/*
 * 949_xmod_fnptr_const_run — #124: a CROSS-MODULE `&module.fn` inside a
 * module-level const emits its &fn->DATAR reloc + the wwstage checker
 * accepts the const table.
 *
 * #117/#119 wired the &fn->DATAR reloc for SAME-module `&fn` only. The
 * cgen detect helper (node_fnptr_sym cgen.c / nodefnptr cgen.ww) was
 * N_IDENT-only and mangled the leaf with cur_mod — so a cross-module
 * `&cc.isa` (operand is N_DOT) returned NULL → no reloc → no DATA →
 * w6l undefined-reference, BOTH stages. fold-6's charclass_map needs
 * 12x cross-module `&ascii.isXXX` inside a const `[](str, *fn(rune)bool)`.
 *
 * The #124 fix is ONE both-stage, consumer-coupled commit:
 *   - cgen reloc (BOTH stages): node_fnptr_sym / nodefnptr grow an N_DOT
 *     arm forming mafn(leaf, MODULE-ident) — the same TEXT symbol the
 *     working runtime `&mod.fn` / direct call already emit. Shared by the
 *     scalar (#119) and tuple-row (#117) callers (one helper = SSoT).
 *   - wwstage checker (ww-only, align-UP): exprtype's TK_AMP arm now
 *     types a cross-module `&mod.fn` as `*fn(...)` (the N_DOT twin of the
 *     #206 N_IDENT synthesis, via scopelookupinmodule) — so the const
 *     table's nested cross-module &fn element typeeqs its `*fn` slot and
 *     isassignable AFFIRMATIVELY accepts (cstage types `&mod.fn` as `*fn`
 *     natively → ww aligns up to cstage's actual acceptance reason). The
 *     SK_FN gate keeps the accept narrow to genuine fn-pointers.
 *
 * POLARITY: align-BOTH — both stages were LOUD at base 754944a (cstage
 * link-fail, wwstage checker reject). byte-id is the wwstage-correctness
 * net (#263); the fn-reloc is pinned at runtime with DISTINCT fns so a
 * wrong reloc (or swapped per-row offset) is caught, not masked.
 *
 *   row             | shape                              | exit | byte-id
 *   ----------------+------------------------------------+------+--------
 *   xmod_table_scalar| const tbl:[](str,*fn) of (&cc.isa,|  0   | cs==ww
 *                   |  &cc.isz) DISTINCT + scalar &cc.isa|      |
 *                   |  — index tbl[i].1, call each back  |      |
 *   wrong_sig_table | const t:[](str,*fn(i32)i32) =      | LOUD | (n/a)
 *                   |  [(..,&cc.isa)] — sig mismatch must |      |
 *                   |  reject BOTH (pins the *fn typeeq   |      |
 *                   |  is real, not accept-everything)    |      |
 *   nonfn_dotted_   | const t:[](str,*fn) =[(..,&cc.kval)| LOUD | (n/a)
 *    table          |  )] — &<xmod NON-fn> must reject    |      |
 *                   |  BOTH (pins the SK_FN/N_FNDECL gate |      |
 *                   |  — the #117 over-accept hazard)     |      |
 *
 * Cross-module via OWN 2-module fixtures in a PRIVATE mktemp dir (784
 * model) — NOT the real lib/ascii: the driver writes intermediates next
 * to traversed sources, so importing lib/ would race; a synthetic module
 * `cc` exercises the IDENTICAL `&mod.fn` mangle (mafn(leaf, module)).
 * NNN<950 so test-unit runs it; the private mktemp dir makes the ww_ww
 * driver race-free (946 ww_ww-driver precedent).
 */
#include <stdio.h>
#include <stdlib.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;
}

static int
slurp_eq(const char *a, const char *b)
{
	FILE *fa = fopen(a, "rb");
	FILE *fb = fopen(b, "rb");
	if (!fa || !fb) { if (fa) fclose(fa); if (fb) fclose(fb); return -1; }
	int rc = 0;
	for (;;) {
		int ca = fgetc(fa);
		int cb = fgetc(fb);
		if (ca != cb) { rc = -1; break; }
		if (ca == EOF) break;
	}
	fclose(fa); fclose(fb);
	return rc;
}

#define K_RUN      0	/* build+run BOTH drivers, exit==want, + cs==ww byte-id */
#define K_BUILDERR 1	/* build must FAIL on BOTH drivers (rule 7 loud) */

struct file { const char *name; const char *src; };

struct scenario {
	const char *label;
	const struct file *files;	/* name==NULL terminates */
	int kind;
	int want_exit;
};

