/*
 * 771_widen_transitive — project #199 (α): cstage type_assignable +
 * wwstage isassignable must REJECT transitive nested-tagged widen.
 * Cgen has no wrapped-slot layout (#199b deferred future-work); the
 * pre-α recursive `type_assignable(p->type, src)` walk admitted
 * `let r: (size|io.eof|io.error) = u` for u: io.underread, then cgen
 * silently miscompiled (cg_tag_for_variant returned -1 → tag=0 → r
 * reads as variant 0 = size at runtime).
 *
 * Fix (cmd/wcc/type.c:308 + selfhost/cmd/wcc/check.ww:3063): the
 * tagged-non-tagged arm now matches direct variants ONLY. NAMED-tagged
 * wrapper variants (vu.kind == TY_TAGGED) compare nominally (type_eq /
 * typeeqast); other variants keep the leaf recursion for primitive
 * compat / untyped resolution. wwstage additionally preserves the
 * spread-recursion path: `...wrapper` variants (op == TK_ELLIPSIS) drill
 * through because the AST list hasn't pre-flattened (cstage flattens at
 * resolve_type, wwstage stays AST-keyed).
 *
 * Restores SSoT inside the checker pair: `is` / `as` / `match` arm
 * lookup is already non-recursive (#198 sibling), and the LET-init /
 * return / assign arms now agree. Aligns DOWN to the leaner side
 * (rule-10 stage symmetry). ww-stricter than Hare; harec keeps the
 * drill at ref/harec/src/types.c:702-739 (#199b — wrapped-slot layout
 * port deferred per drew).
 *
 * Coverage (5 rows):
 *   1. reject_transitive_widen — `let r: (size|wrapper) = u` with
 *      u: underread, wrapper = !(underread | nomem). BOTH stages
 *      MUST reject at the checker. The repro.
 *   2. spread_alt_widen        — `let r: (size|...wrapper) = u;`. The
 *      `...` spread inlines wrapper's variants into the parent flat
 *      set, so underread becomes a DIRECT variant; widen succeeds.
 *      CS-only runtime: wwstage's `is`/`match` cross-spread variant
 *      lookup is open-bug #190/#198 (wwstage walks original AST list,
 *      doesn't see expanded variants); byte-id still gates the asm.
 *   3. direct_flat_variant     — `let r: (size|underread|nomem) = u`
 *      with the underlying variants flat in the parent (no wrapper).
 *      Regression gate: direct widen unchanged by the fix.
 *   4. branched_callee_widen   — fn returns (size|underread|nomem),
 *      runtime picks between two flat-variant returns. Verifies the
 *      cg_widen_tagged_store scalar branch's tag synthesis is
 *      unchanged for direct widens.
 *   5. wrapper_typed_widen     — `let r: wrapper = u` with u:
 *      underread (DIRECT variant of wrapper). Regression gate: the
 *      single-level wrapper widen is the supported escape hatch and
 *      MUST continue working.
 *
 * Per-row gates: cstage compile + runtime, wwstage compile + runtime,
 * cs.s == ww.s byte-identical (rule-10). Row 1 uses
 * expected_exit = -2 to indicate "build must fail" — the driver
 * invocation is expected to return non-zero from the checker.
 */
#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;
}

#define STAGE_CS	1
#define STAGE_WW	2

#define EXPECT_REJECT	(-2)

struct row {
	const char *label;
	const char *src;
	int expected_exit;	/* EXPECT_REJECT means build must fail */
	int stage_mask;
	int byte_id;		/* run cs.s == ww.s diff (works rows only) */
};

