/*
 * 954_tuprecv_run — runtime + byte-id regression net for #102: the 16B
 * whole-tuple-from-call receive (`let t = mk()`, then field reads t.0 /
 * t.1).
 *
 * Root: wwstage's cglet had NO 16B tuple-from-call receive branch, so a
 * `let t = call()` whose callee returns a 2-eightbyte (16B) tuple fell
 * through to the generic single-word store (`MOVQ AX, off(BP)`) and
 * never spilled word1 (the DX eightbyte) — silent loss of t.1. cstage
 * has the branch (cmd/w6c/cgen.c:6652: spill AX -> off+0 AND DX ->
 * off+8). The fix mirrors it in cglet.
 *
 * NOTE on the diagnosis: this is NOT a tupstore cursor off-by-one, and
 * it is NOT f64-specific. The destructure form `let (a,b) = mk()`
 * (cgmlet + tupstore cursor) was already byte-id; only the whole-tuple
 * N_LET receive dropped word1. An f64 element only made it visible
 * first, but the all-integer (i64,i64) receive dropped DX too — so the
 * "all-integer control" row below is ALSO a fix row (it diverges on
 * master 60c3e51, byte-id after the fix), not a pure no-op control.
 *
 * THIS TEST MUST CATCH A WWSTAGE-ONLY DIVERGENCE. cstage is correct
 * before and after, so a cstage-only probe is gate-blind. Each row
 * carries BOTH dimensions (modelled on 953_f64crossmod_run):
 *   (a) cstage `ww build` + run, asserting the exit code — pins the asm
 *       both stages converge on as runtime-correct.
 *   (b) w6c vs w6c_ww `.s` cmp — FAILS if the stages diverge. On master
 *       60c3e51 (pre-fix) the three scalar-pair single-var rows each
 *       diverge by exactly one dropped `MOVQ DX, -8(BP)`; post-fix all
 *       are byte-identical.
 *
 * Three CONTROL rows pin that the fix touches nothing else: the
 * destructure form `let (a,b) = mk()` (cgmlet + tupstore cursor), a
 * 32B wide/str-element single-var tuple, and a 16B struct{i64,i64}
 * single-var receive — all stay byte-id both pre- and post-fix. The fix
 * is in cglet/N_LET, gated on sz==16 AND rettupleof != nil; the struct
 * row is the over-catch guard: sz IS 16 but rettupleof returns nil for a
 * non-tuple return, so the new branch must NOT hijack the struct's
 * generic store. Without that guard a struct receive would route through
 * the AX/DX tuple spill and miscompile any struct whose layout differs
 * from {word0,word1}.
 */
#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; int chk_stamped; };

