/*
 * 903_tuple_elem_slice_len_run — project #235: `len(t.N)` where t is a tuple
 * and t.N is a slice/str-typed element.
 *
 * The len() builtin special-cased only a PLAIN N_IDENT slice operand (load
 * .len at BP+off+8) and an array operand (fold $alen); every other shape fell
 * back to a bare `cgexpr(operand)`, which for a slice leaves AX=.ptr. The
 * tuple-element read (`t.N`) loads only AX=.ptr (it has no slice-header
 * sibling — that gap is the separate #238), so `len(t.N)` returned the slice's
 * .ptr word AS the length — a SILENT miscompile, gate-blind because the
 * bootstrap never does len() on a slice-typed tuple element.
 *
 * Fix (both stages, byte-identical per rule 10): for a slice/str tuple-element
 * len() operand, load the element's .len word directly at
 * BP + tuple_off + element_off + 8 — mirroring the N_IDENT slice arm and the
 * tuple-field-offset walk. The +8 is the {ptr,len,cap}-header .len offset, the
 * same constant the N_IDENT arm and the .len pseudo-field use; element_off sums
 * preceding element sizes through the type table.
 *
 * Rows (every element a DISTINCT length so a dropped/wrong field is caught;
 * each ww program self-asserts and returns 0 only when every len(t.N) is
 * correct). Tuples are slice/str-ONLY — a leading scalar element exercises a
 * SEPARATE pre-existing mixed-tuple sret-layout cs/ww divergence (filed apart
 * from #235), out of scope here.
 *   two_slice    ([]u8,[]u8)         lens 3,5
 *   three_slice  ([]u8,[]u8,[]u8)    lens 3,5,11
 *   str_slice    (str,[]u8)          len("abcd")=4, slice 6
 *   slice_str    ([]u8,str)          slice 7, len("hi")=2
 *
 * All K_RUN: build+run exit 0 on BOTH drivers AND cs==ww byte-identical.
 * NNN<950, self-contained (/tmp, no imports), so rule-14's selfhost-sibling
 * race does not apply (940/945/799 precedent).
 */
#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;
}

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), cb = fgetc(fb);
		if (ca != cb) { rc = -1; break; }
		if (ca == EOF) break;
	}
	fclose(fa); fclose(fb);
	return rc;
}

struct row { const char *label; const char *src; int want; };

static const struct row rows[] = {
	{ "two_slice",
	  "package main;\n"
	  "fn mk() ([]u8, []u8) = {\n"
	  "	let a: []u8; a.len = 3; a.cap = 7;\n"
	  "	let b: []u8; b.len = 5; b.cap = 9;\n"
	  "	return (a, b);\n"
	  "};\n"
	  "export fn main() i32 = {\n"
	  "	let t: ([]u8, []u8) = mk();\n"
	  "	if (len(t.0) != 3) { return 1; };\n"
	  "	if (len(t.1) != 5) { return 2; };\n"
	  "	return 0;\n"
	  "};\n", 0 },
	{ "three_slice",
	  "package main;\n"
	  "fn mk() ([]u8, []u8, []u8) = {\n"
	  "	let a: []u8; a.len = 3; a.cap = 7;\n"
	  "	let b: []u8; b.len = 5; b.cap = 9;\n"
	  "	let c: []u8; c.len = 11; c.cap = 13;\n"
	  "	return (a, b, c);\n"
	  "};\n"
	  "export fn main() i32 = {\n"
	  "	let t: ([]u8, []u8, []u8) = mk();\n"
	  "	if (len(t.0) != 3) { return 1; };\n"
	  "	if (len(t.1) != 5) { return 2; };\n"
	  "	if (len(t.2) != 11) { return 3; };\n"
	  "	return 0;\n"
	  "};\n", 0 },
	{ "str_slice",
	  "package main;\n"
	  "fn mk() (str, []u8) = {\n"
	  "	let s: str = \"abcd\";\n"
	  "	let b: []u8; b.len = 6; b.cap = 8;\n"
	  "	return (s, b);\n"
	  "};\n"
	  "export fn main() i32 = {\n"
	  "	let t: (str, []u8) = mk();\n"
	  "	if (len(t.0) != 4) { return 1; };\n"
	  "	if (len(t.1) != 6) { return 2; };\n"
	  "	return 0;\n"
	  "};\n", 0 },
	{ "slice_str",
	  "package main;\n"
	  "fn mk() ([]u8, str) = {\n"
	  "	let b: []u8; b.len = 7; b.cap = 9;\n"
	  "	let s: str = \"hi\";\n"
	  "	return (b, s);\n"
	  "};\n"
	  "export fn main() i32 = {\n"
	  "	let t: ([]u8, str) = mk();\n"
	  "	if (len(t.0) != 7) { return 1; };\n"
	  "	if (len(t.1) != 2) { return 2; };\n"
	  "	return 0;\n"
	  "};\n", 0 },
};

