#include "stdafx.h"

#include <stdarg.h>

#include "ttd.h"
#include "sprite.h"


struct SpriteGroup *EvalDeterministicSpriteGroup(struct DeterministicSpriteGroup *dsg, int value)
{
	int i;

	value >>= dsg->shift_num; // This should bring us to the byte range.
	value &= dsg->and_mask;

	if (dsg->operation != DSG_OP_NONE)
		value += (signed char) dsg->add_val;

	switch (dsg->operation) {
		case DSG_OP_DIV:
			value /= (signed char) dsg->divmod_val;
			break;
		case DSG_OP_MOD:
			value %= (signed char) dsg->divmod_val;
			break;
		case DSG_OP_NONE:
			break;
	}

	for (i = 0; i < dsg->num_ranges; i++) {
		struct DeterministicSpriteGroupRange *range = &dsg->ranges[i];

		if (range->low <= value && value <= range->high)
			return &range->group;
	}

	return dsg->default_group;
}

int GetDeterministicSpriteValue(byte var)
{
	switch (var) {
		case 0x00:
			return _date;
		case 0x01:
			return _cur_year;
		case 0x02:
			return _cur_month;
		case 0x03:
			return _opt.landscape;
		case 0x09:
			return _date_fract;
		case 0x0A:
			return _tick_counter;
		case 0x0C:
			/* If we got here, it means there was no callback or
			 * callbacks aren't supported on our callpath. */
			return 0;
		default:
			return -1;
	}
}