/*
 * 928_str_abi_run — end-to-end runtime coverage for the str->24B
 * {ptr,len,cap} 3-reg ABI (Commit #1 / Phase 3, str IS []u8).
 *
 * The scratch str-ABI probe matrix (task #3) only diffs asm byte-id;
 * byte-identity proves the two stages agree, NOT that the emitted code
 * is correct (a shared miscompile passes byte-id silently). This file
 * pins the *runtime* contract: build each fixture through both the
 * cstage `ww` and the wwstage `ww_ww` driver and confirm the program's
 * own assertions hold (exit 0).
 *
 * Covers the ABI dimensions that exercise the new cap word and the
 * AX/BX/CX value / AX:DX:CX:R8 tagged+tuple register layout: str
 * literal (cap=len), str arg, str return, str struct field, the
 * (i64,str) and (str,i64) tuple return shapes, deref-store `*p = s`,
 * and []str index write+read. Phase 2 collapse folds (str IS []u8):
 * str byte-index read `s[i]` (element stride via the type table,
 * commit a5ca21d) and str widened into a tagged-union variant (the
 * payload store folded onto the common slice arm, commit b416e71).
 *
 * Deliberately NOT covered here (known, separately-tracked gaps found
 * during Commit #1 review — both byte-identical across stages, so the
 * byte-id gates stay green):
 *   - str-containing struct passed BY VALUE: now >16B, falls into the
 *     general ">16B struct byval" limitation (a non-str 24B struct
 *     byval mis-compiles the same way); not a str-specific defect.
 *     (task #10)
 *   - `.cap` VALUE of a top-level str GLOBAL reads 0, not len: the
 *     str-literal global DATAW emits only the 16B {ptr,len} payload,
 *     not the 24B header — byte-identical across stages, but the cap
 *     word is never initialised. Distinct from the .cap field/global
 *     link-error (task #11), which IS fixed: `.cap` on a str field
 *     (stored value) and the global field-read now compile and agree.
 */
#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; };

