package test;

// Plan-9-lean port of Hare's @test runner (ref/hare/test/+test.ha
// __test_main:97-115, run_test:284, do_test:250). MECHANISM DIVERGENCE
// (drew-17-attest-spec.md §a; rob ruling 2026-06-10, task #17): Hare
// isolates each test in ONE process via arch::setjmp + an rt::onabort
// hook + a SIGSEGV signal handler; ww has none of those primitives, so
// we fork per test and read the child's wait-status. A clean child
// exit(0) is a pass; abort/div0/SIGSEGV/nonzero-exit all surface as a
// failing child status, so the fork boundary catches EVERY fault class
// the setjmp+signal path catches, at a process boundary. The proven
// fork+wait4+WEXITSTATUS decode is procrun (selfhost/cmd/ww/main.ww:
// 154-177). CONSEQUENCE (sanctioned): module globals do NOT persist
// test-to-test — each test runs in a fresh fork snapshot. Hare's tests
// share one process, so its globals persist; ww's are hermetic.
//
// D1/D4/D5 reductions also retained from the -T synth era: no
// __test_array linker section (the synth hands us a value table), no
// sort, no file:line reflection.
//
// fnmatch NAME-FILTER (task #17 commit-3, drew spec §d): when the test
// binary is invoked with trailing argv (the driver passes `ww test
// <file> [pattern]` through as argv[1..]), each pattern is a shell glob
// matched against the test name via [[fnmatch.fnmatch]]; a test runs iff
// some pattern matches. No pattern (argv.len == 1) runs ALL tests — the
// no-filter path is byte-for-byte the pre-filter behavior. Zero matches
// prints "No tests run" and exits 0, mirroring Hare's __test_main
// (ref/hare/test/+test.ha:104-117). The synth (`run(__wwtests)`) and the
// value table are UNCHANGED — the pattern reaches us via os.args, so
// 990-997 byte-id and the no-pattern path hold.
//
// BUNDLE-FLOOR CONSEQUENCE (sanctioned, task #17): importing fnmatch
// raises lib/test's auto-bundle floor from os-only to
// os+fnmatch+ascii+strings (+their transitive bytes/encoding.utf8/types/
// rt) in EVERY -T build. fnmatch's module-private symbols co-bundle into
// the same flat "" scope as the test's modules (pre-#8, no package
// isolation); a same-named module-private fn in a tested module would
// collide. Accepted as the cost of name-filtering; #8 (real packages)
// retires it.

import fnmatch;
import os;

// run — execute each test in `tests` in a forked subprocess, report a
// per-test status line, and return the failure count (the synthesized
// `export fn main()` returns this, so the process exits nonzero iff any
// test failed). The table is `[](str, *fn() void)` — Hare models a test
// as `struct { name: str, func: *fn() void }` (+test.ha:23-26); the -T
// synth emits the value-table tuple form (rob ruling), so the runner
// reads `.0`/`.1` off each row rather than named fields.
//
// The private helpers carry a `tst` prefix: until real packages (#8) give
// lib/test symbol isolation, every -T build flat-bundles this module into
// the SAME bare-leaf scope as the test's own modules, so an un-prefixed
// `puts`/`runone` collides with a same-named module-private fn (lib/dirs
// and lib/temp both ship a private `puts(off, s)`). `run` is the bound
// runner name (the synth's callee), reached module-qualified as `test.run`:
// the -T synth prepends `use test;` before name-binding (#80), so this
// runner keys into the `test` module namespace — a symbol distinct from any
// bare user `fn run` in the @test unit. The two COEXIST: `run` and
// `test.run` are separate symbols (ref/hare/test/+test.ha:97 — the runner
// is its own `test` module), so a user `fn run` is no longer a duplicate and
// both stages accept it under @test/-T.
export fn run(tests: [](str, *fn() void)) i32 = {
	let av: []str = os.args();
	let nfail: i32 = 0;
	let nrun: i32 = 0;
	let i: i32 = 0;
	for (i < tests.len) {
		let row: (str, *fn() void) = tests[i];
		let name: str = row.0;
		let f: *fn() void = row.1;
		if (tstenabled(name, av)) {
			tstputs(name);
			tstputs(" ... ");
			let st: i32 = tstrunone(f);
			if (st == 0) {
				tstputs("ok\n");
			} else {
				tstputs("FAIL\n");
				nfail += 1;
			};
			nrun += 1;
		};
		i += 1;
	};
	// Zero tests selected (an over-narrow pattern, or none matched): Hare
	// prints "No tests run" and returns 0 regardless of whether a pattern
	// was given (ref/hare/test/+test.ha:114-117).
	if (nrun == 0) {
		tstputs("No tests run\n");
		return 0;
	};
	tstputuint(nrun - nfail);
	tstputs(" passed, ");
	tstputuint(nfail);
	tstputs(" failed\n");
	return nfail;
};

// tstenabled — does `name` pass the name-filter? `av` is os.args():
// av[0] is the program name, av[1..] the glob patterns the driver
// forwarded. No patterns (av.len <= 1) enables every test; otherwise a
// test is enabled iff SOME pattern fnmatch-matches (Hare's OR-over-args,
// ref/hare/test/+test.ha:106-113). DIVERGENCE: Hare iterates all of
// os::args including [0]; ww skips [0] — the test binary path is never a
// test-name pattern (the driver passes the pattern as the first
// post-program arg, never argv[0]).
fn tstenabled(name: str, av: []str) bool = {
	if (av.len <= 1) { return true; };
	let j: i32 = 1;
	for (j < av.len) {
		if (fnmatch.fnmatch(av[j], name, fnmatch.flag.NONE)) {
			return true;
		};
		j += 1;
	};
	return false;
};

// runone — fork, run `f` in the child, decode the child's wait-status.
// Byte-for-byte the procrun (main.ww:154-177) status decode: low 7 bits
// are the killing signal (abort=SIGABRT, div0/SIGSEGV), 0 if the child
// exited; next byte is the exit code.
fn tstrunone(f: *fn() void) i32 = {
	let pid: i32 = os.fork();
	if (pid < 0) { return -1; };
	if (pid == 0) {
		(*f)();
		os.exit(0i32);
	};
	let status: i32 = 0;
	let r: i32 = os.wait4(pid, &status, 0i32, nil: *void);
	if (r < 0) { return -1; };
	if ((status & 127i32) != 0) { return 1; };
	return (status >> 8i32) & 255i32;
};

fn tstputs(s: str) void = {
	os.write(os.STDOUT_FILENO, s.ptr, s.len: u64);
};

// tstputuint — write a non-negative i32 in decimal. Lean substitute for
// fmt::printf (Hare's test uses fmt); keeping lib/test's bundle floor at
// os-only avoids pulling the io/strconv stack into every -T build.
fn tstputuint(n: i32) void = {
	let buf: [16]u8;
	let i: i32 = 16;
	let v: i32 = n;
	if (v == 0) {
		i -= 1;
		buf[i] = 48u8;
	} else {
		for (v > 0) {
			i -= 1;
			buf[i] = (48 + v % 10): u8;
			v = v / 10;
		};
	};
	os.write(os.STDOUT_FILENO, &buf[i], (16 - i): u64);
};