/*
 * 747_def_modqual_modshadow — sentinel for task #11: cstage Sdef walk #2
 * (cmd/w6c/cgen.c N_DOT mod-qualified bare-value load) + wwstage
 * deflookuprhsmod (selfhost/cmd/wcc/cgenexpr.ww cgdot N_DOT branch).
 * Pins `alpha.MSG` from a third module gamma to resolve via n->lhs->str
 * (= "alpha") rather than head-pick of c.defs / sdefs so the inlined
 * strlit address + length come from alpha's MSG even when beta declares
 * a same-leaf MSG sitting at the head of the table.
 *
 * Pre-fix cstage walk #2 had no prefer-pass at all — head-pick of sdefs
 * regardless of the explicit qualifier. Pre-fix wwstage called the bare-
 * leaf deflookuprhs (#4c) which prefers c.curmod and falls back to head
 * on mismatch — for a 3rd-module qualifier `alpha.MSG` from gamma the
 * curmod hint matches nothing and the head-pick lands on beta.MSG.
 * Sister of #4c's deflookuprhs / Sdef walk #3 graduation: the *mod
 * variant pattern that #4a (enumlookupmod), #28 (fnparamslookupmod) and
 * #31 (fnretlookupmod) established for N_DOT qualifier disambiguation
 * — the dotted LHS module name is the right hint source, not c.curmod.
 *
 * Cstage walk #2 grows the sdef_mod_match_hint helper (sister of the
 * existing sdef_mod_match which keys c->cur_mod) and routes the walk
 * through it with n->lhs->str. Wwstage grows deflookuprhsmod(c, name,
 * mod) (sister of deflookuprhs) and cgdot routes the mod-qualified
 * branch through it with lhs.str. Both stages converge on the same
 * polarity → byte-id holds on the 3rd-module qualifier shape.
 *
 * Was blocked solely on #12 (wwstage str-def value-load shape); #12
 * landed in d985622 so the sentinel-flip byte-id check now passes.
 *
 * Pin: row 1 sentinel-flips both stages' new prefer-pass — revert and
 * row 1 fails on both (LEAQ of beta.MSG's strlit label instead of
 * alpha.MSG's, and MOVQ $27 instead of $38). Asserts the matching
 * `MOVQ $38,` immediate inside gamma.gfn TEXT + bad_imm `MOVQ $27,`
 * anti-check on each stage plus cs-vs-ws byte-id per row.
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.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;
	const char *textsym;	/* TEXT sym containing the load */
	const char *want_imm;	/* the immediate that MUST appear */
	const char *bad_imm;	/* the immediate that MUST NOT appear */
};

/* Source orderings: alpha declared before beta so beta.MSG sits at the
 * HEAD of c.defs / sdefs after the prepend-walk of collectdefs /
 * sdef_collect. Caller lives in a third module gamma (not alpha, not
 * beta) so c.curmod / c->cur_mod doesn't accidentally match either
 * source module — only the lhs.str / n->lhs->str hint resolves to
 * alpha. Strlit lengths 39 vs 27 chosen so neither digit-string is a
 * substring of the other and neither aliases a common frame/offset
 * immediate the asm emits (0/8/16/24/32/40/48 etc).
 *
 * The TY_FN branch above walk #2 in cstage already uses n->lhs->str via
 * mafn — this row pins the parallel polarity on the Sdef walk just
 * below it. */
static const struct row rows[] = {
	{ "third_module_qualifier_shadow",
	  "package gamma;\n"
	  "import alpha;\n"
	  "import beta;\n"
	  "export fn main() i32 = { return 0; };\n"
	  "export fn gfn() str = { return alpha.MSG; };\n"
	  "package alpha;\n"
	  "export def MSG: str = \"alpha_modqual_pin_38chr_aaaaaaaaaaaaaa\";\n"
	  "package beta;\n"
	  "export def MSG: str = \"beta_modqual_pin_27chr_BBBB\";\n",
	  "TEXT gamma.gfn", "$38,", "$27," },
};

static int
slurp(const char *path, char *buf, size_t cap)
{
	FILE *f = fopen(path, "rb");
	if (!f) return -1;
	size_t n = fread(buf, 1, cap - 1, f);
	fclose(f);
	buf[n] = '\0';
	return (int)n;
}

static int
emit_s(const char *w6c, const struct row *r, int i, char *out_s, size_t cap)
{
	char src[64], cmd[1024];
	snprintf(src, sizeof src, "/tmp/dmq_%d_%d.ww", getpid(), i);
	snprintf(out_s, cap, "/tmp/dmq_%d_%d_%s.s",
	    getpid(), i, w6c[strlen(w6c) - 1] == 'w' ? "ww" : "c");

