/*
 * 944_variant_chain_b95_run -- SLIMMED to the one irreducible asymmetric row.
 *
 * The #95 variant-match chain-membership corpus (22 rows) migrated to fold-2
 * homes (#5-C5): the K_RUN value rows -> test/lang/variant_chain_b95_test.ww
 * (@test + T2 byte-id); the two #81-byte-id-waived CALL-source rows ->
 * test/lang/variant_chain_b95_runonly_test.ww (value-only); the K_BUILDERR
 * reject rows -> test/wcc/data/vchain_<name>/case.ww runww //ww:error carriers.
 *
 * callret_bound277 (kb5_v2sE) CANNOT move: it is cstage-runs / wwstage-rejects
 * -- cstage builds+runs it (exit 0) while wwstage LOUD-STOPS with "deferred
 * #277" (the ww aggregate-return capability gap, OUT of #95). That asymmetry is
 * inexpressible as a single-compile @test (which builds one way) or a runww
 * //ww:error carrier (which demands BOTH stages reject). It stays a slim C pin.
 *
 * Non-vacuity (the pin CAN go RED): if cstage stops running it (exit != 0) or
 * wwstage starts accepting it (#277 wired), the row fails; the wwstage leg also
 * requires the EXACT "deferred #277" diagnostic so an unrelated wwstage error
 * cannot masquerade as coverage. Mutation-checked: dropping the cast-to-alias
 * (`mk()` typed plainly) flips cstage and was observed RED.
 */
#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
errlog_has(const char *path, const char *needle)
{
	FILE *f = fopen(path, "rb");
	if (!f) return 0;
	char buf[8192];
	size_t got = fread(buf, 1, sizeof buf - 1, f);
	fclose(f);
	buf[got] = '\0';
	return strstr(buf, needle) != NULL;
}

/* kb5_v2sE: a CALL whose result is typed as the alias ali, widened into
 * (void | ali). cstage's aggregate-return path runs it; wwstage #277 rejects. */
static const char *src =
    "package main;\n"
    "type base = struct { a: int, b: int };\n"
    "type al0 = base;\n"
    "type ali = al0;\n"
    "fn mk() ali = {\n"
    "	let s: ali;\n"
    "	s.a = 4; s.b = 9;\n"
    "	return s;\n"
    "};\n"
    "export fn main() i32 = {\n"
    "	let v: (void | ali) = mk();\n"
    "	if (!(v is ali)) { return 1; };\n"
    "	return 0;\n"
    "};\n";

static const char *experr = "deferred #277";

/* Build src with `driver`; if expect_err, the build must FAIL with experr on
 * stderr. Otherwise build must succeed, then the binary runs and its exit must
 * equal `want`. Returns 0 on the expected outcome, 1 otherwise. */
static int
check(const char *driver, int expect_err, int want)
{
	char tmpdir[96], srcp[128], outbin[128], errf[128], rmcmd[160], cmd[1024];
	snprintf(tmpdir, sizeof tmpdir, "/tmp/vc277_%d_%d", getpid(), expect_err);
	mkdir(tmpdir, 0755);
	snprintf(srcp, sizeof srcp, "%s/c.ww", tmpdir);
	snprintf(outbin, sizeof outbin, "%s/c", tmpdir);
	snprintf(errf, sizeof errf, "%s/err", tmpdir);
	snprintf(rmcmd, sizeof rmcmd, "rm -rf %s", tmpdir);

	FILE *f = fopen(srcp, "wb");
	if (!f) { runwait(rmcmd); return 1; }
	fputs(src, f);
	fclose(f);

	snprintf(cmd, sizeof cmd, "timeout 20 %s build -o %s %s >/dev/null 2>%s",
	    driver, outbin, srcp, errf);
	int brc = runwait(cmd);

	int rc = 0;
	if (expect_err) {
		if (brc == 0 || !errlog_has(errf, experr)) {
			fprintf(stderr, "callret_bound277: %s expected loud "
			    "builderr \"%s\" (brc=%d)\n", driver, experr, brc);
			rc = 1;
		}
	} else if (brc != 0) {
		fprintf(stderr, "callret_bound277: build via %s failed\n", driver);
		rc = 1;
	} else {
		int got = runwait(outbin);
		if (got != want) {
			fprintf(stderr, "callret_bound277: %s exit %d, want %d\n",
			    driver, got, want);
			rc = 1;
		}
	}
	runwait(rmcmd);
	return rc;
}

int
main(void)
{
	const char *bin = getenv("BIN");
	if (!bin) bin = "out/bin";
	char absbin[2080];
	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 cdrv[2120], wdrv[2120];
	snprintf(cdrv, sizeof cdrv, "%s/ww", bin);
	snprintf(wdrv, sizeof wdrv, "%s/ww_ww", bin);

	int fail = 0;
	fail += check(cdrv, 0, 0);		/* cstage runs, exit 0 */
	if (access(wdrv, X_OK) == 0)
		fail += check(wdrv, 1, 0);	/* wwstage loud-stops #277 */

	if (fail) {
		fprintf(stderr, "variant_chain_b95: %d checks failed\n", fail);
		return 1;
	}
	printf("variant_chain_b95: callret_bound277 pin ok\n");
	return 0;
}