static const struct row rows[] = {
	/* mixed (f64, i64): f=2.5 -> i32 2, i=7 -> i32 7, 2+7 = 9. The
	 * f64 element rides its eightbyte in AX at receive and is re-read
	 * from X0 at field-read; the i64 (t.1) rides DX — the dropped
	 * word. */
	{ "f64_i64",
	  "package main;\n"
	  "fn mk() (f64, i64) = { return (2.5, 7); };\n"
	  "export fn main() i32 = {\n"
	  "\tlet t = mk();\n"
	  "\tlet f: f64 = t.0;\n"
	  "\tlet i: i64 = t.1;\n"
	  "\treturn (f: i32) + (i: i32);\n"
	  "};\n", 9 },
	/* order-swap (i64, f64): f64 in the 2nd slot. i=7, f=2.5 -> 2,
	 * 7+2 = 9. Confirms the spill is position-agnostic (both words go
	 * over the integer cursor regardless of which holds the f64). */
	{ "i64_f64",
	  "package main;\n"
	  "fn mk() (i64, f64) = { return (7, 2.5); };\n"
	  "export fn main() i32 = {\n"
	  "\tlet t = mk();\n"
	  "\tlet i: i64 = t.0;\n"
	  "\tlet f: f64 = t.1;\n"
	  "\treturn (i: i32) + (f: i32);\n"
	  "};\n", 9 },
	/* all-integer (i64, i64): a=5, b=7, 5+7 = 12. NOT a no-op control
	 * — pre-fix wwstage dropped DX here too (proves the fix is not
	 * f64-gated). */
	{ "i64_i64",
	  "package main;\n"
	  "fn mk() (i64, i64) = { return (5, 7); };\n"
	  "export fn main() i32 = {\n"
	  "\tlet t = mk();\n"
	  "\tlet a: i64 = t.0;\n"
	  "\tlet b: i64 = t.1;\n"
	  "\treturn (a: i32) + (b: i32);\n"
	  "};\n", 12 },
	/* CONTROL — destructure form `let (f,i) = mk()` (cgmlet + tupstore
	 * cursor, a different and already-correct path; bootstrap relies on
	 * it, which is why 990-997 pass). The fix is in cglet/N_LET only, so
	 * this stays byte-id pre- and post-fix. f=2.5->2, i=7, 2+7 = 9. */
	{ "ctl_destr",
	  "package main;\n"
	  "fn mk() (f64, i64) = { return (2.5, 7); };\n"
	  "export fn main() i32 = {\n"
	  "\tlet (f, i) = mk();\n"
	  "\treturn (f: i32) + (i: i32);\n"
	  "};\n", 9, 1 },
	/* CONTROL — wide/str element single-var (i64, str) is a 32B tuple
	 * handled by the separate 32B receive branch; the fix's sz==16 gate
	 * excludes it, so it stays byte-id pre- and post-fix. t.0 = 7. */
	{ "ctl_str",
	  "package main;\n"
	  "fn mk() (i64, str) = { return (7, \"hi\"); };\n"
	  "export fn main() i32 = {\n"
	  "\tlet t: (i64, str) = mk();\n"
	  "\treturn t.0: i32;\n"
	  "};\n", 7 },
	/* CONTROL — over-catch guard. A 16B struct{i64,i64} from-call receive
	 * is sz==16 like the bug rows, but rettupleof returns nil for a
	 * non-tuple return, so the fix's new branch must NOT hijack it; it
	 * stays on the generic struct store and byte-id pre- and post-fix.
	 * Pins that the fix's tuple/struct discrimination (#102) holds. a=5,
	 * b=7, 5+7 = 12. */
	{ "ctl_struct",
	  "package main;\n"
	  "type pair = struct { a: i64, b: i64 };\n"
	  "fn mk() pair = { return pair { a = 5, b = 7 }; };\n"
	  "export fn main() i32 = {\n"
	  "\tlet t = mk();\n"
	  "\treturn (t.a: i32) + (t.b: i32);\n"
	  "};\n", 12 },
	{ 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, "tuprecv: 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/wwtup_%d_%d.ww", getpid(), i);
		FILE *f = fopen(src, "wb");
		if (f == NULL) { fail++; continue; }
		fputs(rows[i].src, f);
		fclose(f);

		/* (a) cstage build + run in a scratch dir so the output binary
		 * (and any intermediates) land there. */
		char tmpdir[64];
		snprintf(tmpdir, sizeof tmpdir, "/tmp/wwtup_%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);

		/* (b) cs==ww byte-id gate: emit .s from both stages, cmp.
		 * FAILS on the pre-fix wwstage divergence (dropped MOVQ DX). */
		char cs_s[64], ws_s[64];
		snprintf(cs_s, sizeof cs_s, "/tmp/wwtup_%d_%d_cs.s",
		    getpid(), i);
		snprintf(ws_s, sizeof ws_s, "/tmp/wwtup_%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++;
		}

		/* (c) #121 A-narrow stamp gate: the un-annotated float-
		 * destructure binding must now carry a checker type stamp, so
		 * w6c_ww emits no `asserttyped:` diagnostic. Non-vacuous —
		 * pre-stamp (HEAD) w6c_ww fires asserttyped on the f64 binding
		 * ident (nil n.type_). */
		if (rows[i].chk_stamped) {
			char errf[80];
			snprintf(errf, sizeof errf,
			    "/tmp/wwtup_%d_%d_err.txt", getpid(), i);
			snprintf(cmd, sizeof cmd,
			    "%s -o /dev/null %s 2>%s", w6c_ww, src, errf);
			runwait(cmd);
			snprintf(cmd, sizeof cmd,
			    "grep -q asserttyped %s", errf);
			if (runwait(cmd) == 0) {
				fprintf(stderr, "row[%s]: w6c_ww emitted "
				    "asserttyped (destructure binding "
				    "unstamped)\n", rows[i].label);
				fail++;
			}
			unlink(errf);
		}
		unlink(src); unlink(cs_s); unlink(ws_s);
	}

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