/*
 * 911_attest_drop — the #6 @test DROP/KEEP/LINK emission property, driven
 * by `w6c` / `w6c_ww` DIRECTLY on import-free fixtures (task #83, M4 E2-C2b).
 *
 * The drop/keep behavior is a property of w6c's `-T` flag, NOT the build
 * model: a @test fn is spliced out of a non-test build (harec-faithful,
 * ref/harec/src/check.c:3941 — checked but never emitted) and kept under
 * -T (the synth entry references it). Direct-w6c is the only host that can
 * compare BOTH flags on the same input — `ww test` is always -T, `ww build`
 * always non-T. The fixtures are import-free so they feed w6c with no driver
 * resolution; the -T synth's `test.run` callee is left as an external CALL
 * (resolved at link, never needed for the emission grep), so no combined
 * unit is required. Re-hosts the 910/997 nondrop+undefbody+linkfail legs,
 * which die when those gates are deleted at the M4 flip.
 *
 * Legs:
 *   nondrop   — @test defs ABSENT non-T, PRESENT under -T (8 rows); the .s
 *               is cs==ww in BOTH modes (rule 10 — the drop is symmetric).
 *   undefbody — a @test body referencing an undef sym rejects in non-T:
 *               the body is type-checked BEFORE the splice drops it
 *               (harec checks at :3913, drops at :3941). Both stages.
 *   linkfail  — non-test code CALLs a @test fn: non-T drops the def but the
 *               CALL survives, so the link fails on the dangling symbol —
 *               harec-faithful loud failure, never a silent mis-link. Both
 *               stages.
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.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 const char *
absbin(void)
{
	const char *b = getenv("BIN");
	if (!b) b = "out/bin";
	if (b[0] == '/') return b;
	static char buf[2048];
	char cwd[1024];
	if (getcwd(cwd, sizeof cwd) == NULL) return NULL;
	snprintf(buf, sizeof buf, "%s/%s", cwd, b);
	return buf;
}

static int
slurp(const char *path, char **outbuf, size_t *outlen)
{
	FILE *f = fopen(path, "rb");
	if (!f) return -1;
	fseek(f, 0, SEEK_END);
	long n = ftell(f);
	fseek(f, 0, SEEK_SET);
	if (n < 0) { fclose(f); return -1; }
	char *b = malloc((size_t)n + 1);
	if (!b) { fclose(f); return -1; }
	if (fread(b, 1, (size_t)n, f) != (size_t)n) { free(b); fclose(f); return -1; }
	b[n] = '\0';
	fclose(f);
	*outbuf = b;
	*outlen = (size_t)n;
	return 0;
}

/* cmp_asm — w6c and w6c_ww asm for the same input must be byte-identical
 * (rule 10). Returns 0 on match. */
static int
cmp_asm(const char *csa, const char *wsa, const char *what)
{
	char *bc = NULL, *bw = NULL;
	size_t nc = 0, nw = 0;
	int rc = 0;
	if (slurp(csa, &bc, &nc) < 0 || slurp(wsa, &bw, &nw) < 0) {
		fprintf(stderr, "911 FAIL: slurp %s asm\n", what);
		rc = 1;
	} else if (nc != nw || memcmp(bc, bw, nc) != 0) {
		fprintf(stderr, "911 FAIL: %s asm cs!=ww (cs %zu, ww %zu)\n",
		    what, nc, nw);
		rc = 1;
	}
	free(bc); free(bw);
	return rc;
}