/* The fold-6 consumer shape: a const cross-module `[](str,*fn(rune)bool)`
 * + a scalar `*fn` global, both initialised with `&cc.<pred>`. DISTINCT
 * predicates per row so a wrong reloc routes the wrong fn and a call-back
 * catches it. The tuple's *fn is element .1 (the consumer ordering). */
static const struct file table_files[] = {
	{ "cc.ww",
	  "package cc;\n"
	  "export fn isa(c: rune) bool = { return c == 'a'; };\n"
	  "export fn isz(c: rune) bool = { return c == 'z'; };\n" },
	{ "main.ww",
	  "package main;\n"
	  "import cc;\n"
	  "const tbl: [](str, *fn(c: rune) bool) ="
	  " [(\":a\", &cc.isa), (\":z\", &cc.isz)];\n"
	  "const pf: *fn(c: rune) bool = &cc.isa;\n"
	  "export fn main() i32 = {\n"
	  "	if (len(tbl) != 2) { return 10; };\n"
	  "	let e0 = tbl[0];\n"
	  "	let e1 = tbl[1];\n"
	  "	let f0 = e0.1;\n"
	  "	let f1 = e1.1;\n"
	  "	if (!(*f0)('a')) { return 1; };\n"
	  "	if ((*f0)('z')) { return 2; };\n"
	  "	if (!(*f1)('z')) { return 3; };\n"
	  "	if ((*f1)('a')) { return 4; };\n"
	  "	if (!(*pf)('a')) { return 5; };\n"
	  "	if ((*pf)('z')) { return 6; };\n"
	  "	return 0;\n"
	  "};\n" },
	{ NULL, NULL }
};

/* The SK_FN-gated bound: a cross-module &fn whose SIGNATURE doesn't match
 * the declared `*fn` slot must still reject on BOTH stages (the *fn typeeq
 * is real — the lever is affirmative recognition, not accept-everything). */
static const struct file wrong_sig_files[] = {
	{ "cc.ww",
	  "package cc;\n"
	  "export fn isa(c: rune) bool = { return c == 'a'; };\n" },
	{ "main.ww",
	  "package main;\n"
	  "import cc;\n"
	  "const t: [](str, *fn(x: i32) i32) = [(\":a\", &cc.isa)];\n"
	  "export fn main() i32 = { return len(t): i32; };\n" },
	{ NULL, NULL }
};

/* The SK_FN/N_FNDECL-gated bound (distinct axis from wrong_sig_files):
 * a cross-module dotted address-of a NON-fn export (`&cc.kval`, kval an
 * exported var) must NOT synthesize a `*fn` and must reject the table on
 * BOTH stages. This locks the lever's narrowness — the over-accept hazard
 * reviewer-117 caught — so a future widening of the exprtype N_DOT arm
 * past genuine fn-pointers is a loud test failure, not a silent accept. */
static const struct file nonfn_dotted_files[] = {
	{ "cc.ww",
	  "package cc;\n"
	  "export let kval: int = 7;\n" },
	{ "main.ww",
	  "package main;\n"
	  "import cc;\n"
	  "const t: [](str, *fn(c: rune) bool) = [(\":k\", &cc.kval)];\n"
	  "export fn main() i32 = { return len(t): i32; };\n" },
	{ NULL, NULL }
};

static const struct scenario scenarios[] = {
	{ "xmod_table_scalar", table_files,       K_RUN,      0 },
	{ "wrong_sig_table",   wrong_sig_files,   K_BUILDERR, 0 },
	{ "nonfn_dotted_table", nonfn_dotted_files, K_BUILDERR, 0 },
};

/* Build `driver build --sep -o <dir>/<stem>` in the fixture dir; returns
 * the driver's build rc and (for K_RUN) runs the produced binary, comparing
 * exit to want_exit. #94: the per-package asm lands in <dir>/<stem>.sepwork/
 * (cachetag keys a private WW_PKGCACHE so out/.pkgcache is untouched). */
static int
build_run(const char *dir, const char *driver, const struct scenario *sc,
    const char *stem, const char *cachetag)
{
	char cmd[4096], path[1024];
	snprintf(cmd, sizeof cmd,
	    "cd %s && WW_PKGCACHE=%s/pkgc_%s %s build --sep -I %s -o %s/%s "
	    "%s/main.ww >/dev/null 2>%s/err",
	    dir, dir, cachetag, driver, dir, dir, stem, dir, dir);
	int brc = runwait(cmd);
	if (sc->kind == K_BUILDERR) {
		if (brc == 0) {
			fprintf(stderr, "949[%s]: %s built but expected LOUD "
			    "reject\n", sc->label, driver);
			return -1;
		}
		return 0;
	}
	if (brc != 0) {
		fprintf(stderr, "949[%s]: %s build failed\n", sc->label, driver);
		return -1;
	}
	snprintf(path, sizeof path, "%s/%s", dir, stem);
	int got = runwait(path);
	if (got != sc->want_exit) {
		fprintf(stderr, "949[%s]: %s exit %d, want %d\n",
		    sc->label, driver, got, sc->want_exit);
		return -1;
	}
	return 0;
}

