#include "dat.h"
#include "fn.h"

#include <locale.h>
#include <xkbcommon/xkbcommon.h>
#include <xkbcommon/xkbcommon-compose.h>

/*
 * One state per frontend, all made before the procs are: xkbcommon locks
 * nothing, and even its table refcount is a plain increment.  cowner is
 * the context whose sequence a state holds.
 */
static struct xkb_compose_state *cstate[Ncompose];
static void *cowner[Ncompose];

/* Dead keys and Compose: no frontend's client does them for us. */
void
composeinit(void)
{
	struct xkb_context *ctx;
	struct xkb_compose_table *table;
	char *locale;
	int i;

	locale = setlocale(LC_CTYPE, "");
	ctx = xkb_context_new(XKB_CONTEXT_NO_FLAGS);
	if(ctx == nil)
		return;
	table = xkb_compose_table_new_from_locale(ctx,
		locale != nil ? locale : "C", XKB_COMPOSE_COMPILE_NO_FLAGS);
	if(table != nil)
		for(i = 0; i < Ncompose; i++)
			cstate[i] = xkb_compose_state_new(table,
				XKB_COMPOSE_STATE_NO_FLAGS);
	xkb_compose_table_unref(table);
	xkb_context_unref(ctx);
}

/* The context is going, and the sequence it left half typed with it. */
void
composedrop(int who, void *owner)
{
	if(cstate[who] == nil || owner != cowner[who])
		return;
	xkb_compose_state_reset(cstate[who]);
	cowner[who] = nil;
}

/*
 * Feeds sym to the Compose table.  Returns 1 while a sequence is
 * unfinished: the key belongs to the sequence, not to the engine.  A
 * finished sequence leaves its text in buf, which the caller commits
 * after whatever the engine had pending.  A sequence belongs to the
 * context that started it: a key from another one starts over.
 */
int
composekey(int who, void *owner, u32int sym, char *buf, int n)
{
	struct xkb_compose_state *cs;

	buf[0] = '\0';
	cs = cstate[who];
	if(cs == nil)
		return 0;
	if(owner != cowner[who]){
		xkb_compose_state_reset(cs);
		cowner[who] = owner;
	}
	if(xkb_compose_state_feed(cs, sym) != XKB_COMPOSE_FEED_ACCEPTED)
		return 0;
	switch(xkb_compose_state_get_status(cs)){
	case XKB_COMPOSE_COMPOSING:
	case XKB_COMPOSE_CANCELLED:
		return 1;
	case XKB_COMPOSE_COMPOSED:
		xkb_compose_state_get_utf8(cs, buf, n);
		break;
	default:
		break;
	}
	return 0;
}