/*
 * 811_inferred_let_struct — cstage and wwstage agree, byte-for-byte and
 * at runtime, on field access through an ANNOTATION-LESS struct-literal
 * binding `let p = pt { ... };` (task #24, fold-5 prereq; the PG5
 * wwstage pair).
 *
 * The bug (wwstage only): for an inferred binding the checker planted
 * the struct decl's BODY node (N_TSTRUCT, exprtype N_STRUCTLIT returns
 * ms.decl.lhs per #66) as the let's type — but every cgen local-arm
 * dispatch (cgdot field read, cgassign tagged-field store, the alias
 * peel) is N_TNAME-keyed. The body matched no arm, so `p.f` fell
 * through to the module-qualified fallback and emitted the FIELD NAME
 * as a global symbol (`MOVQ f(SB), AX` — the #211 name-leak family;
 * loud at link, silent corruption if a same-named global exists), and
 * a tagged-field assign fell to the assign-resolver's TY_TAGGED loud
 * bound ("assign-resolver: tagged field not wired"). cstage was
 * unaffected: check.c:1477 clet carries Sym.type (tinfo) and its
 * emission is annotation-invariant.
 *
 * The fix (wwstage checker, check.ww checkletassign): normalize the
 * inferred binding to the synthesized N_TNAME (mktname), making it
 * indistinguishable from the annotated form downstream — every read/
 * assign/is/as arm then takes the already-byte-id annotated route.
 *
 * Mutation coverage: on pre-fix wwstage every unannotated row LINK-
 * FAILS (undefined reference to the field name), so run_driver's -1
 * catches a regression outright; the annotated rows pin that the
 * normalization didn't perturb the annotated path (byte-id rows assert
 * cstage == wwstage asm for all rows).
 *
 *   row                  | shape                              | want
 *   ---------------------+------------------------------------+------
 *   plain_read           | let p = pt{..}; p.x*10 + p.y       | 42
 *   tagged_read_is_as    | (void|size) field: read + is/as    | 6
 *   tagged_void_read     | min=void; `is void` arm            | 7
 *   tagged_assign        | r.min = 2: size through inferred   | 3
 *   tagged_str_field     | (void|str): assign + as-str .len   | 14
 *   boxed_prebound       | field-wise build, box into union,  | 103
 *                        | match-extract, is/as (PG5h)        |
 *   annotated_pin        | same as tagged_assign but with an  | 3
 *                        | explicit `: rep` annotation        |
 *   nested_read          | plain nested s.f.g read (master    | 42
 *                        | ran right but cs!=ww asm)          |
 *   ellipsis_fill        | pt{ x = 4, ... } autofill (master  | 40
 *                        | wwstage link-failed)               |
 *   paren_form           | (pt{..}) — parser unwraps parens,  | 42
 *                        | same N_STRUCTLIT rhs (master       |
 *                        | wwstage link-failed)               |
 */
#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[] = {
	{ "plain_read",
	  "package main;\n"
	  "type pt = struct { x: size, y: size };\n"
	  "export fn main() i32 = {\n"
	  "\tlet p = pt { x = 4: size, y = 2: size };\n"
	  "\treturn (p.x * 10 + p.y): i32;\n"
	  "};\n",
	  42 },

	{ "tagged_read_is_as",
	  "package main;\n"
	  "type rep = struct { id: size, min: (void | size) };\n"
	  "export fn main() i32 = {\n"
	  "\tlet r = rep { id = 1: size, min = 5: size };\n"
	  "\tlet acc = 0: size;\n"
	  "\tacc += r.id;\n"
	  "\tif (r.min is size) { acc += r.min as size; };\n"
	  "\treturn acc: i32;\n"
	  "};\n",
	  6 },

	{ "tagged_void_read",
	  "package main;\n"
	  "type rep = struct { id: size, min: (void | size) };\n"
	  "export fn main() i32 = {\n"
	  "\tlet r = rep { id = 0: size, min = void };\n"
	  "\tlet acc = 0: size;\n"
	  "\tif (r.min is void) { acc += 7; };\n"
	  "\tif (r.min is size) { acc += r.min as size; };\n"
	  "\treturn acc: i32;\n"
	  "};\n",
	  7 },

	{ "tagged_assign",
	  "package main;\n"
	  "type rep = struct { id: size, min: (void | size) };\n"
	  "export fn main() i32 = {\n"
	  "\tlet r = rep { id = 0: size, min = void };\n"
	  "\tr.id = 1;\n"
	  "\tr.min = 2: size;\n"
	  "\tlet acc = 0: size;\n"
	  "\tacc += r.id;\n"
	  "\tif (r.min is size) { acc += r.min as size; };\n"
	  "\treturn acc: i32;\n"
	  "};\n",
	  3 },

	{ "tagged_str_field",
	  "package main;\n"
	  "type rep = struct { id: size, min: (void | size), name: (void | str) };\n"
	  "export fn main() i32 = {\n"
	  "\tlet b = rep { id = 0: size, min = void, name = void };\n"
	  "\tb.id = 2;\n"
	  "\tb.min = 9: size;\n"
	  "\tb.name = \"hey\";\n"
	  "\tlet acc = 0: size;\n"
	  "\tacc += b.id;\n"
	  "\tif (b.min is size) { acc += b.min as size; };\n"
	  "\tif (b.name is str) { acc += (b.name as str).len: size; };\n"
	  "\treturn acc: i32;\n"
	  "};\n",
	  14 },

