
** Seen CL|CP, in the modified LB25 regexp.
*/
static int next_lb25_seennuclcp(unicode_lb_info_t i, uint8_t uclass)
{
	if (uclass == UNICODE_LB_CM)
		return RESULT(UNICODE_LB_NONE); /* LB9 */

	i->next_handler=next_def;
	i->end_handler=end_def;

	if (uclass == UNICODE_LB_PR || uclass == UNICODE_LB_PO)
	{
		i->prevclass=i->prevclass_nsp=uclass;

		return RESULT(UNICODE_LB_NONE);
	}

	return next_def(i, uclass);
}

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

struct unicode_lbc_info {
	unicode_lb_info_t handle;

	struct unicode_buf buf;

	size_t buf_ptr;

	int (*cb_func)(int, unicode_char, void *);
	void *cb_arg;
};

static int unicode_lbc_callback(int value, void *ptr)
{
	unicode_lbc_info_t h=(unicode_lbc_info_t)ptr;

	if (h->buf_ptr >= unicode_buf_len(&h->buf))
	{
		errno=EINVAL;
		return -1; /* Shouldn't happen */
	}

	return (*h->cb_func)(value, unicode_buf_ptr(&h->buf)[h->buf_ptr++],
			     h->cb_arg);
}

unicode_lbc_info_t unicode_lbc_init(int (*cb_func)(int, unicode_char, void *),
				    void *cb_arg)
{
	unicode_lbc_info_t h=
		(unicode_lbc_info_t)calloc(1, sizeof(struct unicode_lbc_info));

	if (!h)
		return NULL;

	h->cb_func=cb_func;
	h->cb_arg=cb_arg;

	if ((h->handle=unicode_lb_init(unicode_lbc_callback, h)) == NULL)
	{
		free(h);
		return NULL;
	}
	unicode_buf_init(&h->buf, (size_t)-1);
	return h;
}

void unicode_lbc_set_opts(unicode_lbc_info_t i, int opts)
{
	unicode_lb_set_opts(i->handle, opts);
}
	
int unicode_lbc_next(unicode_lbc_info_t i, unicode_char ch)
{
	if (i->buf_ptr >= unicode_buf_len(&i->buf))
	{
		i->buf_ptr=0;
		unicode_buf_clear(&i->buf);
	}

	unicode_buf_append(&i->buf, &ch, 1);
	return unicode_lb_next(i->handle, ch);
}

int unicode_lbc_end(unicode_lbc_info_t i)
{
	int rc=unicode_lb_end(i->handle);

	unicode_buf_deinit(&i->buf);
	free(i);
	return rc;
}