/* radare - LGPL - Copyright 2012-2024 - pancake */

#include <r_lib.h>
#include <r_flag.h>
#include <r_anal.h>
#include <r_asm.h>

static int can_replace(const char *str, int idx, int max_operands) {
	if (str[idx] > '9' || str[idx] < '1') {
		return false;
	}
	if (str[idx + 1] != '\x00' && str[idx + 1] <= '9' && str[idx + 1] >= '1') {
		return false;
	}
	if ((int)((int)str[idx] - 0x30) > max_operands) {
		return false;
	}
	return true;
}

static char *replace(int argc, const char *argv[]) {
	int i, j;
	struct {
		const char *op;
		const char *str;
		int max_operands;
	} ops[] = {
		{ "add", "1 = 2 + 3", 3},
		{ "addi",  "1 = 2 + 3", 3},
		{ "addiu",  "1 = 2 + 3", 3},
		{ "addu",  "1 = 2 + 3", 3},
		{ "and",  "1 = 2 & 3", 3},
		{ "andi",  "1 = 2 & 3", 3},
		{ "b",  "goto 1", 1},
		{ "bal",  "call 1", 1},
		{ "begzal", "if (1 >= 0) call 2", 2},
		{ "beq",  "if (1 == 2) goto 3", 3},
		{ "beqz",  "if (!1) goto 2", 2},
		{ "bgez", "if (1 >= 0) goto 2", 2},
		{ "bgtz", "if (1 > 0) goto 2", 2},
		{ "blez", "if (1 <= 0) goto 2", 2},
		{ "bltz", "if (1 < 0) goto 2", 2},
		{ "bltzal", "if (1 < 0) call 2", 2},
		{ "bne",  "if (1 != 2) goto 3", 3},
		{ "bnez",  "if (1) goto 2", 2},
		{ "j",   "goto 1", 1},
		{ "jal",   "call 1", 1},
		{ "jalr",  "call 1", 1},
		{ "jr",   "goto 1", 1},
		{ "lb",  "1 = byte [3 + 2]", 3},
		{ "lbu",  "1 = (unsigned) byte [3 + 2]", 3},
		{ "lh",  "1 = halfword [3 + 2]", 3},
		{ "lhu",  "1 = (unsigned) halfword [3 + 2]", 3},
		{ "li",   "1 = 2", 2},
		{ "lui",  "1 = 2 << 16", 2},
		{ "lw",  "1 = [3 + 2]", 3},
		{ "mfhi",  "1 = hi", 1},
		{ "mflo",  "1 = lo", 1},
		{ "move",  "1 = 2", 2},
		{ "movn",  "if (3) 1 = 2", 3},
		{ "movz",  "if (!3) 1 = 2", 3},
		{ "mult",  "(hi,lo) = 1 * 2", 2},
		{ "multu",  "unsigned (hi,lo) = 1 * 2", 2},
		{ "mul",  "1 = 2 * 3", 3},
		{ "mulu",  "1 = 2 * 3", 3},
		{ "negu",  "1 = ~2", 2},
		{ "nop",   "", 0},
		{ "nor",   "1 = ~(2 | 3)", 3},
		{ "or",   "1 = 2 | 3", 3},
		{ "ori",   "1 = 2 | 3", 3},
		{ "sb",  "byte [3 + 2] = 1", 3},
		{ "sh",  "halfword [3 + 2] = 1", 3},
		{ "sll",  "1 = 2 << 3", 3},
		{ "sllv",  "1 = 2 << 3", 3},
		{ "slr",  "1 = 2 >> 3", 3}, // logic
		{ "slt",  "1 = (2 < 3)", 3},
		{ "slti",  "1 = (2 < 3)", 3},
		{ "sltiu",  "1 = (unsigned) (2 < 3)", 3},
		{ "sltu",  "1 = (unsigned) (2 < 3)", 3},
		{ "sra",  "1 = (signed) 2 >> 3", 3}, // arithmetic
		{ "srl",  "1 = 2 >> 3", 3},
		{ "srlv",  "1 = 2 >> 3", 3},
		{ "subu",  "1 = 2 - 3", 3},
		{ "sub",  "1 = 2 - 3", 3},
		{ "sw",  "[3 + 2] = 1", 3},
		{ "syscall",  "syscall", 0},
		{ "xor",  "1 = 2 ^ 3", 3},
		{ "xori",  "1 = 2 ^ 3", 3},
		{ NULL }
	};
	RStrBuf *sb = r_strbuf_new ("");
	for (i = 0; ops[i].op; i++) {
		if (!strcmp (ops[i].op, argv[0])) {
			const char *str = ops[i].str;
			for (j = 0; str[j]; j++) {
				if (can_replace (str, j, ops[i].max_operands)) {
					const char *w = argv[str[j] - '0'];
					if (w) {
						r_strbuf_append (sb, w);
					}
				} else {
					r_strbuf_append_n (sb, str + j, 1);
				}
			}
			return r_strbuf_drain (sb);
		}
	}

