/*
 * 940_tuple_in_union_run — project #242: a mixed-scalar tuple WRAPPED IN A
 * TAGGED UNION must construct, match-bind, and destructure IDENTICALLY in
 * both stages and round-trip every element. BARE tuples already worked
 * (#240/#83); only the union-wrapped variant was broken.
 *
 * Three SILENT, gate-blind (no bootstrap tuple-in-union) cs!=ww divergences
 * met here, all on the `(neg, n)`-shape tuple Hare's strconv parseint returns
 * (`((bool, u64) | invalid | overflow)`, stou.ha):
 *
 *  (a) cstage CONSTRUCTION (cgen.c N_RETURN tagged arm): a tuple variant fell
 *      through the scalar shuffle, which ZEROED the whole value (MOVQ $0 to
 *      tag + payload) — the operands were never packed. Fix: route the tuple
 *      variant through the scratch-slot widen path (cg_widen_tagged_store's
 *      new TY_TUPLE arm), packing each element into the union payload + tag.
 *
 *  (b) wwstage CHECKER (check.ww N_MLET): `let (a,b)=t` over a plain tuple
 *      ident (the match-bound union payload) left the un-annotated binders
 *      UNTYPED — the bin node reading them was untyped → asserttyped abort.
 *      The element-type distribution only fired for an N_CALL rhs. Fix:
 *      consume the rhs tuple type for ANY rhs (mirror cstage check.c:2017).
 *
 *  (c) BOTH stages DESTRUCTURE (N_MLET / cgmlet): the register-cursor receive
 *      assumes the rhs left every element in AX/DX/CX (a call's tuple-return
 *      ABI). For a tuple IDENT cgexpr loads only word0->AX, so the 2nd binder
 *      read a STALE DX. Fix: copy each element from the ident's slot at the
 *      register-ABI 8B stride.
 *
 * Construction is correct at ANY variant position (the variant tag, not a
 * default-0) — `tuple_tag1` and `tuple_after_int` place the tuple at index 1.
 *
 * SCOPE (rule 7 loud-stop, PINNED by the K_BUILDERR row): a tuple built
 * from a BARE LITERAL element (cstage mis-types `true`/`false`/untyped `7` →
 * tag unresolved, #241 literal-init family; wwstage types them but mirrors
 * cstage's CONDITION down per rule 10) loud-stops in cgen on BOTH stages
 * rather than silently miscompile. The old eightbyte-share loud-stop
 * ((i32,i32,u64), #243) DISSOLVED with the slot-SSoT tuple layout (tuple
 * arc C-t0) — that row graduated to K_RUN below. The K_RUN rows build
 * their tuple from TYPED expressions — the supported, byte-identical shape.
 *
 * K_RUN rows: build+run exit 0 on BOTH drivers AND cs==ww byte-identical.
 * K_BUILDERR rows: build FAILS with the #242 diagnostic on BOTH drivers.
 * NNN<950, self-contained (/tmp, no imports), so rule-14's selfhost-sibling
 * race does not apply (903/940/945 precedent).
 */
#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;
}

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), cb = fgetc(fb);
		if (ca != cb) { rc = -1; break; }
		if (ca == EOF) break;
	}
	fclose(fa); fclose(fb);
	return rc;
}

static int
file_contains(const char *path, const char *needle)
{
	FILE *f = fopen(path, "rb");
	if (!f) return 0;
	char buf[8192];
	size_t n = fread(buf, 1, sizeof buf - 1, f);
	fclose(f);
	buf[n] = '\0';
	return strstr(buf, needle) != NULL;
}

#define K_RUN      0	/* build+run both drivers, exit==want, + cs==ww byte-id */
#define K_BUILDERR 1	/* build must FAIL with experr on BOTH drivers (rule 7) */

struct row { const char *label; const char *src; int kind; int want;
             const char *experr; };