/*
 * #6: each row asserts whether a symbol's TEXT def appears in the asm emitted
 * for attest_nondrop.ww in a given mode. A @test fn is spliced out of a
 * non-test build (ref/harec/src/check.c:3941) and kept under -T (the synth
 * entry references it); a plain fn is always emitted. The fixture layout
 * exercises the splice loop's unlink edges: @test head (prev==nil), a
 * surviving plain fn, then two consecutive @test fns (unlink-after-unlink).
 */
static const struct {
	const char *sym;	/* TEXT label to grep for */
	int testmode;		/* 1 => -T, 0 => plain build */
	int present;		/* expected: 1 present, 0 absent */
	const char *what;
} nondrop_rows[] = {
	{ "data.nondrop_keep",   0, 1, "plain fn kept non-T" },
	{ "data.nondrop_test_a", 0, 0, "head @test dropped non-T" },
	{ "data.nondrop_test_b", 0, 0, "mid @test dropped non-T" },
	{ "data.nondrop_test_c", 0, 0, "consecutive @test dropped non-T" },
	{ "data.nondrop_keep",   1, 1, "plain fn kept under -T" },
	{ "data.nondrop_test_a", 1, 1, "head @test kept under -T" },
	{ "data.nondrop_test_b", 1, 1, "mid @test kept under -T" },
	{ "data.nondrop_test_c", 1, 1, "consecutive @test kept under -T" },
};

/* nondrop — compile attest_nondrop.ww four ways (cs/ww × non-T/-T) straight
 * to asm (no driver resolution), assert each row's TEXT def is present/absent
 * on the cstage output, then byte-compare cs vs ww in BOTH modes. The
 * present/absent rows run against the cstage .s alone; the cs==ww byte-id
 * carries the assertion onto the wwstage .s by construction. */
static int
nondrop(const char *bin)
{
	int pid = getpid();
	char cp[256], ct[256], wp[256], wt[256], cmd[4096];
	snprintf(cp, sizeof cp, "/tmp/at911nd_cp_%d.s", pid);
	snprintf(ct, sizeof ct, "/tmp/at911nd_ct_%d.s", pid);
	snprintf(wp, sizeof wp, "/tmp/at911nd_wp_%d.s", pid);
	snprintf(wt, sizeof wt, "/tmp/at911nd_wt_%d.s", pid);

	int rc = 0;
	struct { const char *comp; const char *flag; const char *out; } jobs[] = {
		{ "w6c",    "",    cp },
		{ "w6c",    "-T ", ct },
		{ "w6c_ww", "",    wp },
		{ "w6c_ww", "-T ", wt },
	};
	for (size_t i = 0; i < sizeof jobs / sizeof jobs[0]; i++) {
		snprintf(cmd, sizeof cmd,
		    "%s/%s %stest/wcc/data/attest_nondrop.ww -o %s 2>/dev/null",
		    bin, jobs[i].comp, jobs[i].flag, jobs[i].out);
		if (runwait(cmd) != 0) {
			fprintf(stderr, "911 FAIL: %s %snondrop compile\n",
			    jobs[i].comp, jobs[i].flag);
			rc = 1;
		}
	}

	for (size_t i = 0; rc == 0 && i < sizeof nondrop_rows / sizeof nondrop_rows[0]; i++) {
		const char *f = nondrop_rows[i].testmode ? ct : cp;
		snprintf(cmd, sizeof cmd, "grep -q '^TEXT %s,' %s",
		    nondrop_rows[i].sym, f);
		int found = runwait(cmd) == 0;
		if (found != nondrop_rows[i].present) {
			fprintf(stderr, "911 FAIL: %s: %s %s (expected %s)\n",
			    nondrop_rows[i].what, nondrop_rows[i].sym,
			    found ? "present" : "absent",
			    nondrop_rows[i].present ? "present" : "absent");
			rc = 1;
		}
	}
	if (rc == 0 && cmp_asm(cp, wp, "non-T @test-drop") != 0) rc = 1;
	if (rc == 0 && cmp_asm(ct, wt, "-T @test-keep") != 0) rc = 1;

	unlink(cp); unlink(ct); unlink(wp); unlink(wt);
	return rc;
}

/* reject_plain — `<comp> <fixture>` (NON-T) must exit nonzero. Pins that a
 * @test body is type-checked before the #6 splice drops it: an undefined
 * symbol in the body is caught loud even though the fn never reaches codegen
 * (harec checks at :3913, drops at :3941). */
static int
reject_plain(const char *bin, const char *comp, const char *fixture,
    const char *what)
{
	char cmd[4096];
	snprintf(cmd, sizeof cmd, "%s/%s %s -o /dev/null 2>/dev/null",
	    bin, comp, fixture);
	if (runwait(cmd) == 0) {
		fprintf(stderr, "911 FAIL: %s (non-T) accepted %s "
		    "(expected reject)\n", comp, what);
		return 1;
	}
	return 0;
}