	for (i = 0; i < argc; i++) {
		r_strbuf_append (sb, argv[i]);
		r_strbuf_append (sb, (i == 0 || i == argc - 1)? " ": ", ");
	}
	return r_strbuf_drain (sb);
}

#define REPLACE(x,y) do { \
	int snprintf_len1_ = snprintf (a, 32, x, w1, w1); \
	int snprintf_len2_ = snprintf (b, 32, y, w1);	\
	if (snprintf_len1_ < 32 && snprintf_len2_ < 32) { \
		p = r_str_replace (p, a, b, 0); \
	} \
} while (0)
#define WSZ 64

static char *parse(RAsmPluginSession *aps, const char *data) {
	int len = strlen (data);
	char w0[WSZ];
	char w1[WSZ];
	char w2[WSZ];
	char w3[WSZ];
	char w4[WSZ];
	char *buf, *ptr, *optr;

	if (!strcmp (data, "jr ra")) {
		return strdup ("ret");
	}

	// malloc can be slow here :?
	if (!(buf = malloc (len + 1))) {
		return NULL;
	}
	memcpy (buf, data, len + 1);

	r_str_replace_char (buf, '(', ',');
	r_str_replace_char (buf, ')', ' ');
	r_str_trim (buf);
	char *str = NULL;
	if (*buf) {
		w0[0]='\0';
		w1[0]='\0';
		w2[0]='\0';
		w3[0]='\0';
		w4[0]='\0';
		ptr = strchr (buf, ' ');
		if (!ptr) {
			ptr = strchr (buf, '\t');
		}
		if (ptr) {
			*ptr = '\0';
			for (ptr++; *ptr == ' '; ptr++) {
				;
			}
			r_str_ncpy (w0, buf, WSZ);
			r_str_ncpy (w1, ptr, WSZ);

			optr=ptr;
			ptr = strchr (ptr, ',');
			if (ptr) {
				*ptr = '\0';
				for (ptr++; *ptr == ' '; ptr++) {
					;
				}
				r_str_ncpy (w1, optr, WSZ);
				r_str_ncpy (w2, ptr, WSZ);
				optr = ptr;
				ptr = strchr (ptr, ',');
				if (ptr) {
					*ptr = '\0';
					for (ptr++; *ptr == ' '; ptr++) {
						;
					}
					r_str_ncpy (w2, optr, WSZ);
					r_str_ncpy (w3, ptr, WSZ);
					optr=ptr;
// bonus
					ptr = strchr (ptr, ',');
					if (ptr) {
						*ptr = '\0';
						for (ptr++; *ptr == ' '; ptr++) {
							;
						}
						r_str_ncpy (w3, optr, WSZ);
						r_str_ncpy (w4, ptr, WSZ);
					}
				}
			}
		} else {
			r_str_ncpy (w0, buf, WSZ);
		}
		{
			const char *wa[] = { w0, w1, w2, w3, w4 };
			size_t i, nw = 0;
			for (i = 0; i < R_ARRAY_SIZE (wa); i++) {
				if (wa[i][0] != '\0') {
					nw++;
				}
			}
			{
				char *p = replace (nw, wa);
				p = r_str_replace (p, "+ -", "- ", 0);
				p = r_str_replace (p, " + ]", " + 0]", 0);

				p = r_str_replace (p, "zero", "0", 1);
				if (!strncmp (p, "0 = ", 4)) {
					*p = 0; // nop
				}
				if (!strcmp (w1, w2)) {
					char a[32], b[32];