static const struct row rows[] = {
	/* canonical #242 case: (bool,u64) at variant 0, match-bind +
	 * destructure, both elements checked. */
	{ "bool_u64",
	  "package main;\n"
	  "fn mku(x: u64, s: bool) ((bool, u64) | void) = { return (s, x); };\n"
	  "export fn main() i32 = {\n"
	  "	match (mku(7u64, true)) {\n"
	  "	case let t: (bool, u64) => {\n"
	  "		let (sg, u) = t;\n"
	  "		if (u != 7u64) { return 1; };\n"
	  "		if (!sg) { return 2; };\n"
	  "		return 0;\n"
	  "	};\n"
	  "	case void => { return 3; };\n"
	  "	};\n"
	  "	return 4;\n"
	  "};\n", K_RUN, 0, NULL },
	/* the void variant: bare `return;` packs the void tag, the match
	 * takes the void arm. The tuple branch still compiles (typed vars). */
	{ "void_arm",
	  "package main;\n"
	  "fn mku(ok: bool, x: u64, s: bool) ((bool, u64) | void) = {\n"
	  "	if (ok) { return (s, x); };\n"
	  "	return;\n"
	  "};\n"
	  "export fn main() i32 = {\n"
	  "	match (mku(false, 1u64, true)) {\n"
	  "	case let t: (bool, u64) => { return 1; };\n"
	  "	case void => { return 0; };\n"
	  "	};\n"
	  "	return 2;\n"
	  "};\n", K_RUN, 0, NULL },
	/* tuple at variant 1 (`(void | (bool,u64))`): the construct must emit
	 * tag 1, not a default 0 — and the match must dispatch to it. */
	{ "tuple_tag1",
	  "package main;\n"
	  "fn mku(x: u64, s: bool) (void | (bool, u64)) = { return (s, x); };\n"
	  "export fn main() i32 = {\n"
	  "	match (mku(9u64, true)) {\n"
	  "	case void => { return 50; };\n"
	  "	case let t: (bool, u64) => {\n"
	  "		let (sg, u) = t;\n"
	  "		if (u != 9u64) { return 1; };\n"
	  "		if (!sg) { return 2; };\n"
	  "		return 0;\n"
	  "	};\n"
	  "	};\n"
	  "	return 4;\n"
	  "};\n", K_RUN, 0, NULL },
	/* tuple variant 1 of `(int | (bool,u64))`, selected at runtime, built
	 * from typed locals (the parseint shape: an int-or-tuple result). */
	{ "tuple_after_int",
	  "package main;\n"
	  "fn mk(which: bool) (int | (bool, u64)) = {\n"
	  "	let s: bool = true;\n"
	  "	let v: u64 = 88u64;\n"
	  "	if (which) { return (s, v); };\n"
	  "	return 5;\n"
	  "};\n"
	  "export fn main() i32 = {\n"
	  "	match (mk(true)) {\n"
	  "	case let n: int => { return 1; };\n"
	  "	case let t: (bool, u64) => {\n"
	  "		let (sg, u) = t;\n"
	  "		if (u != 88u64) { return 2; };\n"
	  "		if (!sg) { return 3; };\n"
	  "		return 0;\n"
	  "	};\n"
	  "	};\n"
	  "	return 4;\n"
	  "};\n", K_RUN, 0, NULL },
	/* C-t0 graduation (was the #242/#243 loud-stop): under the slot-SSoT
	 * tuple layout narrow elements never share an eightbyte —
	 * (i32,i32,u64) is 24B (3 slots), the slotted union write fits by
	 * construction, and the whole tuple round-trips through the union.
	 * cg_widen_tagged_store's size guard stays as a safety net but can
	 * no longer fire for an in-cap tuple. */
	{ "eightbyte_share",
	  "package main;\n"
	  "fn f(a: i32, b: i32, c: u64) ((i32, i32, u64) | void) = {\n"
	  "	return (a, b, c);\n"
	  "};\n"
	  "export fn main() i32 = {\n"
	  "	match (f(-3, 4, 9u64)) {\n"
	  "	case let t: (i32, i32, u64) => {\n"
	  "		let (x, y, z) = t;\n"
	  "		if (x != -3) { return 1; };\n"
	  "		if (y != 4) { return 2; };\n"
	  "		if (z != 9u64) { return 3; };\n"
	  "		return 0;\n"
	  "	};\n"
	  "	case void => { return 4; };\n"
	  "	};\n"
	  "	return 5;\n"
	  "};\n", K_RUN, 0, NULL },
	/* rule-7 loud-stop (ii): a tuple built from a BARE LITERAL element
	 * (`true`). cstage's cg_tag_for_variant can't type the literal (#241)
	 * so it returns -1 and loud-stops; wwstage types `true` as bool and
	 * WOULD resolve the tag, so it mirrors cstage's CONDITION with an
	 * explicit bare-literal guard (rule 10 — align the richer side DOWN).
	 * Both stages MUST loud-stop with the SAME diagnostic. Lift both guards
	 * together when #241 lands cstage literal typing. */
	{ "bool_literal",
	  "package main;\n"
	  "fn f(x: u64) ((bool, u64) | void) = { return (true, x); };\n"
	  "export fn main() i32 = { return 0; };\n",
	  K_BUILDERR, 0, "variant tag unresolved (untyped/literal tuple element" },
};

/* build+run via a driver (ww / ww_ww); returns 0 pass, nonzero fail. */
static int
run_driver(const char *driver, const struct row *r, int i)
{
	char src[96], tmpdir[96], errf[96], cmd[1024];
	snprintf(src, sizeof src, "/tmp/tiu_%d_%d.ww", getpid(), i);
	snprintf(tmpdir, sizeof tmpdir, "/tmp/tiu_%d_d_%d", getpid(), i);
	snprintf(errf, sizeof errf, "/tmp/tiu_%d_e_%d", getpid(), i);