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

	snprintf(cmd, sizeof cmd, "%s -o %s %s 2>/dev/null", w6c, out_s, src);
	int rc = runwait(cmd);
	unlink(src);
	return rc;
}

/* Inside the named TEXT sym, before its first RET, want_imm MUST appear
 * and bad_imm MUST NOT. bad_imm flags pre-fix head-walk picking
 * beta.MSG's strlit length (27) instead of alpha.MSG's (39). */
static int
check_imm(const char *spath, const struct row *r, const char *stage)
{
	char buf[1 << 14];
	if (slurp(spath, buf, sizeof buf) < 0) {
		fprintf(stderr, "row[%s][%s]: cannot read %s\n",
		    r->label, stage, spath);
		return -1;
	}
	const char *fn = strstr(buf, r->textsym);
	if (!fn) {
		fprintf(stderr, "row[%s][%s]: no %s in %s\n",
		    r->label, stage, r->textsym, spath);
		return -1;
	}
	const char *ret = strstr(fn, "\tRET");
	if (!ret) {
		fprintf(stderr, "row[%s][%s]: no RET inside %s\n",
		    r->label, stage, r->textsym);
		return -1;
	}
	const char *good = strstr(fn, r->want_imm);
	if (!good || good >= ret) {
		fprintf(stderr,
		    "row[%s][%s]: want_imm %s missing inside %s\n",
		    r->label, stage, r->want_imm, r->textsym);
		return -1;
	}
	const char *bad = strstr(fn, r->bad_imm);
	if (bad && bad < ret) {
		fprintf(stderr,
		    "row[%s][%s]: bad_imm %s present inside %s — wrong-module MSG\n",
		    r->label, stage, r->bad_imm, r->textsym);
		return -1;
	}
	return 0;
}

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 w6c[640], w6c_ww[640];
	snprintf(w6c, sizeof w6c, "%s/w6c", bin);
	snprintf(w6c_ww, sizeof w6c_ww, "%s/w6c_ww", bin);

	int have_ww = (access(w6c_ww, X_OK) == 0);
	int n = (int)(sizeof rows / sizeof rows[0]);
	int total = 0, fail = 0;

	for (int i = 0; i < n; i++) {
		char cs_path[128], ws_path[128];

		if (emit_s(w6c, &rows[i], i, cs_path, sizeof cs_path) != 0) {
			fprintf(stderr,
			    "def_modqual_modshadow[cstage][%s]: w6c failed\n",
			    rows[i].label);
			fail++; total++; continue;
		}
		total++;
		if (check_imm(cs_path, &rows[i], "cstage") != 0) fail++;

		if (!have_ww) { unlink(cs_path); continue; }

		if (emit_s(w6c_ww, &rows[i], i, ws_path, sizeof ws_path) != 0) {
			fprintf(stderr,
			    "def_modqual_modshadow[wwstage][%s]: w6c_ww failed\n",
			    rows[i].label);
			fail++; total++;
			unlink(cs_path); continue;
		}
		total++;
		if (check_imm(ws_path, &rows[i], "wwstage") != 0) fail++;

		total++;
		char cmd[512];
		snprintf(cmd, sizeof cmd, "cmp -s %s %s", cs_path, ws_path);
		if (runwait(cmd) != 0) {
			fprintf(stderr,
			    "def_modqual_modshadow[%s]: cstage vs wwstage asm differs\n",
			    rows[i].label);
			fail++;
		}

		unlink(cs_path); unlink(ws_path);
	}

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