					// TODO: optimize
					REPLACE ("%s = %s +", "%s +=");
					REPLACE ("%s = %s -", "%s -=");
					REPLACE ("%s = %s &", "%s &=");
					REPLACE ("%s = %s |", "%s |=");
					REPLACE ("%s = %s ^", "%s ^=");
					REPLACE ("%s = %s >>", "%s >>=");
					REPLACE ("%s = %s <<", "%s <<=");
				}
				str = p;
			}
		}
	}
	free (buf);
	return str;
}

static char *subvar(RAsmPluginSession *aps, RAnalFunction *f, ut64 addr, int oplen, const char *data) {
	RAsm *a = aps->rasm;
	RParse *p = a->parse;
	RListIter *iter;
	char *oldstr;
	char *tstr = strdup (data);
	RAnal *anal = a->analb.anal;

	if (f && p->varlist) {
		RList *bpargs = p->varlist (f, 'b');
		RList *spargs = p->varlist (f, 's');
		const bool ucase = isupper (*tstr);
		RAnalVarField *var;
		r_list_foreach (spargs, iter, var) {
			st64 delta = p->get_ptr_at
				? p->get_ptr_at (f, var->delta, addr)
				: ST64_MAX;
			if (delta == ST64_MAX && var->field) {
				delta = var->delta;
			} else if (delta == ST64_MAX) {
				continue;
			}
			const char *reg = NULL;
			if (p->get_reg_at) {
				reg = p->get_reg_at (f, var->delta, addr);
			}
			if (!reg) {
				reg = anal->reg->alias[R_REG_ALIAS_SP];
			}
			//TODO: honor asm pseudo
			const ut64 adelta = R_ABS (delta);
			oldstr = r_str_newf ((adelta < 10)? "%s%" PFMT64u "(%s)": "%s0x%" PFMT64x "(%s)", delta < 0? "-": "", adelta, reg);
			if (ucase) {
				char *comma = strchr (oldstr, ',');
				if (comma) {
					*comma = 0;
					r_str_case (oldstr, true);
					*comma = ',';
				}
			}
			if (strstr (tstr, oldstr)) {
				char *newstr = (p->localvar_only)
					? r_str_newf ("(%s)", var->name)
					: r_str_newf ("%s%s(%s)", delta > 0 ? "" : "-", var->name, reg);
				tstr = r_str_replace (tstr, oldstr, newstr, 1);
				free (newstr);
				free (oldstr);
				break;
			}
			free (oldstr);
		}
		r_list_foreach (bpargs, iter, var) {
			st64 delta = p->get_ptr_at
				? p->get_ptr_at (f, var->delta, addr)
				: ST64_MAX;
			if (delta == ST64_MAX && var->field) {
				delta = var->delta + f->bp_off;
			} else if (delta == ST64_MAX) {
				continue;
			}
			const char *reg = NULL;
			if (p->get_reg_at) {
				reg = p->get_reg_at (f, var->delta, addr);
			}
			if (!reg) {
				reg = anal->reg->alias[R_REG_ALIAS_BP];
			}
			const ut64 adelta = R_ABS (delta);
			oldstr = r_str_newf ((adelta < 10)? "%s%" PFMT64u "(%s)": "%s0x%" PFMT64x "(%s)", delta < 0? "-": "", adelta, reg);
			if (ucase) {
				char *comma = strchr (oldstr, ',');
				if (comma) {
					*comma = 0;
					r_str_case (oldstr, true);
					*comma = ',';
				}
			}
			if (strstr (tstr, oldstr)) {
				char *newstr = (p->localvar_only)
					? r_str_newf ("(%s)", var->name)
					: r_str_newf ("%s%s(%s)", delta > 0 ? "" : "-", var->name, reg);
				tstr = r_str_replace (tstr, oldstr, newstr, 1);
				free (newstr);
				free (oldstr);
				break;
			}
			free (oldstr);
		}
		r_list_free (bpargs);
		r_list_free (spargs);
	}
	return tstr;
}

RAsmPlugin r_asm_plugin_mips = {
	.meta = {
		.name = "mips",
		.desc = "MIPS pseudo syntax",
		.author = "pancake",
		.license = "LGPL-3.0-only",
	},
	.parse = parse,
	.subvar = subvar,
};

#ifndef R2_PLUGIN_INCORE
R_API RLibStruct radare_plugin = {
	.type = R_LIB_TYPE_ASM,
	.data = &r_asm_plugin_mips,
	.version = R2_VERSION
};
#endif