	FILE *f = fopen(src, "wb");
	if (!f) return -1;
	fputs(r->src, f);
	fclose(f);

	mkdir(tmpdir, 0755);
	snprintf(cmd, sizeof cmd, "cd %s && %s build %s >/dev/null 2>%s",
	    tmpdir, driver, src, errf);
	int brc = runwait(cmd);

	if (r->kind == K_BUILDERR) {
		int ok = (brc != 0)
		    && (r->experr == NULL || file_contains(errf, r->experr));
		if (!ok)
			fprintf(stderr, "row[%s]: %s expected loud #242 builderr "
			    "(brc=%d)\n", r->label, driver, brc);
		unlink(src); unlink(errf); rmdir(tmpdir);
		return ok ? 0 : 1;
	}

	if (brc != 0) {
		fprintf(stderr, "row[%s]: build via %s failed\n",
		    r->label, driver);
		unlink(src); unlink(errf); rmdir(tmpdir);
		return -1;
	}

	const char *base = strrchr(src, '/');
	base = base ? base + 1 : src;
	char outbin[256];
	snprintf(outbin, sizeof outbin, "%s/%s", tmpdir, base);
	char *dot = strrchr(outbin, '.');
	if (dot && strcmp(dot, ".ww") == 0) *dot = '\0';
	int got = runwait(outbin);

	unlink(src); unlink(outbin); unlink(errf); rmdir(tmpdir);
	if (got != r->want) {
		fprintf(stderr, "row[%s]: %s exit %d, want %d\n",
		    r->label, driver, got, r->want);
		return 1;
	}
	return 0;
}

/* cs==ww .s byte-id (rule 10). */
static int
byteid(const char *w6c, const char *w6c_ww, const struct row *r, int i)
{
	char src[96], cs_s[96], ws_s[96], cmd[1024];
	snprintf(src, sizeof src, "/tmp/tiu_bi_%d_%d.ww", getpid(), i);
	snprintf(cs_s, sizeof cs_s, "/tmp/tiu_bi_%d_%d_cs.s", getpid(), i);
	snprintf(ws_s, sizeof ws_s, "/tmp/tiu_bi_%d_%d_ww.s", getpid(), i);

	FILE *f = fopen(src, "wb");
	if (!f) return -1;
	fputs(r->src, f);
	fclose(f);

	int rc = 0;
	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", r->label); rc = 1; }
	else {
		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", r->label); rc = 1; }
		else if (slurp_eq(cs_s, ws_s) != 0) {
			fprintf(stderr, "row[%s]: cstage/wwstage .s DIFFER "
			    "(#242 tuple-in-union construct/destructure regression)\n",
			    r->label);
			rc = 1;
		}
	}
	unlink(src); unlink(cs_s); unlink(ws_s);
	return rc;
}

int
main(void)
{
	const char *bin = getenv("BIN");
	if (!bin) bin = "out/bin";
	char absbin[512];
	if (bin[0] != '/') {
		char cwd[256];
		if (getcwd(cwd, sizeof cwd) == NULL) return 1;
		snprintf(absbin, sizeof absbin, "%s/%s", cwd, bin);
		bin = absbin;
	}

	char cdrv[640], wdrv[640], w6c[640], w6c_ww[640];
	snprintf(cdrv, sizeof cdrv, "%s/ww", bin);
	snprintf(wdrv, sizeof wdrv, "%s/ww_ww", bin);
	snprintf(w6c, sizeof w6c, "%s/w6c", bin);
	snprintf(w6c_ww, sizeof w6c_ww, "%s/w6c_ww", bin);

	struct { const char *name; const char *path; int gated; }
	drivers[] = {
		{ "cstage",  cdrv, 0 },
		{ "wwstage", wdrv, 1 },
		{ NULL, NULL, 0 },
	};

	int n = (int)(sizeof rows / sizeof rows[0]);
	int total = 0, fail = 0;

	for (int d = 0; drivers[d].name; d++) {
		if (drivers[d].gated && access(drivers[d].path, X_OK) != 0) {
			fprintf(stderr, "tuple_in_union: skip %s (no %s)\n",
			    drivers[d].name, drivers[d].path);
			continue;
		}
		for (int i = 0; i < n; i++) {
			total++;
			if (run_driver(drivers[d].path, &rows[i], i) != 0) fail++;
		}
	}

	/* cs==ww byte-id for the K_RUN rows only; a K_BUILDERR row emits no
	 * .s on either stage (both loud-stop), so byte-id does not apply. */
	if (access(w6c_ww, X_OK) == 0) {
		for (int i = 0; i < n; i++) {
			if (rows[i].kind != K_RUN) continue;
			total++;
			if (byteid(w6c, w6c_ww, &rows[i], i) != 0) fail++;
		}
	}

	if (fail) {
		fprintf(stderr, "tuple_in_union: %d/%d checks failed\n",
		    fail, total);
		return 1;
	}
	printf("tuple_in_union: %d/%d ok\n", total, total);
	return 0;
}