/* build+run via a driver (ww / ww_ww); returns 0 pass, nonzero fail. */
static int
run_driver(const char *driver, const struct row *r, int i)
{
	char src[96], tmpdir[96], errf[96], cmd[1024];
	snprintf(src, sizeof src, "/tmp/telen_%d_%d.ww", getpid(), i);
	snprintf(tmpdir, sizeof tmpdir, "/tmp/telen_%d_d_%d", getpid(), i);
	snprintf(errf, sizeof errf, "/tmp/telen_%d_e_%d", getpid(), i);

	FILE *f = fopen(src, "wb");
	if (!f) return -1;
	fputs(r->src, f);
	fclose(f);

	mkdir(tmpdir, 0755);
	snprintf(cmd, sizeof cmd, "cd %s && %s build %s >/dev/null 2>%s",
	    tmpdir, driver, src, errf);
	int brc = runwait(cmd);
	if (brc != 0) {
		fprintf(stderr, "row[%s]: build via %s failed\n",
		    r->label, driver);
		unlink(src); unlink(errf); rmdir(tmpdir);
		return -1;
	}

	const char *base = strrchr(src, '/');
	base = base ? base + 1 : src;
	char outbin[256];
	snprintf(outbin, sizeof outbin, "%s/%s", tmpdir, base);
	char *dot = strrchr(outbin, '.');
	if (dot && strcmp(dot, ".ww") == 0) *dot = '\0';
	int got = runwait(outbin);

	unlink(src); unlink(outbin); unlink(errf); rmdir(tmpdir);
	if (got != r->want) {
		fprintf(stderr, "row[%s]: %s exit %d, want %d\n",
		    r->label, driver, got, r->want);
		return 1;
	}
	return 0;
}

/* cs==ww .s byte-id (rule 10). */
static int
byteid(const char *w6c, const char *w6c_ww, const struct row *r, int i)
{
	char src[96], cs_s[96], ws_s[96], cmd[1024];
	snprintf(src, sizeof src, "/tmp/telen_bi_%d_%d.ww", getpid(), i);
	snprintf(cs_s, sizeof cs_s, "/tmp/telen_bi_%d_%d_cs.s", getpid(), i);
	snprintf(ws_s, sizeof ws_s, "/tmp/telen_bi_%d_%d_ww.s", getpid(), i);

	FILE *f = fopen(src, "wb");
	if (!f) return -1;
	fputs(r->src, f);
	fclose(f);

	int rc = 0;
	snprintf(cmd, sizeof cmd, "%s -o %s %s 2>/dev/null", w6c, cs_s, src);
	if (runwait(cmd) != 0) { fprintf(stderr, "row[%s]: w6c failed\n", r->label); rc = 1; }
	else {
		snprintf(cmd, sizeof cmd, "%s -o %s %s 2>/dev/null", w6c_ww, ws_s, src);
		if (runwait(cmd) != 0) { fprintf(stderr, "row[%s]: w6c_ww failed\n", r->label); rc = 1; }
		else if (slurp_eq(cs_s, ws_s) != 0) {
			fprintf(stderr, "row[%s]: cstage/wwstage .s DIFFER "
			    "(rule-10 byte-id)\n", r->label);
			rc = 1;
		}
	}
	unlink(src); unlink(cs_s); unlink(ws_s);
	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], w6c[640], w6c_ww[640];
	snprintf(cdrv, sizeof cdrv, "%s/ww", bin);
	snprintf(wdrv, sizeof wdrv, "%s/ww_ww", bin);
	snprintf(w6c, sizeof w6c, "%s/w6c", bin);
	snprintf(w6c_ww, sizeof w6c_ww, "%s/w6c_ww", bin);

	struct { const char *name; const char *path; 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].path, X_OK) != 0) {
			fprintf(stderr, "tuple_elem_slice_len: skip %s (no %s)\n",
			    drivers[d].name, drivers[d].path);
			continue;
		}
		for (int i = 0; i < n; i++) {
			total++;
			if (run_driver(drivers[d].path, &rows[i], i) != 0) fail++;
		}
	}

	if (access(w6c_ww, X_OK) == 0) {
		for (int i = 0; i < n; i++) {
			total++;
			if (byteid(w6c, w6c_ww, &rows[i], i) != 0) fail++;
		}
	}

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