/*
 * 989_ampfncollide_run (#4, c2) — `&fn` synthesis must prefer the current
 * module's fn when a same-leaf fn is declared in a later module.
 *
 * THE BUG (review item #4, 2026-06-11): unoptype's TK_AMP fn-ident synth
 * (check.ww ~2677) and assignableaddrfn (check.ww ~4182) looked the fn up
 * with bare scopelookup — no (name,module) preference. scopedefineinmodule
 * PREPENDS, so a LATER module's same-leaf fn heads the bucket chain and the
 * bare lookup binds ITS signature. Two faces:
 *   - LOUD: `let p: *hfn = &handler` in beta (hfn = fn(i32)i32, beta.handler
 *     is i32->i32) is REJECTED by wwstage ("let: not assignable") because it
 *     binds gamma.handler(str)str, while cstage (scope_lookup_prefer with
 *     cur_mod, check.c:410/1305) binds beta.handler and accepts. Valid code
 *     wrongly rejected.
 *   - SILENT (cat-A): `let p: *gfn = &handler` where gfn = fn(str)str (the
 *     FOREIGN sig) is REJECTED by cstage (beta.handler is i32->i32, not
 *     assignable) but ACCEPTED by wwstage (it binds gamma.handler(str)str,
 *     which matches gfn) — a type-confused fn pointer (LEAQ beta.handler
 *     into a *fn(str)str slot) in a green build.
 * THE FIX: both sites use scopelookupprefer(c.cur, c.curmod, ...).
 *
 *   row    | shape                                   | result (cs==ww)
 *   -------+-----------------------------------------+-----------------
 *   loud   | *hfn = &handler (own-sig slot)          | run 42 (was ww reject)
 *   silent | *gfn = &handler (foreign-sig slot)      | build FAIL (was ww ok)
 *
 * Single-file multi-package source is the sanctioned shape (cmd/ww/main.c).
 * want = -1 means "build must fail 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; };

static const struct row rows[] = {
	{ "loud",
	  "package beta;\n"
	  "export type hfn = fn(x: i32) i32;\n"
	  "export fn handler(x: i32) i32 = { return x + 41; };\n"
	  "export fn usebeta() i32 = {\n"
	  "	let p: *hfn = &handler;\n"
	  "	return (*p)(1);\n"
	  "};\n"
	  "package gamma;\n"
	  "export fn handler(s: str) str = { return s; };\n"
	  "package main;\n"
	  "import beta;\n"
	  "import gamma;\n"
	  "fn main() int = { return beta.usebeta(): int; };\n",
	  42 },

	{ "silent",
	  "package beta;\n"
	  "export type gfn = fn(s: str) str;\n"
	  "export fn handler(x: i32) i32 = { return x + 41; };\n"
	  "export fn usebeta() i32 = {\n"
	  "	let p: *gfn = &handler;\n"
	  "	if (p == p) { return 1; };\n"
	  "	return 0;\n"
	  "};\n"
	  "package gamma;\n"
	  "export fn handler(s: str) str = { return s; };\n"
	  "package main;\n"
	  "import beta;\n"
	  "import gamma;\n"
	  "fn main() int = { return beta.usebeta(): int; };\n",
	  -1 },
};

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/afc_%d_%d.ww", getpid(), i);
	snprintf(tmpdir, sizeof tmpdir, "/tmp/afc_%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;	/* -1 == build failed */
}

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);
	int have_ww = (access(wdrv, X_OK) == 0);

	int n = (int)(sizeof rows / sizeof rows[0]);
	int total = 0, fail = 0;

	for (int i = 0; i < n; i++) {
		total++;
		int gc = run_build(cdrv, &rows[i], i);
		if (gc != rows[i].want) {
			fprintf(stderr, "ampfncollide[cstage][%s]: got=%d want=%d\n",
			    rows[i].label, gc, rows[i].want);
			fail++;
		}
		if (!have_ww) {
			fprintf(stderr, "ampfncollide: skip wwstage (no %s)\n", wdrv);
			continue;
		}
		int gw = run_build(wdrv, &rows[i], i);
		if (gw != gc) {
			fprintf(stderr, "ampfncollide[%s]: cs=%d != ww=%d "
			    "(&fn cross-module same-leaf misbind — #4 c2)\n",
			    rows[i].label, gc, gw);
			fail++;
		}
		if (gw != rows[i].want) {
			fprintf(stderr, "ampfncollide[wwstage][%s]: got=%d want=%d\n",
			    rows[i].label, gw, rows[i].want);
			fail++;
		}
	}

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