static int
run_scenario(const char *bin, const struct scenario *sc)
{
	char dir[] = "/tmp/ww949_XXXXXX";
	if (mkdtemp(dir) == NULL) {
		fprintf(stderr, "949[%s]: mkdtemp failed\n", sc->label);
		return -1;
	}

	char path[1024], cmd[4096], csdrv[2200], wwdrv[2200];
	int rc = 0;

	for (int i = 0; sc->files[i].name; i++) {
		snprintf(path, sizeof path, "%s/%s", dir, sc->files[i].name);
		FILE *f = fopen(path, "wb");
		if (!f) { fprintf(stderr, "949[%s]: write %s\n", sc->label,
		    sc->files[i].name); rc = -1; goto done; }
		fputs(sc->files[i].src, f);
		fclose(f);
	}

	/* cstage driver --sep build (+run for K_RUN) → <dir>/main_c.sepwork/. */
	snprintf(csdrv, sizeof csdrv, "%s/ww", bin);
	if (build_run(dir, csdrv, sc, "main_c", "c") != 0) { rc = -1; goto done; }

	/* wwstage driver --sep build (+run for K_RUN) — race-free in the
	 * private mktemp dir. Direct proof the wwstage emits a runnable
	 * binary. Distinct stem so its sepwork doesn't clobber cstage's. */
	snprintf(wwdrv, sizeof wwdrv, "%s/ww_ww", bin);
	if (build_run(dir, wwdrv, sc, "main_w", "w") != 0) { rc = -1; goto done; }

	if (sc->kind == K_BUILDERR) goto done;

	/* Byte-id net (#263 — the wwstage-correctness proof on a gate-blind
	 * align-BOTH fix): the per-package w6c-emitted .s (cstage sep build)
	 * vs w6c_ww-emitted .s (wwstage sep build) must be byte-identical.
	 * Concat each stem's per-package sepwork asm (sorted glob = same set). */
	{
		char cs_s[1024], ws_s[1024];
		snprintf(cs_s, sizeof cs_s, "%s/all_cs.s", dir);
		snprintf(ws_s, sizeof ws_s, "%s/all_ww.s", dir);
		snprintf(cmd, sizeof cmd, "cat %s/main_c.sepwork/*.s > %s 2>/dev/null",
		    dir, cs_s); if (system(cmd)) {}
		snprintf(cmd, sizeof cmd, "cat %s/main_w.sepwork/*.s > %s 2>/dev/null",
		    dir, ws_s); if (system(cmd)) {}
		if (slurp_eq(cs_s, ws_s) != 0) {
			fprintf(stderr, "949[%s]: cs.s/ww.s DIFFER (rule-10 "
			    "byte-id violation)\n", sc->label);
			rc = -1;
		}
	}

done:
	snprintf(cmd, sizeof cmd, "rm -rf %s", dir);
	(void)runwait(cmd);
	return rc;
}

int
main(void)
{
	const char *bin = getenv("BIN");
	if (!bin) bin = "out/bin";
	char absbin[2048];
	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 wdrv[2100];
	snprintf(wdrv, sizeof wdrv, "%s/ww_ww", bin);
	if (access(wdrv, X_OK) != 0) {
		fprintf(stderr, "949: ww_ww missing — cannot run the cs==ww "
		    "byte-id gate (the whole point of this test)\n");
		return 1;
	}

	int n = (int)(sizeof scenarios / sizeof scenarios[0]);
	int fail = 0;
	for (int i = 0; i < n; i++) {
		if (run_scenario(bin, &scenarios[i]) != 0)
			fail++;
	}

	if (fail) {
		fprintf(stderr, "949 xmod_fnptr_const: %d/%d scenarios failed\n",
		    fail, n);
		return 1;
	}
	printf("xmod_fnptr_const: %d/%d ok (cs+ww run + cs==ww byte-id)\n",
	    n, n);
	return 0;
}