/*
 * 906_callret_unsigned_arith_run — runtime + byte-id net for #168, the
 * N_CALL twin of #134. The cgen signedness classifier must treat a
 * div/mod/shift whose operand is a *call result* (`f() / d`, `f() % d`,
 * `f() >> n`) as unsigned iff the callee's return type is unsigned —
 * picking DIVQ/SHRQ over IDIVQ/SARQ.
 *
 * The wwstage `nodeisunsigned` (cgenutil.ww) walked surface nodes but
 * had no N_CALL arm, so a call-result operand fell through to
 * `return false` (signed) → signed IDIVQ/SARQ on an unsigned-returning
 * call → silent wrong arithmetic. The cstage was already correct: it
 * reads `type_isunsigned(n->lhs->type)` on the operand's stamped tinfo
 * (cgen.c TK_SLASH/TK_PERCENT/TK_RSHIFT), and the N_CALL result type is
 * stamped at check.c N_CALL (`n->type = u->ret`). #168 brings the
 * wwstage arm up to read the same stamp — exactly as #134 did for the
 * N_INDEX arm (which also touched no C).
 *
 * Gate-blind: the bootstrap never divides/shifts a call result by an
 * unsigned type (strconv dodged it via local-bind, which lands on the
 * N_IDENT arm). So only a direct call-result probe catches it — a
 * `let a = f();` bind would hide the bug.
 *
 * Discrimination:
 *   - byte-id (.s cmp, the primary #168 gate): for ANY unsigned-
 *     returning call, w6c picks DIVQ/SHRQ but pre-fix w6c_ww picks
 *     IDIVQ/SARQ → .s DIFFER. Holds for every unsigned width (the
 *     classifier diverges regardless of the runtime value).
 *   - cstage runtime: validates the unsigned *semantics*. Only the
 *     machine-word rows (u64/uint, high bit set) differ at runtime
 *     between signed/unsigned div on the 64-bit register; the u32 row
 *     is a byte-id discriminator + runtime control (zero-extends to a
 *     positive 64-bit value, so the value alone can't tell the ops
 *     apart — the .s cmp does).
 *   - signed rows (i64/i32/int) guard against an over-broad fix: a
 *     signed-returning call must STILL pick IDIVQ/SARQ in both stages.
 *
 * Same dual-driver shape as 912_sar_shr_run.c: each row is (a) cstage
 * `ww build` + run asserting exit 42, and (b) w6c vs w6c_ww `.s` cmp
 * (rule-10 byte-id). Hard-fails if w6c_ww is missing so the wwstage
 * side — the side that carried the bug — can never silently skip.
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/wait.h>

static int
runwait(const char *cmd)
{
	int rc = system(cmd);
	if (rc == -1) return -1;
	if (WIFEXITED(rc)) return WEXITSTATUS(rc);
	return -1;
}

struct row { const char *label; const char *src; int want_exit; };

