/*
 * 989_separchive_run — M3-tail commit-5a gate (#46, task #62): the
 * per-package `.a` substrate + its archive-path #31 dup-detect, both
 * stages, COLD. Commit 5a makes `ww build --sep` wrap each DEP package's
 * `.o` in a deterministic single-member `.a` (cstage archive_o /
 * wwstage archiveo) and link the ROOT as a positional `.o` (force-loaded)
 * + dep `.a` reverse-topo + libwwrt.a. The #31 dup the selective pull
 * would mask is caught by a post-pull PASS 3 in w6l/w6l_ww load_archive.
 *
 * Legs (all COLD — `<stem>.sepwork` is wiped each run):
 *  1. POSITIVE: root→helper builds + runs exit 7, BOTH stages, through
 *     the `.a` link path (root `.o` + helper `.a`).
 *  2. ★ DETERMINISM (ken, load-bearing): re-archive the same package 3×
 *     → byte-identical `.a` (proves zeroed mtime/uid/gid + fixed mode +
 *     fixed member name; a floating md5 would poison the 5b cache key).
 *  3. ★ cs `.a` == ww `.a` (rule 10, the NEW byte-id substrate ken binds):
 *     the dep `.a` from `ww --sep` is byte-identical to the one from
 *     `ww_ww --sep`.
 *  4. ★ #31 dup THROUGH the `.a` path (ken #263 + D3, the leg that proves
 *     PASS 3 closed the selective-pull hole): two DEP packages each export
 *     the same link symbol via `@symbol("dup_sym")`, referenced by root.
 *     One dep's member is pulled; the OTHER lands UNPULLED and defines an
 *     already-`defined` name — exactly what selective-pull skips. BOTH
 *     stages must (exit≠0) ∧ (stderr contains "duplicate symbol") ∧ (no
 *     partial binary). NON-VACUITY flip: give the second dep a DISTINCT
 *     symbol → both stages build + run (exit 3), proving the leg actually
 *     discriminates (without PASS 3 the dup leg would WRONGLY pass green).
 *  5. ACHIEVABLE-parity posture (same as c4's 989_sepcycle_dup, because
 *     #61 is a separate commit): cs vs ww is `both exit≠0 ∧ both stderrs
 *     contain "duplicate symbol"` — NOT exact-stderr-equal (cstage names
 *     `<path>: duplicate symbol <sym>`, wwstage the bare form).
 *
 * Light wwstage-driver test (CLAUDE.md rule 14): all fixtures + scratch
 * live under /tmp, COLD each run. Models 989_sepbuild_run.c conventions.
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/wait.h>
#include <sys/stat.h>

#define EXPECT_EXIT 7

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(const char *path, char **outbuf, size_t *outlen)
{
	FILE *f = fopen(path, "rb");
	if (!f) return -1;
	fseek(f, 0, SEEK_END);
	long n = ftell(f);
	fseek(f, 0, SEEK_SET);
	if (n < 0) { fclose(f); return -1; }
	char *b = malloc((size_t)n + 1);
	if (!b) { fclose(f); return -1; }
	if (fread(b, 1, (size_t)n, f) != (size_t)n) { free(b); fclose(f); return -1; }
	b[n] = '\0';
	fclose(f);
	*outbuf = b;
	*outlen = (size_t)n;
	return 0;
}

static int
files_eq(const char *a, const char *b)
{
	char *ba = NULL, *bb = NULL;
	size_t na = 0, nb = 0;
	if (slurp(a, &ba, &na) < 0 || slurp(b, &bb, &nb) < 0) {
		free(ba); free(bb);
		return -1;
	}
	int eq = (na == nb && memcmp(ba, bb, na) == 0);
	free(ba); free(bb);
	return eq ? 0 : 1;
}

static int
file_has(const char *path, const char *needle)
{
	char *b = NULL;
	size_t n = 0;
	if (slurp(path, &b, &n) < 0) return 0;
	int found = (strstr(b, needle) != NULL);
	free(b);
	return found;
}

static int
write_file(const char *path, const char *body)
{
	FILE *f = fopen(path, "wb");
	if (!f) return -1;
	fputs(body, f);
	fclose(f);
	return 0;
}

int
main(void)
{
	const char *bin = absbin();
	if (!bin) return 1;
	char td[64], cmd[8192];
	int fail = 0;

	snprintf(td, sizeof td, "/tmp/wwar_%d", getpid());
	snprintf(cmd, sizeof cmd, "rm -rf %s", td);
	runwait(cmd);
	mkdir(td, 0755);

