/*
 * 949_structlit_arrfield_run — runtime + byte-id net for #249: struct
 * array-field init/read silent miscompiles. Two distinct roots, both
 * gate-blind (cs==ww broken identically pre-fix):
 *
 *   BUG B — reading an array field of a module-GLOBAL struct value
 *   (`G.arr[i]`). The N_INDEX fallback's cg_dotbase_addr / dotbaseaddr
 *   helper (the #135 sibling) had no module-global-struct base arm:
 *   cstage emitted `LEAQ (BP)` (read the stack → 0), wwstage fell to
 *   cgexpr(N_DOT) which loaded the field VALUE as a pointer → SEGFAULT.
 *   The .data was already correct (emit_struct_lit_bytes #129 A.3); only
 *   the READ base address was wrong. Fix: a global value-struct base
 *   emits `LEAQ name(SB) (+ ADDQ field_off)`, mirroring the scalar
 *   global-field read (cgen.c:7532). const globals are def_isstructdef.
 *
 *   BUG A — initializing an array field from a struct literal
 *   (`e{ arr = [..] }`) as a local. cg_structlit_fill / cgstructlitfill
 *   had no TY_ARRAY field arm; the array field fell to the generic
 *   scalar tail (cgexpr the N_ARRLIT → AX, store one sized word) which
 *   silently DROPPED every element. Fix: a TY_ARRAY field arm element-
 *   wise stores the N_ARRLIT at base+field_off+i*esz, reusing the proven
 *   N_LET array-init shape. The GLOBAL literal-init path is unaffected
 *   (it goes through emit_struct_lit_bytes, already correct).
 *
 * cstage `ww build` + run for exit code; w6c vs w6c_ww `.s` cmp for the
 * rule-10 byte-id gate. u8 element rows only (a `[N]u8` read cast to i32
 * is byte-id; wider widths hit the i32-return MOVL/MOVSXD cs/ww
 * divergence — see 949_dotbase_arr_run's deferral note).
 */
#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_exit; };

static const struct row rows[] = {
	/* BUG B: read [4]u8 field of a module-global `let` struct at idx 0
	 * (field_off 0). Pre-fix cstage→0, wwstage→SEGFAULT. encmap[0]='A'
	 * (65). */
	{ "global_let_read",
	  "package main;\n"
	  "type e = struct { encmap: [4]u8 };\n"
	  "let g: e = e { encmap = [65u8, 66u8, 67u8, 68u8] };\n"
	  "export fn main() i32 = { return g.encmap[0]: i32; };\n", 65 },
	/* BUG B: read [4]u8 field of a module-global `def` (const) struct
	 * at idx 2, with a non-zero field offset (a [3]u8 pad ahead of it) —
	 * exercises def_isstructdef + the ADDQ $field_off arm. The base64
	 * `const std_encoding` shape. pad ahead, encmap[2]='C' (67). */
	{ "global_def_read_off",
	  "package main;\n"
	  "type e = struct { pad: [3]u8, encmap: [4]u8 };\n"
	  "def G: e = e { pad = [9u8, 9u8, 9u8],"
	  " encmap = [65u8, 66u8, 67u8, 68u8] };\n"
	  "export fn main() i32 = { return G.encmap[2]: i32; };\n", 67 },
	/* BUG A: local struct-literal init of a [4]u8 field, read idx 0.
	 * Pre-fix the array field fell to the generic scalar tail (cgexpr
	 * the N_ARRLIT → AX, store one word) and silently dropped every
	 * element → 0. encmap[0]='A' (65). */
	{ "local_lit_read0",
	  "package main;\n"
	  "type e = struct { encmap: [4]u8 };\n"
	  "export fn main() i32 = {\n"
	  "	let g: e = e { encmap = [65u8, 66u8, 67u8, 68u8] };\n"
	  "	return g.encmap[0]: i32;\n"
	  "};\n", 65 },
	/* BUG A: same init, read idx 3 — asserts the LAST element landed
	 * (the pre-fix single-word store would never reach it). 'D' (68). */
	{ "local_lit_read3",
	  "package main;\n"
	  "type e = struct { encmap: [4]u8 };\n"
	  "export fn main() i32 = {\n"
	  "	let g: e = e { encmap = [65u8, 66u8, 67u8, 68u8] };\n"
	  "	return g.encmap[3]: i32;\n"
	  "};\n", 68 },
	/* NB: a trailing `...` repeat in a struct-LITERAL array field
	 * (`encmap = [7u8...]`) is rejected by the CHECKER ("[1]u8 not
	 * assignable to [4]u8") — the field type-check doesn't apply the
	 * repeat-length inference that bare `let a: [N]T = [v...]` gets.
	 * The cg_structlit_fill array arm mirrors the N_LET `...` handling
	 * for symmetry, but that path is checker-unreachable today (separate
	 * checker gap, not #249). No row exercises it. */
	{ NULL, NULL, 0 }
};