static const struct row rows[] = {
	/* ---- unsigned: call result drives DIVQ/SHRQ ------------------- */
	/* u64 div: 0x8000000000000001 / 2. unsigned = 0x4000000000000000;
	 * signed IDIVQ (CQO sign-extends the high-bit-set dividend) =
	 * 0xC000000000000001. */
	{ "u64_div_callret",
	  "package main;\n"
	  "fn uval() u64 = { return 0x8000000000000001u64; };\n"
	  "export fn main() i32 = {\n"
	  "	if (uval() / 2u64 == 0x4000000000000000u64) { return 42; };\n"
	  "	return 0;\n"
	  "};\n", 42 },
	/* u64 mod: unsigned rem = 1; signed rem = -1. */
	{ "u64_mod_callret",
	  "package main;\n"
	  "fn uval() u64 = { return 0x8000000000000001u64; };\n"
	  "export fn main() i32 = {\n"
	  "	if (uval() % 2u64 == 1u64) { return 42; };\n"
	  "	return 0;\n"
	  "};\n", 42 },
	/* u64 shr: SHRQ (logical) = 0x4000000000000000; SARQ (arithmetic,
	 * sign-fills the set MSB) = 0xC000000000000000. */
	{ "u64_shr_callret",
	  "package main;\n"
	  "fn uval() u64 = { return 0x8000000000000001u64; };\n"
	  "export fn main() i32 = {\n"
	  "	if (uval() >> 1u64 == 0x4000000000000000u64) { return 42; };\n"
	  "	return 0;\n"
	  "};\n", 42 },
	/* u32 div: byte-id discriminator (w6c DIVQ vs pre-fix w6c_ww
	 * IDIVQ); runtime control — 0x80000001 zero-extends to a positive
	 * 64-bit value, so signed/unsigned div agree at runtime. */
	{ "u32_div_callret",
	  "package main;\n"
	  "fn uval() u32 = { return 0x80000001u32; };\n"
	  "export fn main() i32 = {\n"
	  "	if (uval() / 2u32 == 0x40000000u32) { return 42; };\n"
	  "	return 0;\n"
	  "};\n", 42 },
	/* uint (machine word): exercises the TY_UINT arm of typeisunsigned
	 * on a call result. High bit set → discriminates like u64. */
	{ "uint_div_callret",
	  "package main;\n"
	  "fn uval() uint = { return (0x8000000000000001u64): uint; };\n"
	  "export fn main() i32 = {\n"
	  "	if (uval() / 2 == (0x4000000000000000u64): uint) { return 42; };\n"
	  "	return 0;\n"
	  "};\n", 42 },

	/* ---- signed guards: call result STAYS IDIVQ/SARQ -------------- */
	/* i64 div: -100 / 7 = -14 (toward zero). If wrongly unsigned, -100
	 * as u64 is huge → quotient huge ≠ -14. */
	{ "i64_div_callret",
	  "package main;\n"
	  "fn sval() i64 = { return -100i64; };\n"
	  "export fn main() i32 = {\n"
	  "	if (sval() / 7i64 == -14i64) { return 42; };\n"
	  "	return 0;\n"
	  "};\n", 42 },
	/* i64 shr: -8 >> 1 = -4 via SARQ (sign-fill). SHRQ would zero-fill
	 * → large positive. */
	{ "i64_shr_callret",
	  "package main;\n"
	  "fn sval() i64 = { return -8i64; };\n"
	  "export fn main() i32 = {\n"
	  "	if (sval() >> 1i64 == -4i64) { return 42; };\n"
	  "	return 0;\n"
	  "};\n", 42 },
	/* i32 div: -100 / 7 = -14. */
	{ "i32_div_callret",
	  "package main;\n"
	  "fn sval() i32 = { return -100i32; };\n"
	  "export fn main() i32 = {\n"
	  "	if (sval() / 7i32 == -14i32) { return 42; };\n"
	  "	return 0;\n"
	  "};\n", 42 },
	/* int (machine word, signed): -100 / 7 = -14; exercises the signed
	 * machine-word path on a call result. */
	{ "int_div_callret",
	  "package main;\n"
	  "fn sval() int = { return -100; };\n"
	  "export fn main() i32 = {\n"
	  "	if (sval() / 7 == -14) { return 42; };\n"
	  "	return 0;\n"
	  "};\n", 42 },
	{ NULL, NULL, 0 }
};

static int
slurp_eq(const char *a, const char *b)
{
	FILE *fa = fopen(a, "rb");
	FILE *fb = fopen(b, "rb");
	if (!fa || !fb) { if (fa) fclose(fa); if (fb) fclose(fb); return -1; }
	int rc = 0;
	for (;;) {
		int ca = fgetc(fa);
		int cb = fgetc(fb);
		if (ca != cb) { rc = -1; break; }
		if (ca == EOF) break;
	}
	fclose(fa); fclose(fb);
	return rc;
}