	/* ---- root → helper fixture (one dep `.a`) ------------------------ */
	char helpdir[1024], helpww[1100], rootww[1100];
	snprintf(helpdir, sizeof helpdir, "%s/helper", td);
	mkdir(helpdir, 0755);
	snprintf(helpww, sizeof helpww, "%s/h.ww", helpdir);
	snprintf(rootww, sizeof rootww, "%s/root.ww", td);
	if (write_file(helpww,
	        "package helper;\n"
	        "export fn val() i32 = { return 7; };\n") ||
	    write_file(rootww,
	        "package main;\n"
	        "import helper;\n"
	        "fn main() i32 = { return helper.val(); };\n")) {
		fail++; goto out;
	}

	struct { const char *drv, *tag; char prog[1024]; }
	stg[] = { { "ww", "cs", {0} }, { "ww_ww", "ww", {0} } };

	/* Leg 1: POSITIVE build + run through the `.a` path, both stages. */
	for (int s = 0; s < 2; s++) {
		snprintf(stg[s].prog, sizeof stg[s].prog, "%s/prog.%s", td, stg[s].tag);
		snprintf(cmd, sizeof cmd,
		    "timeout 240 %s/%s build --sep -I %s -o %s %s >/dev/null 2>&1",
		    bin, stg[s].drv, td, stg[s].prog, rootww);
		if (runwait(cmd) != 0) {
			fprintf(stderr, "separchive FAIL: %s build --sep\n", stg[s].drv);
			fail++;
			continue;
		}
		int rc = runwait(stg[s].prog);
		if (rc != EXPECT_EXIT) {
			fprintf(stderr, "separchive FAIL: %s prog exit=%d expected %d\n",
			    stg[s].drv, rc, EXPECT_EXIT);
			fail++;
		}
	}

	/* Root is a positional `.o` (force-loaded), so NO __root.a exists;
	 * the dep is the only `.a`. Assert the layout the driver produced. */
	{
		char roota[1100], rooto[1100], helpa[1100];
		snprintf(roota, sizeof roota, "%s/prog.cs.sepwork/__root.a", td);
		snprintf(rooto, sizeof rooto, "%s/prog.cs.sepwork/__root.o", td);
		snprintf(helpa, sizeof helpa, "%s/prog.cs.sepwork/helper.a", td);
		if (access(roota, 0) == 0) {
			fprintf(stderr, "separchive FAIL: root wrapped in .a "
			    "(should stay positional .o)\n");
			fail++;
		}
		if (access(rooto, 0) != 0) {
			fprintf(stderr, "separchive FAIL: missing root .o\n");
			fail++;
		}
		if (access(helpa, 0) != 0) {
			fprintf(stderr, "separchive FAIL: missing dep helper.a\n");
			fail++;
		}
	}

	/* Leg 3: cs `.a` == ww `.a` (rule 10, the new byte-id substrate). */
	{
		char a[1100], b[1100];
		snprintf(a, sizeof a, "%s/prog.cs.sepwork/helper.a", td);
		snprintf(b, sizeof b, "%s/prog.ww.sepwork/helper.a", td);
		if (files_eq(a, b) != 0) {
			fprintf(stderr, "separchive FAIL: cs helper.a != ww helper.a "
			    "(rule 10 .a byte-id)\n");
			fail++;
		}
	}

	/* Leg 2: DETERMINISM — re-archive the same package 3× (cold each),
	 * the `.a` must be byte-identical (zeroed mtime/uid/gid, fixed mode,
	 * fixed member name). Copy each build's helper.a aside, compare. */
	{
		char det[3][1100];
		int ok = 1;
		for (int i = 0; i < 3; i++) {
			char prog[1100];
			snprintf(prog, sizeof prog, "%s/det%d", td, i);
			snprintf(cmd, sizeof cmd,
			    "timeout 240 %s/ww build --sep -I %s -o %s %s >/dev/null 2>&1",
			    bin, td, prog, rootww);
			if (runwait(cmd) != 0) { ok = 0; break; }
			snprintf(det[i], sizeof det[i], "%s/det%d.sepwork/helper.a", td, i);
		}
		if (!ok) {
			fprintf(stderr, "separchive FAIL: determinism build\n");
			fail++;
		} else if (files_eq(det[0], det[1]) != 0 ||
		           files_eq(det[1], det[2]) != 0) {
			fprintf(stderr, "separchive FAIL: .a not deterministic across "
			    "3 builds (floating md5 → poisons 5b cache)\n");
			fail++;
		}
	}

