/*
 * 993_ww_ww — phase-10 marker for the ww-side driver port.
 *
 * Diffs the C-built `ww` against the ww-built `ww_ww`. Both drivers
 * orchestrate the same w6c/w6a/w6l, so the resulting binaries must be
 * byte-identical for every program in the corpus. The corpus mixes:
 *   - a tiny single-file program (no -I flags)
 *   - a multi-import build (selfhost/cmd/wwdump/main.ww), exercising
 *     `use` resolution + the -I search path + the libwwrt.a link.
 *
 * Each build runs from a per-driver scratch directory so the
 * intermediate .combined.ww/.s/.o files don't collide.
 */
#include <stdio.h>
#include <stdlib.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;
}

static const char *
absbin(void)
{
	const char *b = getenv("BIN");
	if (!b) b = "out/bin";
	if (b[0] == '/') return b;
	static char buf[2048];
	char cwd[1024];
	if (getcwd(cwd, sizeof cwd) == NULL) return NULL;
	snprintf(buf, sizeof buf, "%s/%s", cwd, b);
	return buf;
}

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;
}

/* Build `src` via the named driver, expecting output binary `out` in
 * the build directory. `incs` may be a colon-separated list of include
 * dirs (the ww driver accepts -I path1:path2:path3). Returns 0 on
 * success. */
static int
build_via(const char *bin, const char *driver, const char *src,
    const char *workdir, const char *incs)
{
	char cmd[4096];
	if (incs && incs[0]) {
		snprintf(cmd, sizeof cmd,
		    "cd %s && timeout 180 %s/%s build -I %s %s 2>/dev/null",
		    workdir, bin, driver, incs, src);
	} else {
		snprintf(cmd, sizeof cmd,
		    "cd %s && timeout 180 %s/%s build %s 2>/dev/null",
		    workdir, bin, driver, src);
	}
	return runwait(cmd);
}

static int
diff_one(const char *bin, const char *cwd, const char *label,
    const char *src, const char *out_basename,
    const char *incs)
{
	char dc[64], dw[64];
	snprintf(dc, sizeof dc, "/tmp/ww_d_%d_c", getpid());
	snprintf(dw, sizeof dw, "/tmp/ww_d_%d_w", getpid());

	char cmd[256];
	snprintf(cmd, sizeof cmd, "rm -rf %s %s && mkdir -p %s %s", dc, dw, dc, dw);
	if (runwait(cmd) != 0) return -1;

	if (build_via(bin, "ww",    src, dc, incs) != 0) {
		fprintf(stderr, "ww_ww FAIL: C ww errored on %s\n", label);
		return -1;
	}
	if (build_via(bin, "ww_ww", src, dw, incs) != 0) {
		fprintf(stderr, "ww_ww FAIL: ww ww errored on %s\n", label);
		return -1;
	}

	char co[1024], wo[1024];
	snprintf(co, sizeof co, "%s/%s", dc, out_basename);
	snprintf(wo, sizeof wo, "%s/%s", dw, out_basename);

	int rc = 0;
	if (slurp_eq(co, wo) != 0) {
		fprintf(stderr, "ww_ww FAIL: %s — driver outputs differ\n", label);
		rc = -1;
	}
	snprintf(cmd, sizeof cmd, "rm -rf %s %s", dc, dw);
	runwait(cmd);
	(void)cwd;
	return rc;
}

int
main(void)
{
	const char *bin = absbin();
	if (!bin) return 1;

	char cwd[1024];
	if (getcwd(cwd, sizeof cwd) == NULL) return 1;

	/* Stage a tiny program in a place both drivers can reach.
	 * pid-keyed so concurrent runs of this test (or shards of it) don't
	 * race on the staging file. */
	char hello_src[64], hello_out[64];
	snprintf(hello_src, sizeof hello_src, "/tmp/ww_d_hello_%d.ww", getpid());
	snprintf(hello_out, sizeof hello_out, "ww_d_hello_%d", getpid());
	{
		FILE *f = fopen(hello_src, "w");
		if (!f) return 1;
		fputs("import os;\n\n"
		    "export fn main() i32 = {\n"
		    "\tos.write(1, \"hi\\n\".ptr, 3u64);\n"
		    "\treturn 0;\n"
		    "};\n", f);
		fclose(f);
	}

	struct {
		const char *label;
		const char *src;	/* may be relative to cwd */
		const char *out;	/* basename of expected output */
		const char *incs;	/* colon-separated -I list, may be NULL */
	} cases[] = {
		{ "hello",   NULL, NULL, "" },		/* filled in below */
		{ "wwdump",  NULL, "main", NULL },	/* filled in below */
		{ NULL, NULL, NULL, NULL },
	};
	cases[0].src = hello_src;
	cases[0].out = hello_out;

	/* wwdump case: absolute paths so the driver finds the imports
	 * regardless of the per-driver workdir. */
	static char wwdump_src[2048], wwdump_incs[4096];
	snprintf(wwdump_src,  sizeof wwdump_src,  "%s/selfhost/cmd/wwdump/main.ww", cwd);
	snprintf(wwdump_incs, sizeof wwdump_incs,
	    "%s/lib/ww:%s/lib/ww/lex:%s/lib/ww/parse:%s/lib/encoding/utf8:%s/selfhost/cmd/wcc",
	    cwd, cwd, cwd, cwd, cwd);
	cases[1].src  = wwdump_src;
	cases[1].incs = wwdump_incs;

	int fail = 0;
	int n = 0;
	for (int i = 0; cases[i].label; i++) {
		if (diff_one(bin, cwd, cases[i].label, cases[i].src,
		    cases[i].out, cases[i].incs) != 0)
			fail++;
		n++;
	}
	unlink(hello_src);
	if (fail) {
		fprintf(stderr, "ww_ww: %d/%d diff(s) failed\n", fail, n);
		return 1;
	}
	printf("ww_ww: byte-identical to C ww on %d corpus builds "
	    "(single-file + selfhost/wwdump multi-import)\n", n);
	return 0;
}