/*
 * 823_inferred_global_let — an inferred-type (annotation-less) module-global
 * `let g = <init>;` must type-resolve at every downstream read. cstage's
 * module N_LET pass-2 (cmd/wcc/check.c) stamped `d->type` from the rhs but
 * never repointed the Sym that pass-1 installed with the annotation-less NULL
 * type — so every later N_IDENT read of the global resolved its type as nil:
 *   `let n = 5; return n + 0`    → `arithmetic on non-numeric type`
 *   `let g = pt{..}; g.a + g.b`  → `arithmetic on non-numeric type`
 *   `let g = pt{..}; take(g)`    → `argument type <nil> not assignable to pt`
 *
 * The fix (cmd/w6c/cgen.c sibling check.c) mirrors the #11 [_]-array Sym
 * repoint a few lines up: after `d->type = type_default(rt)`, repoint the
 * Sym at the stamped type. cstage-ONLY — wwstage's single-pass resolve
 * already stamps the inferred global (all three rows built clean pre-fix),
 * so this LIFTS cstage from loud-reject to accept, converging acceptance.
 * No asm moves for code that already built; the inferred form now reaches
 * the same cgen as the explicit-typed form, so cstage==wwstage byte-id.
 *
 *   row           | shape                                       | want
 *   --------------+---------------------------------------------+-----
 *   scalar        | let n = 5; return n + 0    (broadest case)  | 5
 *   struct_field  | let g = pt{a=7,b=9}; g.a + g.b              | 16
 *   struct_arg    | let g = pt{a=5,b=9}; take(g) (rides #150-A) | 14
 *
 * All three are mutation-sane: pre-fix cstage loud-rejects each (the build
 * fails), so a regression that drops the repoint re-louds and fails the row.
 * The byte-id rows pin cstage==wwstage `.s` for the now-accepted inferred
 * source.
 */
#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;
}

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

static const struct row rows[] = {
	/* scalar — the broadest case: an inferred scalar global read in
	 * arithmetic. The read must flow through the repointed Sym's numeric
	 * type; pre-fix cstage `arithmetic on non-numeric type` (a bare
	 * `return n: i32` would NOT loud — the cast's target type masks the
	 * nil Sym — so `+ 0` is the mutation-sane shape). */
	{ "scalar",
	  "package main;\n"
	  "let n = 5;\n"
	  "export fn main() i32 = {\n"
	  "\treturn (n + 0): i32;\n"
	  "};\n",
	  5 },

	/* struct_field — inferred struct global, both fields read. pre-fix
	 * cstage `arithmetic on non-numeric type`. */
	{ "struct_field",
	  "package main;\n"
	  "type pt = struct { a: int, b: int };\n"
	  "let g = pt { a = 7, b = 9 };\n"
	  "export fn main() i32 = {\n"
	  "\treturn (g.a + g.b): i32;\n"
	  "};\n",
	  16 },

	/* struct_arg — inferred struct global passed BY VALUE; rides the
	 * #150 Commit A cgen marshalling. pre-fix cstage `argument type
	 * <nil> not assignable to pt`. */
	{ "struct_arg",
	  "package main;\n"
	  "type pt = struct { a: int, b: int };\n"
	  "let g = pt { a = 5, b = 9 };\n"
	  "fn take(x: pt) int = {\n"
	  "\treturn x.a + x.b;\n"
	  "};\n"
	  "export fn main() i32 = {\n"
	  "\treturn take(g): i32;\n"
	  "};\n",
	  14 },
};

static int
run_driver(const char *driver, const struct row *r, int i)
{
	char tmpdir[64], src[128], outbin[128], rmcmd[160], cmd[1024];
	snprintf(tmpdir, sizeof tmpdir, "/tmp/igl_%d_d_%d", getpid(), i);
	mkdir(tmpdir, 0755);
	snprintf(src,    sizeof src,    "%s/igl_%d_%d.ww", tmpdir, getpid(), i);
	snprintf(outbin, sizeof outbin, "%s/igl_%d_%d",    tmpdir, getpid(), i);
	snprintf(rmcmd,  sizeof rmcmd,  "rm -rf %s", tmpdir);

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

	snprintf(cmd, sizeof cmd, "%s build -o %s %s 2>/dev/null",
	    driver, outbin, src);
	if (runwait(cmd) != 0) {
		fprintf(stderr, "row[%s]: build via %s failed\n",
		    r->label, driver);
		runwait(rmcmd);
		return -1;
	}

	int got = runwait(outbin);

	runwait(rmcmd);
	return got;
}

/* asm_byte_identical — w6c vs w6c_ww .s for the same source must match. */
static int
asm_byte_identical(const char *bin, const struct row *r, int i)
{
	char src[64], cs[64], ws[64], cmd[1024];
	snprintf(src, sizeof src, "/tmp/igl_asm_%d_%d.ww", getpid(), i);
	snprintf(cs,  sizeof cs,  "/tmp/igl_asm_%d_%d_c.s", getpid(), i);
	snprintf(ws,  sizeof ws,  "/tmp/igl_asm_%d_%d_w.s", getpid(), i);

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

	snprintf(cmd, sizeof cmd, "%s/w6c -o %s %s 2>/dev/null", bin, cs, src);
	if (runwait(cmd) != 0) {
		fprintf(stderr, "row[%s]: w6c errored\n", r->label);
		unlink(src);
		return -1;
	}
	snprintf(cmd, sizeof cmd, "%s/w6c_ww -o %s %s 2>/dev/null",
	    bin, ws, src);
	if (runwait(cmd) != 0) {
		fprintf(stderr, "row[%s]: w6c_ww errored\n", r->label);
		unlink(src); unlink(cs);
		return -1;
	}

	FILE *fc = fopen(cs, "rb");
	FILE *fw = fopen(ws, "rb");
	int rc = 0;
	if (!fc || !fw) {
		rc = -1;
	} else {
		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);
	if (rc != 0)
		fprintf(stderr, "row[%s]: cstage vs wwstage asm differs\n",
		    r->label);
	unlink(src); unlink(cs); unlink(ws);
	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 cdrv[1024];
	snprintf(cdrv, sizeof cdrv, "%s/ww", bin);
	char wdrv[1024];
	snprintf(wdrv, sizeof wdrv, "%s/ww_ww", bin);

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

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

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