/*
 * 989_dotbasehijack_run — F8-c4 (report-item #20): indexing an `[N]T` field
 * of a module-GLOBAL struct (`gs.fld[i]`) must address gs's field, not be
 * hijacked by an unrelated module-global that shares the FIELD's name.
 *
 * THE BUG (cat-A silent miscompile, align-UP): cgenexpr.ww dotbaseaddr's
 * #128b probe (for a module-qualified `mod.arr` array base) did
 * `letvartnode(base.str)` — base.str is the DOT's FIELD name — whenever the
 * inner ident wasn't a local. For `gs.fld` with `gs` a module-global struct,
 * the inner gs is global (no local slot) so the probe fired and, finding an
 * unrelated module-global `fld: [N]T`, emitted `LEAQ fld(SB)` — addressing
 * the wrong symbol. cstage cg_dotbase_addr gates the #128b probe on
 * inner->type == NULL || ty_err (cgen.c:2109 — a module qualifier has no
 * struct type), so a typed-struct inner skips it and resolves the field off
 * the struct (LEAQ gs(SB) + foff). 990-997 never hit a field-name/global
 * collision, so the gate stayed green — a runtime row is the net.
 *
 * THE FIX: gate the wwstage #128b probe on tichase(inner.type_) == nil ||
 * TY_ERR (the untyped module-qualifier case); a typed struct inner falls to
 * the #249 isglobal struct path. align ww UP; the .s is byte-identical.
 *
 * Rows (build+run on cstage `ww` and wwstage `ww_ww`; rule-10 — agree+hit):
 *   row        | shape                                          | want
 *   -----------+------------------------------------------------+-----
 *   collide_0  | gs:{pad,fld:[2]i64}; gs.fld=[7,8]; global fld=  | 7 [#20:
 *              |   [9,10]; gs.fld[0]                             |   pre-fix ww=9]
 *   collide_1  | same; gs.fld[1]                                 | 8 [#20:
 *              |                                                 |   pre-fix ww=10]
 *   no_collide | gs2:{pad,arr:[2]i64}=[5,6]; NO global arr;      | 5 (control:
 *              |   gs2.arr[0]                                    |   typed inner)
 */
#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;
};

#define PRELUDE \
	"package main;\n" \
	"type s = struct { pad: i64, fld: [2]i64 };\n" \
	"type s2 = struct { pad: i64, arr: [2]i64 };\n" \
	"let gs: s = s { pad = 0, fld = [7, 8] };\n" \
	"let gs2: s2 = s2 { pad = 0, arr = [5, 6] };\n" \
	"let fld: [2]i64 = [9, 10];\n"

static const struct row rows[] = {
	{ "collide_0",
	  PRELUDE
	  "export fn main() int = { return gs.fld[0]: int; };\n",
	  7 },

	{ "collide_1",
	  PRELUDE
	  "export fn main() int = { return gs.fld[1]: int; };\n",
	  8 },

	/* typed-struct inner with NO name collision — the probe-skip must not
	 * break the ordinary global-struct array-field index. */
	{ "no_collide",
	  PRELUDE
	  "export fn main() int = { return gs2.arr[0]: int; };\n",
	  5 },
};

/* run_build — build+run `src` via `driver`; returns the binary's exit
 * code, or -1 on a build failure. */
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/dbh_%d_%d.ww", getpid(), i);
	snprintf(tmpdir, sizeof tmpdir, "/tmp/dbh_%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;
}

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, "dotbasehijack_run: skip %s (no %s)\n",
			    drivers[d].name, drivers[d].drv);
			continue;
		}
		for (int i = 0; i < n; i++) {
			total++;
			int got = run_build(drivers[d].drv, &rows[i], i);
			if (got != rows[i].want_exit) {
				fprintf(stderr, "dotbasehijack_run[%s][%s]: exit=%d "
				    "want=%d\n", drivers[d].name, rows[i].label,
				    got, rows[i].want_exit);
				fail++;
			}
		}
	}

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