#include <gb.h>
#include <r_esil.h>

static bool gb_custom_op_halt (REsil *esil) {
	GB *gb = esil->user;
	ut64 ime = 0ULL;
	if (R_UNLIKELY (!r_esil_reg_read (esil, "ime", &ime, NULL))) {
		return false;
	}
	if (!ime) {
		//pandocs says to also check for pending interrupts
		//but https://github.com/nitro2k01/little-things-gb/tree/main/double-halt-cancel doesn't mention this
		//so, wat du?
		gb->mode = GB_MODE_HALT_DOUBLE_BYTE_FETCH;
		return true;
	}
	if (gb->interrupts.flags & (0x1 << GB_INTERRUPT_ENABLE_WAIT)) {
		gb->mode = GB_MODE_HALT_ENTER;
		return true;
	}
	gb->mode = GB_MODE_HALT;
	return true;
}

static bool gb_custom_op_stop (REsil *esil) {
	GB *gb = esil->user;
	//check if any button is held
	if (((gb->joypad.data & 0x30) ^ 0x30) && ((gb->joypad.data & 0x0f) ^ 0x0f)) {
		//check for pending interrupts
		ut32 i;
		for (i = 0; i < GB_INTERRUPT_N; i++) {
			const ut32 imask = (0x1 << i) | (0x1 << (i + GB_INTERRUPT_N));
			if ((gb->interrupts.flags & imask) == imask) {
				return true;
			}
		}
#if 0
		gb->mode = GB_MODE_HALT;
		return r_reg_setv (esil->anal->reg, "pc"
			r_reg_getv (esil->anal->reg, "pc") + 1);
#else
		ut64 pc = 0ULL;
		if (R_UNLIKELY (!r_esil_reg_read (esil, "pc", &pc, NULL))) {
			return false;
		}
		pc = (pc + 1) & 0xffff;
		if (R_UNLIKELY (!r_esil_reg_write (esil, "pc", pc))) {
			return false;
		}
		gb->mode = GB_MODE_HALT;
		return true;
#endif
	}
	gb->mode = GB_MODE_STOP;
	gb_timers_reset_div (&gb->timers);
	ut32 i;
	for (i = 0; i < GB_INTERRUPT_N; i++) {
		const ut32 imask = (0x1 << i) | (0x1 << (i + GB_INTERRUPT_N));
		if ((gb->interrupts.flags & imask) == imask) {
			return true;
		}
	}
	ut64 pc = 0ULL;
	if (R_UNLIKELY (!r_esil_reg_read (esil, "pc", &pc, NULL))) {
		return false;
	}
	pc = (pc + 1) & 0xffff;
	if (R_UNLIKELY (!r_esil_reg_write (esil, "pc", pc))) {
		return false;
	}
	return true;
}

bool gb_esil_setup (GB *gb) {
	if (!gb) {
		return false;
	}
#if 0
	gb->esil = r_esil_new (4096, 0, 1);
	if (!gb->esil) {
		return false;
	}
#else
	gb->esil = gb->anal->esil;
#endif
	gb->anal->arch->esil = gb->anal->esil;
	r_esil_setup (gb->esil, gb->anal, false, false, false);
	r_arch_esilcb (gb->anal->arch, R_ARCH_ESIL_ACTION_INIT);
	gb->esil->user = gb;
	r_esil_set_op (gb->esil, "halt", gb_custom_op_halt, 0, 0, R_ESIL_OP_TYPE_CUSTOM);
	r_esil_set_op (gb->esil, "stop", gb_custom_op_stop, 0, 0, R_ESIL_OP_TYPE_CUSTOM);
	return true;
}