	/* PG5h: field-wise construction through the inferred binding,
	 * boxed into a tagged union, match-extracted, is/as off the
	 * binding — the fold-5b inst_repeat consumer shape. */
	{ "boxed_prebound",
	  "package main;\n"
	  "type inst_lit = rune;\n"
	  "type rep3 = struct { id: size, min: (void | size), max: (void | size) };\n"
	  "type inst = (inst_lit | rep3);\n"
	  "export fn main() i32 = {\n"
	  "\tlet r = rep3 { id = 0: size, min = void, max = void };\n"
	  "\tr.id = 1;\n"
	  "\tr.min = 2: size;\n"
	  "\tr.max = 5: size;\n"
	  "\tlet pre = 0: size;\n"
	  "\tif (r.min is size) { pre += r.min as size; };\n"
	  "\tif (pre != 2) { return 200 + pre: i32; };\n"
	  "\tlet v: inst = r;\n"
	  "\tlet acc = 0: size;\n"
	  "\tmatch (v) {\n"
	  "\tcase let ir: rep3 => {\n"
	  "\t\tacc += ir.id;\n"
	  "\t\tif (ir.min is size) { acc += ir.min as size; };\n"
	  "\t\tif (ir.max is size && ir.max as size == 5) { acc += 100; };\n"
	  "\t};\n"
	  "\tcase let l: inst_lit => { acc += 1; };\n"
	  "\t};\n"
	  "\treturn acc: i32;\n"
	  "};\n",
	  103 },

	/* Regression pin: the explicit annotation must stay on its prior
	 * (already byte-id) route — the normalization only fires for the
	 * inferred binding. */
	{ "annotated_pin",
	  "package main;\n"
	  "type rep = struct { id: size, min: (void | size) };\n"
	  "export fn main() i32 = {\n"
	  "\tlet r: rep = rep { id = 0: size, min = void };\n"
	  "\tr.id = 1;\n"
	  "\tr.min = 2: size;\n"
	  "\tlet acc = 0: size;\n"
	  "\tacc += r.id;\n"
	  "\tif (r.min is size) { acc += r.min as size; };\n"
	  "\treturn acc: i32;\n"
	  "};\n",
	  3 },

	/* Plain nested s.f.g through the inferred binding: on master
	 * wwstage this RAN correctly but emitted different asm (the body-
	 * node planting took a divergent cgdot route) — pins byte-id. */
	{ "nested_read",
	  "package main;\n"
	  "type in_ = struct { g: size };\n"
	  "type out_ = struct { f: in_ };\n"
	  "export fn main() i32 = {\n"
	  "\tlet s = out_ { f = in_ { g = 6: size } };\n"
	  "\treturn (s.f.g * 7): i32;\n"
	  "};\n",
	  42 },

	/* Trailing-`...` autofill (parse/expr.ww TK_ELLIPSIS, stash on
	 * s.op): same N_STRUCTLIT rhs kind, so the normalization must
	 * cover it — master wwstage link-failed this form too. */
	{ "ellipsis_fill",
	  "package main;\n"
	  "type pt = struct { x: size, y: size };\n"
	  "export fn main() i32 = {\n"
	  "\tlet p = pt { x = 4: size, ... };\n"
	  "\treturn (p.x * 10 + p.y): i32;\n"
	  "};\n",
	  40 },

	/* Parenthesized literal: the parser unwraps parens (no N_PAREN
	 * node), so the rhs is the same bare N_STRUCTLIT — pins that the
	 * form-coverage claim holds at the parse layer. */
	{ "paren_form",
	  "package main;\n"
	  "type pt = struct { x: size, y: size };\n"
	  "export fn main() i32 = {\n"
	  "\tlet p = (pt { x = 4: size, y = 2: size });\n"
	  "\treturn (p.x * 10 + p.y): i32;\n"
	  "};\n",
	  42 },
};

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/ils_%d_d_%d", getpid(), i);
	mkdir(tmpdir, 0755);
	snprintf(src, sizeof src, "%s/ils_%d_%d.ww", tmpdir, getpid(), i);
	snprintf(outbin, sizeof outbin, "%s/ils_%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 — generate .s via cstage's w6c and wwstage's
 * w6c_ww and diff. Pre-fix the unannotated rows emitted `MOVQ
 * <field>(SB), AX` on wwstage only, so the diff was non-empty (and
 * the wwstage link failed). */
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/ils_asm_%d_%d.ww", getpid(), i);
	snprintf(cs,  sizeof cs,  "/tmp/ils_asm_%d_%d_c.s", getpid(), i);
	snprintf(ws,  sizeof ws,  "/tmp/ils_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_let_struct: 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_let_struct[%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_let_struct: %d/%d fixtures failed\n", fail, total);
		return 1;
	}
	printf("inferred_let_struct: all %d fixtures passed\n", total);
	return 0;
}