static const struct row rows[] = {
	{ "reject_transitive_widen",
	  "package main;\n"
	  "type underread = !i32;\n"
	  "type nomem = !void;\n"
	  "type wrapper = !(underread | nomem);\n"
	  "export fn main() i32 = {\n"
	  "    let u: underread;\n"
	  "    let r: (size | wrapper) = u;\n"
	  "    return 0;\n"
	  "};\n",
	  EXPECT_REJECT,
	  STAGE_CS | STAGE_WW, 0 },
	{ "spread_alt_widen",
	  "package main;\n"
	  "type underread = !i32;\n"
	  "type nomem = !void;\n"
	  "type wrapper = !(underread | nomem);\n"
	  "export fn main() i32 = {\n"
	  "    let u: underread;\n"
	  "    let r: (size | ...wrapper) = u;\n"
	  "    if (r is underread) { return 70; };\n"
	  "    return 99;\n"
	  "};\n",
	  70,
	  STAGE_CS, 0 },
	{ "direct_flat_variant",
	  "package main;\n"
	  "type underread = !i32;\n"
	  "type nomem = !void;\n"
	  "export fn main() i32 = {\n"
	  "    let u: underread;\n"
	  "    let r: (size | underread | nomem) = u;\n"
	  "    if (r is underread) { return 71; };\n"
	  "    return 99;\n"
	  "};\n",
	  71,
	  STAGE_CS | STAGE_WW, 1 },
	{ "branched_callee_widen",
	  "package main;\n"
	  "type underread = !i32;\n"
	  "type nomem = !void;\n"
	  "fn pick(b: bool) (size | underread | nomem) = {\n"
	  "    if (b) { let u: underread; return u; };\n"
	  "    return 42: size;\n"
	  "};\n"
	  "export fn main() i32 = {\n"
	  "    let r: (size | underread | nomem) = pick(true);\n"
	  "    if (r is underread) { return 72; };\n"
	  "    return 99;\n"
	  "};\n",
	  72,
	  STAGE_CS | STAGE_WW, 1 },
	{ "wrapper_typed_widen",
	  "package main;\n"
	  "type underread = !i32;\n"
	  "type nomem = !void;\n"
	  "type wrapper = !(underread | nomem);\n"
	  "export fn main() i32 = {\n"
	  "    let u: underread;\n"
	  "    let r: wrapper = u;\n"
	  "    if (r is underread) { return 73; };\n"
	  "    return 99;\n"
	  "};\n",
	  73,
	  STAGE_CS | STAGE_WW, 1 },
};

static int
write_source(const char *path, const char *src)
{
	FILE *f = fopen(path, "wb");
	if (!f) return -1;
	fputs(src, f);
	fclose(f);
	return 0;
}

static void
cleanup_tmp(const char *tmpdir, const char *base)
{
	char p[512];
	snprintf(p, sizeof p, "%s/%s.ww", tmpdir, base); unlink(p);
	snprintf(p, sizeof p, "%s/%s.o",  tmpdir, base); unlink(p);
	snprintf(p, sizeof p, "%s/%s.combined.ww", tmpdir, base); unlink(p);
	snprintf(p, sizeof p, "%s/%s",    tmpdir, base); unlink(p);
	/* #93: the sep scratch dir + the tmpdir-pinned pkgcache. */
	snprintf(p, sizeof p, "rm -rf %s/%s.sepwork %s/pkgc", tmpdir, base, tmpdir);
	if (system(p)) {} /* best-effort */
	rmdir(tmpdir);
}

static int
build_via_driver(const char *driver, const char *tmpdir, const char *src)
{
	char cmd[1024];
	/* #93 sep layout: emit asm to <src-stem>.sepwork/__root.s; pin
	 * WW_PKGCACHE under tmpdir so out/.pkgcache is untouched. */
	snprintf(cmd, sizeof cmd,
	    "cd %s && b='%s'; WW_PKGCACHE=%s/pkgc timeout 180 %s build --sep "
	    "-o \"${b%%.ww}\" \"$b\" 2>/dev/null",
	    tmpdir, src, tmpdir, driver);
	return runwait(cmd);
}

static int
run_row(const char *driver, const struct row *r, int seq)
{
	char tmpdir[256], src[512], base[64], outbin[768];
	snprintf(tmpdir, sizeof tmpdir, "/tmp/wt_%d_d_%d", getpid(), seq);
	snprintf(src,    sizeof src,    "%s/main771.ww", tmpdir);
	snprintf(base,   sizeof base,   "main771");
	mkdir(tmpdir, 0755);
	if (write_source(src, r->src) != 0) {
		cleanup_tmp(tmpdir, base);
		return -1;
	}
	int rc;
	int br = build_via_driver(driver, tmpdir, src);
	if (r->expected_exit == EXPECT_REJECT) {
		/* Build must fail with a non-zero exit (checker error). */
		rc = (br != 0) ? r->expected_exit : 0;
	} else if (br == 0) {
		snprintf(outbin, sizeof outbin, "%s/%s", tmpdir, base);
		rc = runwait(outbin);
	} else {
		rc = -1;
	}
	cleanup_tmp(tmpdir, base);
	return rc;
}

