#include "ovm.h"
#include <glib/gstdio.h>

void ovm_free(ovm_t *ovm) {
	if (!ovm) return;
	g_slice_free1(ovm->limit * sizeof(instruction_t), ovm->instructions);
	g_slice_free1(ovm->limit * sizeof(gdouble), ovm->values);
	g_slice_free(ovm_t, ovm);
}

ovm_t* ovm_load(const gchar *filename) {
	GError *err = NULL;
	gchar *buf = NULL, *cur;
	gsize len = 0, i;
	instruction_t *oi;
	gdouble *vi;

	ovm_t *ovm = g_slice_new(ovm_t);
	ovm->limit = 0x4000;

	ovm->instructions = g_slice_alloc0(ovm->limit * sizeof(instruction_t));
	ovm->values = g_slice_alloc0(ovm->limit * sizeof(gdouble));

	if (!g_file_get_contents(filename, &buf, &len, &err)) {
		fprintf (stderr, "Unable to read file: %s\n", err->message);
		g_error_free (err);
		exit(1);
	}

	oi = ovm->instructions;
	vi = ovm->values;
	for (cur = buf, i = 0; i < len; i++) {
		*vi++ = *(gdouble*)buf;
		buf += sizeof(gdouble);
		*oi++ = *(guint32*)buf;
		buf += sizeof(guint32);
		if (++i < len) {
			*oi++ = *(guint32*)buf;
			buf += sizeof(guint32);
			*vi++ = *(gdouble*)buf;
			buf += sizeof(gdouble);
		} else {
			break;
		}
	}
	ovm->used = i;

	return ovm;
}

static const gchar* cmp_op_strings[] = {
	"<", "<=", "==", ">=", ">"
};

void ovm_print_c(ovm_t *ovm, const gchar *filename) {
	guint i;
	instruction_t *oi = ovm->instructions;
	gdouble *vi = ovm->values;
	guint64 *uvi = (guint64*) ovm->values;
	guchar *usedv = g_slice_alloc0(ovm->used*sizeof(guchar));
	GString *str = g_string_sized_new(0), *buf = g_string_sized_new(0);
	int f = g_open(filename, O_CREAT | O_TRUNC | O_WRONLY, 0644);

	if (-1 == f) {
		fprintf(stderr, "Couldn't open file %s: %s\n", filename, g_strerror(errno));
		exit(2);
	}

	g_string_append_len(buf, CONST_STR_LEN(
		"void ovm_step(gdouble scenario, gdouble *in, gdouble *out) {\n"
	));
#define USED(i) (usedv[i] = TRUE, i)
	for (i = 0; i < ovm->used; i++) {
		g_string_printf(str, "\t/* Invalid command: 0x%X */\n", (guint) oi[i]);
		switch (instr_dop(oi[i])) {
		case OP_STYPE:
			switch (instr_sop(oi[i])) {
			case SOP_NOOP:
				g_string_printf(str, "/* NOOP */\n");
				g_string_truncate(str, 0);
				break;
			case SOP_CMPZ:
				g_string_printf(str, "\tovm_status = (v%u.d %s 0.0);\n", USED(instr_sop_r1(oi[i])), cmp_op_strings[instr_sop_cmp(oi[i])]);
				break;
			case SOP_SQRT:
				g_string_printf(str, "\tv%u.d = sqrt(v%u.d);\n", USED(i), USED(instr_sop_r1(oi[i])));
				break;
			case SOP_COPY:
				g_string_printf(str, "\tv%u.d = v%u.d;\n", USED(i), USED(instr_sop_r1(oi[i])));
				break;
			case SOP_IN:
				if (0x3e80 == instr_sop_r1(oi[i])) {
					g_string_printf(str, "\tv%u.d = scenario;\n", USED(i));
				} else {
					g_string_printf(str, "\tv%u.d = in[%u];\n", USED(i), instr_sop_r1(oi[i]));
				}
				break;
			}
			break;
		case OP_ADD:
			g_string_printf(str, "\tv%u.d = v%u.d + v%u.d;\n", USED(i), USED(instr_dop_r1(oi[i])), USED(instr_dop_r2(oi[i])));
			break;
		case OP_SUB:
			g_string_printf(str, "\tv%u.d = v%u.d - v%u.d;\n", USED(i), USED(instr_dop_r1(oi[i])), USED(instr_dop_r2(oi[i])));
			break;
		case OP_MULT:
			g_string_printf(str, "\tv%u.d = v%u.d * v%u.d;\n", USED(i), USED(instr_dop_r1(oi[i])), USED(instr_dop_r2(oi[i])));
			break;
		case OP_DIV:
			g_string_printf(str, "\tv%u.d = (v%u.d == 0.0) ? 0.0 : v%u.d / v%u.d;\n", USED(i), USED(instr_dop_r2(oi[i])), USED(instr_dop_r1(oi[i])), instr_dop_r2(oi[i]));
			break;
		case OP_OUT:
			g_string_printf(str, "\tout[%u] = v%u.d;\n", instr_dop_r1(oi[i]), USED(instr_dop_r2(oi[i])));
			break;
		case OP_PHI:
			g_string_printf(str, "\tv%u.d = ovm_status ? v%u.d : v%u.d;\n", USED(i), USED(instr_dop_r1(oi[i])), USED(instr_dop_r2(oi[i])));
			break;
		}
		g_string_append_len(buf, GSTR_LEN(str));
	}
#undef USED

	g_string_append_len(buf, CONST_STR_LEN(
		"}\n"
		"\n"
	));

	write(f, CONST_STR_LEN(
		"#include \"task.h\"\n"
		"#include <math.h>\n"
		"\n"
		"typedef union { gdouble d; guint64 i; } double_int;\n"
		"\n"
		"static gboolean ovm_status = FALSE;\n"
		"\n"
		"static double_int v0"
	));
	for (i = 1; i < ovm->used; i++) {
		if (!usedv[i]) continue;
		g_string_printf(str, ", v%u", i);
		write(f, GSTR_LEN(str));
	}
	write(f, CONST_STR_LEN(
		";\n"
		"\n"
		"void ovm_init() {\n"
		"\tovm_status = FALSE;\n"
		"\n"
	));
	for (i = 0; i < ovm->used; i++) {
		if (!usedv[i]) continue;
		g_string_printf(str, "\tv%u.i = G_GUINT64_CONSTANT(%" G_GUINT64_FORMAT "); /* %f */ \n", i, uvi[i], vi[i]);
		write(f, GSTR_LEN(str));
	}

	write(f, CONST_STR_LEN(
		"}\n"
		"\n"
	));

	write(f, GSTR_LEN(buf));

	close(f);

	g_string_free(str, TRUE);
	g_string_free(buf, TRUE);
}