/*
 * 989_globptrfield_run — inverse-set cstage fix (report-item [58], ww correct):
 * a field store through a module-GLOBAL `*struct` pointer must load the pointer
 * value from g(SB), not deref the saved-BP word.
 *
 * THE BUG (cat-A divergence — cstage SEGV, wwstage correct): in cgen.c the
 * N_DOT-lhs scalar field-store via_ptr arm loaded the base pointer with
 * `MOVQ boff(BP),BX`. For a module-global `*struct` ident boff==0, so cstage
 * emitted `MOVQ (BP),BX` — derefing the saved BP word as if it were the
 * pointer → store through garbage → SEGV (rc=139). wwstage already loaded the
 * pointer from the symbol (`LEAQ gp(SB),BX; MOVQ (BX),BX`) and ran correctly
 * (rc=7). This is the INVERSE of the F8 #263 set: ww is the runtime-correct
 * reference; the cstage half is filed as ww-core TASK #47.
 *
 * THE CSTAGE FIX (align cstage UP to ww): the via_ptr scalar store detects a
 * global base (boff==0 && let_islet) and emits the ww-correct global-pointer
 * load — PUSHQ AX; LEAQ gp(SB),BX; MOVQ (BX),BX; POPQ AX — before the store.
 * Local bases keep the BP load (byte-id). Both stages now emit the identical
 * .s and exit 7.
 *
 * The static-init form `let gp: *S = &backing;` is blocked on wwstage by a
 * separate static-init-of-&global gap (ww-core TASK #48), so the repro uses
 * the nil-init + runtime `gp = &backing` form, which builds on both stages.
 */
#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;	/* cs==ww==want */
};

static const struct row rows[] = {
	{ "global_ptr_field_store",
	  "package main;\n"
	  "type S = struct { f: i64, g: i64 };\n"
	  "let backing: S = S { f = 0, g = 0 };\n"
	  "let gp: *S = nil;\n"
	  "export fn main() int = {\n"
	  "	gp = &backing;\n"
	  "	gp.f = 7;\n"
	  "	return backing.f: int;\n"
	  "};\n",
	  7 },
};

/* 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/gpf_%d_%d.ww", getpid(), i);
	snprintf(tmpdir, sizeof tmpdir, "/tmp/gpf_%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, "globptrfield_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) {
				fprintf(stderr, "globptrfield_run[%s][%s]: exit=%d "
				    "want=%d\n", drivers[d].name, rows[i].label,
				    got, rows[i].want);
				fail++;
			}
		}
	}

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