/*
 * 945_rvalue_tuple_destructure_run — project #241: materialise an RVALUE
 * tuple into the register cursor before a destructure / let bind.
 *
 * cgexpr could not produce a tuple VALUE: a literal `(a, b)` fell to the
 * `cgexpr_int(0)` / `MOVQ $0, AX` default, a tuple-typed IDENT loaded only
 * word0 into AX, and the `?`/`!` unwrap of a tuple-in-union payload lifted
 * only word0->AX (stranding word1 in CX). So `let (x, y) = <rvalue tuple>`
 * read GARBAGE past the first element (cstage), and the un-typed binder left
 * wwstage's checker aborting (asserttyped). DANGEROUS gate-blind cs!=ww — the
 * strconv blocker (`let (sign, u) = parseint(s, base)?`).
 *
 * Fix (both stages, byte-identical per rule 10): cgexpr packs an N_TUPLE
 * literal and a tuple IDENT into the SysV register-return cursor (the SAME
 * ABI a tuple-returning call leaves, which the cgmlet/cgmassign consumers
 * already read); the ?/! unwrap shifts a tuple success payload down one
 * integer reg past the tag. wwstage's checker recovers the popped match-arm
 * binder type for a `yield <binder>` (scope-free, via the arm's declared
 * type) so the destructured binders stamp.
 *
 * Rows assert BOTH elements on BOTH drivers AND cs==ww byte-identical:
 *   literal_destructure  `let (a, b) = (true, 11u64)`
 *   match_yield          `let (sg, u) = match (mk()) { case let t => yield t }`
 *   trycall_strconv      `let (sign, u) = parseint(base)?`   (the strconv shape)
 *
 * NOT covered (separate root, deferred): single-var `let q = (true, 9u64)`
 * then `q.N` rides #238 — the N_LET tuple-init sz==16||32 gate + the N_DOT
 * tuple-field PACKED-offset reader vs tuple_store's 8B stride disagree for a
 * narrow-first tuple. Out of scope for #241 (the rvalue-into-cursor fix); see
 * task #6 / proj #238.
 *
 * All K_RUN: build+run exit 0 on BOTH drivers AND cs==ww byte-identical.
 * 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;
}

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

static const struct row rows[] = {
	{ "literal_destructure",
	  "package main;\n"
	  "export fn main() i32 = {\n"
	  "	let (a, b) = (true, 11u64);\n"
	  "	if (b != 11u64) { return 1; };\n"
	  "	if (!a) { return 2; };\n"
	  "	return 0;\n"
	  "};\n", 0 },
	{ "match_yield",
	  "package main;\n"
	  "type myerr = !void;\n"
	  "fn mk(x: u64, s: bool) ((bool, u64) | myerr) = { return (s, x); };\n"
	  "export fn main() i32 = {\n"
	  "	let (sg, u) = match (mk(6u64, true)) {\n"
	  "	case let t: (bool, u64) => yield t;\n"
	  "	case myerr => { return 9; };\n"
	  "	};\n"
	  "	if (u != 6u64) { return 1; };\n"
	  "	if (!sg) { return 2; };\n"
	  "	return 0;\n"
	  "};\n", 0 },
	{ "trycall_strconv",
	  "package main;\n"
	  "type invalid = !void;\n"
	  "fn parseint(base: int) ((bool, u64) | invalid) = {\n"
	  "	let sg: bool = true;\n"
	  "	let n: u64 = 42u64;\n"
	  "	return (sg, n);\n"
	  "};\n"
	  "fn stoi(base: int) (u64 | invalid) = {\n"
	  "	let (sign, u) = parseint(base)?;\n"
	  "	if (!sign) { return 0u64; };\n"
	  "	return u;\n"
	  "};\n"
	  "export fn main() i32 = {\n"
	  "	match (stoi(10)) {\n"
	  "	case let v: u64 => { if (v != 42u64) { return 1; }; };\n"
	  "	case invalid => { return 2; };\n"
	  "	};\n"
	  "	return 0;\n"
	  "};\n", 0 },
};

/* 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/rvtd_%d_%d.ww", getpid(), i);
	snprintf(tmpdir, sizeof tmpdir, "/tmp/rvtd_%d_d_%d", getpid(), i);
	snprintf(errf, sizeof errf, "/tmp/rvtd_%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 (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/rvtd_bi_%d_%d.ww", getpid(), i);
	snprintf(cs_s, sizeof cs_s, "/tmp/rvtd_bi_%d_%d_cs.s", getpid(), i);
	snprintf(ws_s, sizeof ws_s, "/tmp/rvtd_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 "
			    "(rule-10 byte-id)\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, "rvalue_tuple_destructure: 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++;
		}
	}

	if (access(w6c_ww, X_OK) == 0) {
		for (int i = 0; i < n; i++) {
			total++;
			if (byteid(w6c, w6c_ww, &rows[i], i) != 0) fail++;
		}
	}

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