static const struct row rows[] = {
	/* Literal: cap = len for a static literal (no spare storage),
	 * and .cap on a LOCAL str reads back. The new third word. */
	{ "literal_len_cap",
	  "export fn main() i32 = {\n"
	  "    let s: str = \"hello\";\n"
	  "    if (s.len: i32 != 5) { return 1; };\n"
	  "    if (s.cap: i32 != 5) { return 2; };\n"
	  "    return 0;\n"
	  "};\n",
	  0 },
	/* Arg: str passed as a 3-word arg (ptr,len,cap), len read in
	 * the callee. Both a let-bound str and a bare literal arg. */
	{ "arg_len",
	  "fn slen(s: str) i32 = { return s.len: i32; };\n"
	  "export fn main() i32 = {\n"
	  "    let s: str = \"hello\";\n"
	  "    if (slen(s) != 5) { return 1; };\n"
	  "    if (slen(\"hi\") != 2) { return 2; };\n"
	  "    return 0;\n"
	  "};\n",
	  0 },
	/* Return: callee returns a str in AX/BX/CX (no AX:DX shuffle —
	 * str returns exactly like a slice now). */
	{ "return_str",
	  "fn greet() str = { return \"hello world\"; };\n"
	  "export fn main() i32 = {\n"
	  "    let g: str = greet();\n"
	  "    if (g.len: i32 != 11) { return 1; };\n"
	  "    return 0;\n"
	  "};\n",
	  0 },
	/* Struct field: store a str into a 3-word field, read .len and
	 * .cap back (field-store routes the base through DX to dodge
	 * CX=cap; the cap word is stored, so b.s.cap == len here). */
	{ "struct_field_store_load",
	  "type box = struct { s: str, n: i32 };\n"
	  "export fn main() i32 = {\n"
	  "    let b: box;\n"
	  "    b.s = \"abcd\";\n"
	  "    b.n = 7i32;\n"
	  "    if (b.s.len: i32 != 4) { return 1; };\n"
	  "    if (b.n != 7) { return 2; };\n"
	  "    if (b.s.cap: i32 != 4) { return 3; };\n"
	  "    return 0;\n"
	  "};\n",
	  0 },
	/* Tuple (i64, str) return: AX=scalar, DX=ptr, CX=len, R8=cap;
	 * 32B receive slot. */
	{ "tuple_int_str",
	  "fn pair() (i64, str) = { return (42i64, \"hello\"); };\n"
	  "export fn main() i32 = {\n"
	  "    let n, s = pair();\n"
	  "    if (n: i32 != 42) { return 1; };\n"
	  "    if (s.len: i32 != 5) { return 2; };\n"
	  "    return 0;\n"
	  "};\n",
	  0 },
	/* Tuple (str, i64) return: reversed order, registers keyed by
	 * element type not position. */
	{ "tuple_str_int",
	  "fn pair() (str, i64) = { return (\"hi\", 7i64); };\n"
	  "export fn main() i32 = {\n"
	  "    let s, n = pair();\n"
	  "    if (s.len: i32 != 2) { return 1; };\n"
	  "    if (n: i32 != 7) { return 2; };\n"
	  "    return 0;\n"
	  "};\n",
	  0 },
	/* Deref-store: `*p = s` writes all three words through the
	 * pointer (cap stashed across the pointer eval). */
	{ "deref_store",
	  "fn setit(p: *str, v: str) void = { *p = v; };\n"
	  "export fn main() i32 = {\n"
	  "    let s: str = \"hello\";\n"
	  "    let d: str;\n"
	  "    setit(&d, s);\n"
	  "    if (d.len: i32 != 5) { return 1; };\n"
	  "    return 0;\n"
	  "};\n",
	  0 },
	/* []str index write + read: the str-element store pushes
	 * cap/len and writes 3 words; the read loads them back. Guards
	 * the str-element gate against the slice=24B collision (#7/754,
	 * write-side). */
	{ "index_write_read",
	  "export fn main() i32 = {\n"
	  "    let xs: [2]str;\n"
	  "    xs[0] = \"hi\";\n"
	  "    xs[1] = \"abc\";\n"
	  "    if (xs[0].len: i32 != 2) { return 1; };\n"
	  "    if (xs[1].len: i32 != 3) { return 2; };\n"
	  "    return 0;\n"
	  "};\n",
	  0 },
	/* str byte index read: `s[i]` strides by the u8 element size (1),
	 * routed through the type table post-collapse (a5ca21d). Guards
	 * the N_INDEX str-element stride against a slice-width (24B)
	 * miscompute now that str shares the slice path. */
	{ "str_index_read",
	  "export fn main() i32 = {\n"
	  "    let s: str = \"hello\";\n"
	  "    if (s[0]: i32 != 104) { return 1; };\n"
	  "    if (s[1]: i32 != 101) { return 2; };\n"
	  "    if (s[4]: i32 != 111) { return 3; };\n"
	  "    return 0;\n"
	  "};\n",
	  0 },
	/* str widened into a tagged-union variant: the payload store
	 * folds onto the common slice arm (3-word ptr/len/cap @
	 * slot+8/+16/+24 + tag, b416e71). Exercises literal, str-variable
	 * and a str returned from a fn into `(str | i64)`, plus the i64
	 * arm so the variant-tag selection is checked both ways. */
	{ "tagged_union_str_store",
	  "type sv = (str | i64);\n"
	  "fn wrap(s: str) sv = { return s; };\n"
	  "export fn main() i32 = {\n"
	  "    let x: sv = \"hello\";\n"
	  "    match (x) {\n"
	  "    case let s: str => { if (s.len: i32 != 5) { return 1; }; };\n"
	  "    case let n: i64 => { return 2; };\n"
	  "    };\n"
	  "    let a: str = \"world\";\n"
	  "    let y: sv = a;\n"
	  "    match (y) {\n"
	  "    case let s: str => { if (s.len: i32 != 5) { return 3; }; };\n"
	  "    case let n: i64 => { return 4; };\n"
	  "    };\n"
	  "    let z: sv = wrap(\"abcd\");\n"
	  "    match (z) {\n"
	  "    case let s: str => { if (s.len: i32 != 4) { return 5; }; };\n"
	  "    case let n: i64 => { return 6; };\n"
	  "    };\n"
	  "    let w: sv = 42i64;\n"
	  "    match (w) {\n"
	  "    case let s: str => { return 7; };\n"
	  "    case let n: i64 => { if (n: i32 != 42) { return 8; }; };\n"
	  "    };\n"
	  "    return 0;\n"
	  "};\n",
	  0 },
};

static int
run_driver(const char *driver, const struct row *r, int i)
{
	char src[96], tmpdir[96], cmd[1024];
	snprintf(src, sizeof src, "/tmp/strabi_run_%d_%d.ww", getpid(), i);
	snprintf(tmpdir, sizeof tmpdir, "/tmp/strabi_run_%d_d_%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",
	    tmpdir, driver, src);
	if (runwait(cmd) != 0) {
		fprintf(stderr, "row[%s]: build via %s failed\n",
		    r->label, driver);
		unlink(src); rmdir(tmpdir);
		return -1;
	}

	const char *base = strrchr(src, '/');
	base = base ? base + 1 : src;
	char outbin[160];
	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); rmdir(tmpdir);
	return got;
}

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];
	snprintf(cdrv, sizeof cdrv, "%s/ww", bin);
	char wdrv[640];
	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,
			    "str_abi_run: 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,
				    "str_abi_run[%s][%s]: exit=%d want=%d\n",
				    drivers[d].name, rows[i].label,
				    got, rows[i].want);
				fail++;
			}
		}
	}

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