/* asm_byte_identical — diff cstage vs wwstage .s. Parallel trees so
 * ww_ww writing intermediates next to the source doesn't clobber the
 * cstage .s (CLAUDE.md rule 14 phase split). */
static int
asm_byte_identical(const char *cdrv, const char *wdrv,
    const struct row *r, int seq)
{
	char src[512], tdc[256], tdw[256], base[64], cs[512], ws[512];
	snprintf(tdc, sizeof tdc, "/tmp/wt_%d_c_%d", getpid(), seq);
	snprintf(tdw, sizeof tdw, "/tmp/wt_%d_w_%d", getpid(), seq);
	snprintf(base, sizeof base, "main771");
	mkdir(tdc, 0755);
	mkdir(tdw, 0755);
	snprintf(src, sizeof src, "%s/main771.ww", tdc);
	if (write_source(src, r->src) != 0) { cleanup_tmp(tdc, base); cleanup_tmp(tdw, base); return -1; }
	int rc = -1;
	if (build_via_driver(cdrv, tdc, src) != 0) goto out;
	snprintf(cs, sizeof cs, "%s/%s.sepwork/__root.s", tdc, base);

	snprintf(src, sizeof src, "%s/main771.ww", tdw);
	if (write_source(src, r->src) != 0) goto out;
	if (build_via_driver(wdrv, tdw, src) != 0) goto out;
	snprintf(ws, sizeof ws, "%s/%s.sepwork/__root.s", tdw, base);

	FILE *fc = fopen(cs, "rb");
	FILE *fw = fopen(ws, "rb");
	if (fc && fw) {
		rc = 0;
		for (;;) {
			int a = fgetc(fc);
			int b = fgetc(fw);
			if (a != b) { rc = -1; break; }
			if (a == EOF) break;
		}
	}
	if (fc) fclose(fc);
	if (fw) fclose(fw);
out:
	cleanup_tmp(tdc, base);
	cleanup_tmp(tdw, base);
	return rc;
}

int
main(void)
{
	const char *bin = getenv("BIN");
	if (!bin) bin = "out/bin";
	char absbin[512];
	if (bin[0] != '/') {
		char cwd[256];
		if (getcwd(cwd, sizeof cwd) == NULL) return 1;
		snprintf(absbin, sizeof absbin, "%s/%s", cwd, bin);
		bin = absbin;
	}

	char cdrv[640], wdrv[640];
	snprintf(cdrv, sizeof cdrv, "%s/ww",    bin);
	snprintf(wdrv, sizeof wdrv, "%s/ww_ww", bin);

	int n = (int)(sizeof rows / sizeof rows[0]);
	int total = 0, fail = 0;
	int wwpresent = (access(wdrv, X_OK) == 0);
	int seq = 0;

	for (int i = 0; i < n; i++) {
		if (rows[i].stage_mask & STAGE_CS) {
			total++;
			int got = run_row(cdrv, &rows[i], seq++);
			if (got != rows[i].expected_exit) {
				fprintf(stderr,
				    "widen_transitive[cstage run][%s]: exit=%d want=%d\n",
				    rows[i].label, got, rows[i].expected_exit);
				fail++;
			}
		}
		if (wwpresent && (rows[i].stage_mask & STAGE_WW)) {
			total++;
			int got = run_row(wdrv, &rows[i], seq++);
			if (got != rows[i].expected_exit) {
				fprintf(stderr,
				    "widen_transitive[wwstage run][%s]: exit=%d want=%d\n",
				    rows[i].label, got, rows[i].expected_exit);
				fail++;
			}
			if (rows[i].byte_id) {
				total++;
				if (asm_byte_identical(cdrv, wdrv, &rows[i], seq++) != 0) {
					fprintf(stderr,
					    "widen_transitive[byte-id][%s]: cstage vs wwstage asm differs\n",
					    rows[i].label);
					fail++;
				}
			}
		}
	}

	if (!wwpresent)
		fprintf(stderr, "widen_transitive: skip wwstage (no %s)\n", wdrv);

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