/*
 * 989_unknowndecl_reject — F14 #55: parsefile's recovery fallback
 * (lib/ww/parse/parse.ww) chewed an unrecognized top-level construct to
 * the next ';' WITHOUT emitting an error or bumping p.errs, so a typo'd
 * keyword / stray token / stray decl was silently dropped from the AST
 * and the build succeeded rc=0 with the work gone. The C twin
 * (parse.c:1395-1400) emits errorf("expected top-level decl") + p->errs++
 * and rejects. The fix calls errmsg in the fallback arm, aligning wwstage
 * UP to cstage.
 *
 * Each REJECT row carries an unknown top-level construct and must FAIL to
 * build on BOTH driver twins; each control is well-formed and must
 * build+run. The fn-drop row is the live silent-loss case (a whole
 * declared fn vanished with no diagnostic pre-fix).
 *
 * Rule-10: every row runs on cstage `ww` and wwstage `ww_ww`; both must
 * agree. wwstage rows are gated on out/bin/ww_ww.
 */
#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 expect_build;	/* 1 = build+run to want_exit; 0 = must FAIL */
	int want_exit;
	const char *diag;	/* expected reject diagnostic (NULL for build rows) */
};

static const struct row rows[] = {
	/* REJECT — a misspelled `fn` keyword: the whole decl was silently
	 * dropped pre-fix (grep -c helper of the .s gave 0). */
	{ "misspelled_fn",
	  "package main;\n"
	  "fnn helper() i32 = { return 42; };\n"
	  "export fn main() i32 = { return 0; };\n",
	  0, 0, "expected top-level decl" },

	/* REJECT — a stray run of bare identifiers at top level. */
	{ "stray_idents",
	  "package main;\n"
	  "bogus token here;\n"
	  "export fn main() i32 = { return 0; };\n",
	  0, 0, "expected top-level decl" },

	/* REJECT — a stray decl whose body has internal ';'s, exercising the
	 * brace-balanced chew recovery (still must error, not silently skip). */
	{ "stray_block",
	  "package main;\n"
	  "gizmo foo { let a = 1; let b = 2; };\n"
	  "export fn main() i32 = { return 0; };\n",
	  0, 0, "expected top-level decl" },

	/* control — a clean program builds + runs. */
	{ "clean_ok",
	  "package main;\n"
	  "fn helper() i32 = { return 5; };\n"
	  "export fn main() i32 = { return helper(); };\n",
	  1, 5 },

	/* control — a valid def/type/fn mix builds + runs. */
	{ "decls_ok",
	  "package main;\n"
	  "def K: i32 = 3;\n"
	  "type t = i32;\n"
	  "export fn main() i32 = { let x: t = K; return x: i32; };\n",
	  1, 3 },
};

static int
run_build(const char *driver, const struct row *r, int i)
{
	char src[64], tmpdir[64], cmd[1024];
	snprintf(src, sizeof src, "/tmp/und_%d_%d.ww", getpid(), i);
	snprintf(tmpdir, sizeof tmpdir, "/tmp/und_%d_d_%d", getpid(), i);

	FILE *f = fopen(src, "wb");
	if (!f) return -2;
	fputs(r->src, f);
	fclose(f);

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

	const char *base = strrchr(src, '/');
	base = base ? base + 1 : src;
	char outbin[128];
	snprintf(outbin, sizeof outbin, "%s/%s", tmpdir, base);
	char *dot = strrchr(outbin, '.');
	if (dot && strcmp(dot, ".ww") == 0) *dot = '\0';

	int got = -1;
	if (brc == 0) got = runwait(outbin);

	unlink(src); unlink(outbin); rmdir(tmpdir);
	return brc == 0 ? got : -1;
}

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

/* build_should_fail — the build must FAIL *and* emit `diag`. A crash
 * (segfault) wraps as a nonzero "w6c failed" with no diagnostic, so the
 * substring check distinguishes it from a clean reject (#20). cstage
 * names the offending token ("expected top-level decl, got IDENT"),
 * wwstage prints "parse: expected top-level decl"; the shared core is
 * "expected top-level decl". */
static int
build_should_fail(const char *driver, const char *src, const char *diag,
    int i)
{
	char s[64], tmpdir[64], cmd[1024], errf[64];
	snprintf(s, sizeof s, "/tmp/undn_%d_%d.ww", getpid(), i);
	snprintf(tmpdir, sizeof tmpdir, "/tmp/undn_%d_d_%d", getpid(), i);
	snprintf(errf, sizeof errf, "/tmp/undn_%d_e_%d.txt", getpid(), i);

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

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

	unlink(s);
	unlink(errf);
	const char *base = strrchr(s, '/');
	base = base ? base + 1 : s;
	char outbin[128];
	snprintf(outbin, sizeof outbin, "%s/%s", tmpdir, base);
	char *dot = strrchr(outbin, '.');
	if (dot && strcmp(dot, ".ww") == 0) *dot = '\0';
	unlink(outbin);
	rmdir(tmpdir);
	/* build must NOT succeed AND must emit its diagnostic. */
	return (rc != 0 && hasmsg) ? 0 : -1;
}

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 cdrv[1024], wdrv[1024];
	snprintf(cdrv, sizeof cdrv, "%s/ww", bin);
	snprintf(wdrv, sizeof wdrv, "%s/ww_ww", bin);

	struct { const char *name; const char *drv; 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].drv, X_OK) != 0) {
			fprintf(stderr, "unknowndecl_reject: skip %s (no %s)\n",
			    drivers[d].name, drivers[d].drv);
			continue;
		}
		for (int i = 0; i < n; i++) {
			total++;
			if (rows[i].expect_build) {
				int got = run_build(drivers[d].drv, &rows[i], i);
				if (got != rows[i].want_exit) {
					fprintf(stderr, "unknowndecl_reject[%s][%s]: "
					    "exit=%d want=%d\n", drivers[d].name,
					    rows[i].label, got, rows[i].want_exit);
					fail++;
				}
			} else {
				if (build_should_fail(drivers[d].drv, rows[i].src,
				    rows[i].diag, 100 + i) != 0) {
					fprintf(stderr, "unknowndecl_reject[%s][%s]: "
					    "built ok, expected a loud reject\n",
					    drivers[d].name, rows[i].label);
					fail++;
				}
			}
		}
	}

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