	/* ---- Leg 4: #31 dup THROUGH the `.a` path (PASS 3) --------------- */
	/* Two DEP packages each export the SAME link symbol via @symbol;
	 * root references both. One member is pulled, the other lands
	 * UNPULLED defining an already-`defined` name → the masked dup PASS 3
	 * catches (#53 path-qualifies normal exports, so @symbol is the
	 * cleanest forced cross-package clash). */
	char pkgad[1024], pkgbd[1024], paww[1100], pbww[1100], droot[1100];
	snprintf(pkgad, sizeof pkgad, "%s/pkga", td);
	snprintf(pkgbd, sizeof pkgbd, "%s/pkgb", td);
	mkdir(pkgad, 0755); mkdir(pkgbd, 0755);
	snprintf(paww, sizeof paww, "%s/a.ww", pkgad);
	snprintf(pbww, sizeof pbww, "%s/b.ww", pkgbd);
	snprintf(droot, sizeof droot, "%s/droot.ww", td);
	if (write_file(paww,
	        "package pkga;\n"
	        "@symbol(\"dup_sym\") export fn afn() i32 = { return 1; };\n") ||
	    write_file(pbww,
	        "package pkgb;\n"
	        "@symbol(\"dup_sym\") export fn bfn() i32 = { return 2; };\n") ||
	    write_file(droot,
	        "package main;\n"
	        "import pkga;\n"
	        "import pkgb;\n"
	        "fn main() i32 = { return pkga.afn() + pkgb.bfn(); };\n")) {
		fail++; goto out;
	}

	for (int s = 0; s < 2; s++) {
		char prog[1100], errf[1100];
		snprintf(prog, sizeof prog, "%s/dup.%s", td, stg[s].tag);
		snprintf(errf, sizeof errf, "%s/dup.%s.err", td, stg[s].tag);
		snprintf(cmd, sizeof cmd,
		    "timeout 240 %s/%s build --sep -I %s -o %s %s >/dev/null 2>%s",
		    bin, stg[s].drv, td, prog, droot, errf);
		int rc = runwait(cmd);
		if (rc == 0) {
			fprintf(stderr, "separchive FAIL: %s accepted a masked "
			    "cross-pkg dup through .a (exit 0 — PASS 3 missing?)\n",
			    stg[s].drv);
			fail++;
		}
		if (!file_has(errf, "duplicate symbol")) {
			fprintf(stderr, "separchive FAIL: %s missing 'duplicate "
			    "symbol' on the .a dup path\n", stg[s].drv);
			fail++;
		}
		if (access(prog, 0) == 0) {
			fprintf(stderr, "separchive FAIL: %s produced a partial "
			    "binary on the dup reject\n", stg[s].drv);
			fail++;
		}
	}

	/* Leg 4 NON-VACUITY: give pkgb a DISTINCT symbol → no collision →
	 * both stages build + run (exit 3 = 1 + 2). Proves the dup leg
	 * actually discriminates (not a vacuous always-fail). */
	if (write_file(pbww,
	        "package pkgb;\n"
	        "@symbol(\"uniq_sym\") export fn bfn() i32 = { return 2; };\n")) {
		fail++; goto out;
	}
	for (int s = 0; s < 2; s++) {
		char prog[1100];
		snprintf(prog, sizeof prog, "%s/ok.%s", td, stg[s].tag);
		snprintf(cmd, sizeof cmd,
		    "timeout 240 %s/%s build --sep -I %s -o %s %s >/dev/null 2>&1",
		    bin, stg[s].drv, td, prog, droot);
		if (runwait(cmd) != 0) {
			fprintf(stderr, "separchive FAIL(non-vacuity): %s could not "
			    "build the distinct-symbol graph\n", stg[s].drv);
			fail++;
			continue;
		}
		int rc = runwait(prog);
		if (rc != 3) {
			fprintf(stderr, "separchive FAIL(non-vacuity): %s prog "
			    "exit=%d expected 3\n", stg[s].drv, rc);
			fail++;
		}
	}

out:
	snprintf(cmd, sizeof cmd, "rm -rf %s", td);
	runwait(cmd);
	if (fail) {
		fprintf(stderr, "separchive: %d check(s) failed\n", fail);
		return 1;
	}
	printf("separchive: per-pkg .a (root=.o force-load, deps=.a) build+run "
	    "(exit %d) + .a determinism (3x identical) + cs.a==ww.a (rule 10) + "
	    "#31 masked-dup reject THROUGH .a (PASS 3, both stages loud+non-zero, "
	    "non-vacuity flip exit 3)\n", EXPECT_EXIT);
	return 0;
}