int
main(void)
{
	const char *bin = getenv("BIN");
	if (!bin) bin = "out/bin";
	char absbin[1024];
	if (bin[0] != '/') {
		char cwd[1024];
		if (getcwd(cwd, sizeof cwd) == NULL) return 1;
		snprintf(absbin, sizeof absbin, "%s/%s", cwd, bin);
		bin = absbin;
	}

	char w6c[1100], w6c_ww[1100];
	snprintf(w6c, sizeof w6c, "%s/w6c", bin);
	snprintf(w6c_ww, sizeof w6c_ww, "%s/w6c_ww", bin);
	if (access(w6c_ww, X_OK) != 0) {
		fprintf(stderr, "callret_unsigned: w6c_ww missing — cannot run "
		    "the cs==ww byte-id gate (the whole point of this test)\n");
		return 1;
	}

	int n = 0, fail = 0;
	for (int i = 0; rows[i].src; i++, n++) {
		char src[64];
		snprintf(src, sizeof src, "/tmp/wwcr_%d_%d.ww", getpid(), i);
		FILE *f = fopen(src, "wb");
		if (f == NULL) { fail++; continue; }
		fputs(rows[i].src, f);
		fclose(f);

		char tmpdir[64];
		snprintf(tmpdir, sizeof tmpdir, "/tmp/wwcr_%d_d_%d",
		    getpid(), i);
		mkdir(tmpdir, 0755);

		char cmd[2048];
		snprintf(cmd, sizeof cmd, "cd %s && %s/ww build %s",
		    tmpdir, bin, src);
		if (runwait(cmd) != 0) {
			fprintf(stderr, "row[%s]: cstage build failed\n",
			    rows[i].label);
			fail++;
			unlink(src); rmdir(tmpdir);
			continue;
		}

		char outbin[128];
		const char *base = strrchr(src, '/');
		base = base ? base + 1 : src;
		snprintf(outbin, sizeof outbin, "%s/%s", tmpdir, base);
		char *dot = strrchr(outbin, '.');
		if (dot && strcmp(dot, ".ww") == 0) *dot = '\0';

		int got = runwait(outbin);
		if (got != rows[i].want_exit) {
			fprintf(stderr, "row[%s]: cstage exit %d, want %d\n",
			    rows[i].label, got, rows[i].want_exit);
			fail++;
		}
		unlink(outbin); rmdir(tmpdir);

		char cs_s[64], ws_s[64];
		snprintf(cs_s, sizeof cs_s, "/tmp/wwcr_%d_%d_cs.s",
		    getpid(), i);
		snprintf(ws_s, sizeof ws_s, "/tmp/wwcr_%d_%d_ww.s",
		    getpid(), i);

		snprintf(cmd, sizeof cmd, "%s -o %s %s 2>/dev/null",
		    w6c, cs_s, src);
		if (runwait(cmd) != 0) {
			fprintf(stderr, "row[%s]: w6c failed\n", rows[i].label);
			fail++; unlink(src); continue;
		}
		snprintf(cmd, sizeof cmd, "%s -o %s %s 2>/dev/null",
		    w6c_ww, ws_s, src);
		if (runwait(cmd) != 0) {
			fprintf(stderr, "row[%s]: w6c_ww failed\n",
			    rows[i].label);
			fail++; unlink(src); unlink(cs_s); continue;
		}
		if (slurp_eq(cs_s, ws_s) != 0) {
			fprintf(stderr,
			    "row[%s]: cstage/wwstage .s DIFFER (rule-10 "
			    "byte-id violation)\n", rows[i].label);
			fail++;
		}
		unlink(src); unlink(cs_s); unlink(ws_s);
	}

	if (fail) {
		fprintf(stderr, "%d/%d callret_unsigned tests failed\n",
		    fail, n);
		return 1;
	}
	printf("callret_unsigned: %d/%d ok (cstage run + cs==ww byte-id)\n",
	    n, n);
	return 0;
}