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;
}

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 w6c[1100], w6c_ww[1100];
	snprintf(w6c, sizeof w6c, "%s/w6c", bin);
	snprintf(w6c_ww, sizeof w6c_ww, "%s/w6c_ww", bin);
	if (access(w6c_ww, X_OK) != 0) {
		fprintf(stderr, "structlit_arrfield: w6c_ww missing — cannot run "
		    "the cs==ww byte-id gate (the whole point of this test)\n");
		return 1;
	}

	int n = 0, fail = 0;
	for (int i = 0; rows[i].src; i++, n++) {
		char src[64];
		snprintf(src, sizeof src, "/tmp/wwsaf_%d_%d.ww", getpid(), i);
		FILE *f = fopen(src, "wb");
		if (f == NULL) { fail++; continue; }
		fputs(rows[i].src, f);
		fclose(f);

		char tmpdir[64];
		snprintf(tmpdir, sizeof tmpdir, "/tmp/wwsaf_%d_d_%d",
		    getpid(), i);
		mkdir(tmpdir, 0755);

		char cmd[2048];
		snprintf(cmd, sizeof cmd, "cd %s && %s/ww build %s",
		    tmpdir, bin, src);
		if (runwait(cmd) != 0) {
			fprintf(stderr, "row[%s]: cstage build failed\n",
			    rows[i].label);
			fail++;
			unlink(src); rmdir(tmpdir);
			continue;
		}

		char outbin[128];
		const char *base = strrchr(src, '/');
		base = base ? base + 1 : src;
		snprintf(outbin, sizeof outbin, "%s/%s", tmpdir, base);
		char *dot = strrchr(outbin, '.');
		if (dot && strcmp(dot, ".ww") == 0) *dot = '\0';

		int got = runwait(outbin);
		if (got != rows[i].want_exit) {
			fprintf(stderr, "row[%s]: cstage exit %d, want %d\n",
			    rows[i].label, got, rows[i].want_exit);
			fail++;
		}
		unlink(outbin); rmdir(tmpdir);

		char cs_s[64], ws_s[64];
		snprintf(cs_s, sizeof cs_s, "/tmp/wwsaf_%d_%d_cs.s",
		    getpid(), i);
		snprintf(ws_s, sizeof ws_s, "/tmp/wwsaf_%d_%d_ww.s",
		    getpid(), i);

		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", rows[i].label);
			fail++; unlink(src); continue;
		}
		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",
			    rows[i].label);
			fail++; unlink(src); unlink(cs_s); continue;
		}
		if (slurp_eq(cs_s, ws_s) != 0) {
			fprintf(stderr,
			    "row[%s]: cstage/wwstage .s DIFFER (rule-10 "
			    "byte-id violation)\n", rows[i].label);
			fail++;
		}
		unlink(src); unlink(cs_s); unlink(ws_s);
	}

	if (fail) {
		fprintf(stderr, "%d/%d structlit-arrfield tests failed\n",
		    fail, n);
		return 1;
	}
	printf("structlit_arrfield: %d/%d ok (cstage run + cs==ww byte-id)\n",
	    n, n);
	return 0;
}