/* linkfail — a plain fn calling a @test fn, built non-T: compile + assemble
 * succeed, but the link MUST fail (the dropped @test def leaves the call's
 * symbol dangling — harec-faithful loud failure, never a silent mis-link). */
static int
linkfail(const char *bin, const char *comp, const char *asmt, const char *linkt)
{
	int pid = getpid();
	char asmf[256], obj[256], exe[256], lerr[256], rt[1024], cmd[4096];
	snprintf(asmf, sizeof asmf, "/tmp/at911lf_%s_%d.s", comp, pid);
	snprintf(obj,  sizeof obj,  "/tmp/at911lf_%s_%d.o", comp, pid);
	snprintf(exe,  sizeof exe,  "/tmp/at911lf_%s_%d.exe", comp, pid);
	snprintf(lerr, sizeof lerr, "/tmp/at911lf_%s_%d.err", comp, pid);
	snprintf(rt,   sizeof rt,   "%s/../lib/libwwrt.a", bin);

	int rc = 0;
	snprintf(cmd, sizeof cmd,
	    "%s/%s test/wcc/data/attest_calldropped.ww -o %s 2>/dev/null",
	    bin, comp, asmf);
	if (runwait(cmd) != 0) {
		fprintf(stderr, "911 FAIL: %s non-T calldropped compile\n", comp);
		rc = 1;
	}
	if (rc == 0) {
		snprintf(cmd, sizeof cmd, "%s/%s -o %s %s 2>/dev/null",
		    bin, asmt, obj, asmf);
		if (runwait(cmd) != 0) {
			fprintf(stderr, "911 FAIL: %s calldropped\n", asmt);
			rc = 1;
		}
	}
	if (rc == 0) {
		snprintf(cmd, sizeof cmd, "%s/%s -o %s %s %s 2>%s",
		    bin, linkt, exe, obj, rt, lerr);
		if (runwait(cmd) == 0) {
			fprintf(stderr, "911 FAIL: %s linked calldropped (expected "
			    "undefined-reference to the dropped @test sym)\n", linkt);
			rc = 1;
		} else {
			/* Non-vacuity: the link must fail ON the dropped @test
			 * symbol, not for an unrelated reason — a libwwrt path drift
			 * would otherwise mask the property by failing every link. */
			snprintf(cmd, sizeof cmd, "grep -q calldropped_test %s", lerr);
			if (runwait(cmd) != 0) {
				fprintf(stderr, "911 FAIL: %s link failed but not on the "
				    "dropped @test sym (masked)\n", linkt);
				rc = 1;
			}
		}
	}
	unlink(asmf); unlink(obj); unlink(exe); unlink(lerr);
	return rc;
}

/* Both stages: each tool triple compiles + assembles + links the same
 * import-free fixtures, so the drop/keep/link property is pinned on cstage
 * AND wwstage (the nondrop leg's cs==ww byte-id proves the .s identical;
 * the reject + link legs re-run the whole pipeline per stage). */
static const struct {
	const char *comp;
	const char *asmt;
	const char *linkt;
} stages[] = {
	{ "w6c",    "w6a",    "w6l"    },
	{ "w6c_ww", "w6a_ww", "w6l_ww" },
};

int
main(void)
{
	const char *bin = absbin();
	if (!bin) { fprintf(stderr, "911 FAIL: getcwd\n"); return 1; }

	if (nondrop(bin) != 0) return 1;
	for (size_t i = 0; i < sizeof stages / sizeof stages[0]; i++) {
		if (reject_plain(bin, stages[i].comp,
		    "test/wcc/data/attest_undefbody.ww",
		    "undefined symbol in @test body") != 0) return 1;
		if (linkfail(bin, stages[i].comp, stages[i].asmt,
		    stages[i].linkt) != 0) return 1;
	}

	printf("@test -T direct-w6c: non-T drop + -T keep (8 rows, cs==ww both "
	    "modes) + checked-body reject + dangling-call link-fail, both "
	    "stages (#6)\n");
	return 0;
}